图片仅供参考

详细数据请看参考数据手册

Datasheet下载
  • 型号: MAX17498AATE+
  • 制造商: Maxim
  • 库位|库存: xxxx|xxxx
  • 要求:
数量阶梯 香港交货 国内含税
+xxxx $xxxx ¥xxxx

查看当月历史价格

查看今年历史价格

MAX17498AATE+产品简介:

ICGOO电子元器件商城为您提供MAX17498AATE+由Maxim设计生产,在icgoo商城现货销售,并且可以通过原厂、代理商等渠道进行代购。 MAX17498AATE+价格参考。MaximMAX17498AATE+封装/规格:PMIC - AC-DC 转换器,离线开关, Converter Offline 反激,升压 Topology 250kHz 16-TQFN(3x3)。您可以下载MAX17498AATE+参考资料、Datasheet数据手册功能说明书,资料中有MAX17498AATE+ 详细功能的应用电路图电压和使用方法及教程。

产品参数 图文手册 常见问题
参数 数值
产品目录

集成电路 (IC)半导体

描述

IC OFF-LINE CONVERTER 16TQFN交流/直流转换器 Uvrsl AC/DC & Iso DC/DC Flyback ctlr

产品分类

PMIC - AC-DC 转换器,离线开关

品牌

Maxim Integrated

产品手册

点击此处下载产品Datasheet

产品图片

rohs

符合RoHS无铅 / 符合限制有害物质指令(RoHS)规范要求

产品系列

电源管理 IC,交流/直流转换器,Maxim Integrated MAX17498AATE+-

数据手册

点击此处下载产品Datasheet

产品型号

MAX17498AATE+

产品

Current Mode Converters

产品种类

交流/直流转换器

供应商器件封装

16-TQFN-EP(3x3)

功率(W)

-

包装

管件

占空比-最大

92 %

商标

Maxim Integrated

安装风格

SMD/SMT

封装

Tube

封装/外壳

16-WFQFN 裸露焊盘

封装/箱体

TQFN-16

工作温度

-40°C ~ 125°C

工作温度范围

- 40 C to + 125 C

工厂包装数量

100

开关频率

250 kHz

标准包装

1

电压-击穿

-

电压-输入

4.5 V ~ 29 V

电压-输出

-

电源电流

1.8 mA

类型

Current Mode PWM Controllers

系列

MAX17498A

输入/电源电压—最大值

29 V

输入/电源电压—最小值

4.5 V

输出电压

5 V

输出端数量

1 Output

输出隔离

任意一种

配用

/product-detail/zh/MAXREFDES24%23/MAXREFDES24%23-ND/4866384

零件号别名

MAX17498A

频率范围

235kHz ~ 265kHz

MAX17498AATE+ 相关产品

UCC2809P-2

品牌:Texas Instruments

价格:

UCC3813PW-4

品牌:Texas Instruments

价格:

STR-A6053M

品牌:Sanken

价格:

ICE2A280Z

品牌:Infineon Technologies

价格:

NCP1338DR2G

品牌:ON Semiconductor

价格:

MC33364DR2

品牌:ON Semiconductor

价格:

FSDL0365RNB

品牌:ON Semiconductor

价格:

LNK564DN

品牌:Power Integrations

价格:

PDF Datasheet 数据手册内容提取

EVALUATION KIT AVAILABLE MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications General Description Benefits and Features The MAX17498A/MAX17498B/MAX17498C devices are S Peak Current-Mode Converter current-mode fixed-frequency flyback/boost converters S Current-Mode Control Provides Excellent with a minimum number of external components. They Transient Response contain all the control circuitry required to design wide input voltage isolated and nonisolated power supplies. S Fixed Switching Frequency The MAX17498A has its rising/falling undervoltage lock-  250kHz: MAX17498A/MAX17498C out (UVLO) thresholds optimized for universal offline (85V  500kHz: MAX17498B AC to 265V AC) applications, while the MAX17498B/ MAX17498C support UVLO thresholds suitable to low- S Flexible Error Amplifier to Regulate Both Positive voltage DC-DC applications. and Negative Outputs The switching frequency of the MAX17498A/MAX17498C S Programmable Soft-Start to Reduce Input Inrush is 250kHz, while that of the MAX17498B is 500kHz. These Current frequencies allow the use of tiny magnetic and filter com- S Programmable Voltage or Current Soft-Start ponents, resulting in compact, cost-effective power sup- S Power-Good Signal (PGOOD) plies. An EN/UVLO input allows the user to start the power supply precisely at the desired input voltage, while also S Reduced Power Dissipation Under Fault functioning as an on/off pin. The OVI pin enables imple-  Overcurrent Protection mentation of an input overvoltage-protection scheme that  Thermal Shutdown with Hysteresis ensures that the converter shuts down when the DC input voltage exceeds the desired maximum value. S Robust Protection Features  Programmable Current Limit The devices incorporate a flexible error amplifier and an accurate reference voltage (REF) to enable the end user to  Input Overvoltage Protection regulate both positive and negative outputs. Programmable S Optimized Loop Performance current limit allows proper sizing and protection of the primary  Programmable Slope Compensation switching FET. The devices support a maximum duty cycle greater than 92% and provide programmable slope com- S High Efficiency pensation to allow optimization of control loop performance.  Low RDSON, 175mI, 65V Rated Internal The devices provide an open-drain PGOOD pin that serves n-Channel MOSFET as a power-good indicator and enters the high-impedance  No Current-Sense Resistor state to indicate that the flyback/boost converter is in regu- lation. An SS pin allows programmable soft-start time for the S Optional Spread Spectrum flyback/boost converter. Hiccup-mode overcurrent pro- S Space-Saving, 16-Pin (3mm x 3mm) TQFN tection and thermal shutdown are provided to minimize Package dissipation under overcurrent and overtemperature fault conditions. The devices are available in a space-saving, Applications 16-pin (3mm x 3mm) TQFN package with 0.5mm lead spacing. Front-End AC-DC Power Supplies for Industrial Applications (Isolated and Nonisolated) Ordering Information and Typical Application Circuits Telecom Power Supplies appear at end of data sheet. Wide Input Range DC Input Flyback/Boost Industrial Power Supplies For related parts and recommended products to use with this part, refer to www.maximintegrated.com/MAX17498A.related. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com. 19-6043; Rev 3; 4/13

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications ABSOLUTE MAXIMUM RATINGS IN to SGND ............................................................-0.3V to +40V PGND to SGND ....................................................-0.3V to +0.3V EN/UVLO to SGND .........................................-0.3V to IN + 0.3V Continuous Power Dissipation (Single-Layer Board) OVI to SGND ..............................................-0.3V to VCC + 0.3V TQFN (derate 20.8mW/°C above +70°C)..................1700mW VCC to SGND ..........................................................-0.3V to +6V Operating Temperature Range ........................-40°C to +125°C SS, LIM, EA-, EA+, COMP, SLOPE, Storage Temperature Range ............................-65°C to +160°C REF to SGND ........................................-0.3V to (VCC + 0.3V) Junction Temperature (continuous) ................................+150°C LX to SGND ...........................................................-0.3V to +70V Lead Temperature (soldering, 10s) ................................+300°C PGOOD to SGND ....................................................-0.3V to +6V Soldering Temperature (reflow) ......................................+260°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera- tion of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS INPUT SUPPLY (VIN) MAX17498A 4.5 29 IN Voltage Range (VIN) V MAX17498B/MAX17498C 4.5 36 IN Supply Startup Current Under IINSTARTUP, VIN < UVLO or EN/UVLO = SGND 22 36 µA UVLO Switching, fSW = 250kHz (MAX17498A/MAX17498C) 1.8 3 IN Supply Current (IIN) mA Switching, fSW = 500kHz (MAX17498B) 2 3.25 MAX17498A 19 20.5 22 IN Boostrap UVLO Rising V Threshold MAX17498B/MAX17498C 3.85 4.15 4.4 IN Bootstrap UVLO Falling 3.65 3.95 4.25 V Threshold IN Clamp Voltage EN/UVLO = SGND, IIN = 1mA (MAX17498A) (Note 2) 31 33.5 36 V LINEAR REGULATOR (VCC) VCC Output Voltage Range 6V < VIN < 29V, 0mA < IVCC < 50mA 4.8 5 5.2 V VCC Dropout Voltage VIN = 4.5V, IVCC = 20mA 160 300 mV VCC Current Limit VCC = 0V, VIN = 6V 50 100 mA ENABLE (EN/UVLO) Rising 1.18 1.23 1.28 EN/UVLO Threshold V Falling 1.11 1.17 1.21 EN/UVLO Input Leakage Current 0V < VEN/UVLO < 1.5V, TA = +25NC -100 0 +100 nA Maxim Integrated 2

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications ELECTRICAL CHARACTERISTICS (continued) (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS OVERVOLTAGE PROTECTION (OVI) Rising 1.18 1.23 1.28 OVI Threshold V Falling 1.11 1.17 1.21 OVI Masking Delay 2 µs OVI Input Leakage Current 0V < VOVI < 1.5V, TA = +25NC -100 0 +100 nA SWITCHING FREQUENCY AND MAXIMUM DUTY CYCLE (fSW and DMAX) MAX17498A/MAX17498C 235 250 265 Switching Frequency kHz MAX17498B 470 500 530 MAX17498A/MAX17498C 92 94.5 97 Maximum Duty Cycle % MAX17498B 90 92 94 Minimum Controllable On Time tONMIN 110 ns SOFT-START (SS) SS Set-Point Voltage 1.2 1.22 1.24 V SS Pullup Current VSS = 400mV 9 10 11 µA SS Peak Current-Limit-Enable 1.11 1.17 1.21 V Threshold ERROR AMPLIFIER (EA+, EA-, and COMP) EA+ Input Bias Current VEA+ = 1.5V, TA = +25NC -100 +100 nA EA- Input Bias Current VEA- = 1.5V, TA = +25NC -100 +100 nA Error-Amplifier Open-Loop 90 dB Voltage Gain Error-Amplifier VCOMP = 2V, VLIM = 1V 1.5 1.8 2.1 mS Transconductance Error-Amplifier Source Current VCOMP = 2V, EA- < EA+ 80 120 210 µA Error-Amplifier Sink Current VCOMP = 2V, EA- > EA+ 80 120 210 µA Current-Sense Transresistance 0.45 0.5 0.55 I INTERNAL SWITCH DMOS Switch On-Resistance ILX = 200mA 175 380 mI (RDSON) DMOS Peak Current Limit LIM = 100K 1.62 1.9 2.23 A DMOS Runaway Current Limit LIM = 100K 1.9 2.3 2.6 A LX Leakage Current VLX = 65V, TA = +25NC 0.1 1 µA CURRENT LIMIT (LIM) LIM Reference Current 9 10 11 µA Peak Switch Current Limit with 0.39 0.45 0.54 A LIM Open Runaway Switch Current Limit 0.39 0.5 0.6 A with LIM Open Maxim Integrated 3

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications ELECTRICAL CHARACTERISTICS (continued) (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN TYP MAX UNITS Number of Runaway Current- 1 # Limit Hits Before Hiccup Timeout Overcurrent Hiccup Timeout 32 ms SLOPE COMPENSATION (SLOPE) SLOPE Pullup Current 9 10 11 µA SLOPE-Compensation Resistor MAX17498B 30 150 kI Range Default SLOPE-Compensation SLOPE = open 60 mV/µs Ramp POWER-GOOD SIGNAL (PGOOD) PGOOD Output-Leakage VPGOOD = 5V, TA = +25NC -1 +1 µA Current (Off State) PGOOD Output Voltage IPGOOD = 10mA 0 0.4 V (On State) PGOOD Higher Threshold EA- rising 93.5 95 96.5 % PGOOD Lower Threshold EA- falling 90.5 92 93.5 % PGOOD Delay After 4 ms EA- Reaches 95% Regulation THERMAL SHUTDOWN Thermal-Shutdown Threshold Temperature rising +160 NC Thermal-Shutdown Hysteresis 20 NC Note 1: All devices are 100% production tested at TA = +25NC. Limits over temperature are guaranteed by design. Note 2: The MAX17498A is intended for use in universal input power supplies. The internal clamp circuit at IN is used to prevent the bootstrap capacitor from charging to a voltage beyond the absolute maximum rating of the device when EN/UVLO is low (shutdown mode). Externally limit the maximum current to IN (hence to clamp) to 2mA (max) when EN/UVLO is low. Maxim Integrated 4

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Typical Operating Characteristics (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted.) BOOTSTRAP UVLO WAKE-UP LEVEL IN UVLO WAKE-UP LEVEL vs. TEMPERATURE vs. TEMPERATURE (MAX17498A) (MAX17498B/MAX17498C) 20.26 4.15 VEL (V) 20.24 MAX17498 toc01 V) 4.10 MAX17498 toc02 KE-UP LE 20.22 P LEVEL ( 4.05 A U STRAP UVLO W 2200..1280 N UVLO WAKE- 4.00 OOT 20.16 I 3.95 B 20.14 3.90 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) IN UVLO SHUTDOWN LEVEL EN/UVLO RISING LEVEL vs. TEMPERATURE vs. TEMPERATURE 4.015 1.235 N LEVEL (V)444...000001050 MAX17498 toc03 LEVEL (V)11..222350 MAX17498 toc04 W G O N UTD3.995 RISI IN UVLO SH33..998950 EN/UVLO 11..221250 3.980 3.975 1.210 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) EN/UVLO FALLING LEVEL OVI RISING LEVEL vs. TEMPERATURE vs. TEMPERATURE V) 11..116750 MAX17498 toc05 1.225 MAX17498 toc06 O FALLING LEVEL ( 11..115650 RISING LEVEL (V)1.220 VL 1.150 VI 1.215 U O N/ E 1.145 1.140 1.210 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) Maxim Integrated 5

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Typical Operating Characteristics (continued) (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted.) OVI FALLING LEVEL IN CURRENT UNDER UVLO vs. TEMPERATURE vs. TEMPERATURE 1.160 30 1.155 MAX17498 toc07 µA) 28 MAX17498 toc08 V) O ( L ( VL OVI FALLING LEVE11..114550 URRENT UNDER U 2246 C 1.140 IN 22 1.135 20 -40 -20 0 20 40 60 80 100 120 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) TEMPERATURE (°C) IN CURRENT DURING SWITCHING vs. TEMPERATURE LX AND PRIMARY CURRENT WAVEFORM 2.6 MAX17498 toc10 G (mA) 2.4 MAX17498 toc09 TCHIN 2.2 V20LXV/div WI S NG 2.0 RI U ENT D 1.8 I0P.R5IA/div R R U C 1.6 N I 1.4 -40 -20 0 20 40 60 80 100 120 1µs/div TEMPERATURE (°C) EN STARTUP WAVEFORM EN SHUTDOWN WAVEFORM MAX17498 toc11 MAX17498 toc12 EN/UVLO 5V/div EN/UVLO 5V/div VOUT 5V/div VOUT 5V/div VCOMP 1V/div VCOMP 1V/div 400µs/div 400µs/div Maxim Integrated 6

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Typical Operating Characteristics (continued) (VIN = +15V, VEN/UVLO = +2V, COMP = open, CIN = 1µF, CVCC = 1µF, TA = TJ = -40°C to +125°C, unless otherwise noted.) PEAK CURRENT LIMIT (ILIM) PEAK CURRENT LIMIT AT RLIM = 100kI vs. RLIM AT ROOM TEMPERATURE vs. TEMPERATURE 1800 2.00 K CURRENT LIMIT (mA)1111680246000000000000 MAX17498 toc13 URRENT LIMIT AT R (A)LIM 1111....99996789 MAX17498 toc14 A C PE 400 EAK P 1.95 200 0 1.94 0 10 20 30 40 50 60 70 80 -40 -20 0 20 40 60 80 100 120 RLIM AT ROOM TEMPERATURE (kI) TEMPERATURE AT GIVEN RLIM (°C) TRANSIENT RESPONSE FOR 50% LOAD STEP ON FLYBACK OUTPUT (5V) BODE PLOT - (5V OUTPUT AT 24V INPUT) MAX17498 toc15 MAX17498 toc16 ILOAD 500mA/div PHASE 36°/div VOUT 200mV/div GAIN BW = 8.3kHz 10dB/div PM = 63° 2ms/div LOG (F) EFFICIENCY GRAPH AT 24V INPUT (FLYBACK REGULATOR) 100 8900 VIN = 24V MAX17498 toc17 70 %) Y ( 60 C EN 50 CI FI 40 F E 30 20 10 0 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 LOAD CURRENT (A) Maxim Integrated 7

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Pin Configuration TOP VIEW N.C. REF N.C. EA+ 12 11 10 9 PGOOD 13 8 SS PGND 14 MAX17498A 7 COMP MAX17498B LX 15 MAX17498C 6 EA- IN 16 EP (SGND) 5 SLOPE + 1 2 3 4 VLO VCC OVI LIM U N/ E TQFN-EP Pin Description PIN NAME FUNCTION Enable/Undervoltage-Lockout Pin. Drive to > 1.23V to start the devices. To externally program the UVLO 1 EN/UVLO threshold of the input supply, connect a resistor-divider between input supply EN/UVLO and SGND. 2 VCC Lpionsesaibr lRee tgo utlhaeto IrC O.utput. Connect input bypass capacitor of at least 1µF from VCC to SGND as close as Overvoltage Comparator Input. Connect a resistor-divider between the input supply (OVI) and SGND to 3 OVI set the input overvoltage threshold. Current-Limit Setting Pin. Connect a resistor between LIM and SGND to set the peak-current limit for 4 LIM nonisolated flyback converter. Peak-current limit defaults to 500mA if unconnected. Slope Compensation Input Pin. Connect a resistor between SLOPE and SGND to set slope- 5 SLOPE compensation ramp. Connect to VCC for minimum slope compensation. See the Programming Slope Compensation (SLOPE) section. Inverting Input of the Flexible Error Amplifier. Connect to mid-point of resistor-divider from the positive 6 EA- terminal output to SGND. Flexible Error-Amplifier Output. Connect the frequency-compensation network between COMP and 7 COMP SGND. 8 SS Soft-Start Pin. Connect a capacitor from SS to SGND to set the soft-start time interval. 9 EA+ Noninverting Input of the Flexible Error Amplifier. Connect to SS to use 1.22V as the reference. 10, 12 N.C. No Connection 11 REF Internal 1.22V Reference Output Pin. Connect a 100pF capacitor from REF to SGND. Maxim Integrated 8

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Pin Description (continued) PIN NAME FUNCTION Open-Drain Output. PGOOD goes high when EA- is within 5% of the set point. PGOOD pulls low when 13 PGOOD EA- falls below 92% of its set-point value. 14 PGND Power Ground for Converter 15 LX External Transformer/Inductor Connection for the Converter Internal Linear Regulator Input. Connect IN to the input-voltage source. Bypass IN to PGND with a 1µF 16 IN (min) ceramic capacitor. EP Exposed Pad. Internally connected to SGND. Connect EP to a large copper plane at SGND potential to — (SGND) provide adequate thermal dissipation. Connect EP (SGND) to PGND at a single point. Detailed Description The MAX17498A is therefore well suited for opera- tion from the rectified DC bus in AC-DC power-supply The MAX17498A offers a bootstrap UVLO wakeup level applications typically encountered in front-end industrial of 20V with a wide hysteresis of 15V (min) optimized power-supply applications. As such, the MAX17498A for implementing an isolated and nonisolated universal has no limitation on the maximum input voltage as long (85V AC to 265V AC) offline single-switch flyback as the external components are rated suitably and the converter or telecom (36V to 72V) power supplies. The maximum operating voltages of the MAX17498A are MAX17498B/MAX17498C offer a UVLO wakeup level of respected. The MAX17498A can successfully be used 4.4V and are well suited for low-voltage DC-DC flyback/ in universal input-rectified (85V to 265V AC) bus applica- boost power supplies. An internal reference (1.22V) tions, rectified 3-phase DC bus applications, and tele- can be used to regulate the output down to 1.23V in com (36V to 72V DC) applications. nonisolated flyback and boost applications. Additional The MAX17498B/MAX17498C are intended for imple- semi-regulated outputs, if needed, can be generated menting a flyback (isolated and nonisolated) and by using additional secondary windings on the flyback boost converter with an on-board 65V rated n-channel converter transformer. A flexible error amplifier and REF MOSFET. The IN pin of the MAX17498B/MAX17498C has allow the end-user selection between regulating positive a maximum operating voltage of 36V. The MAX17498B/ and negative outputs. MAX17498C implement rising and falling thresholds on The devices utilize peak current-mode control and exter- the IN pin that assume power-supply startup schemes, nal compensation for optimizing the loop performance for typical of lower voltage DC-DC applications, down to an various inductors and capacitors. The devices include a input voltage of 4.5V DC. Therefore, flyback converters runaway current limit feature that triggers hiccup mode with a 4.5V to 36V supply voltage range can be imple- operation to protect the external component by halting mented with the MAX17498B/MAX17498C. switching for 32ms before restart. The devices include Internal Linear Regulator (VCC) voltage soft-start for nonisolated designs and current The internal functions and driver circuits are designed soft-start for isolated designs to allow monotonic rise of to operate from a 5V Q5% power-supply voltage. The the output voltage. The voltage or current soft-start can devices have an internal linear regulator that is powered be selected using the SLOPE pin. See the Block Diagram from the IN pin and generates a 5V power rail. The output for more information. of the linear regulator is connected to the VCC pin and Input Voltage Range should be decoupled with a 2.2µF capacitor to ground The MAX17498A has different rising and falling UVLO for stable operation. The VCC converter output supplies thresholds on the IN pin than those of the MAX17498B/ the operating current for the devices. The maximum MAX17498C. The thresholds for the MAX17498A are operating voltage of the IN pin is 29V for the MAX17498A optimized for implementing power-supply startup and 36V for the MAX17498B/MAX17498C. schemes typically used for offline AC-DC power supplies. Maxim Integrated 9

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Configuring the Power Stage (LX) Maximum Duty Cycle The devices use an internal n-channel MOSFET to imple- The MAX17498A/MAX17498C operate at a maximum ment internal current sensing for current-mode control and duty cycle of 94%. The MAX17498B offers a maximum overcurrent protection of the flyback/boost converter. To duty cycle of 92%. The devices can be used to imple- facilitate this, the drain of the internal nMOSFET is connect- ment flyback and boost converters involving large input- ed to the source of the external MOSFET in the MAX17498A to-output voltage ratios in DC-DC applications. high-input-voltage applications. The gate of the external Power-Good Signal (PGOOD) MOSFET is connected to the IN pin. Ensure by design that The devices include a PGOOD signal that serves as the IN pin voltage does not exceed the maximum operating a power-good signal to the system. PGOOD is an gate-voltage rating of the external MOSFET. The external MOSFET gate-source voltage is controlled by the switch- open-drain signal and requires a pullup resistor to the ing action of the internal nMOSFET, while also sensing the preferred supply voltage. The PGOOD signal monitors source current of the external MOSFET. In the MAX17498B/ EA- and pulls high when EA- is 95% (typ) of its regulation MAX17498C-based applications, the LX pin is directly con- value (1.22V). For isolated power supplies, PGOOD can- nected to either the flyback transformer primary winding or not serve as a power-good signal. to the boost-converter inductor. IN REF 10µA CHIPEN SSDONE HICCUP SSDONE VOLTAGE SS SS VCC 5V, 50mA 33V CLAMP SS LDO (MAX17498A ONLY) SSDONEF CURRENT SS MAX17498A 1.17V POK MAX17498B BG MAX17498C EN/UVLO CHIPEN OSC VSLOPE VCS 1.23V VSUM LX OVI CLK VCS 1.23V RUNAWAY SSDONE 1 RUNAWAY PEAK 10µA CONTROL LIMINT LIM LOGIC AND PGND DRIVER 1.23V VSUM PWM PGOOD PGOOD 250mV COMP COMP 10µA EA- SLOPE DECODER FIXED SLOPE BLOCK EA+ VARIABLE SLOPE EA- VOLTAGE SS CURRENT SS CHIPEN Figure 1. MAX17498A/MAX17498B/MAX17498C Block Diagram Maxim Integrated 10

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Soft-Start resistor values for the divider can be calculated as fol- The devices implement soft-start operation for the lows, assuming a 24.9kI resistor for ROVI: flyback/boost converter. A capacitor connected to the SS pin programs the soft-start period for the flyback/  V  boost converter. The soft-start feature reduces the input REN=ROVI×VSTOAVRIT −1kΩ inrush current. These devices allow the end user to select between voltage soft-start usually preferred in nonisolat- where ROVI is in kI while VSTART and VOVI are in volts. ed applications and current soft-start, which is useful in ivsoolltaatgeed. aSpepel icthaeti oPnrso gtora gmemt ain mg oSnooftto-Sntiacr rt isoef tinh eth Fel yobuatpcukt/ RSUM=ROVI+REN×VSTART −1kΩ  1.23  Boost Converter (SS) section. Spread-Spectrum Factory Option where REN and ROVI are in kI. In universal AC input For EMI-sensitive applications, a spread-spectrum- applications, RSUM might need to be implemented as enabled version of the device can be requested from equal resistors in series (RDC1, RDC2, RDC3) so that the factory. The frequency-dithering feature modulates voltage across each resistor is limited to its maximum the switching frequency by Q10% at a rate of 4kHz. operation voltage. This spread-spectrum-modulation technique spreads the energy of switching-frequency harmonics over a R =R =R =RSUMkΩ DC1 DC2 DC3 wider band while reducing their peaks, helping to meet 3 stringent EMI goals. For low-voltage DC-DC applications based on the Applications Information MAX17498B/MAX17498C, a single resistor can be used in the place of RSUM, as the voltage across it is Startup Voltage and Input Overvoltage- approximately 40V. Protection Setting (EN/UVLO, OVI) The devices’ EN/UVLO pin serves as an enable/disable VDC input, as well as an accurate programmable input UVLO pin. The devices do not commence startup operation unless the EN/UVLO pin voltage exceeds 1.23V (typ). RDC1 The devices turn off if the EN/UVLO pin voltage falls below 1.17V (typ). A resistor-divider from the input DC bus to ground can be used to divide down and apply a RSUM RDC2 fraction of the input DC voltage (VDC) to the EN/UVLO pin. The values of the resistor-divider can be selected RDC3 so that the EN/UVLO pin voltage exceeds the 1.23V (typ) turn-on threshold at the desired input DC bus voltage. The EN/UVLO same resistor-divider can be modified with an additional MAX17498A resistor (ROVI) to implement input overvoltage protection REN MAX17498B MAX17498C in addition to the EN/UVLO functionality as shown in OVI Figure 2. When voltage at the OVI pin exceeds 1.23V (typ), the devices stop switching and resume switching opera- ROVI tions only if voltage at the OVI pin falls below 1.17V (typ). For given values of startup DC input voltage (VSTART), and input overvoltage-protection voltage (VOVI), the Figure 2. Programming EN/UVLO and OVI Maxim Integrated 11

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Startup Operation resistors in series (RIN1, RIN2, and RIN3) to share the The MAX17498A is optimized for implementing an offline applied high DC voltage in offline applications so that single-switch flyback converter and has a 20V IN UVLO the voltage across each resistor is limited to the maximum wake-up level with hysteresis of 15V (min). In offline appli- continuous operating-voltage rating. RSTART and CSTART cations, a simple cost-effective RC startup circuit is used. can be calculated as: When the input DC voltage is applied, the startup resis- tor (RSTART) charges the startup capacitor (CSTART), CSTART=0.75CVCC+IIN×tSS×0.1+ 0.04×tSS×6QG×fswµF causing the voltage at the IN pin to increase towards the  10  wake-up IN UVLO threshold (20V typ). During this time, the MAX17498A draws a low startup current of 20µA where IIN is the supply current drawn at the IN (typ) through RSTART. When the voltage at IN reaches pin in mA, QG is the gate charge of the external the wake-up IN UVLO threshold, the MAX17498A com- nMOSFET in nC, fSW is the switching frequency of mences switching operations and drives the internal the converter in Hz, and tSS is the soft-start time n-channel MOSFET whose drain is connected to the LX programmed for the flyback converter in ms. CVCC is pin. In this condition, the MAX17498A draws 1.8mA cur- the cummulative capacitor used in VCC node. See the rent from CSTART, in addition to the current required to Programming Soft-Start of the Flyback/Boost Converter switch the gate of the external nMOSFET. Since this cur- (SS) section. rent cannot be supported by the current through RSTART, the voltage on CSTART starts to drop. When suitably con- R =(VSTART −10)×50kΩ figured, as shown in Figure 10, the external nMOSFET is START 1+CSTART switched by the LX pin and the flyback converter gener- ates pulses in bias winding NB. The soft-start period of where CSTART is the startup capacitor in µF. the converter should be programmed so the bias winding pulses sustain the voltage on CSTART before it falls below For designs that cannot accept power dissipation in the 5V, thus allowing continued operation. The large hystere- startup resistors at high DC input voltages in offline appli- sis (15V typ) of the MAX17498A allows for a small startup cations, the startup circuit can be set up with a current capacitor (CSTART). The low startup curent (20µA typ) source instead of a startup resistor as shown in Figure 4. allows the use of a large start resistor (RSTART), thus reduc- ing power dissipation at higher DC bus voltages. Figure 3 shows the typical RC startup scheme for the MAX17498A. VDC RSTART might need to be implemented as equal, multiple VDC VOUT RIN1 D2 VDC VOUT D2 D1 D1 RSTART RIN2 VDC NB NP NS COUT NB NP NS COUT RIN3 RIN1 IN RSTART RIN2 MAX17498A RIN3 MAX17498A RISRC LX LX IN IN LDO LDO CSTART VCC VCC CSTART CVCC CVCC Figure 3. MAX17498A RC-Based Startup Circuit Figure 4. MAX17498A Current Source-Based Startup Circuit Maxim Integrated 12

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications the MAX17498B/MAX17498C can be tolerated, the IN VDC VOUT pin is directly connected to the DC input, as shown in Figure 5. In the case of higher DC input voltages D1 (e.g., 16V to 32V DC), a startup circuit, such as that shown in Figure 6, can be used to minimize power dis- IN VCC IN LDO sipation. In this startup scheme, the transistor (Q1) CIN CVCC COUT supplies the switching current until a bias winding NB MAX17498B comes up and turns off Q1. The resistor (RZ) can be MAX17498C calculated as: LX Np Ns R =2×(V −6.3)kΩ Z INMIN where VINMIN is the minimum input DC voltage. Programming Soft-Start of the Flyback/Boost Converter (SS) The soft-start period in the voltage soft-start scheme of the devices can be programmed by selecting the value Figure 5. MAX17498B/MAX17498C Typical Startup Circuit with IN Connected Directly to DC Input of the capacitor connected from the SS pin to GND. The capacitor CSS can be calculated as: VDC C =8.13×t nF SS SS D2 VOUT where tSS is expressed in ms. RZ The soft-start period in the current soft-start scheme Q1 D1 depends on the load at the output and the soft-start ZD1 NB capacitor. 6.3V MAX17498B Programming Output Voltage MAX17498C COUT The devices incorporate a flexible error amplifier that IN IN LDO allows regulating to both the positive and negative LX Np Ns outputs. The positive output voltage of the converter CIN can be programmed by selecting the correct values VCC for the resistor-divider connected from VOUT, the fly- back/boost output to ground, with the midpoint of the CVCC divider connected to the EA- pin (Figure 7). With RB selected in the range of 20kI to 50kI, RU can be calculated as: Figure 6. MAX17498B/MAX17498C Typical Startup Circuit with Bias Winding to Turn Off Q1 and Reduce Power Dissipation R =R ×VOUT −1kΩ U B    1.22  Resistors RSUM and RISRC can be calculated as: where RB is in kI. The negative output voltage of the converter can be V RSUM= START MΩ programmed by selecting the correct values for the 10 resistor-divider connected from VOUT, the flyback/boost V R = BEQ1MΩ output to REF with the midpoint of the divider connected ISRC 70 to the EA+ pin (Figure 8). With R1 selected in the range of 20kI to 50kI, R2 can be calculated as: The IN UVLO wakeup threshold of the MAX17498B/ MesAisX, 17o4p9ti8mCiz iesd s efot rt ol o3w.9-vVo l(ttaygpe) wDitCh -Da C2 0a0pmpVl ichaytsiotenrs- R2=R1×VOUTkΩ  1.22  down to 4.5V. For applications where the input DC voltage is low enough (e.g., 4.5V to 5.5V DC) that the where R1 is in kI. power loss incurred to supply the operating current of Maxim Integrated 13

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Current-Limit Programming (LIM) The devices include a robust overcurrent-protection VOUT scheme that protects the device under overload and short-circuit conditions. For the flyback/boost con- verter, the devices include a cycle-by-cycle peak RU MAX17498A current limit that turns off the driver whenever the EA- MAX17498B current into the LX pin exceeds an internal limit that is MAX17498C programmed by the resistor connected from the LIM RB pin to GND. The devices include a runaway current limit that protects the device under short-circuit conditions. One occurrence of the runaway current limit triggers a hiccup mode that protects the converter by immediately suspending switching for a period of time (32ms). This Figure 7. Programming the Positive Output Voltage allows the overload current to decay due to power loss in the converter resistances, load, and the output diode of the flyback/boost converter before soft-start is attempted again. The resistor at the LIM pin for a desired current VOUT limit (IPK) can be calculated as: REF MAX17498A R =50×I kΩ MAX17498B LIM PK EA- R1 R2 MAX17498C where IPK is expressed in amperes. REA- EA+ For a given peak current-limit setting, the runaway current limit is typically 20% higher. The runaway current- limit-triggered hiccup operation is always enabled even during soft-start. Figure 8. Programming the Negative Output Voltage Programming Slope Compensation (SLOPE) When the MAX17498A//MAX17498B/MAX17498C devic- rent-mode-controlled converters operating at duty cycles es operate at a maximum duty cycle of 49%, in theory greater than 50%, the converter needs slope compen- they do not require slope compensation for preventing subharmonic instability that occurs naturally in continu- sation. A minimum amount of slope signal is added to ous-mode peak current-mode-controlled converters. In the sensed current signal even for converters operating practice, the devices require a minimum amount of slope below 50% duty to provide stable, jitter-free operation. compensation to provide stable, jitter-free operation. The SLOPE pin allows the user to program the necessary These devices allow the user to program this default value slope compensation by setting the value of the resistor of slope compensation simply by connecting the SLOPE (RSLOPE) connected from SLOPE pin to ground. pin to VCC. It is recommended that discontinuous-mode designs also use this minimum amount of slope compen- R =0.5× S kΩ SLOPE E sation to provide noise immunity and jitter-free operation. To avoid subharmonic instability that occurs naturally where the slope (SE) is expressed in millivolts per micro- over all specified load and line conditions in peak cur- second. Maxim Integrated 14

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Thermal Considerations The junction-temperature rise of the devices can be It should be ensured that the junction temperature of the estimated at any given maximum ambient temperature devices does not exceed +125°C under the operating con- (TAMAX) from the following equation: ditions specified for the power supply. The power dissipat- T =T +(θ ×P ) ed in the devices to operate can be calculated using the JMAX AMAX JA LOSS following equation: If the application has a thermal-management system P =V ×I that ensures that the exposed pad of the devices is IN IN IN maintained at a given temperature (TEPMAX) by using where VIN is the voltage applied at the IN pin and IIN is proper heatsinks, then the junction-temperature rise of operating supply current. the devices can be estimated at any given maximum The internal n-channel MOSFET experiences conduction ambient temperature from the following equation: loss and transition loss when switching between on and off states. These losses are calculated as: T =T +(θ ×P ) üüüüüüü 2 P =I ×R Layout, Grounding, and Bypassing CONDUCTION LXRMS DSONLX P =0.5×V ×I ×(t +t )×f All connections carrying pulsed currents must be very TRANSITION INMAX PK R F SW short and as wide as possible. The inductance of these where tR and tF are the rise and fall times of the internal connections must be kept to an absolute minimum nMOSFET in CCM operation. In DCM operation, since due to the high di/dt of the currents in high-frequency switching power converters. This implies that the loop the switch current starts from zero, only tF exists and the areas for forward and return pulsed currents in various transition-loss equation changes to: parts of the circuit should be minimized. Additionally, P =0.5×V ×I ×t ×f small-current loop areas reduce radiated EMI. Similarly, TRANSITION INMAX PK F SW the heatsink of the main MOSFET presents a dV/dt source, Additional loss occurs in the system in every switch- and therefore, the surface area of the MOSFET heatsink ing cycle due to energy stored in the drain-source should be minimized as much as possible. capacitance of the internal MOSFET being lost when Ground planes must be kept as intact as possible. The the MOSFET turns on and discharges the drain-source ground plane for the power section of the converter capacitance voltage to zero. This loss is estimated as: should be kept separate from the analog ground plane, except for a connection at the least noisy section of the P =0.5×C ×V ×f CAP DS DSMAX SW power ground plane, typically the return of the input filter The total power loss in the devices can be calculated capacitor. The negative terminal of the filter capacitor, from the following equation: ground return of the power switch, and current-sensing resistor must be close together. PCB layout also affects P =P +P +P +P LOSS IN CONDUCTION TRANSITION CAP the thermal performance of the design. A number of ther- mal vias that connect to a large ground plane should be The maximum power that can be dissipated in the provided under the exposed pad of the part for efficient devices is 1666mW at +70°C temperature. The power- heat dissipation. For a sample layout that ensures first- dissipation capability should be derated as the tem- pass success, refer to the MAX17498B Evaluation Kit. perature rises above +70°C at 21mW/°C. For a multilayer board, the thermal-performance metrics for the package For universal AC input designs, follow all applicable are given below: safety regulations. Offline power supplies can require UL, VDE, and other similar agency approvals. θ =48°C/W JA θ =10°C/W JC Maxim Integrated 15

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Typical Application Circuits VOUT28.7V, 0.3A PGND VOUT1-3.3V, 2A VOUT2 C16OPEN VOUT1 C1510µF,16V C1410µF,16V C18141µF,6.3V D4RF101L2STE25 T1 D6 M C102.2nF,250V D3US1K-TP N1FQD1N80T R16I100k, 0.5W R20I10 D5BZT52C18-7F VOUT1 REF IN C80.1µF,25V C3100pF R10I133k R22I49.3k REF EPIN SS LIM MAX17498A LXVCC SLOPEPGOOD EA-N.C. REF COMP N.C.PGND EA+EN/UVLO OVI IN C1247nF R11I49.9k VCCC42.2µF R17I1k C1147pF R9I15k N2FQT1N80TF R23I10k INC60.47µF,35V C922nF Q1BC849CW VIN R2I2.2M R3I2.2M R4I2.2M R5I82k R6I20.5k VIN R12I3M I3M C2100µFR14I3M R15I3M VOUT2 D2M-60TR C72.2µF,50V R7IM R8IM RB160 L11µH 1.2 1.2 R1I10 C10.1µF,630V D1S5KC-13-F LINE 85V AC TO265V AC NEUTRAL Figure 9. MAX17498A Nonisolated Multiple-Output AC-DC Power Supply Maxim Integrated 16

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications VIN VOUT D2 T1 VIN VOUT C4 C12 C13 C14 18V TO 36V 47µCF1, 4.7µCF2, 4.7µF, 50V R7.15kI C333nF 2126µVF, 2126µVF, 2126µVF, 5OVU,T 1P.5UAT INPUT 63V 50V C5 GND 0.22µF, 50V D1 PGND IN SS LX C9 REF 68nF EA+ PGOOD PGOOD U1 R12 86R.66kI MAX17498B 10kI VCC LIM VOUT VCC C6 2.2µF, 16V R9 10kI VCC VCC R15 VFB EA- 1kI R11 R20 15kI C18 30.3kI COMP REFC10 OPEN C15 100pF 4.7nF VIN PGND REF VFB R18 R13 U2 15kI C16 R3 511I 33pF 348kI EN/UVLO EN/UVLO SLOPE 2 1 R4 R7 U3 20kI 0I 3 R19 OVI OVI 10kI R5 10kI PGND Figure 10. MAX17498B Isolated DC-DC Power Supply Maxim Integrated 17

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications VIN VIN IN EP C5 SS 47nF 4.5V TO C1 C7 10V DC 10µF 1µF SS IN R2 71.5kI LIM L1 PGND 56µH D1 VOUT C2 VCC 24V, 0.1A LX 2.2µF C6 VCC 2.2µF, 50V R2 MAX17498B 12kI SLOPE PGOOD PGOOD R9 R3 10kI 374kI VCC EA- R4 20kI N.C. VOUT REF C8 R5 100pF 2.73kI REF COMP C3 C4 100nF 270pF VIN N.C. PGND R6 SS 0I EN/UVLO EA+ R7 OPEN OVI R8 0I Figure 11. MAX17498B Boost Power Supply Maxim Integrated 18

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Ordering Information PART TEMP RANGE PIN-PACKAGE DESCRIPTION MAX17498AATE+ -40°C to +125°C 16 TQFN-EP* 250kHz, Offline Flyback Converter MAX17498BATE+ -40°C to +125°C 16 TQFN-EP* 500kHz, Low-Voltage DC-DC Flyback/Boost Converter MAX17498CATE+ -40°C to +125°C 16 TQFN-EP* 250kHz, Low-Voltage DC-DC Flyback Converter +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 16 TQFN-EP T1633+5 21-0136 90-0032 Maxim Integrated 19

MAX17498A/MAX17498B/MAX17498C AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applications Revision History REVISION REVISION PAGES DESCRIPTION NUMBER DATE CHANGED 0 9/11 Initial release — 1 3/12 Removed future product references for MAX17498B and MAX17498C 27 Changed the maximum duty cycle for the A/C variants to 92% (min), 94.5% (typ), and 97% (max); updated General Description, Benefits and Features, Detailed 1, 3, 9, 10, 14, 2 2/13 Description, Maximum Duty Cycle, Current-Limit Programming (LIM), Programming 15 Slope Compensation (SLOPE), and Peak/RMS-Current Calculation secondary RMS current equation Updated Benefits and Features, removed sections on pages 15–21, updated Figures 1, 10, 12, 13, 3 4/13 1, 3–6, 11, 12 15–22, 24, 25 Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 20 © 2013 Maxim Integrated Products, Inc. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.