MCP1603 2.0 MHz, 500 mA Synchronous Buck Regulator Features General Description • Over 90% Typical Efficiency The MCP1603 is a high efficient, fully integrated • Output Current Up To 500mA 500mA synchronous buck regulator whose 2.7V to 5.5V input voltage range makes it ideally suited for • Low Quiescent Current = 45µA, typical applications powered from 1-cell Li-Ion or 2-cell/3-cell • Low Shutdown Current = 0.1µA, typical NiMH/NiCd batteries. • Adjustable Output Voltage: At heavy loads, the MCP1603 operates in the 2.0MHz - 0.8V to 4.5V fixed frequency PWM mode which provides a low • Fixed Output Voltage: noise, low output ripple, small-size solution. When the - 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V load is reduced to light levels, the MCP1603 • 2.0MHz Fixed-Frequency PWM (Heavy Load) automatically changes operation to a PFM mode to minimize quiescent current draw from the battery. No • Automatic PWM to PFM Mode Transition intervention is necessary for a smooth transition from • 100% Duty Cycle Operation one mode to another. These two modes of operation • Internally Compensated allow the MCP1603 to achieve the highest efficiency • Undervoltage Lockout (UVLO) over the entire operating current range. • Overtemperature Protection The MCP1603 is available with either an adjustable or • Space Saving Packages: fixed output voltage. The available fixed output voltage - 5-Lead TSOT options are 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V. When a - 8-Lead 2X3 DFN fixed option is used, only three additional small external components are needed to form a complete solution. Applications Couple this with the low profile, small-foot print packages and the entire system solution is achieved • Cellular Telephones with minimal size. • Portable Computers Additional protection features include: UVLO, • Organizers / PDAs overtemperature, and overcurrent protection. • USB Powered Devices • Digital Cameras • Portable Equipment • +5V or +3.3V Distributed Systems Package Types 5-Lead TSOT 8-Lead 2x3 DFN VIN 1 5 LX SHDN 1 5 VFB/VOUT LX 1 8 GND NC 2 7 VIN GND 2 GND 2 SHDN 3 6 NC SHDN 3 4 VFB/VOUT LX 3 4 VIN VFB/VOUT 4 5 NC MCP1603 MCP1603L © 2007 Microchip Technology Inc. DS22042A-page 1

MCP1603 Typical Application Circuit V L V IN 1 OUT 2.7VTo4.5V 4.7µH 1.8V@500mA V L IN X CIN COUT 4.7µF SHDN V 4.7µF FB GND 100 V = 1.8V 95 OUT V = 2.7V IN 90 V = 3.6V %) 85 IN ( 80 y c n 75 e ci 70 i ff 65 E 60 V = 4.5V IN 55 50 0.1 1 10 100 1000 Output Current (mA) DS22042A-page 2 © 2007 Microchip Technology Inc.

MCP1603 Functional Block Diagram V IN V Band REF UVLO Soft Start Gap Thermal Shutdown SHDN UVLO ILIM PWM ILIM TSD I Limit PFM IPEAK PK PWM IPEAK PFM Slope Comp OSC -ILPK S Q POFF NOFF L X Switch Drive Logic and timing R Q PWM/PFM PFM Error Amp PWM/PFM GND Logic IPEAK V PFM REF IPEAK PWM PWM Error Amp EA -ILPK -I Limit PK V REF OV Threshold UVLO Disable Switcher TSD VFB/VOUT UV Threshold © 2007 Microchip Technology Inc. DS22042A-page 3

MCP1603 1.0 ELECTRICAL † Notice: Stresses above those listed under "Maximum Ratings" may cause permanent damage to the device. This is CHARACTERISTICS a stress rating only and functional operation of the device at those or any other conditions above those indicated in the Absolute Maximum Ratings † operational sections of this specification is not intended. Exposure to maximum rating conditions for extended periods VIN - GND.......................................................................+6.0V may affect device reliability. All Other I/O...............................(GND - 0.3V) to (V + 0.3V) IN L to GND..............................................-0.3V to (V + 0.3V) X IN Output Short Circuit Current..................................Continuous Power Dissipation (Note5)..........................Internally Limited Storage Temperature.....................................-65°C to +150°C Ambient Temp. with Power Applied.................-40°C to +85°C Operating Junction Temperature...................-40°C to +125°C ESD Protection On All Pins: HBM..............................................................................4kV MM...............................................................................300V DC CHARACTERISTICS Electrical Characteristics: Unless otherwise indicated, V = SHDN = 3.6V, C = C = 4.7µF, L = 4.7µH, V (ADJ)=1.8V, IN OUT IN OUT I =100mA, T = +25°C. Boldface specifications apply over the T range of -40°C to +85°C. OUT A A Parameters Sym Min Typ Max Units Conditions Input Characteristics Input Voltage V 2.7 — 5.5 V Note1 IN Maximum Output Current I 500 — — mA Note1 OUT Shutdown Current I — 0.1 1 µA SHDN = GND IN_SHDN Quiescent Current I — 45 60 µA SHDN = V , I = 0mA Q IN OUT Shutdown/UVLO/Thermal Shutdown Characteristics SHDN, Logic Input Voltage Low V — — 15 %V V = 2.7V to 5.5V IL IN IN SHDN, Logic Input Voltage High V 45 — — %V V = 2.7V to 5.5V IH IN IN SHDN, Input Leakage Current I -1.0 ±0.1 1.0 µA V = 2.7V to 5.5V L_SHDN IN Undervoltage Lockout UVLO 2.12 2.28 2.43 V V Falling IN Undervoltage Lockout Hysteresis UVLO — 140 — mV HYS Thermal Shutdown T — 150 — °C Note4, Note5 SHD Thermal Shutdown Hysteresis T — 10 — °C Note4, Note5 SHD-HYS Note 1: The minimum V has to meet two conditions: V ≥ 2.7V and V ≥ V + 0.5V. IN IN IN OUT 2: Reference Feedback Voltage Tolerance applies to adjustable output voltage setting. 3: V is the output voltage setting. R 4: The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable temperature and the thermal resistance from junction to air (i.e. T , T , θ ). Exceeding the maximum A J JA allowable power dissipation causes the device to initiate thermal shutdown. 5: The internal MOSFET switches have an integral diode from the L pin to the V pin, and from the L pin X IN X to the GND pin. In cases where these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not able to limit the junction temperature for these cases. 6: The current limit threshold is a cycle-by-cycle peak current limit. DS22042A-page 4 © 2007 Microchip Technology Inc.

MCP1603 DC CHARACTERISTICS (CONTINUED) Electrical Characteristics: Unless otherwise indicated, V = SHDN = 3.6V, C = C = 4.7µF, L = 4.7µH, V (ADJ)=1.8V, IN OUT IN OUT I =100mA, T = +25°C. Boldface specifications apply over the T range of -40°C to +85°C. OUT A A Parameters Sym Min Typ Max Units Conditions Output Characteristics Adjustable Output Voltage Range V 0.8 — 4.5 V Note2 OUT Reference Feedback Voltage V — 0.8 — V FB Reference Feedback Voltage -3.0 — +3.0 % TA = -40°C to +25°C Tolerance -2.5 — +2.5 % T = +25°C to +85°C A Feedback Input Bias Current I — 0.1 — nA VFB Output Voltage Tolerance Fixed V -3.0% V +3.0% % T = -40°C to +25°C, Note3 OUT R A V -2.5 V +2.5 % T = +25°C to +85°C, Note3 OUT R A Line Regulation V — 0.3 — %/V V = V + 1V to 5.5V, LINE- IN R I =100mA REG OUT Load Regulation V — 0.35 — % V =V +1.5V, LOAD- IN R I =100mAto500mA REG LOAD Internal Oscillator Frequency F 1.5 2.0 2.8 MHz OSC Start Up Time T — 0.6 — ms T =10%to90% SS R R P-Channel R — 500 — mΩ I =100mA DSon DSon-P P R N-Channel R — 500 — mΩ I =100mA DSon DSon-N N L Pin Leakage Current I -1.0 ±0.1 1.0 µA SHDN=0V, V =5.5V, X LX IN L =0V, L =5.5V X X Positive Current Limit Threshold +I — 860 — mA Note6 LX(MAX) Note 1: The minimum V has to meet two conditions: V ≥ 2.7V and V ≥ V + 0.5V. IN IN IN OUT 2: Reference Feedback Voltage Tolerance applies to adjustable output voltage setting. 3: V is the output voltage setting. R 4: The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable temperature and the thermal resistance from junction to air (i.e. T , T , θ ). Exceeding the maximum A J JA allowable power dissipation causes the device to initiate thermal shutdown. 5: The internal MOSFET switches have an integral diode from the L pin to the V pin, and from the L pin X IN X to the GND pin. In cases where these diodes are forward-biased, the package power dissipation limits must be adhered to. Thermal protection is not able to limit the junction temperature for these cases. 6: The current limit threshold is a cycle-by-cycle peak current limit. © 2007 Microchip Technology Inc. DS22042A-page 5

MCP1603 TEMPERATURE SPECIFICATIONS Electrical Specifications: Unless otherwise indicated, all limits are specified for: V +2.7Vto5.5V IN Parameters Sym Min Typ Max Units Conditions Temperature Ranges Operating Junction Temperature T -40 — +125 °C Steady State J Range Storage Temperature Range T -65 — +150 °C A Maximum Junction Temperature T — — +150 °C Transient J Package Thermal Resistances Thermal Resistance, 5L-TSOT θ — 256 — °C/W Typical 4-layer Board with JA Internal Ground Plane Thermal Resistance, 8L-2x3 DFN θ — 84.5 — °C/W Typical 4-layer Board with JA Internal Ground Plane and 2-Vias in Thermal Pad DS22042A-page 6 © 2007 Microchip Technology Inc.

MCP1603 2.0 TYPICAL PERFORMANCE CURVES Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range. Note: Unless otherwise indicated, V =SHDN=3.6V, C =C =4.7µF, L =4.7µH, V (ADJ)=1.8V, I =100mA, IN OUT IN OUT LOAD T =+25°C. Adjustable or fixed output voltage options can be used to generate the Typical Performance Characteristics. A 50 52 nt Current (µA) 444444456789 VIN = 4.2V VIN = 3.6V VOUT = 1.8V nt Current (µA) 445680 TA = +25oC TA = +90oC Quiesce 444123 VIN = 3.0V Quiesce 4424 TA = - 40oC 40 40 -40 -25 -10 5 20 35 50 65 80 95 110 125 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Ambient Temperature (oC) Input Voltage (V) FIGURE 2-1: I vs. Ambient Temperature. FIGURE 2-4: I vs. Input Voltage. Q Q 100 100 95 VOUT = 1.2V 90 VOUT = 1.2V VIN = 2.7V y (%) 8950 IOUT = 100 mA y (%) 7800 VIN = 3.6V enc 80 IOUT = 300 mA enc 60 Effici 7705 IOUT = 500 mA Effici 4500 65 30 VIN = 4.2V 60 20 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 0.1 1 10 100 1000 Input Voltage (V) Output Current (mA) FIGURE 2-2: Efficiency vs. Input Voltage FIGURE 2-5: Efficiency vs. Output Load (V = 1.2V). (V = 1.2V). OUT OUT 100 100 VOUT = 1.8V 90 VIN = 2.7V 95 %) 90 IOUT = 100 mA %) 80 VIN = 3.6V y ( y ( 70 enc 85 IOUT = 300 mA enc 60 Effici 80 IOUT = 500 mA Effici 4500 75 30 VIN = 4.2V VOUT = 1.8V 70 20 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 0.1 1 10 100 1000 Input Voltage (V) Output Current (mA) FIGURE 2-3: Efficiency vs. Input Voltage FIGURE 2-6: Efficiency vs. Output Load (V = 1.8V). (V = 1.8V). OUT OUT © 2007 Microchip Technology Inc. DS22042A-page 7

MCP1603 Typical Performance Curves (Continued) Note: Unless otherwise indicated, V =SHDN=3.6V, C =C =4.7µF, L =4.7µH, V (ADJ)=1.8V, I =100mA, IN OUT IN OUT LOAD T =+25°C. Adjustable or fixed output voltage options can be used to generate the Typical Performance Characteristics. A 100 100 VOUT = 2.4V 90 VIN = 2.7V %) 95 IOUT = 100 mA %) 80 VIN = 3.6V ncy ( 90 IOUT = 300 mA ncy ( 70 cie 85 IOUT = 500 mA cie 60 Effi Effi 50 80 40 VIN = 4.2V VOUT = 2.4V 75 30 3 3.5 4 4.5 5 5.5 0.1 1 10 100 1000 Input Voltage (V) Output Current (mA) FIGURE 2-7: Efficiency vs. Input Voltage FIGURE 2-10: Efficiency vs. Output Load (V = 2.4V). (V = 2.4V). OUT OUT 100.0 100 VOUT = 3.3V 97.5 90 IOUT = 100 mA IOUT = 300 mA %) 95.0 %) 80 VIN = 3.6V Efficiency ( 9902..05 IOUT = 500 mA Efficiency ( 567000 87.5 40 VIN = 4.2V 85.0 VOUT = 3.3V 30 3.5 3.75 4 4.25 4.5 4.75 5 5.25 5.5 0.1 1 10 100 1000 Input Voltage (V) Output Current (mA) FIGURE 2-8: Efficiency vs. Input Voltage FIGURE 2-11: Efficiency vs. Output Load (V = 3.3V). (V = 3.3V). OUT OUT 0.6 1.82 %/V) 0.5 VOUT = 1.8V V) 11..8801 TA = +125 oC TA = +90 oC Regualtion ( 00..34 IOUT = 300 mA IOUT = 100 mA put Voltage ( 111...777789 TA = - 40 oC TA = +25 oC ne 0.2 Out 1.76 Li 1.75 0.1 1.74 -40 -25 -10 5 20 35 50 65 80 95 110125 100 150 200 250 300 350 400 450 500 Ambient Temperature (oC) Output Current (mA) FIGURE 2-9: Line Regulation vs. Ambient FIGURE 2-12: Output Voltage vs. Load Temperature (V = 1.8V). Current (V = 1.8V). OUT OUT DS22042A-page 8 © 2007 Microchip Technology Inc.

MCP1603 Typical Performance Curves (Continued) Note: Unless otherwise indicated, V =SHDN=3.6V, C =C =4.7µF, L =4.7µH, V (ADJ)=1.8V, I =100mA, IN OUT IN OUT LOAD T =+25°C. Adjustable or fixed output voltage options can be used to generate the Typical Performance Characteristics. A 2.20 2.20 z) z) H H M 2.15 M 2.15 y ( y ( c c en 2.10 en 2.10 u u q q e e Fr 2.05 Fr 2.05 g g n n hi 2.00 hi 2.00 c c wit wit S 1.95 S 1.95 -40 -25 -10 5 20 35 50 65 80 95 110125 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 Ambient Temperature (oC) Input Voltage (V) FIGURE 2-13: Switching Frequency vs. FIGURE 2-16: Switching Frequency vs. Ambient Temperature. Input Voltage. 0.65 0.9 Ω) 0.60 Ω) 0.8 m m nce ( 0.55 nce ( 0.7 N-Channel Resista 00..4550 P-Channel N-Channel Resista 00..56 h h witc 0.40 witc 0.4 P-Channel S S 0.35 0.3 2.7 3.05 3.4 3.75 4.1 4.45 4.8 5.15 5.5 -40 -25 -10 5 20 35 50 65 80 95 110 125 Input Voltage (V) Ambient Temperature (oC) FIGURE 2-14: Switch Resistance vs. Input FIGURE 2-17: Switch Resistance vs. Voltage. Ambient Temperature. FIGURE 2-15: Output Voltage Startup FIGURE 2-18: Heavy Load Switching Waveform. Waveform. © 2007 Microchip Technology Inc. DS22042A-page 9

MCP1603 Typical Performance Curves (Continued) Note: Unless otherwise indicated, V =SHDN=3.6V, C =C =4.7µF, L =4.7µH, V (ADJ)=1.8V, I =100mA, IN OUT IN OUT LOAD T =+25°C. Adjustable or fixed output voltage options can be used to generate the Typical Performance Characteristics. A FIGURE 2-19: Light Load Switching FIGURE 2-21: Output Voltage Line Step Waveform. Response vs. Time. FIGURE 2-20: Output Voltage Load Step Response vs. Time. DS22042A-page 10 © 2007 Microchip Technology Inc.

MCP1603 3.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table3-1. TABLE 3-1: PIN FUNCTION TABLE Pin No. Description Symbol MCP1603 MCP1603L 2x3 DFN TSOT23 TSOT23 1 4 7 V Power Supply Input Voltage Pin IN 2 2 8 GND Ground Pin 3 1 3 SHDN Shutdown Control Input Pin 4 5 4 V /V Feedback / Output Voltage Pin FB OUT 5 3 1 L Switch Node, Buck Inductor Connection Pin X — — 2, 5, 6 NC No Connect — — Exposed EP For the DFN package, the center exposed pad is a thermal Pad path to remove heat from the device. Electrically this pad is at ground potential and should be connected to GND 3.1 Power Supply Input Voltage Pin 3.4 Feedback / Output Voltage Pin (V ) (V /V ) IN FB OUT Connect the input voltage source to V . The input For adjustable output options, connect the center of the IN source must be decoupled to GND with a 4.7µF output voltage divider to the V /V pin. For fixed- FB OUT capacitor. output voltage options, connect the output directly to the V /V pin. FB OUT 3.2 Ground Pin (GND) 3.5 Switch Node, Buck Inductor Ground pin for the device. The loop area of the ground Connection Pin (L ) traces should be kept as minimal as possible. X Connect the L pin directly to the buck inductor. This X 3.3 Shutdown Control Input Pin pin carries large signal-level current; all connections (SHDN) should be made as short as possible. The SHDN pin is a logic-level input used to enable or 3.6 Exposed Metal Pad (EP) disable the device. A logic high (> 45% of V ) will IN enable the regulator output. A logic-low (< 15% of V ) For the DFN package, connect the Exposed Pad to IN will ensure that the regulator is disabled. GND, with vias into the GND plane. This connection to the GND plane will aid in heat removal from the package. © 2007 Microchip Technology Inc. DS22042A-page 11

MCP1603 4.0 DETAILED DESCRIPTION 4.1 Device Overview 4.2 Synchronous Buck Regulator The MCP1603 is a synchronous buck regulator that The MCP1603 has two distinct modes of operation that operates in a Pulse Frequency Modulation (PFM) allow the device to maintain a high level of efficiency mode or a Pulse Width Modulation (PWM) mode to throughout the entire operating current and voltage maximize system efficiency over the entire operating range. The device automatically switched between current range. Capable of operating from a 2.7V to PWM mode and PFM mode depending upon the output 5.5V input voltage source, the MCP1603 can deliver load requirements. 500mA of continuous output current. 4.2.1 FIXED FREQUENCY, PWM MODE When using the MCP1603, the PCB area required for a complete step-down converter is minimized since During heavy load conditions, the MCP1603 operates both the main P-Channel MOSFET and the synchro- at a high, fixed switching frequency of 2.0MHz (typical) nous N-Channel MOSFET are integrated. Also while in using current mode control. This minimizes output rip- PWM mode, the device switches at a constant ple (10 - 15mV typically) and noise while maintaining frequency of 2.0MHz (typ) which allow for small filter- high efficiency (88% typical with VIN = 3.6V, ing components. Both fixed and adjustable output VOUT=1.8V, IOUT = 300mA). voltage options are available. The fixed voltage options During normal PWM operation, the beginning of a (1.2V, 1.5V 1.8V, 2.5V, 3.3V) do not require an external switching cycle occurs when the internal P-Channel voltage divider which further reduces the required MOSFET is turned on. The ramping inductor current is circuit board footprint. The adjustable output voltage sensed and tied to one input of the internal high-speed options allow for more flexibility in the design, but comparator. The other input to the high-speed compar- require an external voltage divider. ator is the error amplifier output. This is the difference Additionally the device features undervoltage lockout between the internal 0.8V reference and the divided- (UVLO), overtemperature shutdown, overcurrent down output voltage. When the sensed current protection, and enable/disable control. becomes equal to the amplified error signal, the high- speed comparator switches states and the P-Channel MOSFET is turned off. The N-Channel MOSFET is turned on until the internal oscillator sets an internal RS latch initiating the beginning of another switching cycle. PFM-to-PWM mode transition is initiated for any of the following conditions: • Continuous device switching • Output voltage has dropped out of regulation 4.2.2 LIGHT LOAD, PFM MODE During light load conditions, the MCP1603 operates in a PFM mode. When the MCP1603 enters this mode, it begins to skip pulses to minimize unnecessary quies- cent current draw by reducing the number of switching cycles per second. The typical quiescent current draw for this device is 45µA. PWM-to-PFM mode transition is initiated for any of the following conditions: • Discontinuous inductor current is sensed for a set duration • Inductor peak current falls below the transition threshold limit DS22042A-page 12 © 2007 Microchip Technology Inc.

MCP1603 4.3 Soft Start 4.6 Enable/Disable Control The output of the MCP1603 is controlled during start- The SHDN pin is used to enable or disable the up. This control allows for a very minimal amount of MCP1603. When the SHDN pin is pulled low, the V overshoot during start-up from V rising above device is disabled. When pulled high the device is OUT IN the UVLO voltage or SHDN being enabled. enabled and begins operation provided the input voltage is not below the UVLO threshold or a fault 4.4 Overtemperature Protection condition exists. Overtemperature protection circuitry is integrated in the 4.7 Undervoltage Lockout (UVLO) MCP1603. This circuitry monitors the device junction temperature and shuts the device off, if the junction The UVLO feature uses a comparator to sense the temperature exceeds the typical 150°C threshold. If input voltage (V ) level. If the input voltage is lower IN this threshold is exceeded, the device will automatically than the voltage necessary to properly operate the restart once the junction temperature drops by MCP1603, the UVLO feature will hold the converter off. approximately 10°C. The soft start is reset during an When V rises above the necessary input voltage, the IN overtemperture condition. UVLO is released and soft start begins. Hysteresis is built into the UVLO circuit to compensate for input 4.5 Overcurrent Protection impedance. For example, if there is any resistance between the input voltage source and the device when Cycle-by-cycle current limiting is used to protect the it is operating, there will be a voltage drop at the input MCP1603 from being damaged when an external short to the device equal to I x R . The typical hysteresis IN IN circuit is applied. The typical peak current limit is is 140mV. 860mA. If the sensed current reaches the 860mA limit, the P-Channel MOSFET is turned off, even if the output voltage is not in regulation. The device will attempt to start a new switching cycle when the internal oscillator sets the internal RS latch. © 2007 Microchip Technology Inc. DS22042A-page 13

MCP1603 5.0 APPLICATION INFORMATION For adjustable output applications, an additional R-C compensation network is necessary for control loop stability. Recommended values for any output voltage 5.1 Typical Applications are: The MCP1603 500mA synchronous buck regulator R = 4.99kΩ operates over a wide input voltage range (2.7Vto5.5V) COMP and is ideal for single-cell Li-Ion battery powered CCOMP = 33pF applications, USB powered applications, three cell Refer to Figure6-2 for proper placement of R and COMP NiMH or NiCd applications and 3V or 5V regulated C . COMP input applications. The 5-lead TSOT and 8-lead 2x3 DFN packages provide a small footprint with minimal 5.4 Input Capacitor Selection external components. The input current to a buck converter, when operating 5.2 Fixed Output Voltage Applications in continuous conduction mode, is a squarewave with a duty cycle defined by the output voltage (V ) to OUT Typical Application Circuit shows a fixed MCP1603 input voltage (V ) relationship of V /V . To prevent IN OUT IN in an application used to convert three NiMH batteries undesirable input voltage transients, the input capacitor into a well regulated 1.8V@500mA output. A 4.7µF should be a low ESR type with an RMS current rating input capacitor, 4.7µF output capacitor, and a 4.7µH given by Equation5.5. Because of their small size and inductor make up the entire external component solu- low ESR, ceramic capacitors are often used. Ceramic tion for this application. No external voltage divider or material X5R or X7R are well suited since they have a compensation is necessary. In addition to the fixed low temperature coefficient and acceptable ESR. 1.8V option, the MCP1603 is also available in 1.2V, 1.5V, 2.5V, or 3.3V fixed voltage options. EQUATION 5-2: 5.3 Adjustable Output Voltage ⎛ V ×(V –V )⎞ I = I ×⎜ ----O----U----T---------------I--N-------------O----U---T-----⎟ Applications CIN,RMS OUT,MAX ⎝ VIN ⎠ When the desired output for a particular application is Table5-1 contains the recommend range for the input not covered by the fixed voltage options, an adjustable capacitor value. MCP1603 can be used. The circuit listed in Figure6-2 shows an adjustable MCP1603 being used to convert a 5.5 Output Capacitor Selection 5V rail to 1.0V@500mA. The output voltage is adjust- able by using two external resistors as a voltage The output capacitor helps provide a stable output divider. For adjustable-output voltages, it is voltage during sudden load transients, smooths the recommended that the top resistor divider value be current that flows from the inductor to the load, and 200kΩ. The bottom resistor value can be calculated reduces the output voltage ripple. Therefore, low ESR using the following equation: capacitors are a desirable choice for the output capac- itor. As with the input capacitor, X5R and X7R ceramic EQUATION 5-1: capacitors are well suited for this application. V The output ripple voltage is often a design specifica- R = R × ⎛--------------F---B------------⎞ tion. A buck converters’ output ripple voltage is a BOT TOP ⎝V –V ⎠ OUT FB function of the charging and discharging of the output capacitor and the ESR of the capacitor. This ripple Example: voltage can be calculated by Equation5-3. R = 200kΩ TOP EQUATION 5-3: V = 1.0V OUT ΔI VFB = 0.8V ΔV = ΔI ×ESR + -------------L-------- OUT L 8×f×C R = 200kΩ x (0.8V/(1.0V-0.8V)) BOT R = 800kΩ BOT (Standard Value = 787kΩ) DS22042A-page 14 © 2007 Microchip Technology Inc.

MCP1603 Table5-1 contains the recommend range for the output TABLE 5-2: MCP1603 RECOMMENDED capacitor value. INDUCTORS TABLE 5-1: CAPACITOR VALUE RANGE DCR Part Value I Size CIN COUT Number (µH) Ω (SAA)T WxLxH (mm) (max) Minimum 4.7µF 4.7µF Coiltronics® Maximum — 22µF SD3110 3.3 0.195 0.81 3.1x3.1x1.0 5.6 Inductor Selection SD3110 4.7 0.285 0.68 3.1x3.1x1.0 SD3110 6.8 0.346 0.58 3.1x3.1x1.0 When using the MCP1603, the inductance value can SD3812 3.3 0.159 1.40 3.8x3.8x1.2 range from 3.3µH to 10µH. An inductance value of 4.7µH is recommended to achieve a good balance SD3812 4.7 0.256 1.13 3.8x3.8x1.2 between converter load transient response and mini- SD3812 6.8 0.299 0.95 3.8x3.8x1.2 mized noise. Würth Elektronik® The value of inductance is selected to achieve a WE-TPC 3.3 0.225 0.72 3.3x3.5x0.95 desired amount of ripple current. It is reasonable to Type XS assume a ripple current that is 20% of the maximum WE-TPC 4.7 0.290 0.50 3.3x3.5x0.95 load current. The larger the amount of ripple current Type XS allowed, the larger the output capacitor value becomes to meet ripple voltage specifications. The inductor WE-TPC 4.7 0.105 0.90 3.8x3.8x1.65 ripple current can be calculated according to the follow- Type S ing equation. WE-TPC 6.8 0.156 0.75 3.8x3.8x1.65 Type S EQUATION 5-4: Sumida® V V CMD4D06 3.3 0.174 0.77 3.5x4.3x0.8 ΔI = --------O---U----T---- × ⎛1– ----O----U---T--⎞ L F × L ⎝ V ⎠ CMD4D06 4.7 0.216 0.75 3.5x4.3x0.8 SW IN CMD4D06 6.8 0.296 0.62 3.5x4.3x0.8 Where: F = Switching Frequency 5.7 Thermal Calculations SW The MCP1603 is available in two different packages When considering inductor ratings, the maximum DC (TSOT-23 and 2x3 DFN). By calculating the power current rating of the inductor should be at least equal to dissipation and applying the package thermal the maximum load current, plus one half the peak-to- resistance,(θ ), the junction temperature is JA peak inductor ripple current (1/2 * ΔI ). The inductor DC estimated. The maximum continuous junction L resistance adds to the total converter power loss. An temperature rating for the MCP1603 is +125°C. inductor with a low DC resistance allows for higher To quickly estimate the internal power dissipation for converter efficiency. the switching buck regulator, an empirical calculation using measured efficiency can be used. Given the measured efficiency, the internal power dissipation is estimated by: EQUATION 5-5: V × I ⎛----O----U---T-----------O----U---T--⎞ –(V × I ) = P ⎝ Efficiency ⎠ OUT OUT Diss The difference between the first term, input power dissipation, and the second term, power delivered, is the internal power dissipation. This is an estimate assuming that most of the power lost is internal to the MCP1603. There is some percentage of power lost in the buck inductor, with very little loss in the input and output capacitors. © 2007 Microchip Technology Inc. DS22042A-page 15

MCP1603 5.8 PCB Layout Information Therefore, it is important that the components along the high current path should be placed as close as possible Good printed circuit board layout techniques are to the MCP1603 to minimize the loop area. important to any switching circuitry and switching The feedback resistors and feedback signal should be power supplies are no different. When wiring the high routed away from the switching node and this switching current paths, short and wide traces should be used. current loop. When possible ground planes and traces This high current path is shown with red connections in should be used to help shield the feedback signal and Figure5-1. The current in this path is switching. minimize noise and magnetic interference. VIN L1 VOUT 2.7VTo4.5V 4.7µH 1.8V@500mA V L IN X CIN COUT 4.7µF SHDN VFB 4.7µF GND FIGURE 5-1: PCB High Current Path. DS22042A-page 16 © 2007 Microchip Technology Inc.

MCP1603 6.0 TYPICAL APPLICATION CIRCUITS l L 1 4.7µH V V IN V L OUT 3.0VTo4.2V IN X 1.5V@500mA CIN COUT 4.7µF SHDN VFB 4.7µF GND FIGURE 6-1: Single Li-Ion to 1.5V @ 500mA Application. L 1 4.7µH V V IN V L OUT 5.0V IN X R 1.0V@500mA COMP 4.C7INµF SHDN 20R0TkOΩP 4.99kΩ C3C3OMpFP C4.O7UµTF V FB R GND BOT 787kΩ FIGURE 6-2: 5V to 1.0V @ 500mA Application. L 1 4.7µH V V IN V L OUT 2.7VTo4.5V IN X 1.2V@500mA CIN COUT 4.7µF SHDN VFB 4.7µF GND FIGURE 6-3: 3 NiMH Batteries to 1.2V @ 500mA Application.9 © 2007 Microchip Technology Inc. DS22042A-page 17

MCP1603 7.0 PACKAGING INFORMATION 7.1 Package Marking Information (Not to Scale) 8-Lead 2x3 DFN Example: Marking Part Number Code MCP1603-120I/MC AFM XXX AFM YWW MCP1603-150I/MC AFK 711 NNN MCP1603-180I/MC AFJ 25 MCP1603-250I/MC AFG MCP1603-330I/MC AFA MCP1603-ADJI/MC AFQ 5-Lead TSOT Example Marking Part Number Code MCP1603T-120I/OS ETNN XXNN MCP1603T-150I/OS EUNN ET25 MCP1603T-180I/OS EVNN MCP1603T-250I/OS EWNN MCP1603T-330I/OS EXNN MCP1603T-ADJI/OS EYNN Marking Part Number Code MCP1603LT-120I/OS FMNN MCP1603LT-150I/OS FKNN MCP1603LT-180I/OS EJNN MCP1603LT-250I/OS FGNN MCP1603LT-330I/OS FANN MCP1603LT-ADJI/OS FQNN Legend: XX...X Customer-specific information Y Year code (last digit of calendar year) YY Year code (last 2 digits of calendar year) WW Week code (week of January 1 is week ‘01’) NNN Alphanumeric traceability code e3 Pb-free JEDEC designator for Matte Tin (Sn) * This package is Pb-free. The Pb-free JEDEC designator ( e 3 ) can be found on the outer packaging for this package. Note: In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. DS22042A-page 18 © 2007 Microchip Technology Inc.

MCP1603 8-Lead Plastic Dual Flat, No Lead Package (MC) – 2x3x0.9 mm Body [DFN] Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging D e b N N L K E E2 EXPOSED PAD NOTE 1 NOTE 1 1 2 2 1 D2 TOP VIEW BOTTOM VIEW A NOTE 2 A3 A1 Units MILLIMETERS Dimension Limits MIN NOM MAX Number of Pins N 8 Pitch e 0.50 BSC Overall Height A 0.80 0.90 1.00 Standoff A1 0.00 0.02 0.05 Contact Thickness A3 0.20 REF Overall Length D 2.00 BSC Overall Width E 3.00 BSC Exposed Pad Length D2 1.30 – 1.75 Exposed Pad Width E2 1.50 – 1.90 Contact Width b 0.18 0.25 0.30 Contact Length L 0.30 0.40 0.50 Contact-to-Exposed Pad K 0.20 – – Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Package may have one or more exposed tie bars at ends. 3. Package is saw singulated. 4. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. MicrochipTechnologyDrawingC04-123B © 2007 Microchip Technology Inc. DS22042A-page 19

MCP1603 5-Lead Plastic Thin Small Outline Transistor (OS) [TSOT] Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging b N E E1 NOTE 1 1 2 3 e e1 D α A A2 c φ L A1 β L1 Units MILLIMETERS Dimension Limits MIN NOM MAX Number of Leads N 5 Lead Pitch e 0.95 BSC Outside Lead Pitch e1 1.90 BSC Overall Height A – – 1.10 Molded Package Thickness A2 0.70 0.90 1.00 Standoff A1 0.00 – 0.10 Overall Width E 2.80 BSC Molded Package Width E1 1.60 BSC Overall Length D 2.90 BSC Foot Length L 0.30 0.45 0.60 Footprint L1 0.60 REF Foot Angle φ 0° 4° 8° Lead Thickness c 0.08 – 0.20 Lead Width b 0.30 – 0.50 Mold Draft Angle Top α 4° 10° 12° Mold Draft Angle Bottom β 4° 10° 12° Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side. 3. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. MicrochipTechnologyDrawingC04-128B DS22042A-page 20 © 2007 Microchip Technology Inc.

MCP1603 APPENDIX A: REVISION HISTORY Revision A (May 2007) • Original Release of this Document. © 2007 Microchip Technology Inc. DS22042A-page 21

MCP1603 NOTES: DS22042A-page 22 © 2007 Microchip Technology Inc.

MCP1603 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. X X XXX X / XX Examples: 8-Lead DFN: Device TSOT Tape Voltage Temp. Package Config. and Reel Option a) MCP1603-120I/MC: 1.20V Buck Reg., 8LD-DFN pkg. b) MCP1603-150I/MC: 1.50V Buck Reg., Device: MCP1603: 2.0MHz, 500mA Buck Regulator 8LD-DFN pkg. c) MCP1603-180I/MC: 1.80V Buck Reg., 8LD-DFN pkg. TSOT Pin Blank = Standard pinout Config. Designator * L = Alternate pinout d) MCP1603-250I/MC: 2.50V Buck Reg., * Refer to Package Types for an explanation regarding the 8LD-DFN pkg. function of the device pins. e) MCP1603-330I/MC: 3.30V Buck Reg., 8LD-DFN pkg. Tape and Reel: T = Tape and Reel 5-Lead TSOT: Blank = Tube a) MCP1603T-120I/OS:1.20V Buck Reg., 5LD-TSOT pkg. Voltage Option: ADJ= Adjustable b) MCP1603T-180I/OS:1.80V Buck Reg., 120 = 1.20V “Standard” 5LD-TSOT pkg. 150 = 1.50V “Standard” c) MCP1603T-250I/OS:2.50V Buck Reg., 180 = 1.80V “Standard” 250 = 2.50V “Standard” 5LD-TSOT pkg. 330 = 3.30V “Standard” d) MCP1603T-330I/OS:3.30V Buck Reg., 5LD-TSOT pkg. e) MCP1603T-ADJI/OS:Adj. Buck Reg., Temperature: I = -40°C to +85°C 5LD-TSOT pkg. f) MCP1603LT-250I/OS:2.50V Buck Reg., Package Type: MC = Plastic Dual-Flat No-Lead Package (MC), 8-Lead 5LD-TSOT pkg. OS = Plastic Thin Small Outline Transistor (OS), 5-Lead g) MCP1603LT-ADJI/OS:Adj. Buck Reg., 5LD-TSOT pkg. © 2007 Microchip Technology Inc. DS22042A-page 23

MCP1603 NOTES: DS22042A-page 24 © 2007 Microchip Technology Inc.

Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device Trademarks applications and the like is provided only for your convenience The Microchip name and logo, the Microchip logo, Accuron, and may be superseded by updates. It is your responsibility to dsPIC, KEELOQ, KEELOQ logo, microID, MPLAB, PIC, ensure that your application meets with your specifications. PICmicro, PICSTART, PROMATE, rfPIC and SmartShunt are MICROCHIP MAKES NO REPRESENTATIONS OR registered trademarks of Microchip Technology Incorporated WARRANTIES OF ANY KIND WHETHER EXPRESS OR in the U.S.A. and other countries. IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, AmpLab, FilterLab, Linear Active Thermistor, Migratable INCLUDING BUT NOT LIMITED TO ITS CONDITION, Memory, MXDEV, MXLAB, SEEVAL, SmartSensor and The QUALITY, PERFORMANCE, MERCHANTABILITY OR Embedded Control Solutions Company are registered FITNESS FOR PURPOSE. Microchip disclaims all liability trademarks of Microchip Technology Incorporated in the arising from this information and its use. Use of Microchip U.S.A. devices in life support and/or safety applications is entirely at Analog-for-the-Digital Age, Application Maestro, CodeGuard, the buyer’s risk, and the buyer agrees to defend, indemnify and dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, hold harmless Microchip from any and all damages, claims, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, suits, or expenses resulting from such use. No licenses are In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi, conveyed, implicitly or otherwise, under any Microchip MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit, intellectual property rights. PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2007, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. © 2007 Microchip Technology Inc. DS22042A-page 25

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Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: M icrochip: MCP1603-120I/MC MCP1603-150I/MC MCP1603-180I/MC MCP1603-250I/MC MCP1603-330I/MC MCP1603LT- 120I/OS MCP1603LT-150I/OS MCP1603LT-180I/OS MCP1603LT-250I/OS MCP1603LT-330I/OS MCP1603LT- ADJI/OS MCP1603T-120I/MC MCP1603T-120I/OS MCP1603T-150I/MC MCP1603T-150I/OS MCP1603T-180I/MC MCP1603T-180I/OS MCP1603T-250I/MC MCP1603T-250I/OS MCP1603T-330I/MC MCP1603T-330I/OS MCP1603T-ADJI/OS MCP1603RD-TNY MCP1603-ADJI/MC