MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD General Description Benefits and Features The MAX13234E-MAX13237E are a family of 2x2 and • Data Rate Up to 3Mbps for Faster Throughput 1x1 RS-232 and V.28/V.24 transceivers with high speed • Saves Board Space data rates up to 3Mbps that operate from either a 3.3V • Integrated Low-Voltage Logic for Easy Interface or 5V supply. with ASICs and Microcontrollers All devices achieve a 1µA supply current using Maxim’s • Integrated ±15kV HBM ESD Protection AutoShutdown Plus™ feature. These devices automati- cally enter a low-power shutdown mode when the • Integrated Charge-Pump Circuitry Requiring Only RS-232 cable is disconnected or the devices driving Four External 0.1µF Capacitors for 3.3V Operation the transmitter and receiver inputs are inactive for more • +3V to +5.5V Supply Voltage than 30s. • AutoShutdown Plus Achieves 1µA Shutdown Current The MAX13234E–MAX13237E are available in space- Reduces Power Consumption saving TQFN and TSSOP packages and operate over • Available in 20-pin TSSOP, TQFN-EP, and 16-pin the -40°C to +85°C temperature range. TQFN • -40°C to +85°C Operating Temperature Applications Functional Diagrams • Telematics • GPS Systems 1.62V to VCC 3.0V to 5.5V • Industrial Systems • Portable Devices CBYPASS1 CBYPASS2 • Wireless Modules C1+ VL VCC V+ • POS Systems C1 C1- MAX13234E C3 • Communication Systems C2 C2+ MAX13235E V- C4 C2- • Data Cables T1IN T1OUT TTL/CMOS RS-232 INPUTS OUTPUTS T2IN T2OUT TOTLU/TCPMUOTSS RR12OOUUTT LOGIC-ELVEL TRANTIOSLNA 5kΩRR12IINN RINSP-U23T2S FORCEOFF 5kΩ FORCEON READY GND Functional Diagrams continued at end of data sheet. Ordering Information/Selector Guide DRIVERS/ MAXIMUM PART TEMP RANGE PIN-PACKAGE RECEIVERS DATA RATE MAX13234EEUP+ 2 x 2 250kbps -40°C to +85°C 20 TSSOP MAX13234EETP+ 2 x 2 250kbps -40°C to +85°C 20 TQFN-EP* MAX13235EEUP+ 2 x 2 3Mbps -40°C to +85°C 20 TSSOP MAX13235EETP+ 2 x 2 3Mbps -40°C to +85°C 20 TQFN-EP* MAX13236EETE+ 1 x 1 250kbps -40°C to +85°C 16 TQFN-EP* MAX13237EETE+ 1 x 1 3Mbps -40°C to +85°C 16 TQFN-EP* +Denotes a lead-free/RoHS-compliant package. *EP = Exposed pad. 19-4343; Rev 1; 1/15

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Absolute Maximum Ratings (All voltages referenced to GND.) Junction-to-Case Thermal Resistance (θJC) (Note 1) VCC ......................................................................-0.3V to +6.0V 16-Pin TQFN .................................................................2°C/W VL.........................................................................-0.3V to +6.0V 20-Pin TSSOP .............................................................20°C/W V+ ........................................................................-0.3V to +7.0V 20-Pin TQFN .................................................................2°C/W V- .........................................................................+0.3V to -7.0V Junction-to-Ambient Thermal Resistance (θJA) (Note 1) (V+) + |(V-)| .....................................................................+13.0V 16-Pin TQFN ...............................................................30°C/W T_IN, FORCEOFF, FORCEON .....................-0.3V to (VL+ 0.3V) 20-Pin TSSOP .............................................................73°C/W R_IN ...................................................................................±25V 20-Pin TQFN ...............................................................29°C/W T_OUT..............................................................................±13.2V Operating Temperature Range R_OUT, READY ...........................................-0.3V to (VL+ 0.3V) MAX1323x Operating Temperature Range....-40°C to +85°C Short-Circuit Duration MAX1323x Operating Temperature Range..-40°C to +105°C T_OUT to GND .........................................................Continuous Storage Temperature Range ...........................-65°C to +160°C Continuous Power Dissipation (TA= +70°C) Lead Temperature (soldering, 10s) .................................+300ºC 16-Pin TQFN (derate 20.8mW/°C above +70°C) .....1666mW 20-Pn TSSOP (derate 10.9mW/°C above +70°C) ......879mW 20-Pin TQFN (derate 21.3mW/°C above +70°C) .....1702mW Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation 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 (VCC = +3V to +5.5V, VL= +1.62V to VCC, TA= -40°C to +85°C, C1–C4 = 0.1µF, VCC= VL, tested at 3.3V ±10%. Typical values are at TA= +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage VCC 3 5.5 V Logic Supply Voltage VL 1.62 VCC V FORCEOFF = FORCEON = VL, no loads 0.3 1 mA VL = 0V 1 10 VCC Supply Current ICC AutoShutDown Plus, FORCEOFF = VL, µA FORCEON = GND, all R_IN idle, all T_IN 1 10 idle. VCC Shutdown Current ICCSH FORCEOFF = GND 1 10 µA VL Supply Current IL VCC = +5.5V 1 10 µA VL Shutdown Current ILSH FORCEOFF = GND 1 10 µA LOGIC INPUTS (T_IN, FORCEON, FORCEOFF, Referred to VL) Input Threshold Low VIL Tested at room temperature only 1/3 x VL V Input Threshold High VIH Tested at room temperature only 2/3 x VL V Input Hysteresis 60 mV Input Leakage Current ±0.01 ±1 µA RECEIVER OUTPUTS (READY) Output-Voltage Low VOL IOUT = 0.8mA 0.4 V Output-Voltage High VOH IOUT = -0.5mA VL - 0.6 VL - 0.1 V www.maximintegrated.com Maxim Integrated | 2

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Electrical Characteristics (continued) (VCC = +3V to +5.5V, VL= +1.62V to VCC, TA= -40°C to +85°C, C1–C4 = 0.1µF, VCC= VL, tested at 3.3V ±10%. Typical values are at TA= +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RECEIVER INPUTS Input-Voltage Range - 25 +25 V VCC = +3.3V 0.6 1.2 Input Threshold Low VIL TA = +25°C V VCC = +5V 0.8 1.5 VCC = +3.3V 1.5 2.4 Input Threshold High VIH TA = +25°C V VCC = +5V 1.8 2.4 Input Hysteresis 0.5 V Input Resistance 3 5 7 kΩ TRANSMITTER OUTPUTS All transmitter outputs loaded with 3kΩ to Output-Voltage Swing ±5 ±5.4 V GND Output Resistance VCC = V+ = V- = 0V, transmitter outputs = 300 10M Ω ±2V Output Short-Circuit Current -60 +60 mA VCC = 0V or +3V to +5.5V, VOUT = ±12V, Output Leakage Current -25 +25 µA transmitters disabled AutoShutdown Plus (FORCEON = GND, FORCEOFF = VL) Receiver Input Threshold Valid Positive threshold, Figure 1 2.7 V Level Negative threshold, Figure 1 -2.7 V Receiver Input Threshold Figure 1 -0.3 +0.3 V Invalid Level Receiver or Transmitter Edge-to- tWU VL = 5V, Figure 1 (Note 3) 100 µs Transmitters Enabled Receiver or Transmitter Edge-to- tAUTOSHDN VL = 5V, Figure 1 (Note 3) 15 30 60 s Transmitters Shutdown TIMING CHARACTERISTICS (MAX13234E/MAX13236E) RL = 3kΩ, CL = 1000pF, one transmitter Maximum Data Rate 250 kbps switching tRPHL, Receiver Propagation Delay CL = 150pF, Figures 2, 3 0.15 µs tRPLH |tTPHL - Transmitter Skew Figures 4, 5 (Note 4) 100 ns tTPLH| |tRPHL - Receiver Skew Figures 2, 3 50 ns tRPLH| www.maximintegrated.com Maxim Integrated | 3

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Electrical Characteristics (continued) (VCC = +3V to +5.5V, VL= +1.62V to VCC, TA= -40°C to +85°C, C1–C4 = 0.1µF, VCC= VL, tested at 3.3V ±10%. Typical values are at TA= +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VCC = +3.3V, TA = +25°C, RL = 3kΩ to 7kΩ, measured from +3V to -3V or -3V to +3V, Transition-Region Slew Rate 6 30 V/µs one transmitter switching, CL = 150pF to 1000pF TIMING CHARACTERISTICS (MAX13235E/MAX13237E) RL = 3kΩ, CL = 250pF, one transmitter 1 switching Maximum Data Rate Mbps RL = 3kΩ, CL = 150pF, one transmitter 3 switching tRPHL, Receiver Propagation Delay CL = 150pF, Figures 2, 3 0.15 µs tRPLH |tTPHL – Transmitter Skew Figures 4, 5 (Note 4) 25 ns tTPLH| |tRPHL – Receiver Skew Figures 2, 3 50 ns tRPLH| VCC = +3.3V, TA = +25°C, RL = 3kΩ to 7kΩ, measured from T_OUT = +3V to -3V or -3V Transition-Region Slew Rate 24 150 V/µs to +3V, one transmitter switching, CL = 150pF to 1000pF ESD PROTECTION Human Body Model ±15 R_IN, T_OUT to GND IEC 61000-4-2 Air Discharge ±15 kV IEC 61000-4-2 Contact Discharge ±8 Note 2: All devices are 100% production tested at TA= +85°C. All temperature limits are guaranteed by design. Note 3: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input-logic thresholds. Note 4: Transmitter skew is measured at the transmitter zero cross points. www.maximintegrated.com Maxim Integrated | 4

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Test Circuits/Timing Diagram RECEIVER INPUTS TRANSMITTER INPUTS TRANSMITTER OUTPUTS tAUTOSHDN tWU tAUTOSHDN tWU VCC READY 0 V+ V+ VCC 0 V- V- Figure 1. AutoShutdown Plus, and READY Timing Diagram T_IN T_OUT R_IN R_OUT CL Figure 2. Receiver Test Circuit www.maximintegrated.com Maxim Integrated | 5

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Test Circuits/Timing Diagram (continued) R_IN 1.3V tR, tF ≤ 10ns 1.7V tRPHL tRPLH VOH R_OUT VL/2 VL/2 VOL Figure 3. Receiver Propagation Delay T_IN T_OUT VO CL RL Figure 4. Transmitter Test Circuit VL T_IN VL/2 tR, tF ≤ 10ns VL/2 0 tTPHL tTPLH VO 3V 3V T_OUT 0 0 -3V -3V -VO tF SRF = 6/tF SRR = 6/tR tR Figure 5. Transmitter Propagation Delay www.maximintegrated.com Maxim Integrated | 6

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Typical Operating Characteristics (VCC= VL= 3.3V, TA= +25°C, unless otherwise noted.) TRANSMITTER OUTPUT VOLTAGE TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE vs. LOAD CAPACITANCE SLEW RATE vs. LOAD CAPACITANCE 6 6 12 4 V+ MAX13234E toc01 4 V+ MAX13234E toc02 1101 MAX13234E/MARXL1 =3 233k6ΩE MAX13234E toc03 UTPUT VOLTAGE (V) -202 MRT1LA =AX T13 3k2Ω25304kEb/pMsAX13236E UTPUT VOLTAGE (V) -202 TMR1LA =AX T13 3k3Ω2M3b5pEs/MAX13237E μSLEW RATE (V/s) 789 SR- SR+ O O 6 -4 -4 V- V- 5 -6 -6 4 0 500 1000 1500 2000 2500 50 100 150 200 250 300 0 500 1000 1500 2000 2500 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) VCC SUPPLY CURRENT VCC SUPPLY CURRENT SLEW RATE vs. LOAD CAPACITANCE vs. LOAD CAPACITANCE vs. LOAD CAPACITANCE 7705 MAX13235E/MARXL1 =3 233k7ΩE MAX13234E toc04 2350 RTT12L =AA TT3 k21Ω550.6kkbbppss MAX13234E MAX13234E toc05 3450 RTT21L =AA TT3 k13Ω8M7b.5pksbps MAX13235E MAX13234E toc06 μW RATE (V/s) 566505 SR+SR- Y CURRENT (mA) 1250 Y CURRENT (mA) 232005 SLE 50 SUPPL 10 SUPPL 15 45 5 10 40 0 5 50 100 150 200 250 300 0 500 1000 1500 2000 2500 50 100 150 200 250 300 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) TRANSMITTER SKEW TRANSMITTER SKEW READY TURN-ON TIME vs. LOAD CAPACITANCE vs. LOAD CAPACITANCE vs. TEMPERATURE 150 9 100 KEW (ns) 11913000 MR1O LPTA E=RXR A13AN3kTΩ2SI3NM4GIET /ATMETAR 2X5103k2b3p6sE MAX13234E toc07 KEW (ns) 678 MR1O LPTA E=RXR A13AN3kTΩ2SI3MN5GIET /ATMETAR 3XM13b2p3s7E MAX13234E toc08 μTIME (s) 8900 MAX13234E toc09 R S R S 5 ON TE 70 TE N- 70 MIT MIT 4 UR TRANS 3500 TRANS 32 READY T 60 50 10 1 -10 0 40 0 500 1000 1500 2000 2500 50 100 150 200 250 -40 -15 10 35 60 85 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) TEMPERATURE (°C) www.maximintegrated.com Maxim Integrated | 7

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Typical Operating Characteristics (continued) (VCC= VL= 3.3V, TA= +25°C, unless otherwise noted.) READY TURN-OFF TIME vs. TEMPERATURE SUPPLY CURRENT vs. DATA RATE LOGIC-INPUT THRESHOLD vs. VL μREADY TURN-OFF TIME (s) 00111112........00686824 MAX13234E toc10 SUPPLY CURRENT (mA) 112323055005 M1OR LPTA E=RXR A13AN3kTΩ2SI3MN,5 GCIETLT =E R150pF MAX13234E toc11 OGIC-INPUT THRESHOLD (V) 11221112........57133195 VCC = 5.5V VIHVIL MAX13234E toc12 0.4 L 0.9 5 0.2 0.7 0 0 0.5 -40 -15 10 35 60 85 0.001 0.01 0.1 1 10 1.5 2.5 3.5 4.5 5.5 TEMPERATURE (°C) DATA RATE (kbps) VL (V) TRANSMITTER OUTPUT VOLTAGE TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE vs. LOAD CURRENT 8 8 46 V+ MAX13234E toc13 46 V+ MAX13234E toc14 V) V) GE ( 2 MAX13235E/MAX13237E GE ( 2 VOLTA 0 1R LT =R A3NkΩSM, CITLT =E R150pF VOLTA 0 1 TRANSMITTER UT OPERATING AT 1Mbps UT OPERATING, DC TP -2 TP -2 U U O O -4 V- -4 V- -6 -6 -8 -8 3.0 3.5 4.0 4.5 5.0 5.5 0 2 4 6 8 SUPPLY COLTAGE (V) LOAD CURRENT (mA) www.maximintegrated.com Maxim Integrated | 8

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Pin Descriptions PIN MAX13234E/ MAX13236E/ NAME FUNCTION MAX13235E MAX13237E TSSOP TQFN-EP TQFN-EP Ready to Transmit Output, Active-High. READY is enabled 1 19 14 READY high when V- goes below -4V and the device is ready to transmit. Positive Terminal of the Voltage Doubler Charge-Pump 2 1 16 C1+ Capacitor 3 20 15 V+ +5.5V Generated by the Charge Pump Negative Terminal of the Voltage Doubler Charge-Pump 4 2 1 C1- Capacitor 5 3 2 C2+ Positive Terminal of the Inverting Charge-Pump Capacitor 6 4 3 C2- Negative Terminal of the Inverting Charge-Pump Capacitor 7 5 4 V- -5.5V Generated by the Charge Pump 8 6 — T2OUT RS-232 Transmitter Output 2 — — 5 RIN RS-232 Receiver Input 9 7 — R2IN RS-232 Receiver Input 2 — — 6 ROUT CMOS Receiver Output. VL referred logic. 10 8 — R2OUT CMOS Receiver Output 2. VL referred logic. Logic-Level Supply. All CMOS inputs and outputs are related 11 9 7 VL to this supply. — — 8 TIN CMOS Transmitter Input. VL referred logic. 12 10 — T2IN CMOS Transmitter Input 2. VL referred logic. 13 11 — T1IN CMOS Transmitter Input 1. VL referred logic. FORCEON Input, Active-High. VL referenced logic. Drive FORCEON high to override automatic circuitry keeping 14 12 9 FORCEON transmitters on (FORCEOFF must be high). See Table 1. 15 13 — R1OUT CMOS Receiver Output 1. VL referred logic. — — 10 TOUT RS-232 Transmitter Output 16 14 — R1IN RS-232 Receiver Input 1 17 15 — T1OUT RS-232 Transmitter Output 1 18 16 11 GND Ground 19 17 12 VCC +3V to +5.5V Supply Voltage FORCEOFF Input, Active-Low. VL referenced logic. Drive FORCEOFF low to shut down transmitters and on-board 20 18 13 FORCEOFF charge pumps. All receiver and transmitter outputs are tri- stated. This overrides all automatic circuitry and FORCEON (Table 1). — — — EP Exposed Pad. Connect EP to GND or leave unconnected. www.maximintegrated.com Maxim Integrated | 9

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Detailed Description RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic VL Logic Supply Input output levels. The MAX13234E–MAX13237E have The MAX13234E–MAX13237E feature a separate logic inverting outputs that are active when in shutdown supply input (VL) that sets the receiver’s output level (FORCEOFF= GND) (Table 1). (VOH), and sets the transmitter’s input thresholds (VIL, AutoShutdown Plus Mode VIH). This feature allows flexibility in interfacing to UARTs or communication controllers that have different Drive FORCEOFF high and FORCEON low to invoke logic levels. Connect this input to the host logic supply AutoShutdown Plus mode. When these devices do not (1.62V ≤VL≤VCC). sense a valid signal transition on any receiver and transmitter input for 30s, the onboard charge pumps Dual Charge-Pump Voltage Converter are shut down, reducing supply current to 1µA. This The internal power supply consists of a regulated dual occurs if the RS-232 cable is disconnected or charge pump that provides output voltages of +5.5V if the devices driving the transmitter and receiver and -5.5V (inverting charge pump), over the +3.0V to inputs are inactive for more than 30s. The +5.5V range. The charge pump operates in discontinu- MAX13234E–MAX13237E turn on again when a valid ous mode: if the output voltages are less than +5.5V, transition is applied to any RS-232 receiver or transmit- the charge pump is enabled; if the output voltages ter input. As a result, the system saves power without exceed +5.5V, the charge-pump is disabled. The requiring any control. charge pumps require flying capacitors (C1, C2) and Figure 6 and Table 1 summarize the MAX13234E– reservoir capacitors (C3, C4) to generate the V+ and V- MAX13237E operating modes. The FORCEON and supplies. The READY output is low when the charge FORCEOFF inputs override AutoShutdown Plus circuit- pumps are disabled in shutdown mode. The READY ry. When neither control is asserted, the IC selects signal asserts high when V- goes below -4V. between these states automatically based on the last RS-232 Transmitters receiver or transmitter input edge received. The transmitters are inverting level translators that con- Hardware-Controlled Shutdown vert CMOS-logic levels to ±5.0V EIA/TIA-232 levels. Drive FORCEOFF low to place the MAX13234E– The MAX13234E/MAX13236E guarantee a 250kbps MAX13237E into shutdown mode. data rate with worst-case loads of 3kΩ in parallel with 1000pF. The MAX13235E/MAX13237E guarantee a 1Mbps data rate with worst-case loads of 3kΩ in paral- lel with 250pF, and a 3Mbps data rate with worst-case POWER- MASTER SHDN LINE MANAGEMENT loads of 3kΩin parallel with 150pF. Transmitters can be UNIT 0.1μF 1MΩ paralleled to drive multiple receivers. When FORCEOFF is driven to ground or when the AutoShutdown Plus cir- FORCEOFF FORCEON cuitry senses that all receiver and transmitter inputs are inactive for more than 30s, the transmitters are disabled MAX13234E and the outputs go into a high-impedance state. When MAX13235E powered off or shut down, the outputs can be driven to MAX13236E ±12V. The transmitter inputs do not have pullup resis- MAX13237E tors. Connect unused inputs to GND or VL. Figure 7. AutoShutdown Plus Initial Turn-On to Wake Up a Mouse or Another System www.maximintegrated.com Maxim Integrated | 10

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD EDGE T_IN DETECT FORCEOFF FORCEOFF POWERDOWN* S FORCEON 30s EDGE TIMER AUTOSHDN R_IN DETECT R * POWERDOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE OPERATIONAL STATUS OF FORCEON THE TRANSMITTERS AND THE POWER SUPPLIES. Figure 6. AutoShutdown Plus and Shutdown Logic Table 1. Transceiver Mode Control R_IN or T_IN FORCEOFF FORCEON T_OUT R_OUT TRANSCEIVER STATUS EDGE WITHIN 30s 0 X X High-Impedance Active Shutdown (Forced Off) 1 1 X Active Active Normal Operation (Forced On) 1 0 Yes Active Active Normal Operation in AutoShutdown Plus 1 0 No High-Impedance Active Shutdown in AutoShutdown Plus X = Don’t Care. www.maximintegrated.com Maxim Integrated | 11

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD ±15kV ESD Protection an ESD event, Maxim’s E versions keep working without ESD-protection structures are incorporated on all pins latchup. ESD protection can be tested in various ways; to protect against electrostatic discharges encountered the transmitter outputs and receiver inputs of this prod- during handling and assembly. The driver outputs and uct family are characterized for protection to the follow- receiver inputs of the MAX13234E–MAX13237E have ing limits: extra protection against static electricity. Maxim’s engi- 1) ±15V Using the Human Body Model neers have developed state-of-the-art structures to pro- 2) ±15kV Using IEC 61000-4-2 Air-Gap Method tect these pins against ESD of ±15kV without damage. The ESD structures withstand high ESD in all states: 3) ±8kV Using IEC 61000-4-2 Contact-Discharge normal operation, shutdown, and powered down. After Method RC RD RC RD 1MΩ 1500Ω 50MΩ to 100MΩ 330Ω CHARGE-CURRENT DISCHARGE CHARGE-CURRENT DISCHARGE LIMIT RESISTOR RESISTANCE LIMIT RESISTOR RESISTANCE HIGH- DEVICE HIGH- DEVICE VOLTAGE Cs STORAGE UNDER VOLTAGE Cs STORAGE UNDER DC 100pF CAPACITOR TEST DC 150pF CAPACITOR TEST SOURCE SOURCE Figure 8a. Human Body ESD Test Model Figure 9a. IEC61000-4-2 ESD Test Model I IP 100% Ir PEAK-TO-PEAK RINGING 100% 90% (NOT DRAWN TO SCALE) 90% AMPERES K 36.8% PEA I 10% 0 0 TIME tRL tDL CURRENT WAVEFORM 10% Figure 8b. Human Body Current Waveform tr = 0.7ns to 1ns t 30ns 60ns Figure 9b. IEC61000-4-2 ESD Generator Current Waveform www.maximintegrated.com Maxim Integrated | 12

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD ESD Test Conditions larger nominal value. The capacitor’s equivalent series ESD performance depends on a variety of conditions. resistance (ESR), usually rises at low temperatures Contact Maxim for a reliability report that documents influencing the amount of ripple on V+ and V-. test setup, test methodology, and test results. Table 2. Required Minimum Human Body Model Capacitance Values Figure 8a shows the Human Body Model and Figure 8b shows the current waveform it generates when dis- VCC C1, CBYPASS2 CBYPASS1 C2, C3, C4 charged into a low impedance. This model consists of (V) (µF) (µF) (µF) a 100pF capacitor charged to the ESD voltage of inter- 3.0 to 3.6 0.22 0.22 0.22 est, which is then discharged into the test device 3.15 to 3.6 0.1 0.1 0.1 through a 1.5kΩresistor. 4.5 to 5.5 0.047 1 0.33 IEC 61000-4-2 3.0 to 5.5 0.22 1 1 The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifi- Power-Supply Decoupling cally refer to integrated circuits. The MAX13234E– MAX13237E helps design equipment that meets Level In most circumstances, a 0.1µF VCC bypass capacitor 4 (the highest level) of IEC 61000-4-2, without the need and a 1µF VL bypass capacitor are adequate. In appli- for additional ESD-protection components. The major cations that are sensitive to power-supply noise, use difference between tests done using the Human Body capacitors of the same value as charge-pump capaci- Model and IEC 61000-4-2 is higher peak current in IEC tor C1. Connect bypass capacitors as close to the IC 61000-4-2, because series resistance is lower in the as possible. IEC 61000-4-2 model. Hence, the ESD withstand volt- Transmitter Outputs when Exiting age measured to IEC 61000-4-2 is generally lower than Shutdown that measured using the Human Body Model. Figure 9a Figure 10 shows two transmitter outputs when exiting shows the IEC 61000-4-2 model and Figure 9b shows shutdown mode. As they become active, the two trans- the current waveform for the 8kV, IEC 61000-4-2, Level mitter outputs are shown going to opposite RS-232 lev- 4, ESD Contact-Discharge Method. els (one transmitter input is high, the other is low). Each The Air-Gap Method involves approaching the device transmitter is loaded with 3kΩ in parallel with 1000pF. with a charged probe. The Contact-Discharge Method The transmitter outputs display no ringing or undesir- connects the probe to the device before the probe is able transients as they come out of shutdown. Note that energized. the transmitters are enabled only when the magnitude Applications Information of V- exceeds approximately -3V. Capacitor Selection The capacitor type used for C1–C4 is not critical for 5V/div FORCEON = FORCEOFF proper operation; polarized or non-polarized capacitors 0 can be used. The charge pump requires 0.1µF capaci- T1OUT tors for VCC = +3.3V operation. For other supply volt- ages, see Table 2 for required capacitor values. Do not use values smaller than those listed in Table 2. 2V/div Increasing the capacitor values (e.g., by a factor of 2) 0 reduces ripple on the transmitter outputs and slightly reduces power consumption. C2, C3, and C4 can be increased without changing C1’s value. However, do not increase C1 without also increasing the values 5V/div VCC1C– C=4 3 =.3 0V.1μF TR2EOAUDTY 0 of C2, C3, C4, CBYPASS1, and CBYPASS2 to maintain the proper ratios (C1 to the other capacitors). When 5μs/div using the minimum required capacitor values, make sure the capacitor value does not degrade excessively Figure 10. Transmitter Outputs when Exiting Shutdown or with temperature. If in doubt, use capacitors with a Powering Up www.maximintegrated.com Maxim Integrated | 13

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD High Data Rates In Figure 12, all transmitters were driven simultaneously The MAX13234E–MAX13237E maintain the RS-232 ±5V at 120kbps into RS-232 loads in parallel with 1000pF. minimum transmitter output voltage even at high data In Figure 13, a single transmitter was driven at 3Mbps, rates. Figure 11 shows a transmitter loopback test cir- and all transmitters were loaded with an RS-232 receiv- cuit. Figure 12 shows a loopback test result at er in parallel with 150pF. 120kbps, and Figure 13 shows the same test at 3Mbps. 1.62V to VCC VCC T1IN 3V/div CBYPASS1 CBYPASS2 5V/div VL VCC T1OUT C1+ V+ C1 C3* C1- 5V/div MAX13236E R1OUT C2+ MAX13237E V- VCC = 3.3V C2 C4 2μs/div C2- Figure 12. Loopback Test Results at 120kbps T_IN T_OUT R_OUT R_IN 1000pF FORCEON 5kΩ T1IN 3.3V/div FORCEOFF VCC T1OUT GND 5V/div *C3 CAN BE RETURNED TO VCC OR GND. 3.3V/div R1OUT VCC = 3.3V Figure 11. Loopback Test Circuit 100ns/div Figure 13. Loopback Test Results at 3Mbps Chip Information PROCESS: BiCMOS www.maximintegrated.com Maxim Integrated | 14

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Pin Configurations TOP VIEW TOP VIEW TOP VIEW N O READY 1 + 20 FORCEOFF T1OUT R1IN R1OUT FORCE T1IN VCC GND TOUT FORCEON C1+ 2 19 VCC 15 14 13 12 11 12 11 10 9 V+ 3 18 GND GND 16 10 T2IN C1- 4 17 T1OUT FORCEOFF 13 8 TIN MAX13234E VCC 17 9 VL C2+ 5 MAX13235E 16 R1IN MAX13234E READY 14 MAX13236E 7 VL FORCEOFF 18 MAX13235E 8 R2OUT MAX13237E C2- 6 15 R1OUT V+ 15 6 ROUT READY 19 7 R2IN *EP V- 7 14 FORCEON *EP C1+ 16 + 5 RIN V+ 20 + 6 T2OUT T2OUT 8 13 T1IN 1 2 3 4 R2IN 9 12 T2IN 1 2 3 4 5 R2OUT 10 11 VL C1+ C1- C2+ C2- V- C1- C2+ C2- V- TSSOP TQFN TQFN *EXPOSED PAD. CONNECT EP TO GND. *EXPOSED PAD. CONNECT EP TO GND. Functional Diagrams (continued) 1.62V to VCC 3.0V to 5.5V CBYPASS1 CBYPASS2 VL VCC C1+ V+ C1 C3 C1- MAX13236E C2+ MAX13237E V- C2 C4 C2- TTL/CMOS T_IN T_OUT RS-232 INPUT ON OUTPUT ATI L S TTL/CMOS R_OUT RAN R_IN RS-232 OUTPUT L T INPUT E FORCEOFF LEV 5kΩ C- FORCEON GI O L READY GND www.maximintegrated.com Maxim Integrated | 15

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD 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 DOCUMENT NO. 20 TSSOP U20-2 21-0066 20 TQFN-EP* T2055-5 21-0140 16 TQFN-EP* T1655-2 21-0140 *EP = Exposed Pad. www.maximintegrated.com Maxim Integrated | 16

MAX13234E–MAX13237E 3Mbps RS-232 Transceivers with Low-Voltage Interface, ±15kV HBM ESD Revision History REVISION REVISION PAGES DESCRIPTION NUMBER DATE CHANGED 0 10/08 Initial release — 1 1/15 Updated General Description and Benefits and Features sections 1 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. 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2015 Maxim Integrated Products, Inc. | 17

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: M axim Integrated: MAX13234EAUP+ MAX13234EAUP+T MAX13234EETP+ MAX13234EETP+T MAX13234EEUP+ MAX13234EEUP+T MAX13234EIUP+ MAX13234EIUP+T MAX13235EETP+ MAX13235EETP+T MAX13235EEUP+ MAX13235EEUP+T MAX13235EIUP+ MAX13235EIUP+T MAX13236EETE+ MAX13236EETE+T MAX13237EETE+ MAX13237EETE+T