19-0273; Rev 4; 6/96 General Description The MAX3222/MAX3232/MAX3237/MAX3241 trans- ceivers have a proprietary low-dropout transmitter out- put stage enabling true RS-232 performance from a 3.0V to 5.5V supply with a dual charge pump. The devices require only four small 0.1pF external charge- pump capacitors. The MAX3222, MAX3232, and MAX3241 are guaranteed to run at data rates of 120kbps while maintaining RS-232 output levels. The MAX3237 is guaranteed to run at data rates of 250kbps in the normal operating mode and 1Mbps in the MegaBaud operating mode, while maintaining RS-232 output levels. The MAX3222/MAX3232 have 2 receivers and 2 drivers. The MAX3222 features a 1A shutdown mode that reduces power consumption and extends battery life in portable systems. Its receivers remain active in shutdown mode, allowing external devices such as modems to be monitored using only 1pA supply cur- rent. The MAX3222 and MAX3232 are pin, package, and functionally compatible with the industry-standard MAX242 and MAX232, respectively. The MAX3241 is a complete serial port (3 drivers/ 5 receivers) designed for notebook and subnotebook computers. The MAX3237 (5 drivers/3 receivers) is ideal for fast modem applications. Both these devices feature a shutdown mode in which all receivers can remain active while using only 1pA supply current. Receivers R1 (MAX3237/MAX3241) and R2 (MAX3241) have extra out- puts in addition to their standard outputs. These extra outputs are always active, allowing external devices such as a modem to be monitored without forward bias- ing the protection diodes in circuitry that may have Vcc completely removed. The MAX3222, MAX3237, and MAX3241 are available in space-saving SSOP packages. Applications Notebook, Subnotebook, and Palmtop Computers High-Speed Modems Battery-Powered Equipment Hand-Held Equipment Peripherals Printers Typical Operating Circuits appear at end of data sheet. MegaBaud is a trademark of Maxim integrated Products. MA AXKXLM 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Features Low Supply Current: 300HA (MAX3222/MAX3232/MAX3241) 500uA (MAX3237) @ Guaranteed Data Rate: 120kbps (MAX3222/MAX3232/MAX3241) 250kbps (MAX3237Normal Operation) 1Mbps (MAX3237-MegaBaud Operation) 1pA Low-Power Shutdown with Receivers Active (MAX3222/MAX3237/MAX3241) Flow-Through Pinout (MAX3237) + Meets EIA/TIA-232 Specifications Down to 3.0V Guaranteed Mouse Driveability (MAX3241) Pin Compatible with industry-Standard MAX232 (MAX3232) Pin Compatible with Industry-Standard MAX242 (MAX3222) @ Guaranteed Slew Rate: 6V/us (MAX3222/MAX3232/MAX3237/MAX3241) 24V/ps (MAX3237MegaBaud Operation) Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX3222CPN OC to +70C 18 Plastic DIP MAX3222CWN 0C to +70C 18S0 MAX3222CAP 0C to +70C 20 SSOP Ordering Information continued at end of data sheet. Pin Configurations TOP VIEW oJ en] hia} SHON cts [2] Hz} vec ve [3] he] eno c- [4h Anaxiaa [15] Tout cass) MAX3222 [4] BAN cz- [6 13] RIOUT v- [7] 12| THIN reat [a] 11} 72IN ran [3 10} RacUT DIP/SO Pin Configurations continued at end of data sheet. Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809, 152, 4,897,774; 4,999, 761; and other patents pending. MAXIMA For free samples & the latest literature: http:/;www.maxim-ic.com, or phone 1-800-998-8800 + LPCEXVIN/LECEXVW/CECEXVWN/EZCEXUW Maxim Integrated Products 2-137MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors ABSOLUTE MAXIMUM RATINGS VOC eee eececceeeccecceeaeeteececaeceaceneeeeceecsaesaeasseaeassseeaeeass -0.3V to +6V Continuous Power Dissipation (Ta = +70C) V+ (Note 1).. 1-0.3V to +7V 16-Pin Plastic DIP (derate 10.58mW/C above +70C)...842mW V- (Note 1)....... 1 +0.3V to -7V 16-Pin Narrow SO (derate 8.70mW/C above +70C) ....696mW V+ 4 Ve (NOt Doc ec cecseecsetecssseseceeceesessereseesieeesnaassees +13V 16-Pin Wide SO (derate 9.52mW/C above +70C)........ 762mW Input Voltages 18-Pin Plastic DIP (derate 11.11mW/C above +70C) .889mW TIN, SHON, EN . 18-Pin SO (derate 9.S2mW/C above +70C).......0... 762mW 20-Pin SSOP (derate 8.00mW/C above +70C) ..640mWw 28-Pin SO (derate 12.50mW/PC above +70C) ...... cee IW Output Voltages 13.2V 28-Pin SSOP (derate 9.52mW/C above +70C).........762mW POUT Davie icc ogy) Perating Temperature Ranges Shoft-Circuit Duration . MAX32_ Coie cececseccecerececterevsevenseretees OC to +70C TOUT ooceccccccccccsesecseesvsssssseseeescsteseestsesseceneeeatenvenes Continuous MAX32_ EL eosserreeee ~40C to +85C Storage Temperature Range.......... .-65C to +150C Lead Temperature (soldering, 108@C) ............ceee seers +300C Note 1: V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V. 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 attect device reliability. ELECTRICAL CHARACTERISTICS (Voc = +3.0V to +5.5V, C1-C4 = 0.1F (Note 2), Ta = TMIN to Tmax, unless otherwise noted. Typical values are at Ta = +25C.) PARAMETER | CONDITIONS | MIN TYP MAX I UNITS DC CHARACTERISTICS MAX3222/MAX3232/ = 0.3 1.0 Voc Power-Supply Current re toaa vce 3.3V 0 5.0V, | Mmax3ed1 mA MAX3237 0.5 2.0 Shutdown Supply Current SHDN = GND, Ta = +25C 1.0 10 pA LOGIC INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low T_IN, EN, SHON, MBAUD 08 Vv {Note 3) Input Logic Threshold High Voc = 3.3V 2.0 Vv {Note 3) Voc = 5.0V 24 Input Leakage Current T_IN, EN, SHDN, MBAUD #0.01 1.0 pA Output Leakage Current Receivers disabled #0.05 +10 pA Output Voltage Low lout = 1.6mA 0.4 Vv Output Voltage High lout = -1.0mA Vec-0.6 Vec-0.1 Vv RECEIVER INPUTS Input Voltage Range -25 25 Vv Voc = 3.3V 0.6 1.2 Vv Input Threshold Low Voc = 5.0V 08 15 Veco = 3.3V 1.5 2.4 i V Input Threshold High Voc = 50V 18 24 Input Hysteresis 0.3 Vv Input Resistance Ta = +25C 3 5 7 kQ 2-138 MAAXIAA3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors ELECTRICAL CHARACTERISTICS (continued) (Voc = +3.0V to +5.5V, C1-C4 = 0. 1p:F (Note 2), Ta = TMIN to TMAx, unless otherwise noted. Typical values are at Ta = +25C.) PARAMETER | CONDITIONS | MIN TYP MAX | UNITS TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3kQ to ground +5.0 5.4 v Output Resistance Voc = V+ = V- = OV, TouT = 2V 300 10M Q Output Short-Circuit Current +35 +60 mA Output Leakage Current VouT = 12V, Voc = OV to 5.5V, transmitters disabled #25 yA MOUSE DRIVEABILITY (MAX3241) T1iN = T2IN = GND, TIN = Vcc, Transmitter Output Voltage T3OUT loaded with 3kQ to GND, +5.0 Vv TIOUT and T2OUT loaded with 2.5mA each TIMING CHARACTERISTICSMAX3222/MAX3232/MAX3241 (Voc = +3.0V to +5.5V, C1-C4 = 0.1pF (Note 2), Ta = TMiN to Tmax, unless otherwise nated. Typical values are at Ta = +25C.) LOSEXVW/LECEXVW/CEZTEXVW/ECCEXVW PARAMETER CONDITIONS : MIN TYP MAX UNITS Maximum Data Rate RL = 3kQ, CL = 1000pF, one transmitter switching 120 235 kbps . . tPHL 0.3 Receiver Propagation Delay | R_IN to RLOUT, Cy = 150pF ys tPLH 0.3 Receiver Output Enable Time | Normal operation 200 ns Receiver Output Disable Time | Normal operation 200 ns Transmitter Skew | teHL - tet | 300 ns Receiver Skew | teHe - tPLH | 300 ns CL = 150pF to Voc = 3.3V, Ru = 30 to 7kQ, 1000pF 6 30 Transition-Region Slew Rate | +3V to -3V or -3V to +3V, Vius Ta = +25C CL = 150pF to 4 90 2500pF MAAXISA 2-139MAX3222/MAX3232/MAX3237/MAX3241 2-140 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors TIMING CHARACTERISTICSMAX3237 (Vcc = +3.0V to +5.5V, C1-C4 = 0. 1pF (Note 2), Ta = TIN to Tmax, unless otherwise noted. Typical values are at Ta = +25C.) PARAMETER CONDITIONS MIN TYP MAX UNITS Ru = 3kQ, Cy = 1000pF, one transmitter switching, 250 MBAUD = GND . Voc = 3.0V to 4.5V, Ry = 3kQ, CL = 250pF, Maximum Data Rate one transmitter switching, MBAUD = Voc 1000 kbps Voc = 4.5V to 5.5V, RL = 3kQ, CL = 1000pF, 4000 one transmitter switching, MBAUD = Voc t . Receiver Propagation Delay | R_IN ta RLOUT, Cy = 150pF PHL 0.18 us . {tPLH 0.15 Receiver Output Enable Time | Normal operation 200 ns Receiver Output Disable Time | Normal operation 200 ns . | tert - teLH |, MBAUD = GND 100 ns Transmitter Skew | teri. - tet |. MBAUD = Voc 25 ns Receiver Skew Iter, - teu | 50 ns MBAUD = Ct = 150pF | GND 0 Veco = 3.3V, Rt = 39 to 7kQ, to 1000pF MBAUD = Transition-Region Slew Rate | +3V to -3V or -3V to +3V, Vv 24 150 Vius Ta = +25C ce Ci = 150pF to 2500pF, 4 30 MBAUD = GND Note 2: MAX3222/MAX3232/MAX3241: C1-C4 = 0.1pF tested at 3.3V 410%; C1 = 0.047pF, C2-C4 = 0.33pF tested at 5.0V 410%. MAX3237: C1-C4 = 0.1pF tested at 3.3V +5%; C1-C4 = 0.22uF tested at 3.3V 10%; C1 = 0.047pF, C2-C4 = 0.33pF tested at 5.0V +10%. Note 3: Transmitter input hysteresis is typically 250mV. Typical Operating Characteristics (Vcc = +3.3V, 235kbps data rate, 0.1pF capacitors, all transmitters loaded with 3kQ, Ta = +25C, unless otherwise noted.) MAX3222/MAX3232 TRANSMITTER OUTPUT VOLTAGE vs. LOAQ CAPACITANCE vw hae ~O * Ls) -3 TRANSMITTER OUTPUT VOLTAGE (V} 0 1000 LOAD CAPACITANCE (pF) 2000 3000 = 4000 MAN3222/MAX3232 SLEW RATE vs. LOAD CAPACITANCE UP TO SLEW RATE (V/s) 150 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 000 SUPPLY CURRENT (mA) 40 35 30 25 20 1% 10 5 0 '3222/MAX3232 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) MAAXLIA3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1p:F External Capacitors Typical Operating Characteristics (continued) = (Voc = +3.3V, 235kbps data rate, 0.1yF capacitors, all transmitters loaded with 3kQ, Ta = +25C, unless otherwise noted.) MAX324 MAX3241 MAX3241 TRANSMITTER OUTPUT VOLTAGE SLEW RATE SUPPLY CURRENT ys. LOAD vs, LOAD CAPACITANCE vs. LOAD CAPACITANCE CAPACITANCE WHEN TRANSMITTING DATA 75 45 = 40 ND wg 80 N = < 35 =_ 2S 25 q = 30 5 1 TRANSMITTER AT 235kbps Ss Ss - ,- AT # @ 2 S = 3 2 E -25 a 5 5 = 10 @ so @ pt w 75 0 0 1000 2000 3000 4000 5000 0 1000 2000 3000 4000 8000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF} LOAD CAPACITANCE (pF} LOAD CAPACITANCE (pF) MAX3237 MAX3237 MAX3237 TRANSMITTER OUTPUT VOLTAGE TRANSMITTER OUTPUT VOLTAGE SLEW RATE ys. LOAD CAPACITANCE vs. LOAD CAPACITANCE (MBAUD = GND) vs. LOAD CAPACITANCE (BAUD = Vcc) (MBAUD = GND) > 78 75 . 12 8 S S tops i ry | | i Bw 50 y 50 5 19 SK SEW 5 a ee 1SMops} +sLEW PN \ S 25 S 25 a 8 5 1 TRANSMITTER AT 240kbps = 1 TRANSMITTER AT FULL DATA RATE = G 4 TRANSMITTERS AT 15kbps 2 4 TRANSMITTERS AT 1/16 DATA RATE # ~j eB 0 +0, 3B fam+C, LOAD,EACHOUTPUT } @& & po =3.3V Veo =3.3V | | | | qj E -25 E 25 a4 = = 1 TRANSMITTER AT 240khps 2 50 2 9 [4 TRANSMITTERS AT 15kbps e > = $0 po 3kot + C, LOADS Vcc =3.3V | 75 15 91 GQ @ 1000 2000 3000 4000 5000 Q 500 1000 1500 2000 0 1000 2000 3000 4000 5000 PS LOAD CAPACITANCE (pF} LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) iN MAX3237 MAX3237 MAX3237 SLEW RATE vs. LOAD CAPACITANCE SUPPLY CURRENT vs. SKEW vs. LOAD CAPACITANCE ol, (MBAUD = Vcc) LOAD CAPACITANCE (MBAUD = GND) (tpus - tex) 70 2 60 70 j 1 5 60 0 60 |. 4 TRANSMITTERS AT 32kbps SLEW, {Mbps < aka + 0, LOADS = 50 SLEW, Mbps} E 50 AUD. 3 -SLEW, 2Mbps 5 40 weeps Vee = 40 sSLEW, 2Mbps | 40 e a 2 AVERAGE; 10 PARTS = 30 > 30 a E 29 20 ; rey 3 1 AT FULL DATA RATE 20 1 TRANSMITTER AT FULL DATA RATE to | A TRANSMITTERS AT 1/16 DATA RATE__| 10 NOR 10 akg2 + CL LOAD EACH OUTPUT tay a Lies lL | Leer , 0 500 1000 1500 2000 0 1000 2000 3000 4000 5000 0 500 1000 1500 2000 2500 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) MAXIMA 2144MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Pin Description PIN MAX3222 NAME FUNCTION MAX3232 | MAX3237 | MAX3241 DIP/SO | SSOP 1 1 13 23 EN Receiver Enable. Active low. 2 2 { 28 28 Cl+ Positive Terminal of Voltage-Doubler Charge-Pump Capacitor 3 3 2 27 27 V+ +5.5V Generated by the Charge Pump 4 4 3 25 24 Ci Negative Terminal of Voltage-Doubler Charge-Pump apacitor 5 5 4 4 1 C24 Positive Terminal of inverting Charge-Pump Capacitor . Negative Terminal of Inverting Charge-Pump 6 6 5 3 2 Ca- Capacitor 7 7 6 4 3 V- -5.5V Generated by the Charge Pump 8,15 } 8,17 7,14 Se ig | 910.91 | TOUT | RS-232 Transmitter Outputs 9, 14 9, 16 8,13 8,9. 11 4-8 R_IN RS-232 Receiver Inputs 10, 13 10, 15 9, 12 18, 20, 21 15-19 R_OUT | TTL/CMOS Receiver Outputs 17, 19, 22, . 11,12 12, 13 10, 11 23. 24 12, 13, 14 TIN TTL/CMOS Transmitter Inputs 16 18 15 2 25 GND Ground 17 19 16 26 26 Vec +3.0V to +5.5V Supply Voltage 18 20 _ 14 22 SHDN Shutdown Control. Active low. _ 11, 14 _ _ _ N.C. No Connection _ 15 _ MBAUD MegaBaud Control Input. Connect to GND for normal ~ ~ * operation; connect to Vcc for 1Mbps transmission rates. Noninverting Complementary Receiver Outputs. ~ 16 20, 21 R_OUTB Always active. 2-142 PAAXLMA3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Detailed Description Dual Charge-Pump Voltage Converter The MAX3222/MAX3232/MAX3237/MAX3241's internal power supply consists of a regulated dual charge pump that provides output voltages of +5.5V (doubling charge pump) and -5.5V (inverting charge pump), regardless of the input voltage (Vcc) over the 3.0V to 5.5V range. The charge pumps operate in a discontinuous mode: if the output voltages are less than 5.5V, the charge pumps are enabled, and if the output voltages exceed 5.5V, the charge pumps are disabled. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies. RS-232 Transmitters The transmitters are inverting level translators that con- vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. The MAX3222/MAX3232/MAX3241 transmitters guaran- tee a 120kbps data rate with worst-case loads of 3kQ in parallel with 1000pF, providing compatibility with PC-to- PC communication software (such as LapLink). Typically, these three devices can operate at data rates of 235kbps. Transmitters can be paralleled to drive multi- ple receivers or mice. LapLink is a trademark of Traveling Software. The MAX3222/MAX3237/MAX3241's output stage is turned off (high impedance) when the device is in shut- down mode. When the power is off, the MAX3222/ MAX3232/MAX3237/MAX3241 permit the outputs to be driven up to #12V. The transmitter inputs do not have pull-up resistors. Connect unused inputs to GND or Vcc. MAX3237 MegaBaud Operation In normal operating mode (MBAUD = GND), the MAX3237 transmitters guarantee a 250kbps data rate with worst-case loads of 3kQ in parallel with 1000pF. This provides compatibility with PC-to-PC communica- tion software, such as Laplink. For higher speed serial communications, the MAX3237 features MegaBaud operation. In MegaBaud operating mode (MBAUD = Vcc), the MAX3237 transmitters guar- antee a 1Mbps data rate with worst-case loads of 3kQ in parallel with 250pF for 3.0V < Vcc < 4.5V. For 5V 210% operation, the MAX3237 transmitters guarantee a 1Mbps data rate into worst-case loads of 3kQ in parallel with 1000pF. Ver " O.ApF Tr Vv Ct * 7 C3 Toc. ALAXILA T oo MAX3222 = fe MAN3232 v EF C2 as MAX3237 ca G2. MAX3241 F Tu din TOUT ~ ov |_| 3 e iB iH i/-|-_- Vec " O.ApF Tt eq Vec Es. C1 C3 Tc. AAAXLM T MAX3222 = ET MAXI292 -E) ca | MAX3237 = 4 MAX3241 +E Tu fin TOUT ~ | 2 a Z * 19 i{ e IH HAF LOSEXUW/LECEXVW/CESEXVWN/ECTEXUW ec } SHON GND 3k 25000F Nee GND 1500 aa L & = * MAX3220/MAX3241 ONLY MINIMUM SLEW-RATE TEST CIRCUIT MAXIMUM SLEW-RATE TEST CIRCUIT Figure 1. Slew-Rate Test Circuits PAAXI MA 2-1433.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Voc Rx PREVIOUS RS-232 PROTECTION DIODE UART Tx GND L SHON = GND o t | 0 TRANSITION + LOGIC @) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER QUTPUT IN SHUTDOWN. Vcc Ax RIOUTB MAX3222/MAX3232/MAX3237/MAX3241 ARAXLAA MAX3237 MAX3241 5k RiQUT Prone _ 100 EN=Vec UART Ix TtiN GND SHDN = GND L fi HH a 1 n \ RIIN < TOUT b) NEW MAX3237/MAX3241: EN SHUTS DOWN RECEIVER OUTPUTS {EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO BART IN SHUTDOWN. B OUTPUTS INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH. Figure 2. Detection of RS-232 Activity when the UART and Interface are Shut Down; Comparison of MAX3237/MAX3241 (b) with Previous Transceivers (a). 2-144 AS-232 Receivers The receivers convert RS-232 signals to CMOS-logic out- put levels. The MAX3222/MAX3237/MAX3241 receivers have inverting three-state outputs. In shutdown, the receivers can be active or inactive (Table 1). The complementary outputs on the MAX3237 (R1OUTB) and the MAX3241 (R1QUTB, R2OUTB) are always active, regardless of the state of EN or SHDN. This allows for Ring Indicator applications without forward biasing other devices connected to the receiver outputs. This is ideal for systems where Vcc is set to OV in shutdown to accommodate peripherals, such as UARTs (Figure 2). MAX3222/MAX3237/MAX3241 Shutdown Mode Supply current falls to less than 1A in shutdown mode (SHDN = fow). When shut down, the device's charge pumps are turned off, V+ is pulled down to Vcc, V- is pulled to ground, and the transmitter outputs are dis- abled (high impedance). The time required to exit shut- down is typically 100ps, as shown in Figure 3. Connect SHDN to Vcc if the shutdown mode is not used. SHDN has no effect on RLOUT or R_OUTB. MAX3222/MAX3237/MAX3241 Enable Control The inverting receiver outputs (R_OUT) are put into a high-impedance state when EN is high. The complemen- tary outputs R1OUTB and R2OUTB are always active, regardless of the state of EN and SHDN (Table 1). EN has no effect on TOUT. Applications Information Capacitor Selection The capacitor type used for C1-C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. The charge pump requires 0.1uF capaci- tors for 3.3V operation. For other supply voltages, refer to Table 2 for required capacitor values. Do not use values smaller than those listed in Table 2. Increasing the capacitor values (e.g., by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power con- sumption. C2, C3, and C4 can be increased without changing C1's value. However, do not increase C1 with- out also increasing the values of C2, C3, and C4, to maintain the proper ratios (C1 to the other capacitors). When using the minimum required capacitor values, make sure the capacitor value does not degrade exces- sively with temperature. If in doubt, use capacitors with a larger nominal value. The capacitors equivalent series resistance (ESR), which usually rises at low tempera- tures, influences the amount of ripple on V+ and V-. MAXLAA3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Table 1. MAX3222/MAX3237/MAX3241 Shutdown and Enable Control Truth Table R_OUTB SHDN EN T_OUT R_OUT | (MAX3237/ MAX3241) 0 0 High-Z Active Active 0 1 High-Z High-Z Active 1 0 Active Active Active 1 1 Active High-Z Active Table 2. Required Minimum Capacitor Values Voc C1 C2, C3, C4 (V) (uF) (BF) MAX3222/MAX3232/MAX3241 3.0 to 3.6 0.1 0.1 45to5.5 0.047 0.33 3.0 to 5.5 0.1 0.47 MAX3237 3.0 to 3.6 0.22 0.22 3.15 to 3.6 0.1 0.1 45 to 5.5 0.047 0.33 3.0 to 5.5 0.22 1.0 svidw Lf n evidiv = beer beeen reed nN S0ps/div Veo =3.3V C1-C420.1pF Figure 3. Transmitter Outputs when Exiting Shutdown or Powering Up MAXIMA Power-Supply Decoupling In most circumstances, a 0.1pF bypass capacitor is adequate. In applications that are sensitive to power- supply noise, decouple Vcc to ground with a capacitor of the same value as charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possibie. Operation Down to 2.7V Transmitter outputs will meet ElIA/TIA-562 levels of +3.7V with supply voltages as low as 2.7V. Transmitter Outputs when Exiing Shutdown Figure 3 shows two transmitter outputs when exiting shutdown mode. As they become active, the two trans- mitter outputs are shown going to opposite RS-232 lev- els (one transmitter input is high, the other is low). Each transmitter is loaded with 3kQ in parallel with 2500pF. The transmitter outouts display no ringing or undesirable transients as they come out of shutdown. Note that the transmitters are enabled only when the magnitude of V- exceeds approximately 3V. Mouse Driveability The MAX3241 has been specifically designed to power serial mice while operating from low-voltage power sup- plies. It has been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3241 successfully drove ail serial mice tested and met their respective current and voltage requirements. Figure 4a shows the transmitter output voltages under increasing load current at 3.0V. Figure 4b shows a typical mouse connection using the MAX3241. LOSEXVW/LECEXVAV/CEZEXVW/ECCEXUWN 2-145MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pjF External Capacitors TRANSMITTER OUTPUT VOLTAGE (V) aoa onwmiraoaanwa ane Q o1 2 3 #4 6 LOAD CURRENT PER TRANSMITTER (mA) 7 Figure 4a. MAX3241 Transmitter Output Voltage vs. Load Current per Transmitter Vcc = 3V 055Ve oar] = = 26 28 a7 i cc Qi 24 ot " pecs TH] o- 'VAXIA Lt COMPUTER SERIAL PORT 1 3 C =, Cet MAX3241 Vv C4 / C2- L 444 THN LIN, Tour] 9 Lf e~ W 13] T2IN Mm T20uT [10 | L he +V Vo ote NK Ta0uT | 11 a ~ 2 . LF Tno 20 | R20UTB = Tx 19 | RIOUT 4 RAN | 4 4 18] Rout, 4 Sk_="R2N | 5 17 | R30uT < 5k pan | 6 T) 16 | Rsout <4 5k ran 7 15 | RSOUT Sk = Ron | 8 Nw 23 EN SHON 22 GND 25 Figure 4b. Mouse Driver Test Circuit 2-146 MAAK3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Voc a O1uF Tt C Voc ct | Plt, Tot T MAXLAA = C2+ MAX3222 Ve oo MAX3232 Le TJ c2 MAX3237 i MAX3247 Fu A mn 2 z > xz c s Ss , v i IKK! cu ov + ak 1000pF Vec SHDN = GND ae * MAX3222/MAX3241 ONLY Figure 5. Loopback Test Circuit High Data Rates The MAX3222/MAX3232/MAX3241 maintain the RS-232 +5.0V minimum transmitter output voltage even at high data rates. Figure 5 shows a transmitter loopback test circuit, Figure 6 shows a loopback test result at 120kbps, and Figure 7 shows the same test at 235kbps. For Figure 6, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 7, a singie transmitter was driven at 235kbps, and ail transmitters were loaded with an RS-232 receiver in parallel with 1000pF. The MAX3237 maintains the RS-232 +5.0V minimum transmitter output voltage at data rates up to 1Mbps. Figure 8 shows a loopback test result at iMbps with MBAUD = Vcc. For Figure 8, all transmitters were loaded with an RS-232 receiver in parallel with 250pF. PAAXIAA THIN SV/div TIOUT 5Vidiv ROUT 5V/div Sus/div Vec = 3.3V Figure 6. MAX3241 Loopback Test Result at 120kbps THIN SVidiv TIOUT SV/div RIOUT 5V/div 2ps/div Vec = 3.3V Figure 7. MAX3241 Loopback Test Result at 235kbps Sf SHeoeeepet [. T_QUT = R_IN ov treet $ + t + BV ee \d LT / 4 5k +250pF Wo fee ES YD rout i i 150pF 200ns/div Vcc = 3.3V Figure 8. MAX3237 Loopback Test Result at 1000kbps (MBAUD = Vcc) 2-147 LPSEXVW/LETEXVW/CECEXVW/ESCEXUWMAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1p:F External Capacitors interconnection with 3V and 5V Logic The MAX3222/MAX3232/MAX3237/MAX3241 can directly interface with various 5V logic families, includ- Table 3. Logic-Family Compatibility with Various Supply Voltages ing ACT and HCT CMOS. See Table 3 for more informa- SYSTEM MAX32__ tion on possible combinations of interconnections. POWER- Vee SUPPLY SUPPLY COMPATIBILITY VOLTAGE VOLTAGE (Vv) (Vv) 33 33 Compatible with all CMOS . , families. 5 5 Compatible with all TTL and CMOS-logic families. Compatible with ACT and 5 33 HCT CMOS, and with TTL. , Incompatible with AC, HC, and CD4000 CMOS. Typical Operating Circuits 43.3V 43.3 7 O.tpF i Li OApE i | 16 = alone Voc 3 = they Voc 2 cith PSL og tL , VA FS1 gg* oF T__4|,,. AAAXLAN Z osue OME T 3b oy TE ope MAN3292 = MAXIMA = 5 ? 4 MAX3232 6 2 | -F ek || C2+ Vv. rh ca bus EI C24 v. 4 OtpF TL] oy. TE our ET SD TE our 124 THIN > TIOUT 45 Re Ls Pe ie TTL/CMOS RS-232 TTL/CMOS RS-232 INPUTS OUTPUTS INPUTS OUTPUTS 11 2N > T20UT | 8 p10] T2N > T20UT | 7 13] RIOUT RING 14 ae f2p Ri0UT RAIN | 13 TILUCMOS 5k RS-232 TTLYCMOS 5k RS-232 OUTPUTS INPUTS OUTPUTS INPUTS 109 R20UT = R2IN| 9 9] R20UT = ran | 8 in 5k 5k =_. | 18 = GND SHON GND Is Is PIN NUMBERS REFER TO DIF/SO PACKAGES. * C9. CAN BE RETURNED TO EITHER Voc OR GROUND. * 03 CAN BE RETURNED TO ETHER Vcc OR GROUND. SEE TABLE 2 FOR CAPACITOR SELECTION 2-148 MAAXIAA3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Typical Operating Circuits (continued) } orp | oe | = O.AuF Vee * 28 Ct+ 2 Our , ve s AAAXUM ' C2 = MAX3237 ve OApF ac L ope Thee. = TIN 24 [> TOUTS .- 23 | T2N T20UT 6 LoGic 22 | T3IN > Ta0uT 7. | RS-232 INPUTS OUTPUTS 19 | THN > T40UT [10 17 | TSIN fe T50UT 112 ~ rr 16 | RIQUTB J 21 RIOUT Rt RINGS R2OUT = RIN} _ | RS-232 Loaic | 22 A INPUTS OUTPUTS B we 1B GOUT fg{__= Ran 11 5k q MBAUD L154 13 JEN 14 GNo SHON 2 * C3 CAN BE RETURNED TO EITHER Voc OR GROUND. 43.3V aR OMe 2 +28 Ct Nec pz otyrte WT Ds og rc anaxim | Lone 1 3 C2+ MAX3241 V- osu sk 04 Tv C2: TE o1ur rm 14 TIIN | > TIOUT 9 ruemos taf 2 > 120UT 110 Une 290 INPUTS OUTPUTS 42 9 T3iN > T30uT 11 L . 21 PRIOUTR 1 20 | R2OUTB < | 19 PRIOUT RIN 4 = Se wag 18. J R2OUT a = _ RAIN IS TILICMOS < 3s QUTPUTS | 47} Ra0UT = RIN | 6 | AS-232 * P INPUTS 5k 5 ReoUT on zT _t5prsouT_ | |v da 5k 2a EN = Ls GND SHON 22 Ts * C3 CAN BE RETURNED TO EITHER Veg OR GROUND. LOSEXVILESCEXVWI/CECEXVW/ECCEXVN PAAMXISA 2-149MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors Pin Configurations (continued) ni] a SHON cre[2| 13] Vcc ve Lg] 8] GND ct-L4] Anaxaaa [17] Tout car[s| MAXG222 ig] RIN ce- [a] iis} RIOUT v- GI ra] NC. T2out [ ria} TaN ie ira) T2IN rout [10] ira] Nc. ssoP Les fa] 28] C+ GNO [2] 27] V4 C2- [a] 26] Veo v- [a] 25] c1- Tout [5] A AXEAA D5) rn rons MAN3237 [23] TaN TaouT [7] 22) TaN rin [a rat] Riout ran [| [20] R20uT vaout (i0] ra} Tats rain [11] 18] aout tsout [12] fiz] 151N EN 113) 6] ATOUTB SHON 15] weauo SSOP 7 cu [i] 6] Voc ve [2| 15] GND o1- [3] Anarciaa [il tout ca (4) Max3232s [3] niin ca- [5 | iia] Riut v- [6] 7} Tn rout [7] [10] T2IN naw [a 9] R20uT DIP/SO e ca [4] [28] t+ c2- [2 27] vs y- 3 26] Vee niin [4 [25] GND ca] man rain [6 [23] EN RAIN : 22] SHON REIN (8 [21] R1OUTB Trout [9] [20] R2OUTB T20uT [19] ral Riout Ta0uT [14] 1a] ROUT Tain [12] 7] ra0uT ran [13 6} Reaut TIN 15] ASQUT so/SsoP 2-150 PRAMAXLMA3-OV to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1pF External Capacitors _Ordering Information (continued) PART TEMP. RANGE PIN-PACKAGE MAX3222C/D OC to +70C Dice* MAX3222EPN -40C to +85C 18 Plastic DIP MAX3222EWN -40C to +85C 18 SO MAX3222EAP -40C to +85C 20 SSOP MAX3232CPE oC to +70C 16 Plastic DIP MAX3232CSE 0C to +70C 16 Narrow SO MAX3232CWE 0C to +70C 16 Wide SO MAX3232EPE -40C to +85C 16 Plastic DIP MAX3232ESE -40C to +85C 16 Narrow SO MAX3232EWE -40C to +85C 16 Wide SO MAX3237CAI OC to +70C 28 SSOP MAX3237EAI -40C to +85C 28 SSOP MAX3241CW! OC to +70C 28 SO MAX3241CAl QC to +70C 28 SSOP MAX3241EWI -40C to +85C 28 SO MAX3241EAI ~40C to +85C 28 SSOP * Dice are tested at Ta = +25C, DC parameters only. 3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim GUAR- SURELY No. OF Reccivens | ANTEED | EIA/ PART TRANSMITTERS/ DATA TIA-232 FEATURES VOLTAGE RECEIVERS ACTIVE IN RATE OR 562 (Vv) SHUTDOWN (kbps) MAX212 3.0 to 3.6 3/5 5 120 232 Drives mice Operates directly from batteries MAX218 1.8 to 4.25 2/2 2 120 232 without a voltage regulator MAX562 2.7 to .25 o/s 5 230 562 Wide supply range MAX563 3.0 to 3.6 2/2 2 230 562 0.1pF capacitors AutoShutdown, complementary MAX3212 2.7 to 3.6 3/5 5 235 232 receiver, drives mice, transient detection MAX3222 3.0 to 5.5 2/2 2 120 232 0.1pF capacitors MAX3223 3.0 to 6.5 2/2 2 120 232 0.1pF capacitors, AutoShutdown MAX3232 3.0 to 5.5 2/2 N/A 120 232 0.1pF capacitors 0.1pF capacitors, 1 complemen- MAX3237 3.0 to 5.5 5/3 3 250/1000 232 tary receiver, MegaBaud operation MAX3241 3.010 5.5 3/5 5 120 232 | 0.1HF capacitors, 2 complemen- UNOS. tary receivers, drives mice 0.1pF capacitors, AutoShutdown, MAX3243 3.0 to 5.5 3/5 1 120 232 complementary receiver, drives mice MAAXLIA 2-151 LOCEXVW/LECEXVW/CESCEXVW/ESTEXVNMAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1p:F External Capacitors Chip Topography Chip Information MAX3222 _ sam PART TRANSISTOR COUNT MAX3222 339 eno MAX3232 339 c1- MAX3237 1212 Trout MAX3241 894 8.427 (3.228enm) RIN fe R1OUT Poe a T20UT AZIN RZOUT TZIN THIN + 3.087", (2.28mm) TRANSISTOR COUNT: 339 SUBSTRATE CONNECTED TO GND 2-152 SPAAXAAA