19-0273; Rev 7; 1/07 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors __Next Generation Device Features The MAX3222/MAX3232/MAX3237/MAX3241 transceivers have a proprietary low-dropout transmitter output 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 0.1F external chargepump 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 MegaBaudTM operating mode, while maintaining RS-232 output levels. For Smaller Packaging: MAX3228E/MAX3229E: +2.5V to +5.5V RS-232 Transceivers in UCSPTM For Integrated ESD Protection: MAX3222E/MAX3232E/MAX3237E/MAX3241E*/ MAX3246E: 15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V, Up to 1Mbps, True RS-232 Transceivers For Low-Voltage or Data Cable Applications: MAX3380E/MAX3381E: +2.35V to +5.5V, 1A, 2Tx/2Rx RS-232 Transceivers with 15kV ESD-Protected I/O and Logic Pins 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 1A supply current. 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 1A supply current. Receivers R1 (MAX3237/MAX3241) and R2 (MAX3241) have extra outputs in addition to their standard outputs. These extra outputs are always active, allowing external devices such as a modem to be monitored without forward biasing the protection diodes in circuitry that may have VCC completely removed. The MAX3222, MAX3232, and MAX3241 are available in space-saving TSSOP and SSOP packages. _______________Ordering Information PART TEMP RANGE PIN-PACKAGE PKG CODE MAX3222CUP+ 0C to +70C 20 TSSOP U20+2 MAX3222CAP+ 0C to +70C 20 SSOP A20+1 MAX3222CWN+ 0C to +70C 18 SO W18+1 MAX3222CPN+ 0C to +70C 18 Plastic Dip P18+5 +Denotes lead-free package. Ordering Information continued at end of data sheet. _________________Pin Configurations TOP VIEW + EN 1 ________________________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. 18 SHDN 17 VCC C1+ 2 V+ 3 16 GND C1- 4 MAX3222 15 T1OUT C2+ 5 MAX3222 14 R1IN C2- 6 13 R1OUT V- 7 12 T1IN T2OUT 8 11 T2IN R2IN 9 10 R2OUT DIP/SO Pin Configurations continued at end of data sheet. MegaBaud and UCSP are trademarks of Maxim Integrated Products, Inc. *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. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 MAX3222/MAX3232/MAX3237/MAX3241* ________________General Description MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors ABSOLUTE MAXIMUM RATINGS VCC ...........................................................................-0.3V to +6V V+ (Note 1) ...............................................................-0.3V to +7V V- (Note 1) ................................................................+0.3V to -7V V+ + V- (Note 1)...................................................................+13V Input Voltages T_IN, SHDN, EN ...................................................-0.3V to +6V MBAUD...................................................-0.3V to (VCC + 0.3V) R_IN .................................................................................25V Output Voltages T_OUT...........................................................................13.2V R_OUT ....................................................-0.3V to (VCC + 0.3V) Short-Circuit Duration T_OUT ....................................................................Continuous Continuous Power Dissipation (TA = +70C) 16-Pin TSSOP (derate 6.7mW/C above +70C).............533mW 16-Pin Narrow SO (derate 8.70mW/C above +70C) ....696mW 16-Pin Wide SO (derate 9.52mW/C above +70C)........762mW 16-Pin Plastic DIP (derate 10.53mW/C above +70C)...842mW 18-Pin SO (derate 9.52mW/C above +70C)..............762mW 18-Pin Plastic DIP (derate 11.11mW/C above +70C) ..889mW 20-Pin SSOP (derate 7.00mW/C above +70C) .........559mW 20-Pin TSSOP (derate 8.0mW/C above +70C).............640mW 28-Pin TSSOP (derate 8.7mW/C above +70C).............696mW 28-Pin SSOP (derate 9.52mW/C above +70C) .........762mW 28-Pin SO (derate 12.50mW/C above +70C) .....................1W Operating Temperature Ranges MAX32_ _C_ _.....................................................0C to +70C MAX32_ _E_ _ .................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+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 affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +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 UNITS MAX3222/MAX3232/ MAX3241 0.3 1.0 MAX3237 0.5 2.0 1.0 10 A 0.8 V DC CHARACTERISTICS VCC Power-Supply Current No load, VCC = 3.3V or 5.0V, TA = +25C Shutdown Supply Current SHDN = GND, TA = +25C mA LOGIC INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low (Note 3) T_IN, EN, SHDN, MBAUD Input Logic Threshold High (Note 3) VCC = 3.3V 2.0 VCC = 5.0V 2.4 Input Leakage Current T_IN, EN, SHDN, MBAUD 0.01 1.0 A Output Leakage Current Receivers disabled 0.05 10 A Output Voltage Low IOUT = 1.6mA 0.4 V Output Voltage High IOUT = -1.0mA VCC - 0.6 V VCC - 0.1 V RECEIVER INPUTS Input Voltage Range -25 Input Threshold Low TA = +25C Input Threshold High TA = +25C VCC = 5.0V 2 25 VCC = 3.3V 0.6 1.2 VCC = 5.0V 0.8 1.5 V VCC = 3.3V 1.5 2.4 VCC = 5.0V 1.8 2.4 _______________________________________________________________________________________ V V 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors MAX3222/MAX3232/MAX3237/MAX3241 ELECTRICAL CHARACTERISTICS (continued) (VCC = +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 Input Hysteresis TYP MAX UNITS 7 k 0.3 Input Resistance TA = +25C 3 5 V TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3k to ground 5.0 5.4 V Output Resistance VCC = V+ = V- = 0V, VOUT = 2V 300 10M Output Short-Circuit Current Output Leakage Current 35 VOUT = 12V, VCC = 0V or 3V to 5.5V, transmitters disabled 60 mA 25 A MOUSE DRIVEABILITY (MAX3241) Transmitter Output Voltage T1IN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3k to GND, T1OUT and T2OUT loaded with 2.5mA each 5.0 V TIMING CHARACTERISTICS--MAX3222/MAX3232/MAX3241 (VCC = +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 Maximum Data Rate CONDITIONS RL = 3k, CL = 1000pF, one transmitter switching MIN TYP 120 235 tPHL 0.3 tPLH 0.3 MAX UNITS kbps Receiver Propagation Delay R_IN to R_OUT, CL = 150pF Receiver Output Enable Time Normal operation 200 ns Receiver Output Disable Time Normal operation 200 ns 300 ns 300 ns | tPHL - tPLH | | tPHL - tPLH | Transmitter Skew Receiver Skew Transition-Region Slew Rate VCC = 3.3V, RL = 3k to 7k, +3V to -3V or -3V to +3V, TA = +25C, one transmitter switching s CL = 150pF to 1000pF 6 30 CL = 150pF to 2500pF 4 30 V/s _______________________________________________________________________________________ 3 TIMING CHARACTERISTICS--MAX3237 (VCC = +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 Maximum Data Rate MIN RL = 3k, CL = 1000pF, one transmitter switching, MBAUD = GND 250 VCC = 3.0V to 4.5V, RL = 3k, CL = 250pF, one transmitter switching, MBAUD = VCC 1000 VCC = 4.5V to 5.5V, RL = 3k, CL = 1000pF, one transmitter switching, MBAUD = VCC 1000 TYP MAX UNITS kbps tPHL 0.15 tPLH 0.15 Receiver Propagation Delay R_IN to R_OUT, CL = 150pF Receiver Output Enable Time Normal operation 200 ns Receiver Output Disable Time Normal operation 200 ns 100 ns 25 ns 50 ns | tPHL - tPLH |, MBAUD = GND | tPHL - tPLH |, MBAUD = VCC | tPHL - tPLH | Transmitter Skew Receiver Skew VCC = 3.3V, RL = 3 to 7k, +3V to -3V or -3V to +3V, TA = +25C Transition-Region Slew Rate CL = 150pF to 1000pF s MBAUD = GND 6 30 MBAUD = VCC 24 150 4 30 CL = 150pF to 2500pF, MBAUD = GND V/s Note 2: MAX3222/MAX3232/MAX3241: C1-C4 = 0.1F tested at 3.3V 10%; C1 = 0.047F, C2-C4 = 0.33F tested at 5.0V 10%. MAX3237: C1-C4 = 0.1F tested at 3.3V 5%; C1-C4 = 0.22F tested at 3.3V 10%; C1 = 0.047F, C2-C4 = 0.33F tested at 5.0V 10%. Note 3: Transmitter input hysteresis is typically 250mV. __________________________________________Typical Operating Characteristics (VCC = +3.3V, 235kbps data rate, 0.1F capacitors, all transmitters loaded with 3k, TA = +25C, unless otherwise noted.) 40 MAX3222-03 FOR DATA RATES UP TO 235kbps 20 4 3 35 235kbps 2 1 0 -1 -2 -3 SUPPLY CURRENT (mA) SLEW RATE (V/s) 18 16 14 -SLEW 12 10 +SLEW 8 6 -4 2000 3000 4000 LOAD CAPACITANCE (pF) 120kbps 20 15 20kbps 5 0 1000 25 10 2 -6 0 30 4 VOUT- -5 4 22 MAX3222-02 VOUT+ MAX3222-01 6 5 MAX3222/MAX3232 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA MAX3222/MAX3232 SLEW RATE vs. LOAD CAPACITANCE MAX3222/MAX3232 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE TRANSMITTER OUTPUT VOLTAGE (V) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors 5000 0 150 1000 2000 3000 4000 LOAD CAPACITANCE (pF) 5000 0 1000 2000 3000 4000 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 5000 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors MAX3241 SLEW RATE vs. LOAD CAPACITANCE MAX3222-05 VOUT+ 22 5.0 1 TRANSMITTER AT 235kbps 2 TRANSMITTERS AT 30kbps 0 -2.5 18 -SLEW 16 14 12 +SLEW 10 VOUT- -5.0 8 4 0 1000 2000 3000 4000 1000 2000 3000 4000 30 120kbps 25 20 20kbps 15 5 0 5000 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) LOAD CAPACITANCE (pF) MAX3237 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = GND) MAX3237 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = VCC) MAX3237 SLEW RATE vs. LOAD CAPACITANCE (MBAUD = GND) 1 TRANSMITTER AT 240kbps 4 TRANSMITTERS AT 15kbps 3k + CL LOADS VCC = 3.3V 0 -2.5 -5.0 5.0 2Mbps MAX3222-09 MAX3222-08 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3k + CL LOAD, EACH OUTPUT VCC = 3.3V -2.5 -SLEW +SLEW 8 6 4 1 TRANSMITTER AT 240kbps 4 TRANSMITTERS AT 15kbps 3k + CL LOADS VCC = 3.3V 1.5Mbps 2Mbps -5.0 10 1.5Mbps 2.5 0 12 2 1Mbps 0 -7.5 1000 2000 3000 4000 0 5000 MAX3222-10 60 50 SUPPLY CURRENT (mA) 40 30 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3k + CL LOAD EACH OUTPUT VCC = 3.3V 0 500 1000 1500 LOAD CAPACITANCE (pF) 70 3000 4000 1 TRANSMITTER AT 512kbps 4 TRANSMITTERS AT 32kbps 3k + CL LOADS VCC = 3.3V MBAUD = VCC 60 50 120kbps 5000 MAX 40 30 20kbps AVERAGE; 10 PARTS 30 20 20 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3k + CL LOADS VCC = 3.3V 10 10 MIN 0 0 2000 2000 MAX3237 SKEW vs. LOAD CAPACITANCE (tPLH - tPHL) 240kbps 40 1000 LOAD CAPACITANCE (pF) MAX3237 SUPPLY CURRENT vs. LOAD CAPACITANCE (MBAUD = GND) -SLEW, 1Mbps +SLEW, 1Mbps -SLEW, 2Mbps +SLEW, 2Mbps 0 2000 MAX3237 SLEW RATE vs. LOAD CAPACITANCE (MBAUD = VCC) 50 0 1500 LOAD CAPACITANCE (pF) 60 10 1000 LOAD CAPACITANCE (pF) 70 20 500 MAX3222-11 0 SKEW (ns) -7.5 MAX3222-12 2.5 1Mbps SLEW RATE (V/s) 5.0 7.5 TRANSMITTER OUTPUT VOLTAGE (V) MAX3222-07 7.5 TRANSMITTER OUTPUT VOLTAGE (V) 0 5000 35 10 ALL OUTPUTS LOADED WITH 3k +CL 0.1F CHARGE-PUMP CAPACITORS FOR ALL DATA RATES UP TO 235kbps 6 235kbps 40 SUPPLY CURRENT (mA) 2.5 -7.5 SLEW RATE (V/s) 45 20 SLEW RATE (V/s) TRANSMITTER OUTPUT VOLTAGE (V) 24 MAX3222-04 7.5 MAX3241 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA MAX3222-06 MAX3241 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE 0 1000 2000 3000 4000 LOAD CAPACITANCE (pF) 5000 0 500 1000 1500 2000 2500 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 5 MAX3222/MAX3232/MAX3237/MAX3241 _____________________________Typical Operating Characteristics (continued) (VCC = +3.3V, 235kbps data rate, 0.1F capacitors, all transmitters loaded with 3k, TA = +25C, unless otherwise noted.) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors ______________________________________________________________Pin Description PIN NAME MAX3222 6 MAX3232 MAX3237 MAX3241 FUNCTION DIP/SO SSOP 1 1 -- 13 23 EN 2 2 1 28 28 C1+ 3 3 2 27 27 V+ +5.5V Generated by the Charge Pump 4 4 3 25 24 C1- Negative Terminal of Voltage-Doubler Charge-Pump Capacitor 5 5 4 1 1 C2+ Positive Terminal of Inverting Charge-Pump Capacitor 6 6 5 3 2 C2- Negative Terminal of Inverting Charge-Pump Capacitor 7 7 6 4 3 V- 8, 15 8, 17 7, 14 5, 6, 7, 10, 12 9, 10, 11 T_OUT 9, 14 9, 16 8, 13 8, 9, 11 4-8 R_IN 10, 13 10, 15 9, 12 18, 20, 21 15-19 R_OUT TTL/CMOS Receiver Outputs 11, 12 12, 13 10, 11 17, 19, 22, 23, 24 12, 13, 14 T_IN TTL/CMOS Transmitter Inputs 16 18 15 2 25 GND Ground 17 19 16 26 26 VCC +3.0V to +5.5V Supply Voltage 18 20 -- 14 22 SHDN Shutdown Control. Active low. -- 11, 14 -- -- -- N.C. -- -- -- 15 -- MBAUD MegaBaud Control Input. Connect to GND for normal operation; connect to VCC for 1Mbps transmission rates. -- -- -- 16 20, 21 R_OUTB Noninverting Complementary Receiver Outputs. Always active. Receiver Enable. Active low. Positive Terminal of Voltage-Doubler Charge-Pump Capacitor -5.5V Generated by the Charge Pump RS-232 Transmitter Outputs RS-232 Receiver Inputs No Connection _______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors 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 convert CMOS-logic levels to 5.0V EIA/TIA-232 levels. The MAX3222/MAX3232/MAX3241 transmitters guarantee a 120kbps data rate with worst-case loads of 3k in parallel with 1000pF, providing compatibility with PC-toPC communication software (such as LapLinkTM). Typically, these three devices can operate at data rates of 235kbps. Transmitters can be paralleled to drive multiple receivers or mice. The MAX3222/MAX3237/MAX3241's output stage is turned off (high impedance) when the device is in shutdown 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 pullup 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 3k in parallel with 1000pF. This provides compatibility with PC-to-PC communication software, such as LapLink. For higher speed serial communications, the MAX3237 features MegaBaud operation. In MegaBaud operating mode (MBAUD = VCC), the MAX3237 transmitters guarantee a 1Mbps data rate with worst-case loads of 3k in parallel with 250pF for 3.0V < VCC < 4.5V. For 5V 10% operation, the MAX3237 transmitters guarantee a 1Mbps data rate into worst-case loads of 3k in parallel with 1000pF. LapLink is a trademark of Traveling Software, Inc. VCC VCC 0.1F C1+ 0.1F VCC C1+ V+ C1 C1- C2 C2- MAX3222 MAX3232 MAX3237 MAX3241 C2+ VC2 C4 C2T_ OUT 0V 5k GND VC4 T_ OUT R_ IN R_ OUT EN* SHDN* MAX3222 MAX3232 MAX3237 MAX3241 T_ IN R_ IN R_ OUT VCC C3 C1- T_ IN 0V V+ C1 C3 C2+ VCC 3k 2500pF VCC EN* 5k SHDN* GND 7k 150pF *MAX3222/MAX3237/MAX3241 ONLY MINIMUM SLEW-RATE TEST CIRCUIT MAXIMUM SLEW-RATE TEST CIRCUIT Figure 1. Slew-Rate Test Circuits _______________________________________________________________________________________ 7 MAX3222/MAX3232/MAX3237/MAX3241 _______________Detailed Description 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors MAX3222/MAX3232/MAX3237/MAX3241 RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic output 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 (R1OUTB, 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 V CC is set to 0V in shutdown to accommodate peripherals, such as UARTs (Figure 2). VCC PREVIOUS RS-232 VCC Rx PROTECTION DIODE 5k MAX3222/MAX3237/MAX3241 Shutdown Mode UART Tx GND Supply current falls to less than 1A in shutdown mode (SHDN = low). 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 disabled (high impedance). The time required to exit shutdown is typically 100s, as shown in Figure 3. Connect SHDN to VCC if the shutdown mode is not used. SHDN has no effect on R_OUT or R_OUTB. SHDN = GND a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN. MAX3222/MAX3237/MAX3241 Enable Control VCC TO P The inverting receiver outputs (R_OUT) are put into a high-impedance state when EN is high. The complementary outputs R1OUTB and R2OUTB are always active, regardless of the state of EN and SHDN (Table 1). EN has no effect on T_OUT. LOGIC TRANSITION DETECTOR MAX3237 MAX3241 __________Applications Information R1OUTB Capacitor Selection VCC Rx PROTECTION DIODE EN = VCC UART Tx GND R1IN R1OUT T1IN 5k T1OUT SHDN = GND b) NEW MAX3237/MAX3241: EN SHUTS DOWN RECEIVER OUTPUTS (EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO UART 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). 8 The capacitor type used for C1-C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. The charge pump requires 0.1F capacitors for 3.3V operation. For other supply voltages, refer to Table 2 for required capacitor values. Do not use values lower 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 consumption. C2, C3, and C4 can be increased without changing C1's value. However, do not increase C1 without 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 excessively with temperature. If in doubt, use capacitors with a higher nominal value. The capacitor's equivalent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and V-. _______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors R_OUT R_OUTB (MAX3237/ MAX3241) High-Z Active Active Operation Down to 2.7V High-Z High-Z Active Active Active Active High-Z Active Active Transmitter outputs will meet EIA/TIA-562 levels of 3.7V with supply voltages as low as 2.7V. SHDN EN T_OUT 0 0 0 1 1 1 0 1 Table 2. Required Minimum Capacitor Values VCC (V) Power-Supply Decoupling In most circumstances, a 0.1F bypass capacitor is adequate. In applications that are sensitive to powersupply 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 possible. C1 (F) C2, C3, C4 (F) MAX3222/MAX3232/MAX3241 3.0 to 3.6 0.1 0.1 4.5 to 5.5 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 4.5 to 5.5 0.047 0.33 3.0 to 5.5 0.22 1.0 5V/div Transmitter Outputs when Exiting Shutdown Figure 3 shows two transmitter outputs when exiting shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232 levels (one transmitter input is high, the other is low). Each transmitter is loaded with 3k in parallel with 2500pF. The transmitter outputs 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 supplies. It has been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3241 successfully drove all 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. T2 2V/div T1 50s/div VCC = 3.3V C1-C4 = 0.1F Figure 3. Transmitter Outputs when Exiting Shutdown or Powering Up _______________________________________________________________________________________ 9 MAX3222/MAX3232/MAX3237/MAX3241 Table 1. MAX3222/MAX3237/MAX3241 Shutdown and Enable Control Truth Table MAX3222-04 6 5 TRANSMITTER OUTPUT VOLTAGE (V) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors 4 3 VOUT+ VCC = 3.0V 2 1 T1 0 -1 T2 VOUT+ -2 -3 VCC VOUT- T3 VOUT- -4 -5 -6 0 1 2 3 4 5 6 7 LOAD CURRENT PER TRANSMITTER (mA) Figure 4a. MAX3241 Transmitter Output Voltage vs. Load Current per Transmitter VCC = 3V to 5.5V 28 C1 C2 C1+ 24 C1- 1 C2+ 2 0.1F 26 VCC V+ 27 C3 COMPUTER SERIAL PORT MAX3241 V- 3 C4 14 C2T1IN T1OUT 9 13 T2IN T2OUT 10 12 T3IN T3OUT 11 21 R1OUTB 20 R2OUTB 19 R1OUT 18 R2OUT 17 +V +V VCC -V GND R1IN 4 5k R2IN 5 R3OUT 5k R3IN 6 16 R4OUT 5k R4IN 7 15 R5OUT 23 EN Tx MOUSE 5k R5IN 8 SHDN 22 5k GND 25 Figure 4b. Mouse Driver Test Circuit 10 ______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors T1IN 5V/div T1OUT 5V/div R1OUT 5V/div MAX3222/MAX3232/MAX3237/MAX3241 VCC 0.1F VCC C1+ V+ C3 C1 C1- MAX3222 MAX3232 MAX3237 MAX3241 C2+ C2 C2- VC4 5s/div VCC = 3.3V T_ OUT T_ IN Figure 6. MAX3241 Loopback Test Result at 120kbps R_ IN R_ OUT 0V VCC EN* 5k SHDN* 1000pF T1IN 5V/div T1OUT 5V/div R1OUT 5V/div GND *MAX3222/MAX3237/MAX3241 ONLY Figure 5. Loopback Test Circuit 2s/div VCC = 3.3V 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 single transmitter was driven at 235kbps, and all 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 1Mbps with MBAUD = V CC . For Figure 8, all transmitters were loaded with an RS-232 receiver in parallel with 250pF. Figure 7. MAX3241 Loopback Test Result at 235kbps +5V T_IN 0V +5V T_OUT = R_IN 5k + 250pF 0V -5V +5V R_OUT 150pF 0V VCC = 3.3V 200ns/div Figure 8. MAX3237 Loopback Test Result at 1000kbps (MBAUD = VCC) ______________________________________________________________________________________ 11 MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors Interconnection with 3V and 5V Logic The MAX3222/MAX3232/MAX3237/MAX3241 can directly interface with various 5V logic families, including ACT and HCT CMOS. See Table 3 for more information on possible combinations of interconnections. Table 3. Logic-Family Compatibility with Various Supply Voltages SYSTEM POWERSUPPLY VOLTAGE (V) MAX32_ _ VCC SUPPLY VOLTAGE (V) 3.3 3.3 Compatible with all CMOS families. 5 5 Compatible with all TTL and CMOS-logic families. 3.3 Compatible with ACT and HCT CMOS, and with TTL. Incompatible with AC, HC, and CD4000 CMOS. 5 COMPATIBILITY __________________________________________________Typical Operating Circuits +3.3V +3.3V 17 0.1F C1 0.1F 2 C1+ 4 5 C2 0.1F 6 V+ 3 C3* 0.1F C1- MAX3222 C2+ V- 0.1F 0.1F T1OUT 15 10 R2OUT C2+ MAX3232 SHDN R1IN 13 5k 9 R2OUT R2IN 8 18 GND 15 * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. C4 0.1F T2OUT 7 5k PIN NUMBERS REFER TO DIP/SO PACKAGES. * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. SEE TABLE 2 FOR CAPACITOR SELECTION 12 6 RS-232 OUTPUTS 5k GND 16 V- T1OUT 14 TTL/CMOS OUTPUTS R2IN 9 EN C3* 0.1F C2- 12 R1OUT RS-232 INPUTS 5k 2 C1- 10 T2IN R1IN 14 TTL/CMOS OUTPUTS V+ TTL/CMOS INPUTS T2OUT 8 13 R1OUT 5 VCC 11 T1IN RS-232 OUTPUTS 11 T2IN 3 4 C4 0.1F TTL/CMOS INPUTS 1 1 C1+ 7 C2- 12 T1IN 16 0.1F VCC ______________________________________________________________________________________ RS-232 INPUTS 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors 0.1F +3.3V 26 28 C1+ 0.1F VCC 27 28 C1+ V+ 0.1F 1 3 C2+ 23 T2IN LOGIC INPUTS 22 T3IN C3* 0.1F MAX3237 V- 4 1 0.1F 0.1F T1 T2 T3 T1OUT 5 T2OUT 6 T3OUT 7 TTL/CMOS INPUTS RS-232 OUTPUTS 2 C2+ MAX3241 V- 3 C4 0.1F C2- 14 T1IN T1OUT 9 13 T2IN T2OUT 10 12 T3IN T3OUT 11 RS-232 OUTPUTS 21 R1OUTB 19 T4IN T4 T4OUT 10 20 R2OUTB 17 T5IN T5 T5OUT 12 19 R1OUT R1IN 4 16 R1OUTB 5k R2IN 18 R2OUT 21 R1OUT 20 R2OUT 5 R1IN 8 R1 TTL/CMOS OUTPUTS 5k LOGIC OUTPUTS 27 V+ 24 C1- C2- 24 T1IN VCC 0.1F 25 C10.1F 26 0.1F R2IN R2 9 RS-232 INPUTS 5k 17 R3OUT R3IN 6 RS-232 INPUTS 5k 5k 18 R3OUT R3IN 11 R3 16 R4OUT R4IN 7 5k 5k 15 R5OUT MBAUD 13 EN GND SHDN R5IN 8 15 14 2 * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. 5k 23 EN GND SHDN 22 25 * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. ______________________________________________________________________________________ 13 MAX3222/MAX3232/MAX3237/MAX3241 _____________________________________Typical Operating Circuits (continued) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors _____________________________________________Pin Configurations (continued) TOP VIEW + EN 1 20 SHDN C1+ 2 19 VCC C1+ 1 V+ 3 18 GND V+ 2 C1- 4 MAX3222 C2+ 5 C2- 6 17 T1OUT C1- 3 16 R1IN C2+ 4 15 R1OUT C2- 5 + 16 VCC 15 GND 14 T1OUT MAX3232 13 R1IN 12 R1OUT V- 7 14 N.C. V- 6 11 T1IN T2OUT 8 13 T1IN T2OUT 7 10 T2IN R2IN 9 12 T2IN R2IN 8 R2OUT 10 11 N.C. 9 R2OUT DIP/SO/SSOP/TSSOP SSOP/TSSOP + + C2+ 1 28 C1+ C2+ 1 28 C1+ GND 2 27 V+ C2- 2 27 V+ C2- 3 26 VCC V- 3 26 VCC V- 4 25 C1- R1IN 4 25 GND T1OUT 5 24 T1IN R2IN 5 T2OUT 6 23 T2IN R3IN 6 23 EN T3OUT 7 22 T3IN R4IN 7 22 SHDN R1IN 8 21 R1OUT R5IN 8 21 R1OUTB R2IN 9 20 R2OUT T1OUT 9 20 R2OUTB 19 T4IN T2OUT 10 19 R1OUT 18 R3OUT T3OUT 11 18 R2OUT 17 T5IN T3IN 12 17 R3OUT EN 13 16 R1OUTB T2IN 13 16 R4OUT SHDN 14 15 MBAUD T1IN 14 15 R5OUT MAX3237 T4OUT 10 R3IN 11 T5OUT 12 SSOP 14 MAX3241 24 C1- SO/SSOP/TSSOP ______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors PART TEMP RANGE MAX3222EUP+ -40C to +85C PIN-PACKAGE PKG CODE 20 TSSOP U20+2 MAX3232EWE+ -40C to +85C PART TEMP RANGE PIN-PACKAGE PKG CODE 16 Wide SO W16+1 MAX3222EAP+ -40C to +85C 20 SSOP A20+1 MAX3232EPE+ -40C to +85C 16 Plastic DIP P16+1 MAX3222EWN+ -40C to +85C 18 SO W18+1 MAX3232CAE+ 0C to +70C 16 SSOP A28+2 MAX3222EPN+ -40C to +85C 18 Plastic Dip P18+5 MAX3237CAI+ 0C to +70C 28 SSOP A28+1 A28+1 MAX3222C/D 0C to +70C Dice* -- MAX3237ENI+ -40C to +85C 28 SSOP MAX3232CUE+ 0C to +70C 16 TSSOP U16+1 MAX3241CAI+ 0C to +70C 28 SSOP A28+1 MAX3232CSE+ 0C to +70C 16 Narrow SO S16+1 MAX3241CWI+ 0C to +70C 28 SO W28+6 U28+2 MAX3232CWE+ 0C to +70C 16 Wide SO W16+1 MAX3241EUI+ -40C to +85C 28 TSSOP MAX3232CPE+ 0C to +70C 16 Plastic DIP P16+1 MAX3241EAI+ -40C to +85C 28 SSOP A28+1 MAX3232EUE+ -40C to +85C 16 TSSOP U16+1 MAX3241EWI+ -40C to +85C 28 SO W28+6 MAX3232ESE+ -40C to +85C 16 Narrow SO S16+5 *Dice are tested at TA = +25C, DC parameters only. +Denotes lead-free package. ______3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim PART POWERSUPPLY VOLTAGE (V) No. OF TRANSMITTERS/ RECEIVERS No. OF RECEIVERS ACTIVE IN SHUTDOWN GUARANTEED DATA RATE (kbps) EIA/ TIA-232 OR 562 MAX212 3.0 to 3.6 3/5 5 120 232 Drives mice MAX218 1.8 to 4.25 2/2 2 120 232 Operates directly from batteries without a voltage regulator MAX562 MAX563 2.7 to 5.25 3.0 to 3.6 3/5 2/2 5 2 230 230 562 562 MAX3212 2.7 to 3.6 3/5 5 235 232 MAX3222 3.0 to 5.5 2/2 2 120 232 0.1F capacitors MAX3223 MAX3232 3.0 to 5.5 3.0 to 5.5 2/2 2/2 2 N/A 120 120 232 232 0.1F capacitors, AutoShutdown 0.1F capacitors MAX3237 3.0 to 5.5 5/3 3 250/1000 232 0.1F capacitors, 1 complementary receiver, MegaBaud operation MAX3241 3.0 to 5.5 3/5 5 120 232 0.1F capacitors, 2 complementary receivers, drives mice MAX3243 3.0 to 5.5 3/5 1 120 232 0.1F capacitors, AutoShutdown, complementary receiver, drives mice FEATURES Wide supply range 0.1F capacitors AutoShutdown, complementary receiver, drives mice, transient detection ______________________________________________________________________________________ 15 MAX3222/MAX3232/MAX3237/MAX3241 Ordering Information (continued) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors ___________________Chip Topography ___________________Chip Information MAX3222 V+ C1+ EN SHDN V CC GND C1- PART TRANSISTOR COUNT MAX3222 339 MAX3232 339 MAX3237 1212 MAX3241 894 C2+ T1OUT 0.127" (3.225mm) C2- R1IN VR1OUT T2OUT R2IN R2OUT T2IN T1IN 0.087" (2.209mm) TRANSISTOR COUNT: 339 SUBSTRATE CONNECTED TO GND 16 ______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1F External Capacitors TSSOP4.40mm.EPS Revision History Pages changed at Rev 7: 1, 15, 16, 17 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17 (c) 2007 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX3222/MAX3232/MAX3237/MAX3241 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)