19-0273; Rev 5; 3/99 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors ____________________________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 0.1µF 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 MegaBaud™ operating mode, while maintaining RS-232 output levels. ♦ Low Supply Current: 300µA (MAX3222/MAX3232/MAX3241) 500µA (MAX3237) ♦ Guaranteed Data Rate: 120kbps (MAX3222/MAX3232/MAX3241) 250kbps (MAX3237—Normal Operation) 1Mbps (MAX3237—MegaBaud Operation) ♦ 1µA 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/µs (MAX3222/MAX3232/MAX3237/MAX3241) 24V/µs (MAX3237—MegaBaud Operation) The MAX3222/MAX3232 have 2 receivers and 2 drivers. The MAX3222 features a 1µA 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 1µA 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 1µA 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, MAX3237, and MAX3241 are available in space-saving TSSOP and 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. ______________Ordering Information PART MAX3222CUP MAX3222CAP MAX3222CWN TEMP. RANGE 0°C to +70°C 0°C to +70°C 0°C to +70°C MAX3222CPN 0°C to +70°C PIN-PACKAGE 20 TSSOP 20 SSOP 18 SO 18 Plastic DIP Ordering Information continued at end of data sheet. _________________Pin Configurations TOP VIEW EN 1 18 SHDN C1+ 2 17 VCC V+ 3 16 GND 15 T1OUT C1- 4 C2+ 5 C2- 6 MAX3222 14 R1IN 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 is a trademark of Maxim Integrated Products. *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 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. 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 0.1µF External Capacitors ABSOLUTE MAXIMUM RATINGS Continuous Power Dissipation (TA = +70°C) 16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)...842mW 16-Pin Narrow SO (derate 8.70mW/°C above +70°C) ....696mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C)........762mW 16-Pin TSSOP (derate 6.7mW/°C above +70°C).............533mW 18-Pin Plastic DIP (derate 11.11mW/°C above +70°C) ..889mW 18-Pin SO (derate 9.52mW/°C above +70°C)..............762mW 20-Pin SSOP (derate 8.00mW/°C above +70°C) .........640mW 20-Pin TSSOP (derate 7.0mW/°C above +70°C).............559mW 28-Pin SO (derate 12.50mW/°C above +70°C) .....................1W 28-Pin SSOP (derate 9.52mW/°C above +70°C) .........762mW 28-Pin TSSOP (derate 8.7mW/°C above +70°C).............696mW Operating Temperature Ranges MAX32_ _C_ _.....................................................0°C to +70°C MAX32_ _E_ _ .................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+300°C 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 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 = 0.1µF (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN UNITS TYP MAX MAX3222/MAX3232/ MAX3241 0.3 1.0 MAX3237 0.5 2.0 1.0 10 µA 0.8 V DC CHARACTERISTICS VCC Power-Supply Current Shutdown Supply Current No load, VCC = 3.3V or 5.0V, TA = +25°C SHDN = GND, TA = +25°C 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 µA Output Leakage Current Receivers disabled ±0.05 ±10 µA 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 = +25°C Input Threshold High TA = +25°C 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 0.1µF External Capacitors MAX3222/MAX3232/MAX3237/MAX3241 ELECTRICAL CHARACTERISTICS (continued) (VCC = +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN Input Hysteresis TYP MAX UNITS 0.3 Input Resistance TA = +25°C 3 5 V 7 kΩ TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3kΩ to ground ±5.0 ±5.4 Output Resistance VCC = V+ = V- = 0V, TOUT = ±2V 300 10M Output Short-Circuit Current Output Leakage Current ±35 VOUT = ±12V, VCC = 0V or 3V to 5.5V, transmitters disabled V Ω ±60 mA ±25 µA MOUSE DRIVEABILITY (MAX3241) Transmitter Output Voltage T1IN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3kΩ 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 = 0.1µF (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Maximum Data Rate CONDITIONS RL = 3kΩ, 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 = 3Ω to 7kΩ, +3V to -3V or -3V to +3V, TA = +25°C µs CL = 150pF to 1000pF 6 30 CL = 150pF to 2500pF 4 30 V/µs _______________________________________________________________________________________ 3 TIMING CHARACTERISTICS—MAX3237 (VCC = +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS Maximum Data Rate MIN RL = 3kΩ, CL = 1000pF, one transmitter switching, MBAUD = GND 250 VCC = 3.0V to 4.5V, RL = 3kΩ, CL = 250pF, one transmitter switching, MBAUD = VCC 1000 VCC = 4.5V to 5.5V, RL = 3kΩ, CL = 1000pF, one transmitter switching, MBAUD = VCC 1000 TYP UNITS MAX 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 Transition-Region Slew Rate VCC = 3.3V, RL = 3Ω to 7kΩ, +3V to -3V or -3V to +3V, TA = +25°C CL = 150pF to 1000pF µs MBAUD = GND 6 30 MBAUD = VCC 24 150 4 30 CL = 150pF to 2500pF, MBAUD = GND V/µs Note 2: MAX3222/MAX3232/MAX3241: C1–C4 = 0.1µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF tested at 5.0V ±10%. MAX3237: C1–C4 = 0.1µF tested at 3.3V ±5%; C1–C4 = 0.22µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF tested at 5.0V ±10%. Note 3: Transmitter input hysteresis is typically 250mV. __________________________________________Typical Operating Characteristics (VCC = +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) 0 -1 -2 -3 16 14 -SLEW 12 10 +SLEW 8 6 -4 1000 2000 3000 4000 LOAD CAPACITANCE (pF) 25 120kbps 20 15 20kbps 10 5 2 0 0 30 4 VOUT- -5 35 SUPPLY CURRENT (mA) SLEW RATE (V/µs) 2 1 40 235kbps 18 -6 4 FOR DATA RATES UP TO 235kbps 20 MAX3222-03 4 3 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 0.1µF 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 0.1µF External Capacitors VOUT+ 5.0 22 1 TRANSMITTER AT 235kbps 2 TRANSMITTERS AT 30kbps 0 -2.5 VOUT- -5.0 -SLEW 16 14 12 +SLEW 10 8 ALL OUTPUTS LOADED WITH 3kΩ +CL 0.1µF CHARGE-PUMP CAPACITORS FOR ALL DATA RATES UP TO 235kbps 6 4 -7.5 0 1000 2000 3000 4000 5000 0 1000 2000 3000 4000 35 30 120kbps 25 20 20kbps 15 10 5 0 1000 0 5000 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) -2.5 -5.0 -7.5 1.5Mbps 2.5 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3kΩ + CL LOAD, EACH OUTPUT VCC = 3.3V 0 -2.5 1000 2000 3000 4000 6 4 0 0 0 500 1000 1500 LOAD CAPACITANCE (pF) SUPPLY CURRENT (mA) 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3kΩ + CL LOAD EACH OUTPUT VCC = 3.3V MAX3222-11 MAX3222-10 30 70 3000 4000 5000 1 TRANSMITTER AT 512kbps 4 TRANSMITTERS AT 32kbps 3kΩ + CL LOADS VCC = 3.3V MBAUD = VCC 60 50 120kbps MAX 40 30 20kbps AVERAGE; 10 PARTS 30 20 20 1 TRANSMITTER AT FULL DATA RATE 4 TRANSMITTERS AT 1/16 DATA RATE 3kΩ + CL LOADS VCC = 3.3V 10 10 0 2000 2000 MAX3237 SKEW vs. LOAD CAPACITANCE (tPLH - tPHL) 240kbps 40 1000 LOAD CAPACITANCE (pF) 60 50 0 2000 MAX3237 SUPPLY CURRENT vs. LOAD CAPACITANCE (MBAUD = GND) 40 0 1500 MAX3237 SLEW RATE vs. LOAD CAPACITANCE (MBAUD = VCC) -SLEW, 1Mbps +SLEW, 1Mbps -SLEW, 2Mbps +SLEW, 2Mbps 10 1000 LOAD CAPACITANCE (pF) 50 20 500 LOAD CAPACITANCE (pF) 60 1 TRANSMITTER AT 240kbps 4 TRANSMITTERS AT 15kbps 3kΩ + CL LOADS VCC = 3.3V 2 1Mbps 5000 70 MAX3222-09 8 -7.5 0 -SLEW +SLEW 1.5Mbps 2Mbps -5.0 10 MAX3222-12 0 2Mbps SKEW (ns) 1 TRANSMITTER AT 240kbps 4 TRANSMITTERS AT 15kbps 3kΩ + CL LOADS VCC = 3.3V 5.0 12 SLEW RATE (V/µs) 2.5 1Mbps MAX3222-08 5.0 7.5 TRANSMITTER OUTPUT VOLTAGE (V) MAX3222-07 7.5 TRANSMITTER OUTPUT VOLTAGE (V) 18 235kbps 40 SUPPLY CURRENT (mA) SLEW RATE (V/µs) 20 2.5 45 MAX3222-05 24 MAX3222-04 TRANSMITTER OUTPUT VOLTAGE (V) 7.5 SLEW RATE (V/µs) MAX3241 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA MAX3241 SLEW RATE vs. LOAD CAPACITANCE MAX3222-06 MAX3241 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE 0 1000 2000 3000 4000 LOAD CAPACITANCE (pF) 5000 MIN 0 0 500 1000 1500 2000 2500 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ 5 MAX3222/MAX3232/MAX3237/MAX3241 _____________________________Typical Operating Characteristics (continued) (VCC = +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF 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 0.1µF 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 3kΩ in parallel with 1000pF, providing compatibility with PC-toPC communication software (such as LapLink™). 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 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 3kΩ 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 3kΩ 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 3kΩ in parallel with 1000pF. LapLink is a trademark of Traveling Software. VCC VCC 0.1µF 0.1µF VCC C1+ C1+ V+ C1 C3 C1- MAX3222 MAX3232 MAX3237 MAX3241 C2+ C2 C2- C2+ VC2 C4 C2T_ OUT T_ IN 0V 5k GND VC4 T_ OUT R_ IN R_ OUT EN* SHDN* MAX3222 MAX3232 MAX3237 MAX3241 T_ IN R_ IN R_ OUT VCC V+ C1 C3 C1- 0V VCC 3k 2500pF VCC EN* 5k SHDN* GND 7k 150pF * MAX3222/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 0.1µF 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 1µA 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 100µs, 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 µP 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 0.1µF 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 0.1µF 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) C1 (µF) C2, C3, C4 (µF) 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 0.22 0.1 0.1 4.5 to 5.5 0.047 0.33 3.0 to 5.5 0.22 1.0 5V/div 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 3kΩ 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 0.22 3.15 to 3.6 Transmitter Outputs when Exiting Shutdown 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. MAX3237 3.0 to 3.6 Power-Supply Decoupling In most circumstances, a 0.1µF 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. T2 2V/div T1 50µs/div VCC = 3.3V C1–C4 = 0.1µF 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 6 5 4 3 VOUT+ VCC = 3.0V 2 1 T1 0 -1 T2 MAX3222-04 TRANSMITTER OUTPUT VOLTAGE (V) MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors 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 24 C1+ 0.1µF 26 VCC V+ 27 C3 C1- 1 C2+ 2 C214 T1IN COMPUTER SERIAL PORT V- MAX3241 3 C4 T1OUT 9 +V 13 T2IN T2OUT 10 12 T3IN T3OUT 11 +V VCC 21 -V R1OUTB GND 20 R2OUTB 19 R1OUT R1IN 4 5 18 R2OUT 5k R2IN 17 R3OUT 5k R3IN 6 16 R4OUT 5k R4IN 7 Tx MOUSE 5k 15 R5OUT 23 5k EN R5IN 8 SHDN 22 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 0.1µF External Capacitors T1IN 5V/div T1OUT 5V/div R1OUT 5V/div MAX3222/MAX3232/MAX3237/MAX3241 VCC 0.1µF VCC C1+ V+ C3 C1 C1- MAX3222 MAX3232 MAX3237 MAX3241 C2+ C2 C2- VC4 5µs/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/MAX3241 ONLY Figure 5. Loopback Test Circuit 2µs/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 200ns/div VCC = 3.3V 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 0.1µF 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. 5 3.3 Compatible with ACT and HCT CMOS, and with TTL. Incompatible with AC, HC, and CD4000 CMOS. COMPATIBILITY __________________________________________________Typical Operating Circuits +3.3V +3.3V 17 0.1µF C1 0.1µF 2 C1+ 4 5 C2 0.1µF 6 V+ 3 C3* 0.1µF C1- MAX3222 C2+ V- 0.1µF T1OUT 15 10 R2OUT C2+ MAX3232 R1IN 13 5k 9 R2OUT R2IN 8 5k SHDN GND 15 * C3 CAN BE RETURNED TO EITHER VCC OR GROUND. C4 0.1µF T2OUT 7 18 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* 0.1µF 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 0.1µF TTL/CMOS INPUTS 1 1 C1+ 0.1µF 7 C2- 12 T1IN 16 0.1µF VCC ______________________________________________________________________________________ RS-232 INPUTS 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors 0.1µF +3.3V 26 28 C1+ 0.1µF VCC 27 25 1 0.1µF 3 C2+ 24 MAX3237 V- 4 1 0.1µF 0.1µF C2- 23 T2IN 22 T3IN T1 T2 T3 VCC 27 V+ 0.1µF C1- 24 T1IN LOGIC INPUTS 28 C1+ V+ 0.1µF 26 0.1µF T1OUT 5 T2OUT 6 T3OUT 7 TTL/CMOS INPUTS RS-232 OUTPUTS 2 C2+ MAX3241 V- 3 C4 0.1µF 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 C3* 0.1µF C1- 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 0.1µF External Capacitors _____________________________________________Pin Configurations (continued) TOP VIEW EN 1 20 SHDN C1+ 2 19 VCC V+ 3 18 GND 17 T1OUT C1- 4 C2+ 5 MAX3222 16 R1IN 15 R1OUT C2- 6 V- 7 14 N.C. T2OUT 8 13 T1IN R2IN 9 12 T2IN R2OUT 10 11 N.C. C1+ 1 16 VCC V+ 2 15 GND C1- 3 14 T1OUT MAX3232 C2+ 4 C2- 5 13 R1IN 12 R1OUT V- 6 11 T1IN T2OUT 7 10 T2IN 9 R2OUT R2IN 8 DIP/SO/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 5 6 R3IN 6 23 EN 7 22 T3IN R4IN 7 22 SHDN 21 R1OUT R5IN 8 21 R1OUTB 20 R2OUT T1OUT 9 20 R2OUTB MAX3241 T3OUT R1IN 8 R2IN 9 19 T4IN T2OUT 10 19 R1OUT 18 R3OUT T3OUT 11 18 R2OUT T3IN 12 17 R3OUT T4OUT 10 R3IN 11 17 T5IN T5OUT 12 EN 13 16 R1OUTB T2IN 13 16 R4OUT SHDN 14 15 MBAUD T1IN 14 15 R5OUT SSOP 14 24 C1- R2IN 23 T2IN MAX3237 T2OUT SO/SSOP/TSSOP ______________________________________________________________________________________ 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors PART TEMP. RANGE PIN-PACKAGE PART TEMP. RANGE PIN-PACKAGE MAX3222EUP -40°C to +85°C 20 TSSOP MAX3232EWE -40°C to +85°C 16 Wide SO MAX3222EAP MAX3222EWN MAX3222EPN -40°C to +85°C -40°C to +85°C -40°C to +85°C 20 SSOP 18 SO 18 Plastic DIP MAX3232EPE -40°C to +85°C 16 Plastic DIP MAX3237CAI MAX3237EAI MAX3241CUI MAX3241CAI 0°C to +70°C -40°C to +85°C 0°C to +70°C 0°C to +70°C 28 SSOP 28 SSOP 28 TSSOP 28 SSOP MAX3222C/D 0°C to +70°C Dice* MAX3232CUE MAX3232CSE MAX3232CWE 0°C to +70°C 0°C to +70°C 0°C to +70°C 16 TSSOP 16 Narrow SO 16 Wide SO MAX3232CPE 0°C to +70°C 16 Plastic DIP MAX3232EUE MAX3232ESE -40°C to +85°C -40°C to +85°C 16 TSSOP 16 Narrow SO MAX3241CWI 0°C to +70°C MAX3241EUI MAX3241EAI MAX3241EWI -40°C to +85°C -40°C to +85°C -40°C to +85°C 28 SO 28 TSSOP 28 SSOP 28 SO * Dice are tested at TA = +25°C, DC parameters only. ______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 0.1µF capacitors MAX3223 MAX3232 3.0 to 5.5 3.0 to 5.5 2/2 2/2 2 N/A 120 120 232 232 0.1µF capacitors, AutoShutdown 0.1µF capacitors MAX3237 3.0 to 5.5 5/3 3 250/1000 232 0.1µF capacitors, 1 complementary receiver, MegaBaud operation MAX3241 3.0 to 5.5 3/5 5 120 232 0.1µF capacitors, 2 complementary receivers, drives mice MAX3243 3.0 to 5.5 3/5 1 120 232 0.1µF capacitors, AutoShutdown, complementary receiver, drives mice FEATURES Wide supply range 0.1µF capacitors AutoShutdown, complementary receiver, drives mice, transient detection ______________________________________________________________________________________ 15 MAX3222/MAX3232/MAX3237/MAX3241 Ordering Information (continued) ___________________Chip Topography ___________________Chip Information MAX3222 V+ C1+ EN SHDN V CC GND C1C2+ T1OUT PART TRANSISTOR COUNT MAX3222 339 MAX3232 339 MAX3237 1212 MAX3241 894 0.127" (3.225mm) C2- R1IN VR1OUT T2OUT R2IN R2OUT T2IN T1IN 0.087" (2.209mm) TRANSISTOR COUNT: 339 SUBSTRATE CONNECTED TO GND ________________________________________________________Package Information TSSOP.EPS MAX3222/MAX3232/MAX3237/MAX3241 3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.