19-1144; Rev 0; 9/96 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ The MAX3238 true RS-232 transceiver achieves a 1µA supply current with Maxim’s revolutionary AutoShutdown Plus feature. When the device does not sense a valid signal transition on either the receiver or transmitter inputs within 30sec, the on-board power supply and drivers shut down. This occurs if the RS-232 cable is disconnected or if the transmitters of the connected peripheral are inactive. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input, saving power without changes to the existing BIOS or operating system. The MAX3238 5-driver/3-receiver complete serial port is a 3V-powered EIA/TIA-232 and V.28/V.24 communications interface intended for notebook or subnotebook computer applications. A proprietary, high-efficiency, dual charge-pump power supply and a low-dropout transmitter combine to deliver true RS-232 performance from a single +3.0V to +5.5V supply. A guaranteed data rate of 250kbps provides compatibility with popular software for communicating with personal computers. The MAX3238 requires only 0.1µF capacitors in 3.3V operation. It is ideal for 3.3V-only systems, mixed 3.3V and 5.0V systems, or 5V-only systems that require true RS-232 performance. Receiver R1 has an extra, always-active output (in addition to its standard output), which allows external devices, such as a modem, to be monitored without forward biasing the protection diodes in circuitry that may have VCC completely removed. The MAX3238 is available in a space-saving SSOP package. ____________________________Features ♦ 1µA Supply Current Achieved with AutoShutdown Plus ♦ Guaranteed Data Rate: 250kbps ♦ 1µA Low-Power Shutdown ♦ Receivers Active in AutoShutdown Plus Mode ♦ Flow-Through Pinout ♦ Meets EIA/TIA-232 Specifications Down to 3.0V ♦ Guaranteed 6V/µs Slew Rate ______________Ordering Information PART TEMP. RANGE PIN-PACKAGE MAX3238CAI 0°C to +70°C 28 SSOP MAX3238EAI -40°C to +85°C 28 SSOP __________________Pin Configuration TOP VIEW C2+ 1 28 C1+ GND 2 27 V+ C2- 3 26 VCC V- 4 25 C1- High-Speed Modems T1OUT 5 Battery-Powered Equipment T2OUT 6 23 T2IN Hand-Held Equipment T3OUT 7 22 T3IN Peripherals R1IN 8 21 R1OUT Printers R2IN 9 20 R2OUT ________________________Applications Notebook, Subnotebook, and Palmtop Computers MAX3238 19 T4IN T4OUT 10 18 R3OUT R3IN 11 Typical Operating Circuit appears at end of data sheet. AutoShutdown Plus is a trademark of Maxim Integrated Products. *Patents Pending 24 T1IN 17 T5IN T5OUT 12 FORCEON 13 16 R1OUTB FORCEOFF 14 15 INVALID SSOP ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 MAX3238* _______________General Description MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ 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, FORCEOFF, FORCEON ..............................-0.3V to +6V R_IN .................................................................................±25V Output Voltages T_OUT...........................................................................±13.2V R_OUT, INVALID ....................................-0.3V to (VCC + 0.3V) Short-Circuit Duration T_OUT (one at a time) ............................................Continuous Continuous Power Dissipation (TA = +70°C) SSOP (derate 9.52mW/°C above +70°C) ....................762mW Operating Temperature Ranges MAX3238CAI ......................................................0°C to +70°C MAX3238EAI....................................................-40°C to +85°C Storage Temperature Range ............................-65°C to +160°C Lead Temperature (soldering, 10sec) ............................+300°C Note 1: V+ and V- can have a maximum magnitude of +7V, but their absolute difference can not 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 (V CC = +3.0V to +5.5V; C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF (tested at 3.3V ±10%), C1 = 0.047µF and C2–C4 = 0.33µF (tested at 5.0V ±10%); TA = TMIN to TMAX; unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN TYP MAX UNITS 1.0 10 1.0 10 0.5 2.0 mA 0.8 V DC CHARACTERISTICS Supply Current, AutoShutdown Plus VCC = 3.3V or 5.0V, TA = +25°C, receivers idle, transmitters idle, FORCEON = GND, FORCEOFF = VCC Supply Current, Shutdown FORCEOFF = GND, TA = +25°C Supply Current, AutoShutdown Plus Disabled FORCEON = FORCEOFF = VCC, no load µA µA LOGIC INPUTS AND RECEIVER OUTPUTS Input Logic Threshold Low Input Logic Threshold High T_IN, FORCEON, FORCEOFF VCC = 3.3V 2.0 VCC = 5.0V 2.4 V Input Leakage Current T_IN, FORCEON, FORCEOFF ±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 VCC 0.1 V RECEIVER INPUTS Input Voltage Range Input Threshold Low Input Threshold High -25 0.6 1.2 VCC = 5.0V 0.8 1.5 1.5 2.4 VCC = 5.0V 1.8 2.4 2 0.3 TA = +25°C 3 5 _______________________________________________________________________________________ V V VCC = 3.3V Input Hysteresis Input Resistance 25 VCC = 3.3V V V 7 kΩ +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ (V CC = +3.0V to +5.5V; C1–C4 = 0.1µF (tested at 3.3V ±5%), C1–C4 = 0.22µF (tested at 3.3V ±10%), C1 = 0.047µF and C2–C4 = 0.33µF (tested at 5.0V ±10%); TA = TMIN to TMAX; unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS MIN TYP MAX UNITS AutoShutdown (FORCEON = GND, FORCEOFF = VCC) Positive threshold 2.7 Receiver Input Threshold to INVALID Output High Figure 7a Receiver Input Threshold to INVALID Output Low Figure 4a INVALID Output Voltage Low IOUT = 1.6mA INVALID Output Voltage High IOUT = -1.0mA Receiver Positive or Negative Threshold to INVALID High (tINVH) VCC = 5V, Figure 4b 0.1 µs Receiver Positive or Negative Threshold to INVALID Low (tINVL) VCC = 5V, Figure 4b 50 µs Receiver or Transmitter Edge to Transmitters Enabled (tWU) VCC = 5V, Figure 4b (Note 2) 25 µs Receiver or Transmitter Edge to Shutdown (tAUTOSHDN) Figure 4b (Note 2) V Negative threshold -2.7 -0.3 0.3 V 0.4 V VCC 0.6 V 15 30 60 sec TRANSMITTER OUTPUTS Output Voltage Swing All transmitter outputs loaded with 3kΩ to ground ±5.0 ±5.4 Output Resistance VCC = V+ = V- = GND, TOUT = 2V 300 10M Output Short-Circuit Current Output Leakage Current V Ω VCC ≤ 3.6V ±35 ±60 VCC > 3.6V ±40 ±100 VOUT = ±12V, VCC = 0V to 5.5V, transmitters disabled ±25 mA µA TIMING CHARACTERISTICS Maximum Data Rate RL = 3kΩ, CL = 1000pF, one transmitter switching 250 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 Transmitter Skew | tPHL - tPLH | 100 ns Receiver Skew | tPHL - tPLH | 50 ns Transition-Region Slew Rate VCC = 3.3V, TA = +25°C, RL = 3Ω to 7kΩ, measured from +3V to -3V or -3V to +3V tPHL 0.15 tPLH 0.15 CL = 150pF to 1000pF 6 µs 30 V/µs CL = 150pF to 2500pF 4 30 Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds. _______________________________________________________________________________________ 3 MAX3238 ELECTRICAL CHARACTERISTICS (continued) __________________________________________Typical Operating Characteristics (VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA = +25°C, unless otherwise noted.) FOR DATA RATES UP TO 250kbps 1 TRANSMITTER 250kbps 4 TRANSMITTERS 15.6kbps LOADED 3kΩ + CL -2.5 +SLEW 10 8 1 TRANSMITTER 250kbps 4 TRANSMITTERS 15.6kbps LOADED 3kΩ + CL 6 60 SUPPLY CURRENT (mA) 2.5 –SLEW 12 70 MAX3238-02 5.0 SLEW RATE (V/µs) VOUT+ 0 14 MAX3238 TOC-01 7.5 SUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA SLEW RATE vs. LOAD CAPACITANCE 4 250kbps 50 120kbps 40 30 20 VOUT– -5.0 -7.5 0 0 0 1000 2000 3000 4000 5000 LOAD CAPACITANCE (pF) 20kbps 10 2 MAX3238 TOC-03 TRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE TRANSMITTER OUTPUT VOLTAGE (V) MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ 0 2000 4000 1000 3000 LOAD CAPACITANCE (pF) 5000 0 2000 4000 1000 3000 LOAD CAPACITANCE (pF) 5000 ______________________________________________________________Pin Description 4 PIN NAME FUNCTION 1 C2+ Positive Terminal of Inverting Charge-Pump Capacitor 2 GND Ground 3 C2- 4 V- 5, 6, 7, 10, 12 T_OUT 8, 9, 11 R_IN 13 FORCEON Force-Off Input. Drive high to override AutoShutdown Plus, keeping transmitters and receivers on (FORCEOFF must be high) (Table 1). 14 FORCEOFF Force-Off Input. Drive low to shut down transmitters, receivers (except R1OUTB), and onboard supply. This overrides AutoShutdown Plus and FORCEON (Table 1). 15 INVALID Output of the Valid Signal Detector. A logic “1” indicates if a valid RS-232 level is present on receiver inputs. 16 R1OUTB Noninverting Complementary Receiver Output. Always active. 17, 19, 22, 23, 24 T_IN 18, 20, 21 R_OUT 25 C1- Negative Terminal of Voltage-Doubler Charge-Pump Capacitor 26 VCC +3.0V to +5.5V Supply Voltage 27 V+ +5.5V Generated by the Charge Pump 28 C1+ Negative Terminal of Inverting Charge-Pump Capacitor -5.5V Generated by the Charge Pump RS-232 Transmitter Outputs (T1OUT–T5OUT) RS-232 Receiver Inputs (R1IN–R3IN) TTL/CMOS Transmitter Inputs (T5IN–T1IN) TTL/CMOS Receiver Outputs (R3OUT–R1OUT) Positive Terminal of Voltage-Doubler Charge-Pump Capacitor _______________________________________________________________________________________ +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ MAX3238 Table 1. Output Control Truth Table FORCEON FORCEOFF AUTOSHUTDOWN PLUS* X 0 X 1 1 X 0 1 0 1 OPERATION STATUS T_OUT R_OUT R1OUTB Shutdown (Forced Off) High-Z High-Z Active Normal Operation (Forced On) Active Active Active <30sec* Normal Operation (AutoShutdown Plus) Active Active Active >30sec* Shutdown (AutoShutdown Plus) High-Z Active Active X = Don’t Care * Time since last receiver or transmitter input transition. _______________Detailed Description Dual Charge-Pump Voltage Converter The MAX3238’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; 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 MAX3238 transmitters guarantee a 250kbps data rate with worst-case loads of 3kΩ in parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink™). Transmitters can be paralleled to drive multiple receivers. Figure 1 shows a complete system connection. When FORCEOFF is driven to ground, the transmitters and receivers are disabled and the outputs go high impedance, except for R1OUTB. When the AutoShutdown Plus circuitry senses that all receiver and transmitter inputs are inactive for more than 30sec, the transmitters are disabled and the outputs go into a high-impedance state, but the receivers remain active. When the power is off, the MAX3238 permits the outputs to be driven up to ±12V. The transmitter inputs do not have pull-up resistors. Connect unused inputs to GND or VCC. RS-232 Receivers The receivers convert RS-232 signals to CMOS-logic output levels. All receivers have inverting three-state outputs and are inactive in shutdown (FORCEOFF) (Table 1). The MAX3238 also features an extra, alwaysactive noninverting output, R1OUTB. This extra output monitors receiver activity while the other receivers are high impedance, allowing Ring Indicator to be monitored without forward biasing other devices connected to the receiver outputs. This is ideal for systems where VCC is set to 0V in shutdown to accommodate peripherals, such as UARTs (Figure 2). LapLink is a trademark of Traveling Software. _______________________________________________________________________________________ 5 MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ POWER MANAGEMENT UNIT OR KEYBOARD CONTROLLER VCC FORCEOFF FORCEON INVALID PROTECTION DIODE PREVIOUS RS-232 VCC MAX3238 I Rx T1 5k UART T2 Tx T3 CPU I/O CHIP WITH UART GND SHDN = GND T4 RS-232 T5 (a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN. R1 VCC R2 TO µP R3 LOGIC TRANSITION DETECTOR I PROTECTION DIODE Figure 1. Interface Under Control of PMU MAX3238 R1OUTB VCC AutoShutdown Plus Mode 1µA supply current is achieved with Maxim’s AutoShutdown Plus feature, which operates when FORCEOFF is low and FORCEON is high. When the MAX3238 senses no valid signal transitions on all receiver and transmitter inputs for 30sec, the on-board power supply and drivers are shut off, reducing supply current to 1µA. This occurs if the RS-232 cable is disconnected or if the connected peripheral transmitters are turned off. The system turns on again when a valid transition is applied to any RS-232 receiver or transmitter input. As a result, the system saves power without changes to the existing BIOS or operating system. The INVALID output is high when the receivers are active. Since INVALID indicates the receiver inputs’ condition, it can be used in any mode (Figure 3). 6 Rx THREE-STATED UART 5k Tx GND (b) R1IN R1OUT T1IN FORCEOFF = GND NEW MAX3238: IN SHUTDOWN, R1OUTB IS USED TO MONITOR EXTERNAL DEVICES AND R1OUT IS THREE STATED, ELIMINATING A CURRENT PATH THROUGH THE UART'S PROTECTION DIODE. Figure 2. The MAX3238 detects RS-232 activity when the UART and interface are shut down. _______________________________________________________________________________________ T1OUT +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ RS-232 SIGNAL PRESENT AT ANY RECEIVER INPUT MAX3238 Table 2. INVALID Truth Table +0.3V INVALID OUTPUT Yes H No L R_IN 30µs TIMER R -0.3V INVALID INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30µs. Figure 3a. INVALID Functional Diagram, INVALID Low Tables 1 and 2 and Figure 3 summarize the MAX3238’s operating modes. FORCEON and FORCEOFF override the automatic circuitry and force the transceiver into its normal operating state or into its low-power standby state. When neither control is asserted, the IC enters AutoShutdown Plus mode and selects between these states automatically, based on the last receiver or transmitter input edge received. When shut down, the device’s charge pumps turn off, V+ decays to VCC, V- decays to ground, and the transmitter outputs are disabled (high impedance). The time required to exit shutdown is typically 25µs (Figure 4b). +2.7V R_IN 30µs TIMER R -2.7V INVALID INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V FOR LESS THAN 30µs. Figure 3b. INVALID Functional Diagram, INVALID High Software-Controlled Shutdown If direct software control is desired, use INVALID to indicate DTR or Ring Indicator signal. Tie FORCEOFF and FORCEON together to bypass the AutoShutdown feature so the line acts like a SHDN input. T_IN __________Applications Information R_IN 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 0.1µF capacitors for 3.3V operation. For other supply voltages, see Table 3 for required capacitor values. Do not use values smaller than those listed in Table 3. 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, C4, and CBYPASS, to maintain the proper ratios (C1 to the other capacitors). EDGE DETECT FORCEOFF S 30sec TIMER EDGE DETECT AUTOSHDN R FORCEON Figure 3c. AutoShutdown Plus Logic FORCEOFF POWERDOWN* FORCEON AUTOSHDN * POWERDOWN IS ONLY AN INTERNAL SIGNAL. IT CONTROLS THE OPERATIONAL STATUS OF THE TRANSMITTERS AND THE POWER SUPPLIES. Figure 3d. Power-Down Logic _______________________________________________________________________________________ 7 MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ 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 larger nominal value. The capacitor’s equivalent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and V-. INVALID HIGH RECEIVER INPUT LEVELS +2.7V INDETERMINATE +0.3V 0V Table 3. Required Minimum Capacitance Values INVALID LOW -0.3V INDETERMINATE VCC (V) C1 (µF) C2, C3, C4, CBYPASS (µF) 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 -2.7V INVALID HIGH Figure 4a. Receiver Positive/Negative Thresholds for INVALID INVALID REGION * RECEIVER INPUTS VOLTAGE ** TRANSMITTER INPUTS VOLTAGE TRANSMITTER OUTPUTS VOLTAGE INVALID OUTPUT VCC 0 INVL tAUTOSHDN tAUTOSHDN tWU tWU V+ VCC 0 V* ALL RECEIVERS/TRANSMITTERS INACTIVE ** ANY ONE RECEIVER/TRANSMITTER BECOMES ACTIVE FORCEON = GND, FORCEOFF = VCC Figure 4b. AutoShutdown Plus and INVALID Timing Diagram 8 _______________________________________________________________________________________ +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ Transmitter Outputs when Exiting Shutdown Figure 5 shows two transmitter outputs when exiting shutdown mode. As they become active, the 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. Interconnection with 3V and 5V Logic The MAX3238 can directly interface with various 5Vlogic families, including ACT and HCT CMOS. See Table 4 for more information on possible combinations of interconnections. Table 4. Logic Family Compatibility with Various Supply Voltages SYSTEM POWERSUPPLY VOLTAGE (V) VCC SUPPLY VOLTAGE (V) COMPATIBILITY 3.3 3.3 Compatible with all CMOS families. 5 5 Compatible with all TTL and CMOS families. 5 3.3 High Data Rates The MAX3238 maintains the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 6 shows a transmitter loopback test circuit. Figure 7 shows a loopback test result at 120kbps, and Figure 8 shows the same test at 250kbps. For Figure 7, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 8, a single transmitter was driven at 250kbps, and all transmitters were loaded with an RS-232 receiver in parallel with 1000pF. Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS. VCC VCC C1+ V+ C3* C1 C1- FORCEON = FORCEOFF 2V/div T2OUT C2+ MAX3238 VC4 C2 C2- T_ OUT T_ IN 2V/div R_ IN R_ OUT T1OUT VCC = 3.3V C1 - C4 = 0.1µF 5µs/div Figure 5. Transmitter Outputs when Exiting Shutdown or Powering Up 5k FORCEON VCC FORCEOFF 1000pF GND *C3 CAN BE RETURNED TO VCC OR GND. Figure 6. Loopback Test Circuit _______________________________________________________________________________________ 9 MAX3238 Power-Supply Decoupling In applications that are sensitive to power-supply noise, decouple VCC to ground with a capacitor of the same value as capacitors C2, C3, and C4. Connect the bypass capacitor as close to the IC as possible. MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ 5V 0V T1IN 5V 0V T1IN +5V +5V 0V T1OUT T1OUT 0V -5V -5V 5V 0V 5V R1OUT 0V VCC = 3.3V C1 - C4 = 0.1µF CLOAD = 1000pF 2µs/div Figure 7. Loopback Test Result at 120kbps R1OUT VCC = 3.3V C1 - C4 = 0.1µF CLOAD = 1000pF 2µs/div Figure 8. Loopback Test Result at 250kbps ___________________Chip Information TRANSISTOR COUNT: 1404 10 ______________________________________________________________________________________ +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ MAX3238 __________Typical Operating Circuit 0.1µF 26 VCC 28 C1+ 0.1µF V+ 27 * 0.1µF 25 C1- MAX3238 1 C2+ 0.1µF V- 4 0.1µF 3 C224 T1IN T1 23 T2IN LOGIC INPUTS T2 22 T3IN T3 19 T4IN T4 17 T5IN T5 T1OUT 5 T2OUT 6 T3OUT 7 RS-232 OUTPUTS T4OUT 10 T5OUT 12 14 FORCEOFF AUTOSHUTDOWN PLUS 13 FORCEON INVALID 15 16 R1OUTB 21 R1OUT R1IN 8 R1 5k LOGIC OUTPUTS 20 R2OUT R2IN 9 R2 RS-232 INPUTS 5k 18 R3OUT R3IN 11 R3 5k GND 2 *C3 MAY BE RETURNED TO EITHER VCC OR GND. ______________________________________________________________________________________ 11 MAX3238 +3.0V to +5.5V, 1µA, up to 250kbps, True RS-232 Transceiver with AutoShutdown Plus™ ________________________________________________________Package Information DIM α E H C L A A1 B C D E e H L α INCHES MILLIMETERS MIN MAX MIN MAX 0.068 0.078 1.73 1.99 0.002 0.008 0.05 0.21 0.010 0.015 0.25 0.38 0.004 0.008 0.09 0.20 SEE VARIATIONS 0.205 0.209 5.20 5.38 0.0256 BSC 0.65 BSC 0.301 0.311 7.65 7.90 0.025 0.037 0.63 0.95 0˚ 8˚ 0˚ 8˚ DIM PINS e SSOP SHRINK SMALL-OUTLINE PACKAGE A B A1 D D D D D 14 16 20 24 28 INCHES MILLIMETERS MAX MIN MAX MIN 6.33 0.239 0.249 6.07 6.33 0.239 0.249 6.07 7.33 0.278 0.289 7.07 8.33 0.317 0.328 8.07 0.397 0.407 10.07 10.33 21-0056A D 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. 12 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.