19-0199; Rev 1; 8/95 Programmable DTE/DCE, +5V RS-232 Transceiver ____________________________Features ♦ Eliminates Null Modem Cables ________________________Applications ♦ Receivers Active in Shutdown AT-Compatible Laptop Computers ♦ Programmable DTE or DCE Serial Port ♦ 1µF Charge-Pump Capacitors ♦ 116kbps Data Rate—Guaranteed ♦ 20µA Shutdown Mode ______________Ordering Information AT-Compatible Desktop Computers PART Modems, Printers, and Other Peripherals __________Typical Operating Circuit +5V TEMP. RANGE PIN-PACKAGE MAX214CPI 0°C to +70°C 28 Plastic DIP MAX214CWI 0°C to +70°C 28 Wide SO MAX214C/D 0°C to +70°C Dice* MAX214EPI -40°C to +85°C 28 Plastic DIP MAX214EWI -40°C to +85°C 28 Wide SO * Dice are specified at TA = +25°C. 1µF 16 27 1µF 1µF 1µF VCC C1+ 15 __________________Pin Configuration V+ 28 C11 C2+ 2 MAX214 V- 14 C2- 5 TA DTE TRA 9 DCE 6 RA RTA 10 DTE 25 TB TRB 20 DTE DCE 23 RB RTB 19 DTE 24 TC TRC 18 DTE DCE 22 RC RTC 17 DTE DCE DCE 7 RDC 21 26 3 RRE 12 RE DTE/DCE SHDN HI-Z RDTC 11 DTE DTE 8 TOP VIEW 1µF C2+ 1 28 C1- C2- 2 27 C1+ HI-Z 3 26 SHDN N.C. 4 25 TB TA 5 24 TC RA 6 23 RB RDC 7 22 RC RE 8 21 DTE/DCE TRA 9 20 TRB RTA 10 19 RTB RDTC 11 18 TRC RRE 12 17 RTC GND 13 16 VCC V- 14 15 V+ MAX214 GND 13 DIP/SO ________________________________________________________________ Maxim Integrated Products Call toll free 1-800-998-8800 for free samples or literature. 1 MAX214 _______________General Description The MAX214 +5V RS-232 transceiver provides a complete, 8-line, software-configurable, DTE or DCE port RS-232 interface. Tx, Rx, RTS, CTS, DTR, DSR, DCD, and RI circuits can be configured as either Data Terminal Equipment (DTE) or Data Circuit-Terminating Equipment (DCE) using the DTE/DCE control pin. The MAX214 eliminates the need to swap cables when switching between DTE and DCE configurations. MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver ABSOLUTE MAXIMUM RATINGS VCC ...........................................................................-0.3V to +6V Input Voltages TIN, DTE/DCE, SHDN HI-Z ......................-0.3V to (VCC + 0.3V) RIN ....................................................................................±15V Output Voltages: TOUT ..................................................................................±15V ROUT ........................................................-0.3V to (VCC + 0.3V) Short-Circuit (one output at a time) TOUT to GND ...........................................................Continuous ROUT to GND...........................................................Continuous Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW Wide SO (derate 12.50mW/°C above +70°C) ............1000mW Operating Temperature Ranges: MAX214C–I ..............................................0°C to +70°C MAX214E –I ..........................................-40°C to +85°C Storage Temperature Range ......................-65°C to +150°C Lead Temperature (soldering, 10sec) .......................+300°C 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 = 4.5V to 5.5V, C1 to C4 = 1µF, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP 0.8 1.4 MAX UNITS RS-232 TRANSMITTERS Logic Input Threshold Low Logic Input Threshold High Logic Input Pull-Up Current Normal operation 1 Shutdown V 1.4 2.0 10 50 ±0.01 ±1 V µA Output Voltage Swing All transmitter outputs loaded with 3kΩ to ground ±5.0 ±7.5 V Transmitter Output Resistance VCC = V+ = V- = 0V, VOUT = ±2V (Note 1) 300 300k Ω Output Short-Circuit Current VOUT = 0V ±7 ±25 mA Positive Threshold Input Low TA = +25°C, VCC = 5V, normal operation, SHDN = 0V 0.8 1.3 Positive Threshold Input High TA = +25°C, VCC = 5V, normal operation, SHDN = 0V Positive Threshold Input Hysteresis VCC = 5V, normal operation, SHDN = 0V (no hysteresis in shutdown) Negative Threshold Input Low TA = +25°C, VCC = 5V Negative Threshold Input High TA = +25°C, VCC = 5V Negative Threshold Input Hysteresis VCC = 5V, normal operation, SHDN = 0V (no hysteresis in shutdown) HI-Z = 0V and SHDN = 0V HI-Z = 5V or SHDN = 5V RS-232 RECEIVERS Input Voltage Operating Range Input Resistance ±15 TTL/CMOS Output Voltage Low IOUT = 3.2mA TTL/CMOS Output Voltage High IOUT = -1.0mA 2 V V 1.8 2.4 V 0.2 0.5 1.0 V Normal operation, SHDN = 0V -2.6 -1.9 Shutdown, SHDN = 5V 0.8 1.3 V Normal operation, SHDN = 0V -1.5 -0.2 Shutdown, SHDN = 5V 1.3 2.4 0.2 0.4 1.0 3 100 5 300 7 0.2 0.4 3.5 VCC - 0.2 _______________________________________________________________________________________ V V kΩ V V Programmable DTE/DCE, +5V RS-232 Transceiver (VCC = 4.5V to 5.5V, C1 to C4 = 1µF, TA = TMIN to TMAX, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS POWER SUPPLY VCC Supply Current Shutdown Supply Current No load, TA = +25°C DTE/DCE = 0V, SHDN = HI-Z = VCC , Figure 1 TA = +25°C 9 20 mA 4 20 µA 50 TA = TMIN to TMAX CONTROL LOGIC (DTE/DCE, SHDN, HI-Z) Logic Input Threshold Low 0.8 Logic Input Threshold High 1.3 1.3 Input Leakage Current V 2.0 V ±1 µA AC CHARACTERISTICS Data Rate Normal operation, transmitters and receivers 200 Receivers in shutdown mode 20 TA = +25°C, VCC = 5V, RL = 3kΩ to 7kΩ, CL = to 2500pF, measured from 3V to -3V or -3V to 3V 116 kbps 12 30 V/µs tPHLT 1.3 3.5 tPLHT 1.4 3.5 µs Transmitter + to - Propagation-Delay Difference (Normal Operation) tPHLT - tPLHT 100 Receiver Propagation Delay, RS-232 to TTL (Normal Operation) tPHLR, t PLHR 0.4 1.5 µs tPHLR 0.4 10 tPLHR 1.5 10 µs Transition-Region Slew Rate Transmitter Propagation Delay, TTL to RS-232 (Normal Operation) Receiver Propagation Delay, RS-232 to TTL (Shutdown Mode) Receiver Propagation-Delay Difference tPHLT - tPLHT (Normal Operation) 6 ns 100 ns MODE-CHANGE TIMING (DTE/DCE) Transmitter Enable Time tTEN (includes charge-pump start-up time) 250 µs Transmitter Disable Time tTTR 600 ns Transmitter DTE/DCE Switch Time tTSW 600 ns Receiver DTE/DCE Switch Time tRSW 300 ns Receiver Termination-Resistor Connect/Disconnect Time (SHDN = 0V) 300 ns Receiver Termination-Resistor Connect Entering SHDN Time 250 µs Receiver Termination-Resistor Disconnect Exiting SHDN Time 300 ns Note 1: The 300Ω minimum is the EIA/TIA-232E specification, but the actual resistance when in shutdown mode or when VCC = 0V is typically 300kΩ. _______________________________________________________________________________________ 3 MAX214 ELECTRICAL CHARACTERISTICS (continued) __________________________________________Typical Operating Characteristics (VCC = 5V, C1 to C4 = 1µF, all transmitters loaded with 3kΩ in parallel with 2.5nF, TA = +25°C, unless otherwise noted.) TRANSMITTER OUTPUT VOLTAGE (VOH) vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES -6.0 20kbps 7.4 120kbps 7.2 64kbps V OH (V) -7.0 V OH (V) 6.8 120kbps 6.6 8.0 7.5 6.4 20kbps 7.0 6.2 DATA RATE = 0kbps 6.0 -8.5 0 6.5 0 1000 2000 3000 4000 5000 6000 7000 LOAD CAPACITANCE (pF) 1 TRANSMITTER LOADED -8.0 -8.5 DATA RATE = 0kbps -9.5 16 4 V+ AND VEQUALLY 0 LOADED 2 V- LOADED, NO LOAD ON V+ V+ LOADED, NO LOAD ON V- -2 ALL TRANSMITTERS UNLOADED, 0kbps -4 14 SLEW+ 1 TRANSMITTER LOADED 12 10 8 SLEW6 1 TRANSMITTER LOADED -8 4 -10 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 V CC (V) SLEW+ 3 TRANSMITTERS LOADED SLEW3 TRANSMITTERS LOADED 18 6 -6 -9.0 20 MAX214-05 8 T OUT +, T OUT - (V) 2 TRANSMITTERS LOADED SLEW RATE vs. LOAD CAPACITANCE 10 MAX214-04 3 TRANSMITTERS LOADED 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 V CC (V) TRANSMITTER OUTPUT VOLTAGES vs. V+, V- LOAD CURRENT TRANSMITTER OUTPUT VOLTAGE (VOL) vs. POSITIVE SUPPLY VOLTAGE -7.0 1000 2000 3000 4000 5000 6000 7000 LOAD CAPACITANCE (pF) 0 20 40 60 LOAD CURRENT (mA) 80 0 2000 4000 6000 LOAD CAPACITANCE (pF) _______________________________________________________________________________________ MAX214-06 -8.0 SLEW RATE (V/µs) V OL (V) 3 TRANSMITTERS LOADED 64kbps 7.0 -7.5 4 1 TRANSMITTER LOADED 2 TRANSMITTERS LOADED 8.5 -6.5 -7.5 9.0 MAX214-02 7.6 MAX214-01 -5.5 TRANSMITTER OUTPUT VOLTAGE (VOH ) vs. VCC POSITIVE SUPPLY VOLTAGE MAX214-03 TRANSMITTER OUTPUT VOLTAGE (VOL) vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES V OL (V) MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver Programmable DTE/DCE, +5V RS-232 Transceiver PIN NAME FUNCTION 1, 2 C2+, C2- 3 HI-Z RS-232 receiver impedance control. Take high to disconnect the termination resistor. 4 N.C. No connect—not internally connected Terminals for negative charge-pump capacitor 5, 24, 25 TA, TC, TB 6, 8, 22, 23 RA, RE, RC, RB 7 RDC 9, 18, 20 TRA, TRC, TRB RS-232 DTE driver output for DTE/DCE= 0V, or RS-232 DCE receiver input for DTE/DCE = +5V 10, 17, 19 RTA, RTC, RTB RS-232 DTE receiver input for DTE/DCE = 0V, or RS-232 DCE driver output for DTE/DCE = +5V 11 RDTC 12 RRE RS-232 receiver input 13 GND Ground 14 V- -2VCC voltage generated by the charge pump 15 V+ +2VCC voltage generated by the charge pump 16 VCC +4.5V to +5.5V supply voltage 21 DTE/DCE 26 SHDN 27, 28 C1+, C1- TTL/CMOS driver A, C, B inputs TTL/CMOS receiver A, E, C, B outputs TTL/CMOS DTE receiver output D for DTE/DCE = 0V, or TTL/CMOS DCE receiver output C for DTE/DCE = +5V RS-232 DTE receiver input D for DTE/DCE = 0V, or RS-232 DCE driver output C for DTE/DCE = +5V Data terminal equipment (DTE) and data circuit-terminating equipment (DCE) control pin. DCE active high and DTE active low. Shutdown control; shutdown high, normal operation low Terminals for positive charge-pump capacitor _______________Detailed Description The MAX214 RS-232 transceiver provides a complete, 8-line, software-configurable, DTE or DCE port RS-232 interface. Tx, Rx, RTS, CTS, DTR, DSR, DCD, and RI circuits can be configured as either Data Terminal Equipment (DTE) or Data Circuit-Terminating Equipment (DCE) using the DTE/DCE control pin. The MAX214 eliminates the need to swap cables when switching between DTE and DCE configurations. This is useful when, for example, a portable computer is required to communicate with printers, modems, and other computers without carrying multiple cables. The MAX214 runs from a single +5V supply and incorporates a dual charge-pump voltage converter to generate the necessary voltages for the RS-232 transmitters. A shutdown mode is provided to save power when transmission is not required, but the receivers always stay active for simple detection of ring indicator signals. DTE/DCE Operation The DTE/DCE pin allows circuit configuration under software control. Tables 1a and 1b show the pin definitions of the MAX214 in both DTE and DCE modes. The Function columns show the direction of data flow from the input pin to the output pin of the MAX214, and onto the corresponding DB-25 connector’s pin. +5V to ±10V Dual Charge-Pump Voltage Converter The +5V to ±10V conversion is performed by two charge-pump voltage converters (Figure 2). The first uses capacitor C1 to double the +5V to +10V, storing the +10V on the output filter capacitor, C3. The second charge-pump voltage converter uses C2 to invert the +10V to -10V, storing the -10V on the V- output filter capacitor, C4. In shutdown mode, V+ is pulled to VCC by an internal resistor, and V- falls to GND. _______________________________________________________________________________________ 5 MAX214 ______________________________________________________________Pin Description Table 1a. DTE-Operation Pin Configurations TTL/CMOS I/O LABEL MAX214 PIN FUNCTION MAX214 PIN RS-232 I/O LABEL DB-25 PIN INPUT THRESHOLD Transmitter (TxD) 5 9 TxD 2 Receiver (RxD) 6 10 RxD 3 Request to Send (RTS) 25 20 RTS 4 Clear to Send (CTS) 23 19 CTS 5 Data Terminal Ready (DTR) 24 18 DTR 20 Data Set Ready (DSR) 22 17 DSR 6 - Detector Carrier Data (DCD) 7 11 DCD 8 + Ring Indicator (RI) 8 12 RI 22 + - + Table 1b. DCE-Operation Pin Configurations MAX214 PIN MAX214 PIN RS-232 I/O LABEL DB-25 PIN 5 10 RxD 3 6 9 TxD 2 25 19 CTS 5 23 20 RTS 4 17 DSR 6 11 DCD 8 18 DTR 20 - 12 RI 22 + FUNCTION INPUT THRESHOLD + - 24 22 7 8 6 _______________________________________________________________________________________ MAX214 MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver Programmable DTE/DCE, +5V RS-232 Transceiver ISHDN +5.5V 1µF 1µF VCC C1+ 1µF V+ 1µF C1- MAX214 V- C2+ +5V 1µF C2- 400k Tx TIN +5.5V 3k Rx ROUT 0V OR +5.5V DRIVE TOUT RIN 5k DTE/DCE +5.5V HI-Z +5.5V SHDN +5.5V GND RS-232 Receivers CAPACITORS MAY BE POLARIZED OR UNPOLARIZED The receivers convert the RS-232 signals to CMOS-logic levels. They invert, to match the inversion of RS-232 drivers. The guaranteed receiver input thresholds are significantly tighter than the ±3V thresholds required by the EIA/TIA-232E specification, Figure 1. MAX214 Shutdown-Current Test Circuit V+ S1 V CC S2 C1+ C1 S3 S5 C3 S4 GND GND C2 RL + C4 S7 V CC C1- IL + C2+ S6 IL - RL - S8 VC2- 120kHz Figure 2. Charge-Pump Diagram _______________________________________________________________________________________ 7 MAX214 RS-232 Drivers With VCC = 5V, the typical driver output voltage swing is ±8V when loaded with a nominal 5kΩ RS-232 receiver. Under worst-case operating conditions (including 116kbps data rate, 3kΩ 2500pF load, VCC = 4.5V, maximum rated temperature) the output swing is guaranteed to meet the ±5V minimum specified by EIA/TIA-232 and V.28. The open-circuit output voltage swing ranges from (V+ - 0.6V) to V-. Input thresholds are both CMOS and TTL compatible. The inputs of unused drivers can be left unconnected because 400kΩ pull-up resistors to VCC are included on-chip. Since all drivers invert, the pull-up resistors force the outputs of unused drivers low. The input pull-up resistors typically source 10µA; in shutdown mode, they are disconnected to reduce supply current. When in low-power shutdown mode, the driver outputs are turned off and their leakage current is less than 1µA, even if the transmitter output is back-driven with voltages up to ±15V. MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver Table 2. Control Pin Configurations CONTROL INPUTS RS-232 PINS SHUTDOWN HI-Z DTE/DCE TRA, TRB, TRC 0 0 0 Transmit Mode Receive Mode/5kΩ Receive Mode/5kΩ 0 0 1 Receive Mode/5kΩ Transmit Mode Receive Mode/5kΩ 0 1 0 Transmit Mode Receive Mode/HI-Z Receive Mode/HI-Z 0 1 1 Receive Mode/HI-Z Transmit Mode Receive Mode/HI-Z 1 0 0 Disabled/HI-Z Slow Receive/HI-Z Slow Receive/HI-Z 1 0 1 Slow Receive/HI-Z Disabled/HI-Z Slow Receive/HI-Z 1 1 0 Disabled/HI-Z Slow Receive/HI-Z Slow Receive/HI-Z 1 1 1 Slow Receive/HI-Z Disabled/HI-Z Slow Receive/HI-Z which improves noise margins. The polarity of each receiver’s input threshold is shown in Tables 1a and 1b. In normal operating mode, receiver inputs are internally connected to ground with 5kΩ resistors. So unconnected receivers with positive input thresholds have high outputs, and those with negative input thresholds have low outputs. When shut down, all receivers have positive thresholds. This allows the receiver inputs to respond to TTL-/CMOS-logic levels, as well as RS-232 levels. The guaranteed 0.8V input threshold ensures that receivers shorted to ground will have a logic 1 output. Also, the 300kΩ input resistance to ground ensures that a receiver with its input left open will also have a logic 1 output. The receiver’s 0.5V of hysteresis provides clean output transitions, even with slow rise-time and fall-time signals with moderate amounts of noise and ringing. The receivers have no hysteresis in shutdown mode. HI-Z Control The receiver inputs are terminated with 5kΩ resistors, to comply with the requirements of EIA/TIA-232E. However, these internal resistors can be disconnected by taking the HI-Z control pin to a logic high. This makes all of the MAX214’s receiver inputs high impedance, and facilitates the transmission of RS-232 data from a single transmitter to multiple receivers. In this case, all but one of the receiving ICs should be put into the high input-impedance state. 8 RTA, RTB, RTC, RDTC RRE Shutdown Control In shutdown mode, the charge pumps are turned off, V+ is pulled down to VCC, V- is pulled to ground, and the transmitter outputs are disabled. This reduces supply current typically to 4µA. The time required to exit shutdown is about 250µs, as shown in Figure 3. Receivers Receiver outputs never go into a high-impedance state; they are always active, even in shutdown mode (see Table 2). These awake-in-shutdown receivers are useful for monitoring external activity (for example, on RI), while maintaining minimal power consumption. Receivers in shutdown mode are slower (20kbps) than when not shut down (116kbps), and lack the hysteresis present in normal operation. Drivers The driver outputs are high impedance in shutdown mode, even when back-driven with voltages up to ±15V. __________Applications Information Capacitor Selection The type of capacitor (C1 to C4) used is not critical for proper operation. The MAX214 requires 1µF capacitors, although in all cases capacitors of up to 10µF can be used without harm. Ceramic dielectrics are suggested for the 1µF capacitors. _______________________________________________________________________________________ Programmable DTE/DCE, +5V RS-232 Transceiver pump capacitor sizes up to 10µF reduces the impedance of the V+ and V- outputs. High Data Rates The MAX214 maintains the RS-232 ±5.0V minimum driver output voltage even at high data rates. The Typical Operating Characteristics show transmitter output voltage levels driving 3kΩ in parallel with various capacitive loads at data rates up to 120kbps. To reduce the output impedance at V+ and V-, use larger capacitors (up to 10µF). This can be useful when “stealing” power from V+ or from V-. +10V A +5V Driver Outputs when Exiting Shutdown Figure 3 shows the MAX214 driver outputs when exiting shutdown. As they become active, the two driver outputs are shown going to opposite RS-232 levels (one driver input is high, the other is low). Each driver is loaded with 3kΩ in parallel with 2.5nF. 0V -5V B -10V +5V C 0V Power-Supply Bypassing Decouple VCC to ground with a capacitor of the same value as the charge-pump capacitors. V+ and V- as Power Supplies A small amount of power can be drawn from V+ and V-, although this will reduce noise margins. See the Output Voltage vs. Load Current graph in the Typical Operating Characteristics. Increasing the charge- A = TRANSMITTER OUTPUT HIGH, +5V/div B = TRANSMITTER OUTPUT LOW, +5V/div C = SHDN INPUT, +5V/div HORIZONTAL = 200µs Figure 3. Transmitter Outputs When Exiting Shutdown _______________________________________________________________________________________ 9 MAX214 When using the minimum recommended capacitor values, make sure the capacitance value does not degrade excessively as the operating temperature varies. If in doubt, use capacitors with a larger nominal value (for example, 2 times larger). The effective series resistance (ESR) of the capacitors may vary over temperature and increase when below 0°C. ESR influences the amount of ripple on V+ and V-, so if low ripple is required over wide temperature ranges, use larger capacitors or low-ESR types. MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver STANDARD RS-232 CABLE PC1 (DTE MODE) PC2 (DCE MODE) 5 TA TRA 9 3 TxD 3 9 TRA TA 5 6 RA RTA 10 2 RxD 2 10 RTA RA 6 25 TB TRB 20 7 RTS 7 20 TRB TB 25 23 RB RTB 19 8 CTS 8 19 RTB RB 23 24 TC TRC 18 4 DTR 4 18 TRC TC 24 22 RC RTC 17 6 DSR 6 17 RTC RC 22 RDTC 11 1 DCD 1 11 RDTC RRE 12 9 RI 9 12 RRE 7 RDC 8 RE RDC 7 MAX214 MAX214 RE 8 HIGH HIGH HI-Z SHDN 3 26 DTE/DCE 21 DB-9 CONNECTORS HI-Z SHDN 3 26 DTE/DCE POWER CONNECTIONS OMITTED FOR CLARITY. Figure 4. Typical Application Circuit Showing 2 PCs with Both DTE and DCE Operation 10 ______________________________________________________________________________________ 21 V CC Programmable DTE/DCE, +5V RS-232 Transceiver EIA/TIA-232E, V.28 SPECIFICATIONS PARAMETER CONDITIONS Driver Output Voltage 0 Level 1 Level Output Level, Max 3kΩ to 7kΩ load +5.0V to +15V 3kΩ to 7kΩ load -5.0V to -15V No load ±25V 3kΩ ≤ RL ≤ 7kΩ, CL ≤ 2500pF Up to 20kbits/sec Data Rate Receiver Input Voltage 0 Level 1 Level Input Level, Max Instantaneous Slew Rate, Max Driver Output Resistance HI-Z C2- C1C2+ C1+ SHDN TB TA TC RA RB RDC RC +3.0V to +15V 0.178" 4.52mm RE -3.0V to -15V DTE/DCE ±25V 3kΩ ≤ RL ≤ 7kΩ, CL ≤ 2500pF Driver Output Short-Circuit Current, Max Transition Rate on Driver Output ___________________Chip Topography TRA 30V/µs TRB RTB RTA 100mA RRE V.28 1ms or 3% of the period EIA/TIA-232E 4% of the period GND RDTC TRC V+ V- VCC RTC 0.156" 3.96mm TRANSISTOR COUNT: 694; SUBSTRATE CONNECTED TO V+. -2V < VOUT < +2V 300Ω Table 4. DB9/DB25 Cable Connections Commonly Used for EIA/TIA-232 and V.24 Asynchronous Interfaces DB9 PIN DB25 PIN NAME SYMBOL 1 8 Received Line Signal Detector, sometimes called Data Carrier Detect FUNCTION DCD Handshake from DCE 2 3 Receive Data RxD Data from DCE 3 2 Transmit Data TxD Data from DTE 4 20 Data Terminal Ready DTR Handshake from DTE 5 7 Signal Ground GND Reference point for signals 6 6 Data Set Ready DSR Handshake from DCE 7 4 Request to Send RTS Handshake from DTE 8 5 Clear to Send CTS Handshake from DCE 9 22 Ring Indicator RI Handshake from DCE ______________________________________________________________________________________ 11 MAX214 Table 3. Summary of EIA/TIA-232E, V.28 Specifications MAX214 Programmable DTE/DCE, +5V RS-232 Transceiver ________________________________________________________Package Information DIM D1 A A1 A2 A3 B B1 C D D1 E E1 e eA eB L α E A2 A3 E1 D A α A1 e C L eA B1 eB B DIM E A A1 B C D E e H h L α H INCHES MAX MIN 0.200 – – 0.015 0.175 0.125 0.080 0.055 0.020 0.016 0.065 0.045 0.012 0.008 1.470 1.430 0.090 0.050 0.625 0.600 0.575 0.525 0.100 BSC 0.600 BSC 0.700 – 0.150 0.125 15˚ 0˚ MILLIMETERS MIN MAX – 5.08 0.38 – 3.18 4.45 1.40 2.03 0.41 0.51 1.14 1.65 0.20 0.30 36.32 37.34 1.27 2.29 15.24 15.88 13.34 14.61 2.54 BSC 15.24 BSC – 17.78 3.18 3.81 0˚ 15˚ 21-342A 28-PIN PLASTIC DUAL-IN-LINE PACKAGE INCHES MAX MIN 0.104 0.093 0.012 0.004 0.019 0.014 0.013 0.009 0.713 0.697 0.299 0.291 0.050 BSC 0.419 0.394 0.030 0.010 0.050 0.016 8˚ 0˚ MILLIMETERS MIN MAX 2.35 2.65 0.10 0.30 0.35 0.49 0.23 0.32 17.70 18.10 7.40 7.60 1.27 BSC 10.00 10.65 0.25 0.75 0.40 1.27 0˚ 8˚ 21-343A D h x 45˚ α A 0.127mm 0.004in. e B A1 C L 28-PIN PLASTIC SMALL-OUTLINE PACKAGE 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 © 1995 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.