DS232A Dual RS-232 Transmitter/Receiver www.dalsemi.com FEATURES PIN ASSIGNMENT Compatible with LT1181A and MAX232A High data rate - 250 kbits/sec under load 16-pin DIP or SOIC package 20-pin TSSOP package for height restricted applications Operate from single +5V power Meets all EIA-232E and V0.28 specifications Uses small capacitors: 0.1 µF Optional industrial temperature range available (-40°C to +85°C) C1+ V+ C1C2+ C2VT2OUT R2IN 16 15 14 13 12 11 10 9 VCC GND T1OUT R1IN R1OUT T1IN T2IN R2OUT 16-Pin DIP AND SOIC C1+ V+ C1C2+ NC C2VNC T2OUT R2IN ORDERING INFORMATION DS232A DS232A-N DS232AR DS232AR-N DS232AS DS232AS-N DS232AE DS232AE-N 1 2 3 4 5 6 7 8 16-pin DIP 16-pin DIP (Industrial) 16-pin SOIC (150-Mil) 16-pin SOIC (150-Mil) (Industrial) 16-pin SOIC (300-Mil) 16-pin SOIC (300-Mil) (Industrial) 20-pin TSSOP 20-pin TSSOP (Industrial) 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 NC VCC GND T1OUT R1IN R1OUT NC T1IN T2IN R2OUT 20-Pin TSSOP PIN DESCRIPTION VCC GND V+ VT1IN, T2IN T1OUT, T2OUT R1IN, R2IN R1OUT, R2OUT C1+, C1C2+, C2- - +5-Volt Supply - Ground - Positive Supply Output - Negative Supply Output - RS-232 Driver Inputs - RS-232 Driver Outputs - Receiver Inputs - Receiver Outputs - Capacitor 1 Connections - Capacitor 2 Connections DESCRIPTION The DS232A is a dual RS-232 driver/receiver pair that generates RS-232 voltage levels from a single +5volt power supply. Additional ±12-volt supplies are not needed since the DS232A uses on-board charge pumps to convert the +5-volt supply to ±10 volts. The DS232A is fully compliant with EIA RS-232E and V0.28/V0.24 standards. The DS232A contains two drivers and two receivers. Driver slew rates and data rates are guaranteed up to 250k bits/sec. The DS232A operates with only 0.1 µF charge pump capacitors. OPERATION The diagram in Figure 1 shows the main elements of the DS232A. The following paragraphs describe the function of each pin. 1 of 10 112099 DS232A FUNCTIONAL DIAGRAM OF DS232A Figure 1 NOTE: C5 is a recommended decoupling capacitor which is the same value as C1, C2, C3, and C4. ( ) Are for TSSOP package only. PIN DESCRIPTIONS VCC, GND: DC power is provided to the device on these pins. VCC is the +5-volt input. V+: Positive supply output (RS-232). V+ requires an external storage charge capacitor of at least 0.1 µF. A larger capacitor (up to 10 µF) can be used to reduce supply ripple. V-: Negative supply output (RS-232). V- requires an external storage capacitor of at least 0.1 µF. A larger capacitor (up to 10 µF) can be used to reduce supply ripple. T1IN, T2 IN: Standard TTL/CMOS inputs for the RS-232 drivers. The inputs of unused drivers can be left unconnected since each input has a 400 kΩ pullup resistor. T1OUT, T2 OUT: Driver outputs at RS-232 levels. Driver output swing meets RS-232 levels for loads up to 3 kΩ. These driver outputs provide current necessary to meet RS-232 levels for loads up to 2500 pF. 2 of 10 DS232A R1 IN, R2 IN: Receiver inputs. These inputs accept RS-232 level signals (±25 volts) into a protected 5 kΩ terminating resistor. Each receiver provides 0.5V hysteresis (typical) for noise immunity. R1 OUT, R2 OUT: Receiver outputs at TTL/CMOS levels. C1+, C1-, C2+, C2-: Charge pump capacitor inputs. These pins require two external capacitors (0.1 µF minimum, 10 µF maximum and should be the same size as C3 and C4). Capacitor 1 is connected between C1+ and C1-. Capacitor 2 is connected between C2+ and C2-. Capacitor C1 can be omitted if +12 volts is connected directly to V+. Likewise, C2 can be omitted if -12V is connected directly to V-. DUAL CHARGE PUMP CONVERTERS The DS232A has a two-stage on-board charge pump circuit that is used to generate ±10 volts from a single +5-volt supply. In the first stage, capacitor C1 doubles the +5V supply to +10 volts which is then stored on capacitor C3. The second stage uses capacitor C2 to invert the +10V potential to -10V. This charge is then stored on capacitor C4. The ±10-volt supplies allow the DS232A to provide the necessary output levels for RS-232 communication. The DS232A will operate with charge pump capacitors as low as 0.1 µF. Larger capacitors (up to 10 µF) can be used to reduce supply ripple. RS-232 DRIVERS The two RS-232 drivers are powered by the internal ±10-volt supplies generated by the on-board charge pump. The driver inputs are both TTL and CMOS compatible. Each input has an internal 400 kΩ=pullup resistor so that unused transmitter inputs can be left unconnected. The open circuit output voltage swing is from (V+ - 0.6) to V- volts. Worst case conditions for EIA-232E/V.28 of ±5-volt driving a 3 kΩ=load and 2500 pF are met at maximum operating temperature and VCC equal to 4.5 volts. Typical voltage swings of ±8 volts occur when loaded with a nominal 5 kΩ=RS-232 receiver. As required by EIA-232E and V.28 specifications, the slew rate at the output is limited to less than 30 volts/µs. Typical slew rates are 20 volts/µs unloaded and 12 volts/µs with 3 kΩ=and 2500 pF load. These slew rates allow for bit rates of over 250k bits/s. Driver outputs maintain high impedance when power is off. RS-232 RECEIVERS The two receivers conform fully to the RS-232E specifications. The input impedance is typically 5 kΩ=and can withstand up to ±25 volts with or without VCC applied. The input switching thresholds are within the ±3-volt limit of RS-232E specification with an input threshold low of 0.8 volts and an input threshold high of 2.4 volts. The receivers have 0.5 volts of hysteresis (typical) to improve noise rejection. The TTL/CMOS compatible outputs of the receivers will be low whenever the RS-232 input is greater than 2.4 volts. The receiver output will be high when the input is floating or driven between +0.8 volts and -25 volts. 3 of 10 DS232A ABSOLUTE MAXIMUM RATINGS* Absolute Maximum Ratings VCC V+ V- -0.3V to +7.0V (VCC-0.3V) to +14V +0.3V to -14V Input Voltages TIN RIN -0.3V to (VCC+0.3V) ±30V Output Voltages TOUT ROUT Short Circuit Duration, TOUT (V+ + 0.3V) to (V- - 0.3V) -0.3V to (VCC+ 0.3V) Continuous * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. RECOMMENDED DC OPERATING CONDITIONS PARAMETER Operating Supply Voltage SYMBOL VCC MIN 4.5 (0°C to 70°C) TYP MAX 5.5 DC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL UNITS V NOTES 1 (0°C to 70°C) MIN TYP MAX UNITS 10 mA Power Supply Current (No Load) ICC1 4 Power Supply Current (3 kΩ Load All Outputs) ICC2 15 mA NOTES RS-232 Transmitters Output Voltage Swing VORS ±5 ±8 V Input Logic Threshold Low VTTL 0.8 1.4 V Input Logic Threshold High VTTH Maximum Data Rate fD Logic Pullup/Input Current IPU 1.4 250 350 5 Transmitter Output Resistance ROUT 300 10M Output Short-Circuit Current ITSC ±15 ±30 4 of 10 2.0 2 V k bits/s 40 ±100 µA Ω 3 mA 4 DS232A DC ELECTRICAL CHARACTERISTICS (continued) (0°C to 70°C) RS-232 Receivers RS-232 Input Voltage Operating Range VIR ±25 ±30 V RS-232 Input Threshold Low VRTL 0.8 1.3 V RS-232 Input Threshold High VRTH RS-232 Input Hysteresis VHY RS-232 Input Resistance RIN 1.8 2.4 V 0.2 0.5 1 V 3 5 7 kΩ 0.2 0.4 V 5 6 TTL/CMOS Output Voltage Low VROL TTL/CMOS Output Voltage High VROH 3.5 VCC-0.2 V TTL/CMOS Output Short Circuit Current (VOUT=GND) IRSC -2 -10 mA TTL/CMOS Output Short Circuit Current (VOUT=VCC) IRSC 10 30 mA AC ELECTRICAL CHARACTERISTICS PARAMETER Transition Slew Rate SYMBOL tSR (0°C to 70°C) MIN 6 TYP 12 MAX 30 UNITS V/µs Transmitter Propagation Delay TTL to RS-232 tPHLT tPLHT 1.3 1.5 3.5 3.5 µs µs Receiver Propagation Delay RS-232 to TTL tPHLR tPLHR 0.5 0.6 1 1 µs µs Transmitter + to - Propagation Delay Difference tPHLT -tPLHT 300 ns Receiver + to - Propagation Delay Difference tPHLR -tPLHR 100 ns NOTES: 1. All voltages are referenced to ground. 2. All transmitter outputs loaded with 3 kΩ=to ground 3. VCC = V+ = V- = 0V; VOUT = ±2V. 4. VOUT = 0V. 5. IOUT = 3.2 mA. 6. IOUT = -1.0 mA. 7. CL = 50 pF - 2500 pF; RL = 3 kΩ=- 7 kΩ; VCC = 5V; TA = 25°C. 5 of 10 NOTES 7 DS232A TRANSMITTER PROPAGAION DELAY TIMING Figure 2 RECEIVER PROPAGATION DELAY TIMING Figure 3 6 of 10 DS232A 16-PIN DIP (300-MIL) PKG 16-PIN DIM MIN MAX A IN. MM 0.740 18.80 0.780 19.81 B IN. MM 0.240 6.10 0.260 6.60 C IN. MM 0.120 3.05 0.140 3.56 D IN. MM 0.300 7.62 0.325 8.26 E IN. MM 0.015 0.38 0.040 1.02 F IN. MM 0.120 3.04 0.140 3.56 G IN. MM 0.090 2.29 0.110 2.79 H IN. MM 0.320 8.13 0.370 9.40 J IN. MM 0.008 0.20 0.012 0.30 K IN. MM 0.015 0.38 0.021 0.53 7 of 10 DS232A 16-PIN SOIC (150-MIL) PKG 16-PIN DIM MIN MAX A IN. MM 0.053 1.35 0.069 1.75 A1 IN. MM 0.004 0.10 0.010 0.25 A2 IN. MM 0.048 1.24 0.062 1.57 B IN. MM 0.012 0.30 0.020 0.50 C IN. MM 0.007 0.17 0.011 0.28 D IN. MM 0.386 9.80 0.393 9.98 E IN. MM 0.050 BSC 1.27 BSC E1 IN. MM 0.150 3.81 0.158 4.01 H IN. MM 0.230 5.84 0.244 6.20 L IN. MM 0.016 0.40 0.050 0.89 Θ 0° 8° 8 of 10 DS232A 16-PIN SOIC (300-MIL) PKG 16-PIN DIM MIN MAX A IN. MM 0.094 2.39 0.105 2.67 A1 IN. MM 0.004 0.102 0.012 0.30 A2 IN. MM 0.089 2.26 0.095 2.41 b IN. MM 0.013 0.33 0.020 0.51 C IN. MM 0.009 0.229 0.013 0.33 D IN. MM 0.398 10.11 0.412 10.46 E IN. MM 0.050 BSC 1.27 BSC E1 IN. MM 0.290 7.37 0.300 7.62 H IN. MM 0.398 10.11 0.416 10.57 L IN. MM 0.016 0.40 0.040 1.02 Θ 0° 8° 9 of 10 DS232A 20-PIN TSSOP DIM MIN MAX A MM - 1.10 A1 MM 0.05 - A2 MM 0.75 1.05 C MM 0.09 0.18 L MM 0.50 0.70 e1 MM 0.65 BSC B MM 0.18 0.30 D MM 6.40 6.90 E MM 4.40 NOM G MM 0.25 REF H MM 6.25 6.55 phi 0° 8° 10 of 10