ICL232 S E M I C O N D U C T O R +5V Powered, Dual RS-232 Transmitter/Receiver August 1997 Features Description • Meets All RS-232C and V.28 Specifications The ICL232 is a dual RS-232 transmitter/receiver interface circuit that meets all ElA RS-232C and V.28 specifications. It requires a single +5V power supply, and features two onboard charge pump voltage converters which generate +10V and -10V supplies from the 5V supply. • Requires Only Single +5V Power Supply • Onboard Voltage Doubler/Inverter • Low Power Consumption • 2 Drivers - ±9V Output Swing for +5V lnput - 300Ω Power-off Source Impedance - Output Current Limiting - TTL/CMOS Compatible - 30V/µs Maximum Slew Rate The drivers feature true TTL/CMOS input compatibility, slewrate-limited output, and 300Ω power-off source impedance. The receivers can handle up to +30V, and have a 3kΩ to 7kΩ input impedance. The receivers also have hysteresis to improve noise rejection. Ordering Information • 2 Receivers - ±30V Input Voltage Range - 3kΩ to 7kΩ Input Impedance - 0.5V Hysteresis to Improve Noise Rejection TEMP. RANGE (oC) PART NUMBER PKG. NO. PACKAGE ICL232CPE 0 to 70 16 Ld PDIP E16.3 • All Critical Parameters are Guaranteed Over the Entire Commercial, Industrial and Military Temperature Ranges ICL232CBE 0 to 70 16 Ld SOIC M16.3 Applications ICL232lPE -40 to 85 16 Ld PDIP E16.3 ICL232lJE -40 to 85 16 Ld CERDIP F16.3 ICL232lBE -40 to 85 16 Ld SOIC M16.3 ICL232MJE -55 to 125 16 Ld CERDIP F16.3 • Any System Requiring RS-232 Communications Port - Computer - Portable and Mainframe - Peripheral - Printers and Terminals - Portable Instrumentation - Modems • Dataloggers Pinout Functional Diagram +5V ICL232 (PDIP, CERDIP, SOIC) TOP VIEW C1+ 1 V+ 2 C1- 3 C2+ 4 C2- 5 1 16 VCC 1µF 15 GND + 3 4 14 T1OUT 1µF + 5 13 R1IN 12 R1OUT V- 6 11 T1IN T2OUT 7 10 T2IN R2IN 8 + 1.0µF 9 T1IN T2IN C1+ C1C2+ C2- 16 VCC 2 +5V TO 10V VOLTAGE INVERTER V+ +10V TO -10V VOLTAGE INVERTER T1 +5V 400kΩ T2 14 7 12 13 R1OUT R2OUT 1µF T1OUT T2OUT R1IN 5kΩ R1 R2OUT 1µF V- 6 + +5V 400kΩ 11 10 + 9 8 R2IN 5kΩ R2 15 CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures. Copyright © Harris Corporation 1997 8-49 File Number 3020.5 ICL232 Absolute Maximum Ratings Thermal Information VCC to Ground . . . . . . . . . . . . . . . . . . . . . .(GND -0.3V) < VCC < 6V V+ to Ground . . . . . . . . . . . . . . . . . . . . . . . (VCC -0.3V) < V+ < 12V V- to Ground . . . . . . . . . . . . . . . . . . . . . . . -12V < V- < (GND +0.3V) Input Voltages T1IN , T2IN . . . . . . . . . . . . . . . . . . . . (V- -0.3V) < VIN < (V+ +0.3V) R1IN , R2IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±30V Output Voltages T1OUT , T2OUT . . . . . . . . . . . . (V- -0.3V) < VTXOUT < (V+ +0.3V) R1OUT , R2OUT . . . . . . . . .(GND -0.3V) < VRXOUT < (VCC +0.3V) Short Circuit Duration T1OUT , T2OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous R1OUT , R2OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Thermal Resistance (Typical, Note 1) θJA (oC/W) θJC (oC/W) CERDIP Package . . . . . . . . . . . . . . . . 80 18 PDIP Package . . . . . . . . . . . . . . . . . . . 100 N/A SOIC Package . . . . . . . . . . . . . . . . . . . 100 N/A Maximum Junction Temperature Plastic Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150oC Ceramic Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175oC Maximum Storage Temperature Range . . . . . . . . . .-65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oC Operating Conditions Temperature Ranges ICL232C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0oC to 70oC ICL232I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40oC to 85oC ICL232M . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications Test Conditions: VCC = +5V ±10%, TA = Operating Temperature Range. Test Circuit as in Figure 8 Unless Otherwise Specified PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Transmitter Output Voltage Swing, TOUT T1OUT and T2OUT Loaded with 3kΩ to Ground ±5 ±9 ±10 V Power Supply Current, ICC Outputs Unloaded, TA = 25oC - 5 10 mA TIN , Input Logic Low, VlL - - 0.8 V TIN , Input Logic High, VlH 2.0 - - V - 15 200 µA -30 - +30 V Logic Pullup Current, IP T1IN , T2IN = 0V RS-232 Input Voltage Range, VIN Receiver Input Impedance, RIN VIN = ±3V 3.0 5.0 7.0 kΩ Receiver Input Low Threshold, VlN (H-L) VCC = 5V, TA = 25oC 0.8 1.2 - V Receiver Input High Threshold, VIN (L-H) VCC = 5V, TA = 25oC - 1.7 2.4 V 0.2 0.5 1.0 V Receiver Input Hysteresis, VHYST TTL/CMOS Receiver Output Voltage Low, VOL IOUT = 3.2mA - 0.1 0.4 V TTL/CMOS Receiver Output Voltage High, VOH IOUT = -1.0mA 3.5 4.6 - V Propagation Delay, tPD RS-232 to TTL - 0.5 - µs Instantaneous Slew Rate, SR CL = 10pF, RL = 3kΩ, TA = 25oC (Notes 2, 3) - - 30 V/µs Transition Region Slew Rate, SRT RL = 3kΩ, CL = 2500pF Measured from +3V to -3V or -3V to +3V - 3 - V/µs Output Resistance, ROUT VCC = V+ = V- = 0V, VOUT = ±2V 300 - - Ω RS-232 Output Short Circuit Current, ISC T1OUT or T2OUT Shorted to GND - ±10 - mA NOTES: 2. Guaranteed by design. 3. See Figure 4 for definition. 8-50 ICL232 Test Circuits 1 C1+ +4.5V TO +5.5V INPUT - 1µF C3 + 1 C1+ 2 V+ VCC 16 2 V+ VCC 16 GND 15 3 C1- T1OUT 14 4 C2+ R1IN 13 5 C2- R1OUT 12 + 1µF C1 - GND 15 3kΩ 3 1µF + C2 - T1OUT 14 C1- T1 OUTPUT RS-232 ±30V INPUT TTL/CMOS OUTPUT 4 C2+ R1IN 13 5 C2- R1OUT 12 6 V- T1IN 11 TTL/CMOS INPUT 7 T2OUT T2IN 10 TTL/CMOS INPUT 8 R2IN 9 TTL/CMOS OUTPUT 1µF C4 - + 3kΩ T2 OUTPUT RS-232 ±30V INPUT R2OUT 6 V- T1IN 11 7 T2OUT T2IN 10 8 R2IN R2OUT 9 ROUT = VIN/I VIN = ±2V T2OUT A T1OUT FIGURE 1. GENERAL TEST CIRCUIT FIGURE 2. POWER-OFF SOURCE RESISTANCE CONFIGURATION Typical Performance Curves 10 500 9 o 450 TA = 25 C EXTERNAL SUPPLY LOAD 400 1kΩ BETWEEN V+ + GND OR V- + GND 350 TRANSMITTER OUTPUT V- SUPPLY OUTPUT VOLTAGE (|V|) V+, V- SUPPLY IMPEDANCES (Ω) 550 OPEN CIRCUIT 300 250 GUARANTEED OPERATING RANGE V+ SUPPLY V+ (VCC = 5V) 8 V+ (VCC = 4.5V) 7 6 5 TA = 25oC 4 200 150 3 4 5 V- (VCC = 5V) V- (VCC = 4.5V) TRANSMITTER OUTPUTS OPEN CIRCUIT 3 6 0 1 2 3 4 INPUT SUPPLY VOLTAGE VCC (V) 5 6 7 8 9 10 |ILOAD| (mA) FIGURE 3. V+, V- OUTPUT IMPEDANCES vs VCC FIGURE 4. V+, V- OUTPUT VOLTAGES vs LOAD CURRENT Pin Descriptions PDIP, CERDIP SOIC PIN NAME 1 1 C1+ DESCRIPTION 2 2 V+ 3 3 C1- External capacitor “-” for internal voltage doubler. 4 4 C2+ External capacitor “+” internal voltage inverter. 5 5 C2- External capacitor “-” internal voltage inverter. 6 6 V- 7 7 T2OUT External capacitor “+” for internal voltage doubler. Internally generated +10V (typical) supply. Internally generated -10V (typical) supply. RS-232 Transmitter 2 output ±10V (typical). 8 8 R2IN RS-232 Receiver 2 input, with internal 5K pulldown resistor to GND. 9 9 R2out Receiver 2 TTL/CMOS output. 10 10 T2IN Transmitter 2 TTL/CMOS input, with internal 400K pullup resistor to VCC . 11 11 T1IN Transmitter 1 TTL/CMOS input, with internal 400K pullup resistor to VCC . 8-51 ICL232 Pin Descriptions (Continued) PDIP, CERDIP SOIC PIN NAME 12 12 R1OUT 13 13 R1IN 14 14 T1OUT 15 15 GND Supply Ground. 16 16 VCC Positive Power Supply +5V ±10% DESCRIPTION Receiver 1 TTL/CMOS output. RS-232 Receiver 1 input, with internal 5K pulldown resistor to GND. RS-232 Transmitter 1 output ±10V (typical). VOLTAGE DOUBLER S1 C1+ VOLTAGE INVERTER S2 V+ = 2VCC C2+ S5 S6 VCC GND + GND C1- S3 + C1 - + C3 VCC + C2 - C4 GND S4 C2- S7 V- = -(V+) S8 RC OSCILLATOR FIGURE 5. DUAL CHARGE PUMP Detailed Description The ICL232 is a dual RS-232 transmitter/receiver powered by a single +5V power supply which meets all ElA RS232C specifications and features low power consumption. The functional diagram illustrates the major elements of the ICL232. The circuit is divided into three sections: a voltage doubler/inverter, dual transmitters, and dual receivers Voltage Converter. An equivalent circuit of the dual charge pump is illustrated in Figure 5. The voltage quadrupler contains two charge pumps which use two phases of an internally generated clock to generate +10V and -10V. The nominal clock frequency is 16kHz. During phase one of the clock, capacitor C1 is charged to VCC . During phase two, the voltage on C1 is added to VCC , producing a signal across C2 equal to twice VCC . At the same time, C3 is also charged to 2VCC , and then during phase one, it is inverted with respect to ground to produce a signal across C4 equal to -2VCC . The voltage converter accepts input voltages up to 5.5V. The output impedance of the doubler (V+) is approximately 200Ω, and the output impedance of the inverter (V-) is approximately 450Ω . Typical graphs are presented which show the voltage converters output vs input voltage and output voltages vs load characteristics. The test circuit (Figure 3) uses 1µF capacitors for C1-C4, however, the value is not critical. Increasing the values of C1 and C2 will lower the output impedance of the voltage doubler and inverter, and increasing the values of the reservoir capacitors, C3 and C4, lowers the ripple on the V+ and V- supplies. T1IN, T2IN 90% 10% T1OUT, T2OUT tf VOH VOL tr (0.8) (VOH - VOL) (0.8) (VOL - VOH) Instantaneous = or Slew Rate (SR) tr tf FIGURE 6. SLEW RATE DEFINITION Transmitters The transmitters are TTL/CMOS compatible inverters which translate the inputs to RS-232 outputs. The input logic threshold is about 26% of VCC , or 1.3V for VCC = 5V. A logic 1 at the input results in a voltage of between -5V and V- at the output, and a logic 0 results in a voltage between +5V and (V+ - 0.6V). Each transmitter input has an internal 400kΩ pullup resistor so any unused input can be left unconnected and its output remains in its low state. The output voltage swing meets the RS-232C specification of ±5V minimum with the worst case conditions of: both transmitters driving 3kΩ minimum load impedance, VCC = 4.5V, and maximum allowable operating temperature. The transmitters have an internally limited output slew rate which is less than 30V/µs. The outputs are short circuit protected and can be shorted to ground indefinitely. The powered down output impedance is a minimum of 300Ω with ±2V applied to the outputs and VCC = 0V. V+ VCC 400kΩ 300Ω TXIN TOUT GND < TXIN < VCC V- < VTOUT < V+ V- FIGURE 7. TRANSMITTER Receivers The receiver inputs accept up to ±30V while presenting the required 3kΩ to 7kΩ input impedance even it the power is off (VCC = 0V). The receivers have a typical input threshold of 1.3V which is within the ±3V limits, known as the transition region, of the RS-232 specification. The receiver output is 0V to VCC . The output will be low whenever the input is greater than 2.4V and high whenever the input is floating or driven between +0.8V and -30V. The receivers feature 0.5V hysteresis to improve noise rejection. 8-52 ICL232 is generated by driving them through a 5kΩ resistor connected to V+. VCC RXIN -30V < RXIN < +30V ROUT 5kΩ +5V GND 16 1 C1 + 1µF - FIGURE 8. RECEIVER T1IN, T2IN OR R1IN, R2IN T1OUT, T2OUT OR R1OUT, R2OUT - C3 + 1µF 5kΩ 2 GND < VROUT < VCC 5kΩ 3 ICL232 6 4 C2 + 1µF VOH TD T1 11 tPHL + tPLH Average Propagation Delay = 2 CTS 9 R2 1 RTS RD (3) RECEIVE DATA CTS (5) CLEAR TO SEND SIGNAL GROUND (7) - 14 T2 10 + C2 1µF 5 T1 11 TD (2) TRANSMIT DATA 7 RTS (4) REQUEST TO SEND 13 12 RD (3) RECEIVE DATA RD CTS RTS (4) REQUEST TO SEND 4 ICL232 3 9 TD (2) TRANSMIT DATA In applications requiring four RS-232 inputs and outputs (Figure 11), note that each circuit requires two charge pump capacitors (C1 and C2) but can share common reservoir capacitors (C3 and C4). The benefit of sharing common reservoir capacitors is the elimination of two capacitors and the reduction of the charge pump source impedance which effectively increases the output swing of the transmitters. A simple duplex RS-232 port with CTS/RTS handshaking is illustrated in Figure 10. Fixed output signals such as DTR (data terminal ready) and DSRS (data signaling rate select) INPUTS OUTPUTS TTL/CMOS 8 C4 1µF RS-232 INPUTS AND OUTPUTS FIGURE 10. SIMPLE DUPLEX RS-232 PORT WITH CTS/RTS HANDSHAKING The ICL232 may be used for all RS-232 data terminal and communication links. It is particularly useful in applications where ±12V power supplies are not available for conventional RS-232 interface circuits. The applications presented represent typical interface configurations. TD R1 15 Applications 7 13 FIGURE 9. PROPAGATION DELAY DEFINITION C1 + 1µF - 14 T2 INPUTS RTS OUTPUTS 12 TTL/CMOS RD tPLH + 10 VOL tPHL 5 R2 R1 8 CTS (5) CLEAR TO SEND 15 6 - 2 C3 + + C4 V- V+ 2µF 6 - 2 µF 2 16 +5V RS-232 INPUTS AND OUTPUTS ICL232 C1 + 1µF DTR INPUTS OUTPUTS TTL/CMOS DSRS 1 4 3 5 T1 11 14 T2 10 12 7 13 DCD R1 9 R2 CTR (20) DATA TERMINAL READY DSRS (24) DATA SIGNALING RATE SELECT R1 15 8 + C2 1µF - DTR (20) DATA TERMINAL READY DSRS (24) DATA SIGNALING RATE SELECT DCD (8) DATA CARRIER DETECT R1 (22) RING INDICATOR SIGNAL GROUND (7) FIGURE 11. COMBINING TWO ICL232s FOR 4 PAIRS OF RS-232 INPUTS AND OUTPUTS 8-53