LT1381 Low Power 5V RS232 Dual Driver/Receiver with 0.1m F Capacitors DESCRIPTIO FEATURES n ESD Protection over 10kV The LT 1381 is a dual RS232 driver/receiver pair with n Low Cost integral charge pump to generate RS232 voltage levels n Uses Small Capacitors: 0.1m F from a single 5V supply. The circuit features rugged n CMOS Comparable Low Power: 40mW bipolar design to provide operating fault tolerance and n Operates from a Single 5V Supply ESD protection unmatched by competing CMOS designs. n 120kBaud Operation for R = 3k, C = 2500pF Using only 0.1m F external capacitors, the circuit con- L L n 250kBaud Operation for R = 3k, C = 1000pF sumes only 40mW of power and can operate to 120kbaud L L n Rugged Bipolar Design even while driving heavy capacitive loads. New ESD struc- n Outputs Assume a High Impedance State When tures on the chip allow the LT1381 to survive multiple Powered Down 10kV strikes, eliminating the need for costly TransZorbs n Absolutely No Latchup on the RS232 line pins. Driver outputs are protected from n Available in Narrow SO Package overload and can be shorted to ground or up to 25V without damage. During power-off conditions, driver and receiver outputs are in a high impedance state, allowing PP IC I A L AT S line sharing. n Portable Computers n Battery-Powered Systems , LTC and LT are registered trademarks of Linear Technology Corporation. n Power Supply Generator TransZorb is a registered trademark of General Instruments, GSI n Terminals n Modems TYPICAL APPLICATI 1 16 5V INPUT + Output Waveforms 0.1F 3 2 + V OUT + DRIVER 0.1F LT1381 OUTPUT = 3k R L 4 6 C = 2500pF V OUT L + 0.1F 0.1F + 5 11 14 RECEIVER RS232 OUTPUT OUTPUT R LOGIC C = 50pF INPUTS L 10 7 RS232 OUTPUT 12 13 RS232 INPUT INPUT 5k LOGIC OUTPUTS 9 8 S RS232 INPUT LT1381 TA02 5k 15 LT1381 TA01 1 O U UO ULT1381 ABSOLUTEXAI U RATI GS / PACKAGE ORDER I FOR ATIO (Note 1) ORDER PART Supply Voltage (V ) ................................................ 6V TOP VIEW CC NUMBER + V ........................................................................ 13.2V + C1 1 16 V CC V ...................................................................... 13.2V + 2 GND V 15 LT1381CN Input Voltage 3 14 TR1 OUT C1 + LT1381CS Driver ........................................................... V to V + C2 4 13 REC1 IN LT1381IS Receiver ............................................... 30V to 30V 5 C2 12 REC1 OUT Output Voltage 6 11 TR1 IN + V Driver ................................. (V 30V) to (V + 30V) 7 10 TR2 IN TR2 OUT Receiver ................................. 0.3V to (V + 0.3V) CC REC2 IN 8 9 REC2 OUT Short-Circuit Duration + V ................................................................... 30 sec N PACKAGE S PACKAGE 16-LEAD PLASTIC DIP 16-LEAD PLASTIC SOIC V ................................................................... 30 sec Driver Output .............................................. Indefinite T = 125 C, q = 90 C/ W, q = 46 C/W (N) JMAX JA JC Receiver Output .......................................... Indefinite T = 125 C, q = 110 C/ W, q = 34 C/W (S) JMAX JA JC Operating Temperature Range LT1381C ................................................. 0 C to 70 C Consult factory for Military grade parts. LT1381I .............................................. 40 C to 85 C Storage Temperature Range ................ 65 C to 150 C Lead Temperature (Soldering, 10 sec)................. 300 C (Note 2) ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply Generator + V Output 7.9 V V Output 7.0 V Supply Current (V ) (Note 3), T = 25 C814mA CC A l 16 mA Supply Rise Time C1 = C2 = C3 = C4 = 0.1m F 0.2 ms Oscillator Frequency 130 kHz Driver Output Voltage Swing Load = 3k to GND Positive l 5.0 7.5 V Negative l 6.3 5.0 V Logic Input Voltage Level Input Low Level (V = High) l 1.4 0.8 V OUT Input High Level (V = Low) l 2.0 1.4 V OUT Logic Input Current 0.8V V 2.0V l 520 m A IN Output Short-Circuit Current V = 0V 9 17 mA OUT Output Leakage Current Power Off V = 15V l 10 100 m A OUT Data Rate R = 3k, C = 2500pF 120 kBaud L L R = 3k, C = 1000pF 250 kBaud L L Slew Rate R = 3k, C = 51pF 15 30 V/m s L L R = 3k, C = 2500pF 4 6 V/m s L L Propagation Delay Output Transition t High to Low (Note 4) 0.6 1.3 m s HL Output Transition t Low to High 0.5 1.3 m s LH 2 U WU U W W W