LT1280A/LT1281A Low Power 5V RS232 Dual Driver/Receiver with 0.1F Capacitors DESCRIPTIO EA U S F T RE n The LT 1280A/LT1281A are dual RS232 driver/receiver 10mA Max Supply Current n pairs with integral charge pump to generate RS232 volt- ESD Protection over 10kV n age levels from a single 5V supply. These circuits feature Uses Small Capacitors: 0.1F n rugged bipolar design to provide operating fault tolerance 120kBaud Operation for R = 3k, C = 2500pF L L n and ESD protection unmatched by competing CMOS 250kBaud Operation for R = 3k, C = 1000pF L L n designs. Using only 0.1F external capacitors, these cir- Outputs Withstand 30V Without Damage n cuits consume only 40mW of power, and can operate to CMOS Comparable Low Power: 40mW n 120kbaud even while driving heavy capacitive loads. New Operates from a Single 5V Supply n ESD structures on the chip allow the LT1280A/LT1281A to Rugged Bipolar Design n survive multiple 10kV strikes, eliminating the need for Outputs Assume a High Impedance State When Off costly TransZorbs on the RS232 line pins. The LT1280A/ or Powered Down n LT1281A are fully compliant with EIA RS232 standards. Meets All RS232 Specifications n Driver outputs are protected from overload, and can be Available With or Without Shutdown n shorted to ground or up to 30V without damage. During Absolutely No Latch-up n shutdown or power-off conditions, driver and receiver Available in SO Package outputs are in a high impedance state, allowing line sharing. PPLICATI S A The LT1281A is available in 16-pin DIP and SO packages. n Portable Computers The LT1280A is supplied in 18-pin DIP and SO packages n Battery-Powered Systems for applications which require shutdown. n Power Supply Generator n Terminals , LTC and LT are registered trademarks of Linear Technology Corporation. TransZorb is a registered trademark of General Instruments, GSI n Modems P CA A L AT TY I L PP IC I 2 17 5V INPUT + Output Waveforms 0.1F 4 3 + V OUT + 0.1F LT1280A DRIVER OUTPUT 5 7 V OUT + R = 3k L 0.1F C = 2500pF 0.1F + L 6 12 15 RS232 OUTPUT RECEIVER LOGIC OUTPUT INPUTS R 11 8 C = 50pF L RS232 OUTPUT 13 14 RS232 INPUT INPUT 5k LOGIC OUTPUTS 10 9 RS232 INPUT LT1280A TA02 5k 18 16 ON/OFF LT1280A TA01 1 UO UO ULT1280A/LT1281A ABSOLUTEXAI U RATI GS (Note 1) Short-Circuit Duration Supply Voltage (V ) ................................................ 6V CC + + V ................................................................... 30 sec V ........................................................................ 13.2V V ................................................................... 30 sec V ...................................................................... 13.2V Driver Output .............................................. Indefinite Input Voltage + Receiver Output .......................................... Indefinite Driver ........................................................... V to V Operating Temperature Range Receiver ............................................... 30V to 30V LT1280AC/LT1281AC ............................. 0C to 70C ON/OFF ................................................. 0.3V to 12V LT1280AI/LT1281AI .......................... 40C to 85C Output Voltage + Storage Temperature Range ................ 65C to 150C Driver ...................................... V 30V to V + 30V Lead Temperature (Soldering, 10 sec)................. 300C Receiver .................................... 0.3V to V + 0.3V CC PACKAGE/ORDER I FOR ATIO TOP VIEW TOP VIEW ORDER PART ORDER PART + NC 1 18 ON/OFF C1 V 1 16 CC NUMBER NUMBER + + 2 V C1 17 CC V 2 15 GND + 3 16 GND V C1 3 14 TR1 OUT + C1 4 15 TR1 OUT REC1 IN LT1280ACN C2 4 13 LT1281ACN + C2 5 14 REC1 IN C2 5 REC1 OUT 12 LT1280AIN LT1281AIN 6 13 REC1 OUT C2 V 6 11 TR1 IN LT1280ACSW LT1281ACSW 7 12 TR1 IN V TR2 OUT 7 10 TR2 IN LT1280AISW LT1281AISW TR2 OUT 8 11 TR2 IN REC2 IN 8 REC2 OUT 9 9 REC2 OUT REC2 IN 10 N PACKAGE 16-LEAD PDIP SW PACKAGE N PACKAGE 18-LEAD PDIP 16-LEAD PLASTIC SO WIDE SW PACKAGE 18-LEAD PLASTIC SO WIDE T = 125C, = 90C/ W, = 46C/W (N) JMAX JA JC T = 125C, = 80C/ W, = 36C/W (N) JMAX JA JC T = 125C, = 95C/ W, = 27C/W (SW) JMAX JA JC T = 125C, = 90C/ W, = 26C/W (SW) JMAX JA JC Consult factory for Military grade parts. (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 = 25C 8 10 mA CC A l 14 mA Supply Current When OFF (V ) Shutdown (Note 4) LT1280A Only l 110 A CC Supply Rise Time C1 = C2 = C3 = C4 = 0.1F 0.2 ms Shutdown to Turn-On LT1280A Only 0.2 ms ON/OFF Pin Thresholds Input Low Level (Device Shutdown) l 0.8 1.2 V Input High Level (Device Enabled) l 1.6 2.4 V ON/OFF Pin Current 0V V 5V l 15 80 A ON/OFF 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 2 U WU U W W W