LT1237 5V RS232 Transceiver with Advanced Power Management and One Receiver Active in Shutdown FEATURES DESCRIPTIO n One Receiver Remains Active While in Shutdown The LT 1237 is an advanced low power three driver, five n ESD Protection over 15kV receiver RS232 transceiver. Included on the chip is a n Uses Small Capacitors: 0.1m F, 0.2m F, 1.0m F shutdown pin for reducing supply current near zero. n 60m A Supply Current in Shutdown During shutdown one receiver remains active to detect n Pin Compatible with LT1137A incoming RS232 signals, for example, to wake up a n 120kBaud Operation for R = 3k, C = 2500pF system. L L n 250kBaud Operation for R = 3k, C = 1000pF L L The LT1237 is fully compliant with all EIA RS232 specifi- n Operates to 120kBaud cations. New ESD structures on the chip allow the LT1237 n CMOS Comparable Low Power 30mW to survive multiple 15kV strikes, eliminating the need for n Operates from a Single 5V Supply costly TransZorbs on the RS232 line pins. n Easy PC LayoutFlowthrough Architecture n The LT1237 operates in excess of 120kbaud even driving Rugged Bipolar Design n heavy capacitive loads. Two shutdown modes allow the Outputs Assume a High Impedance State When Off driver outputs to be shut down separately from the receiv- or Powered Down n ers for more versatile control of the RS232 interface. Absolutely No Latchup n During shutdown, drivers and receivers assume a high Available in SO and SSOP Packages impedance state. U , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S TransZorb is a registered trademark of General Instruments, GSI n Notebook Computers n Palmtop Computers TYPICAL APPLICATIO Output Waveforms + 1 28 V V LT1237 2 27 1.0m F 0.1m F 5V V RECEIVER CC 2 0.1m F OUTPUT 3 26 C = 50pF L 2 0.1m F 4 25 DRIVER 1 IN 5 24 DRIVER DRIVER 1 OUT RX1 OUT 6 23 OUTPUT RX1 IN DRIVER 2 IN R = 3k L 7 22 C = 2500pF DRIVER 2 OUT RX2 OUT L TO LOGIC R 8 21 RX2 IN RX3 OUT TO 9 20 LINE RX3 IN RX4 OUT INPUT 10 19 RX4 IN DRIVER 3 IN 11 18 RX5 OUT (LOW-Q) DRIVER 3 OUT RING DETECT IN 12 17 GND RX5 IN (LOW-Q) 1237 TA02 m CONTROLLER OR DRIVER 13 16 ON/OFF m PROCESSOR DISABLE 14 15 SHUTDOWN CONTROL OUT LT1237 TA01 1 U ULT1237 ABSOLUTEXAI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART TOP VIEW Supply Voltage (V ) ................................................ 6V CC NUMBER + + V ........................................................................ 13.2V V 1 28 V V ...................................................................... 13.2V 5V V 2 27 C2 CC + + LT1237CG C1 3 26 C2 Input Voltage LT1237CNW + C1 4 25 DR1 IN Driver ........................................................... V to V DR1 OUT 5 24 RX1 OUT LT1237CSW Receiver ............................................... 30V to 30V RX1 IN 6 23 DR2 IN Output Voltage DR2 OUT 7 22 RX2 OUT Driver .................................................... 30V to 30V RX2 IN 8 21 RX3 OUT Receiver .................................... 0.3V to V + 0.3V RX3 IN 9 20 RX4 OUT CC RX4 IN 10 19 DR3 IN Short Circuit Duration RX5 OUT DR3 OUT 11 + 18 (LOW-Q) V ................................................................... 30 sec RX5 IN 12 17 GND (LOW-Q) V ................................................................... 30 sec DRIVER 13 16 ON/OFF DISABLE Driver Output .............................................. Indefinite NC 14 15 NC Receiver Output .......................................... Indefinite G PACKAGE NW PACKAGE Operating Temperature Range 28-LEAD PLASTIC SSOP 28-LEAD (WIDE) PDIP LT1237C ................................................. 0 C to 70 C SW PACKAGE 28-LEAD (WIDE) PLASTIC SO Storage Temperature Range ................ 65 C to 150 C T = 150 C, q = 96 C/ W (G) JMAX JA Lead Temperature (Soldering, 10 sec)................. 300 C T = 150 C, q = 56 C/ W (NW) JMAX JA T = 150 C, q = 85 C/ W (SW) JMAX JA Consult factory for Industrial and Military grade parts. LECTR AL CHARACTERIST The l denotes specifications which apply over the full operating E IC ICS temperature range, otherwise specifications are at T = 25 C. (Note 2) A PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply Generator + V Output 7.9 V V Output 7 V Supply Current (V)T = 25 C (Note 3) 6 12 mA CC A l 614 mA Supply Current when OFF (V ) Shutdown (Note 4) l 0.06 0.15 mA CC Driver Disable 3.00 mA Supply Rise Time C1 = C2 = 0.2m F, 2 ms + Shutdown to Turn-On C = 1.0m F, C = 0.1m F ON/OFF Pin Thresholds Input Low Level (Drivers Enabled) 0.8 1.2 V Input High Level (Drivers Disabled) 1.6 2.4 V ON/OFF Pin Current 0V V 5V l 15 80 m A ON/OFF DRIVER DISABLE Pin Thresholds Input Low Level (Drivers Enabled) l 0.8 1.4 V Input High Level (Drivers Disabled) l 1.4 2.4 V DRIVER DISABLE Pin Current 0V V 5V l 10 500 m A DRIVER DISABLE Oscillator Frequency Driver Outputs Loaded R = 3k 130 kHz L 2 U W W W U WU