LT1780/LT1781 Low Power 5V RS232 Dual Driver/Receiver with ±15kV ESD Protection DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 10mA Max Supply Current ESD Protection to IEC 1000-4-2 Level 4 ±15kV Air Gap, ±8kV Contact Uses Small Capacitors: 0.1µF 120kBaud Operation for RL = 3k, CL = 2500pF 250kBaud Operation for RL = 3k, CL = 1000pF Outputs Withstand ±30V Without Damage CMOS Comparable Low Power: 40mW Operates from a Single 5V Supply Rugged Bipolar Design Outputs Assume a High Impedance State When Off or Powered Down Meets All RS232 Specifications Available With or Without Shutdown Absolutely No Latch-up The LT1780/LT1781 are direct upgrades to the LT1180A/ LT1181A, LT1280A/LT1281A and LT1381 for applications which require the utmost ESD protection. UO APPLICATI ■ ■ ■ ■ ■ The LT®1780/LT1781 are dual RS232 driver/receiver pairs with integral charge pump to generate RS232 voltage levels from a single 5V supply. Using only 0.1µF external capacitors, these circuits consume only 40mW of power, and can operate to 120kbaud even while driving heavy capacitive loads. New ESD structures on the chip allow the LT1780/LT1781 to survive ±15kV air gap and ±8kV contact ESD tests per IEC 1000-4-2, eliminating the need for costly TransZorbs® on the RS232 line pins. The LT1780/ LT1781 are fully compliant with EIA RS232 standards. Driver outputs are protected from overload, and can be shorted to ground or up to ±30V without damage. During SHUTDOWN or power-off conditions, driver and receiver outputs are in a high impedance state, allowing line sharing. S Portable Computers Battery-Powered Systems Power Supply Generator Terminals Modems The LT1781 is available in 16-pin DIP,SO and SW packages. The LT1780 is supplied in 18-pin DIP and SW packages for applications which require SHUTDOWN. , LTC and LT are registered trademarks of Linear Technology Corporation. TransZorb is a registered trademark of General Instruments, GSI. UO TYPICAL APPLICATI 0.1µF 2 17 4 3 5 0.1µF LOGIC INPUTS 7 V – OUT DRIVER OUTPUT RL = 3k CL = 2500pF 0.1µF 6 12 15 11 8 13 14 RS232 OUTPUT RECEIVER OUTPUT R CL = 50pF RS232 OUTPUT RS232 INPUT INPUT 5k LOGIC OUTPUTS 10 ON/OFF V + OUT 0.1µF LT1780 Output Waveforms 5V INPUT 18 9 5k RS232 INPUT 1780/81 • TA02 16 1780/81 • TA01 1 LT1780/LT1781 W W W AXI U U ABSOLUTE RATI GS (Note 1) Short-Circuit Duration V + ................................................................... 30 sec V – ................................................................... 30 sec Driver Output .............................................. Indefinite Receiver Output .......................................... Indefinite Operating Temperature Range ..................... 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C Supply Voltage (VCC) ................................................ 6V V + ........................................................................ 13.2V V – ...................................................................... –13.2V Input Voltage Driver ........................................................... V – to V + Receiver ............................................... – 30V to 30V ON/OFF ................................................. – 0.3V to 12V Output Voltage Driver ...................................... V+ – 30V to V – + 30V Receiver .................................... – 0.3V to VCC + 0.3V U W U PACKAGE/ORDER I FOR ATIO TOP VIEW C1+ 1 16 VCC V+ 2 15 GND C1 – 3 14 TR1 OUT C2+ 4 13 REC1 IN C2 – 5 12 REC1 OUT V– 6 11 TR1 IN TR1 IN TR2 OUT 7 10 TR2 IN 11 TR2 IN REC2 IN 8 9 10 REC2 OUT NC 1 18 ON/OFF C1+ 2 17 VCC V+ 3 16 GND C1 – 4 15 TR1 OUT C2+ 5 14 REC1 IN C2 – 6 13 REC1 OUT V– 7 12 TR2 OUT 8 REC2 IN 9 N PACKAGE 18-LEAD PLASTIC DIP TOP VIEW ORDER PART NUMBER LT1780CN LT1780CSW ORDER PART NUMBER LT1781CN LT1781CS LT1781CSW REC2 OUT S PACKAGE SW PACKAGE N PACKAGE 16-LEAD PLASTIC DIP 16-LEAD PLASTIC SO 16-LEAD PLASTIC SO SW PACKAGE 18-LEAD PLASTIC SO TJMAX = 125°C, θJA = 90°C/ W, θJC = 46°C/W (N) TJMAX = 125°C, θJA = 95°C/ W, θJC = 34°C/W (S) TJMAX = 125°C, θJA = 95°C/ W, θJC = 27°C/W (SW) TJMAX = 125°C, θJA = 80°C/ W, θJC = 36°C/W (N) TJMAX = 125°C, θJA = 90°C/ W, θJC = 26°C/W (SW) Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS (Note 2) PARAMETER Power Supply Generator V + Output V – Output Supply Current (VCC) CONDITIONS Supply Current When OFF (VCC) Supply Rise Time SHUTDOWN to Turn-On ON/OFF Pin Thresholds SHUTDOWN (Note 4) LT1780 Only C1 = C2 = C3 = C4 = 0.1µF LT1780 Only Input Low Level (Device SHUTDOWN) Input High Level (Device Enabled) 0V ≤ VON/OFF ≤ 5V ON/OFF Pin Current Oscillator Frequency Driver Output Voltage Swing Logic Input Voltage Level 2 MIN TYP 7.9 –7 8 (Note 3), TA = 25°C ● ● ● ● 0.8 ● – 15 1 0.2 0.2 1.2 1.6 MAX 10 14 10 2.4 80 130 Load = 3k to GND Input Low Level (VOUT = High) Input High Level (VOUT = Low) Positive Negative ● ● ● ● 5.0 2.0 7.5 – 6.3 1.4 1.4 –5 0.8 UNITS V V mA mA µA ms ms V V µA kHz V V V V LT1780/LT1781 ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS Logic Input Current 0.8V ≤ VIN ≤ 2.0V (Note 2) MIN ● ±7 Output Short-Circuit Current VOUT = 0V Output Leakage Current SHUTDOWN VOUT = ±30V (Note 4) Data Rate RL = 3k, CL = 2500pF RL = 3k, CL = 1000pF 120 250 Slew Rate RL = 3k, CL = 51pF RL = 3k, CL = 2500pF 4 Propagation Delay TYP MAX 5 20 17 10 ● Output Transition tHL High-to-Low (Note 5) Output Transition tLH Low-to-High UNITS µA mA 100 µA kBaud kBaud 15 7 30 V/µs V/µs 0.6 0.5 1.3 1.3 µs µs 1.3 1.7 2.4 V V Receiver Input Voltage Thresholds Input Low Threshold (VOUT = High) Input High Threshold (VOUT = Low) 0.8 Hysteresis Input Resistance ● V IN = ±10V 0.1 0.4 1 V 3 5 7 kΩ Output Leakage Current SHUTDOWN (Note 4) 0 ≤ VOUT ≤ VCC ● 1 10 µA Output Voltage Output Low, IOUT = – 1.6mA Output High, IOUT = 160µA (VCC = 5V) ● ● 0.4 3.5 0.2 4.2 V V – 20 20 – 10 10 mA mA 250 350 600 600 ns ns Output Short-Circuit Current Propagation Delay Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High-to-Low (Note 6) Output Transition tLH Low-to-High The ● denotes specifications which apply over the operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: Testing done at VCC = 5V and VON/OFF = 3V, unless otherwise specified. Note 3: Supply current is measured as the average over several charge pump cycles. C + = C – = C1 = C2 = 0.1µF. All outputs are open, with all driver inputs tied high. Note 4: Supply current measurements in SHUTDOWN are performed with VON/OFF ≤ 0.1V. Note 5: For driver delay measurements, RL = 3k and CL = 51pF. Trigger points are set between the driver’s input logic threshold and the output transition to the zero crossing (t HL = 1.4V to 0V and tLH = 1.4V to 0V). Note 6: For receiver delay measurements, CL = 51pF. Trigger points are set between the receiver’s input logic threshold and the output transition to standard TTL/CMOS logic threshold (t HL = 1.3V to 2.4V and tLH = 1.7V to 0.8V). 3 LT1780/LT1781 U W TYPICAL PERFOR A CE CHARACTERISTICS Driver Maximum Output Voltage vs Load Capacitance Driver Minimum Output Voltage vs Load Capacitance 8.0 Driver Output Voltage 10 –4.0 8 7.0 20k BAUD 6.5 60k BAUD 6.0 120k BAUD 5.5 DRIVER OUTPUT VOLTAGE (V) –4.5 PEAK OUTPUT VOLTAGE (V) PEAK OUTPUT VOLTAGE (V) 7.5 120k BAUD –5.0 60k BAUD –5.5 20k BAUD –6.0 –6.5 RL = 3k 6 4 2 0 –2 –4 VCC = 5.5V VCC = 5V VCC = 4.5V OUTPUT HIGH OUTPUT LOW VCC = 4.5V VCC = 5V VCC = 5.5V –6 –8 5.0 –7.0 0 1 2 3 4 5 6 7 8 LOAD CAPACITANCE (nF) 9 10 0 1780 • G01 1 2 3 4 5 6 7 8 LOAD CAPACITANCE (nF) 9 10 50 25 0 75 TEMPERATURE (°C) 1780 • G02 50 2 DRIVERS ACTIVE RL = 3k CL = 2500pF 2.75 2.50 SUPPLY CURRENT (mA) 40 2.25 INPUT HIGH 2.00 1.75 INPUT LOW 1.50 1.25 1.00 30 20 10 0.75 0.50 –55 –25 0 50 25 0 75 TEMPERATURE (°C) 100 125 0 25 50 75 100 DATA RATE (kBAUD) 2.5 20 SUPPLY CURRENT (mA) THRESHOLD VOLTAGE (V) 25 ON THRESHOLD 1.5 1.0 OFF THRESHOLD 50 25 75 0 TEMPERATURE (°C) 100 125 1780 • G06 4 2 DRIVERS LOADED RL = 3k 15 10 1 DRIVER LOADED RL = 3k NO LOAD 5 0.5 0 –55 –25 150 Supply Current ON/OFF Thresholds 2.0 125 1780 • G05 1780 • G04 3.0 100 125 1780 • G03 Supply Current vs Data Rate Receiver Input Thresholds 3.00 THRESHOLD VOLTAGE (V) –10 –55 –25 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 1780 • G07 LT1780/LT1781 U W TYPICAL PERFOR A CE CHARACTERISTICS Driver Leakage in Shutdown Driver Short-Circuit Current 100 ( µA) SHORT-CIRCUIT CURRENT (mA) 30 LEAKAGE CURRENT 10 VOUT = 30V 1 VOUT = –30V 0.1 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 25 ISC + 20 15 ISC – 10 5 0 –55 –25 125 50 25 75 0 TEMPERATURE (°C) 1780 • G08 125 1780 • G09 Receiver Short-Circuit Current Slew Rate vs Load Capacitance 50 16 14 40 12 RX ISC – SLEW RATE (V/µs) SHORT-CIRCUIT CURRENT (mA) 100 30 RX ISC + 20 10 8 +SLEW 6 –SLEW 4 10 2 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 LOAD CAPACITANCE (nF) 1780 • G10 1780 • G11 Shutdown to Driver Outputs Driver Output Waveforms 10V DRIVER 1 OUTPUT 5V DRIVER OUTPUT RL = 3k CL = 2500pF GND GND DRIVER 2 OUTPUT – 5V DRIVER OUTPUT RL = 3k – 10V ON/OFF PIN INPUT 1780 • G12 1780 • G13 5 LT1780/LT1781 U U U PI FU CTIO S VCC: 5V Input Supply Pin. This pin should be decoupled with a 0.1µF ceramic capacitor close to the package pin. Insufficient supply bypassing can result in low output drive levels and erratic charge pump operation. GND: Ground Pin. ON/OFF: A TTL/CMOS Compatible Operating Mode Control. A logic low puts the LT1780 in SHUTDOWN mode. Supply current drops to zero and both driver and receiver outputs assume a high impedance state. A logic high fully enables the device. V +: Positive Supply Output (RS232 Drivers). V + ≈ 2VCC – 1.5V. This pin requires an external charge storage capacitor C ≥ 0.1µF, tied to ground or VCC. Larger value capacitors may be used to reduce supply ripple. With multiple transceivers, the V+ and V – pins may be paralleled into common capacitors. V –: Negative Supply Output (RS232 Drivers). V – ≈ –(2VCC – 2.5V). This pin requires an external charge storage capacitor C ≥ 0.1µF. Larger value capacitors may be used to reduce supply ripple. With multiple transceivers, the V+ and V – pins may be paralleled into common capacitors. TR1 IN, TR2 IN: RS232 Driver Input Pins. These inputs are TTL/CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC. 6 TR1 OUT, TR2 OUT: Driver Outputs at RS232 Voltage Levels. Driver output swing meets RS232 levels for loads up to 3k. Slew rates are controlled for lightly loaded lines. Output current capability is sufficient for load conditions up to 2500pF. Outputs are in a high impedance state when in SHUTDOWN mode or VCC = 0V. Outputs are fully shortcircuit protected from V – + 30V to V + – 30V. Applying higher voltages will not damage the device if the overdrive is moderately current limited. Short circuits on one output can load the power supply generator and may disrupt the signal levels of the other outputs. The driver outputs are protected against ESD to IEC-1000-4-2 Level 4 discharges. REC1 IN, REC2 IN: Receiver Inputs. These pins accept RS232 level signals (±30V) into a protected 5k terminating resistor. The receiver inputs are protected against ESD to IEC-1000-4-2 Level 4 discharges. Each receiver provides 0.4V of hysteresis for noise immunity. Open receiver inputs result in a logic high receiver output state. REC1 OUT, REC2 OUT: Receiver outputs with TTL/CMOS Voltage Levels. Outputs are in a high impedance state when in SHUTDOWN mode to allow data line sharing. Outputs are fully short-circuit protected to ground or VCC with the power ON, OFF or in the SHUTDOWN mode. C1 +, C1 –, C2 +, C2 –: Commutating Capacitor Inputs. These pins require two external capacitors C ≥ 0.1µF: one from C1+ to C1– and another from C2+ to C2 –. C1 should be deleted if a separate 12V supply is available and connected to pin C1+. Similarly, C2 should be deleted if a separate – 12V supply is connected to pin V –. LT1780/LT1781 U ESD PROTECTIO ESD Test Circuit The RS232 line inputs of the LT1780/LT1781 have on-chip protection from ESD transients up to ±15kV air gap and ±8kV contact tested to IEC-1000-4-2 test methods. The protection structures act to divert the static discharge safely to system ground. In order for the ESD protection to function effectively, the power supply and ground pins of the circuit must be connected to ground through low impedances. The power supply decoupling capacitors and charge pump storage capacitors provide this low impedance in normal application of the circuit. The only constraint is that low ESR capacitors must be used for bypassing and charge storage. ESD testing must be done with pins VCC, VL, V +, V –, and GND shorted to ground or connected with low ESR capacitors. NC C1+ 2 0.1µF V+ 3 0.1µF C1– 4 C2+ 0.1µF LT1780 16 GND 15 0.1µF DR1 OUT RS232 LINE PINS PROTECTED TO IEC-1000-4-2 13 RX1 OUT LEVEL 4 14 12 8 11 9 10 RX2 IN ON/OFF 17 5V VCC V– 7 DR2 OUT RS232 LINE PINS PROTECTED TO IEC-1000-4-2 LEVEL 4 5 C2 – 6 0.1µF 18 1 RX1 IN DR1 IN DR2 IN RX2 OUT 1780 • ESD TC U TYPICAL APPLICATIO Operation Using 5V and 12V Power Supplies 12V INPUT 2 17 4 3 5V INPUT LT1780 5 0.1µF LOGIC INPUTS 7 –12VOUT 0.1µF 6 12 15 11 8 13 14 RS232 OUTPUT RS232 OUTPUT RS232 INPUT 5k LOGIC OUTPUTS 10 9 RS232 INPUT 5k ON/OFF 18 16 1780/81 • TA03 7 LT1780/LT1781 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. N Package 16-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.770* (19.558) MAX 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 0.255 ± 0.015* (6.477 ± 0.381) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( 0.020 (0.508) MIN +0.035 0.325 –0.015 8.255 +0.889 –0.381 0.045 – 0.065 (1.143 – 1.651) ) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.018 ± 0.003 (0.457 ± 0.076) 0.100 ± 0.010 (2.540 ± 0.254) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) N16 1197 N Package 18-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.900* (22.860) MAX 18 17 16 15 14 13 12 11 10 1 2 3 4 5 6 7 8 9 0.255 ± 0.015* (6.477 ± 0.381) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) +0.035 0.325 –0.015 0.045 – 0.065 (1.143 – 1.651) 0.020 (0.508) MIN 0.065 (1.651) TYP 0.005 (0.127) MIN 0.100 ± 0.010 (2.540 ± 0.254) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) ( 8 +0.889 8.255 –0.381 ) 0.125 (3.175) MIN 0.018 ± 0.003 (0.457 ± 0.076) N18 1197 LT1780/LT1781 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. SW Package 16-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1620) 0.398 – 0.413* (10.109 – 10.490) 16 15 14 13 12 11 10 9 0.394 – 0.419 (10.007 – 10.643) NOTE 1 0.291 – 0.299** (7.391 – 7.595) 1 2 3 4 5 6 7 8 0.093 – 0.104 (2.362 – 2.642) 0.010 – 0.029 × 45° (0.254 – 0.737) 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) TYP 0.004 – 0.012 (0.102 – 0.305) 0.014 – 0.019 (0.356 – 0.482) TYP NOTE: 1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS S16 (WIDE) 0396 *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 9 LT1780/LT1781 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. SW Package 18-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1620) 0.447 – 0.463* (11.354 – 11.760) 18 17 16 15 14 13 12 11 10 0.394 – 0.419 (10.007 – 10.643) SEE NOTE 0.291 – 0.299** (7.391 – 7.595) 1 2 3 4 5 6 7 8 9 0.093 – 0.104 (2.362 – 2.642) 0.010 – 0.029 × 45° (0.254 – 0.737) 0.037 – 0.045 (0.940 – 1.143) 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) TYP 0.014 – 0.019 (0.356 – 0.482) TYP NOTE: 1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 10 0.004 – 0.012 (0.102 – 0.305) S18 (WIDE) 0396 LT1780/LT1781 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. S Package 16-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.386 – 0.394* (9.804 – 10.008) 16 15 14 13 12 11 10 9 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 2 3 4 5 6 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) 8 0.004 – 0.010 (0.101 – 0.254) 0° – 8° TYP 0.016 – 0.050 0.406 – 1.270 7 0.050 (1.270) TYP S16 0695 *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LT1780/LT1781 U TYPICAL APPLICATIO Supporting an LT1039 (Triple Driver/Receiver) SHUTDOWN 5V 18 TTL INPUT TTL INPUT VCC ON/OFF LT1780 17 11 8 12 15 18 RS232 OUTPUT TTL INPUT RS232 OUTPUT TTL INPUT TTL INPUT TTL OUTPUT 14 13 RS232 INPUT TTL OUTPUT VCC ON/OFF LT1039 15 4 13 6 11 8 16 3 5k TTL OUTPUT RS232 INPUT TTL OUTPUT 14 5 5k 2 1µF 4 5 1µF 6 RS232 OUTPUT RS232 OUTPUT RS232 OUTPUT RS232 INPUT 30k 9 10 17 RS232 INPUT 30k C1+ TTL OUTPUT 7 12 RS232 INPUT 30k C1– C2 + C2 – V+ 3 1 V+ V– 7 9 V– GND 16 1µF 1µF GND 10 1780/81 • TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1137A 3Driver/5Receiver RS232 Transceiver IEC-1000-4-2 Level 4 ESD Compliance LTC1383 5V Low Power RS232 2Driver/2Receiver Transceiver Low Supply Current ICC = 220µA LTC1387 Single 5V RS232/RS485 Multiprotocol Transceiver Configurable as Dual RS232 or Single RS485 Transceiver 12 Linear Technology Corporation 17801f LT/TP 0498 4K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1998