LT1381CS#PBF

LT1381 Low Power 5V RS232 Dual Driver/Receiver with 0.1µF Capacitors U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ESD Protection over ±10kV Low Cost Uses Small Capacitors: 0.1µF CMOS Comparable Low Power: 40mW Operates from a Single 5V Supply 120kBaud Operation for RL = 3k, CL = 2500pF 250kBaud Operation for RL = 3k, CL = 1000pF Rugged Bipolar Design Outputs Assume a High Impedance State When Powered Down Absolutely No Latchup Available in Narrow SO Package UO APPLICATI ■ ■ ■ ■ Portable Computers Battery-Powered Systems Power Supply Generator Terminals Modems , LTC and LT are registered trademarks of Linear Technology Corporation. TransZorb® is a registered trademark of General Instruments, GSI UO ■ S The LT ®1381 is a dual RS232 driver/receiver pair with integral charge pump to generate RS232 voltage levels from a single 5V supply. The circuit features rugged bipolar design to provide operating fault tolerance and ESD protection unmatched by competing CMOS designs. Using only 0.1µF external capacitors, the circuit consumes only 40mW of power and can operate to 120kbaud even while driving heavy capacitive loads. New ESD structures on the chip allow the LT1381 to survive multiple ±10kV strikes, eliminating the need for costly TransZorbs® on the RS232 line pins. Driver outputs are protected from 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 line sharing. TYPICAL APPLICATI + 0.1µF 1 16 3 2 5V INPUT V + OUT + 0.1µF LT1381 + 0.1µF LOGIC INPUTS 4 6 V – OUT + 5 11 14 10 7 12 13 Output Waveforms DRIVER OUTPUT RL = 3k CL = 2500pF 0.1µF RS232 OUTPUT RECEIVER R OUTPUT CL = 50pF RS232 OUTPUT RS232 INPUT INPUT 5k LOGIC OUTPUTS 9 8 S 5k RS232 INPUT LT1381 • TA02 15 LT1381 • TA01 1 LT1381 U U RATI GS W W W W AXI U U ABSOLUTE PACKAGE/ORDER I FOR ATIO (Note 1) Supply Voltage (VCC) ................................................ 6V V + ........................................................................ 13.2V V – ...................................................................... –13.2V Input Voltage Driver ........................................................... V – to V + Receiver ............................................... – 30V to 30V Output Voltage Driver ................................. (V+ – 30V) to (V – + 30V) Receiver ................................. – 0.3V to (VCC + 0.3V) Short-Circuit Duration V + ................................................................... 30 sec V – ................................................................... 30 sec Driver Output .............................................. Indefinite Receiver Output .......................................... Indefinite Operating Temperature Range LT1381C ................................................. 0°C to 70°C LT1381I .............................................. – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C ELECTRICAL CHARACTERISTICS ORDER PART NUMBER TOP VIEW C1+ 1 16 VCC V+ 2 15 GND – 3 14 TR1 OUT C2+ 4 13 REC1 IN – 5 12 REC1 OUT V– 6 11 TR1 IN TR2 OUT 7 10 TR2 IN REC2 IN 8 9 C1 C2 REC2 OUT S PACKAGE N PACKAGE 16-LEAD PLASTIC DIP 16-LEAD PLASTIC SOIC TJMAX = 125°C, θJA = 90°C/ W, θJC = 46°C/W (N) TJMAX = 125°C, θJA = 110°C/ W, θJC = 34°C/W (S) Consult factory for Military grade parts. (Note 2) PARAMETER Power Supply Generator V + Output V – Output Supply Current (VCC) CONDITIONS Supply Rise Time Oscillator Frequency Driver Output Voltage Swing C1 = C2 = C3 = C4 = 0.1µF MIN (Note 3), TA = 25°C Load = 3k to GND ● Positive Negative ● ● 5.0 ● ● Logic Input Current 0.8V ≤ VIN ≤ 2.0V ● Output Short-Circuit Current VOUT = 0V Output Leakage Current Power Off VOUT = ±15V Data Rate RL = 3k, CL = 2500pF RL = 3k, CL = 1000pF 120 250 Slew Rate RL = 3k, CL = 51pF RL = 3k, CL = 2500pF 4 2 MAX 14 16 0.2 130 Input Low Level (VOUT = High) Input High Level (VOUT = Low) Output Transition tHL High to Low (Note 4) Output Transition tLH Low to High TYP 7.9 – 7.0 8 Logic Input Voltage Level Propagation Delay LT1381CN LT1381CS LT1381IS 2.0 9 V V mA mA ms kHz 7.5 – 6.3 1.4 1.4 – 5.0 0.8 V V V V 5 20 µA 17 10 ● UNITS mA 100 µA kBaud kBaud 15 6 30 V/µs V/µs 0.6 0.5 1.3 1.3 µs µs LT1381 ELECTRICAL CHARACTERISTICS PARAMETER (Note 2) CONDITIONS MIN TYP MAX UNITS Input Low Threshold (VOUT = High) Input High Threshold (VOUT = Low) 0.8 1.3 1.7 2.4 V V 0.4 1.0 V Receiver Input Voltage Thresholds Hysteresis 0.1 ● Input Resistance (Note 6) Output Voltage Output Low, IOUT = – 1.6mA Output High, IOUT = 160µA (VCC = 5V) Output Short-Circuit Current ● ● Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Propagation Delay 3 5 7 0.4 3.5 0.2 4.2 V V – 20 20 – 10 10 mA mA 250 350 600 600 ns ns Output Transition tHL High-to-Low (Note 5) Output Transition tLH Low-to-High The ● denotes specifications which apply over the full 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, 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. kΩ Note 4: 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 t LH = 1.4V to 0V). Note 5: 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 t LH = 1.7V to 0.8V). Note 6: Tested at VIN = ±10V. W U TYPICAL PERFOR A CE CHARACTERISTICS Driver Maximum Output Voltage vs Load Capacitance Driver Minimum Output Voltage vs Load Capacitance 2 DRIVERS LOADED 2 DRIVERS LOADED 8.5 8 120k BAUD 8.0 7.5 20k BAUD 7.0 6.5 60k BAUD 6.0 DRIVER OUTPUT VOLTAGE (V) –4.5 PEAK OUTPUT VOLTAGE (V) PEAK OUTPUT VOLTAGE (V) Driver Output Voltage 10 –4.0 9.0 –5.0 60k BAUD –5.5 –6.0 20k BAUD –6.5 5.5 –7.0 0 1 2 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 120k BAUD 5.0 RL = 3k 3 4 5 6 7 8 LOAD CAPACITANCE (nF) 9 10 LT1381 • TPC01 0 1 2 3 4 5 6 7 8 LOAD CAPACITANCE (nF) 9 10 LT1381 • TPC02 –10 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1381 • TPC03 3 LT1381 W U TYPICAL PERFOR A CE CHARACTERISTICS Supply Current vs Data Rate Receiver Input Threshold 3.00 100 2.50 SUPPLY CURRENT (mA) 40 2.25 INPUT HIGH 2.00 1.75 1.50 INPUT LOW 1.25 1.00 LEAKAGE CURRENT (µA) 2 DRIVERS ACTIVE RL = 3k CL = 2500pF 2.75 THRESHOLD VOLTAGE (V) Driver Leakage in Shutdown 50 30 20 10 VOUT = 30V 1 VOUT = –30V 10 0.75 0.50 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 0 125 0 25 50 75 100 DATA RATE (kBaud) 125 LT1381 • TPC04 0.1 –55 –25 150 LT1381 • TPC05 Receiver Short-Circuit Current 100 125 LT1381 • TPC06 Driver Short-Circuit Current 50 Slew Rate vs Load Capacitance 30 20 ISC – 18 40 30 ISC + 20 10 25 16 ISC + SLEW RATE (V/µs) SHORT-CIRCUIT CURRENT (mA) SHORT-CIRCUIT CURRENT (mA) 50 25 0 75 TEMPERATURE (°C) 20 15 ISC – 10 14 12 10 8 +SLEW RATE 6 4 5 –SLEW RATE 2 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 –55 –25 50 25 75 0 TEMPERATURE (˚C) LTLT1381 • TPC07 100 125 0 0 1 3 2 CAPACITANCE (nF) V – Compliance Curve 10 –10 V + (1µF) 8 –8 V – (1µF) 6 V – (V) V + (V) V + (0.1µF) V – (0.1µF) –4 2 –2 0 0 5 10 LOAD CURRENT + (mA) 15 LT1381 • TPC10 4 –6 4 0 0 5 LT1381 • TPC09 LT1381 • TPC08 V + Compliance Curve 4 5 10 LOAD CURRENT – (mA) 15 LT1381 • TPC11 LT1381 U U U PI FU CTIO S C1 +, C1 –, C2 +, C2 – (Pins 1, 3, 4, 5): Commutating Capacitor Inputs. These pins require two external capacitors C ≥ 0.1µF: one from C1+ to C1– and another from C2+ to C2 –. C1 may be deleted if a separate 12V supply is available and connected to pin C1+. V + (Pin 2): Positive Supply Output (RS232 Drivers). V + ≈ 2VCC – 2.1V. 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 – (Pin 6): Negative Supply Output (RS232 Drivers). V – ≈ –(2VCC – 3V). 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. TR2 OUT, TR1 OUT (Pin 7, 14): 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 VCC = 0V. Outputs are fully shortcircuit protected from V – + 25V to V + – 25V. 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 ±10kV for human body model discharges. REC2 IN, REC1 IN (Pins 8, 13): Receiver Inputs. These pins accept RS232 level signals (±30V) into a protected 5k terminating resistor. The receiver inputs are protected against ESD to ±10kV for human body model discharges. Each receiver provides 0.4V of hysteresis for noise immunity. Open receiver inputs assume a logic low state. REC2 OUT, REC1 OUT (Pins 9, 12): Receiver Outputs with TTL/CMOS Voltage Levels. Outputs are fully short-circuit protected to ground or VCC with the power ON or OFF. TR2 IN, TR1 IN (Pins 10, 11): RS232 Driver Input Pins. These inputs are TTL/CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC. GND (Pin 15): Ground Pin. VCC (Pin 16): 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. U ESD PROTECTIO The RS232 line inputs of the LT1381 have on-chip protection from ESD transients up to ±10kV. 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, V +, V – and GND shorted to ground or connected with low ESR capacitors. ESD Test Circuit 1 0.1µF + +2 0.1µF + 0.1µF RS232 LINE PINS PROTECTED TO ±10kV V+ 5V VCC LT1381 GND 16 + 15 3 C1– TR1 OUT 14 4 C2+ REC1 IN 13 5 C2 – REC1 OUT 12 6 V– 0.1µF + C1+ 7 TR2 OUT 8 REC2 IN 0.1µF RS232 LINE PINS PROTECTED TO ±10kV TR1 IN 11 TR2 IN 10 REC2 OUT 9 LT1381 • ESD TC 5 LT1381 U TYPICAL APPLICATIO S Isolated RS232 Driver/Receiver CTX20-1 1:1 VIN = 5V ±10% FROM SYSTEM ILIM 100µF 1Ω VIN + 13.7V 10k + FB ISOLATOR OUTPUT (DATA TO SYSTEM) 1µF SW2 1k 16 VCC 1 VCC OS 10µF 1N5818 LT1111 VOUT 0.1µF 100µF SW1 GND 5V ±10% LT1121-5 + L1 20µH 47Ω + 1N5818 + IN 0.1µF 3 LTC1145 LT1381 RS232 2 + 4 GND2 GND1 0.1µF + 0.1µF 5 6 + ISOLATOR INPUT (DATA FROM SYSTEM) VIN 9 VCC IN RX OS LTC1145 GND1 11 DX 8 14 0.1µF RS232 INPUT RS232 OUTPUT 15 GND2 FLOATING GROUND LT1381 • TA03 ISOLATION BARRIER SYSTEM GROUND Data Transmission Across Isolation Barrier ISOLATOR INPUT RS232 INPUT RS232 OUTPUT ISOLATOR OUTPUT 1381 TA04 6 1381 TA05 LT1381 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) 0.020 (0.508) MIN 0.009 – 0.015 (0.229 – 0.381) ( +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 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 circuits as described herein will not infringe on existing patent rights. 7 LT1381 U TYPICAL APPLICATIO S Operation Using 5V and 12V Power Supplies 12V INPUT + 0.1µF LOGIC INPUTS 1 16 2 3 LT1381 4 5V INPUT 16 –12VOUT + 5 11 14 10 7 12 13 0.1µF RS232 OUTPUT RS232 OUTPUT RS232 INPUT 5k LOGIC OUTPUTS 9 8 S 5k RS232 INPUT 15 LT1381 • TA06 Sharing Capacitors 5V VCC TTL INPUT TTL INPUT TTL OUTPUT 16 V+ LT1381 V– 2 5V VCC 6 11 14 10 7 12 13 16 LT1381 + RS232 OUTPUT + RS232 OUTPUT RS232 INPUT 0.1µF TTL INPUT TTL INPUT TTL OUTPUT 9 1 6 10 7 12 13 RS232 OUTPUT RS232 OUTPUT RS232 INPUT 5k 8 RS232 INPUT TTL OUTPUT 9 8 RS232 INPUT 5k 4 C1+ C2+ C1– 5 C2 – 0.1µF 3 V– 14 5k + 2 11 5k TTL OUTPUT V+ 1 + + 0.1µF 4 C1+ C2+ C1– 5 C2 – + 0.1µF 3 0.1µF LT1381 • TA07 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1180A/LT1181A 5V 2-Driver/2-Receiver RS232 Transceivers Pin Compatible with LT1280A/LT1280A LT1280A/LT1281A 5V 2-Driver/2-Receiver RS232 Transceivers Pin Compatible with LT1180A/LT1181A LT1780/LT1781 5V 2-Driver/2-Receiver RS232 Transceivers IEC 1000-4-2 Level 4 Compliance 8 Linear Technology Corporation 1381fa, sn1381 LT/TP 1098 REV A 2K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com  LINEAR TECHNOLOGY CORPORATION 1993