LTC1384 5V Low Power RS232 Transceiver with 2 Receivers Active in Shutdown U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ Operates from a Single 5V Supply Low Supply Current: ICC = 220µA ICC = 35µA in Shutdown Mode with Both Receivers Kept Alive ESD Protection Over ±10kV Uses Small Capacitors: 0.1µF Operates to 120kBaud Output Overvoltage Does Not Force Current Back into Supplies RS232 I/O Lines Can Be Forced to ±25V Without Damage Pin Compatible with LT1180A The LTC1384 is an ultra-low power 2-driver/2-receiver RS232 transceiver that operates from a single 5V supply. The charge pump requires only four spacesaving 0.1µF capacitors. The transceiver operates in one of two modes, Normal and Shutdown. In the Normal mode, ICC is only 220µA with the driver outputs unloaded. In the Shutdown mode, the charge pump is turned off, the driver outputs are forced into three-state, both receivers are kept active and ICC drops to 35µA. The receiver outputs may be forced into three-state at any time using the receiver enable (EN) pin. The LTC1384 is fully compliant with all data rate and overvoltage RS232 specifications. The transceiver can operate up to 120kbaud with a 2500pF, 3kΩ load. Both driver outputs and receiver inputs can be forced to ±25V without damage and can survive multiple ±10kV ESD strikes. UO APPLICATI ■ Notebook Computers Palmtop Computers UO ■ S TYPICAL APPLICATI Quiescent and Shutdown Supply Current vs Temperature 2-Drivers/2-Receivers with Shutdown and Receiver Enable 2 LOGIC INPUT 6 0.1µF VCC 300k 15 12 232 OUTPUT VCC 300k LOGIC INPUT LOGIC OUTPUT LOGIC OUTPUT ON/OFF 11 8 13 14 5k 10 18 1 RX EN 232 OUTPUT SHUTDOWN CURRENT 800 40 600 30 400 20 QUIESCENT CURRENT 200 10 232 INPUT 0 –20 9 5k 50 1000 0.1µF 7 SHUTDOWN CURRENT (µA) 0.1µF LTC1384 60 TEST CONDITION: VCC = 5V 3 4 5 1200 VCC = 5V QUIESCENT CURRENT (µA) 0.1µF 17 232 INPUT 0 20 40 TEMPERATURE (°C) 60 80 0 LTC1384 • TA02 16 LTC1384 • TA01 1 LTC1384 W W W AXI U U ABSOLUTE RATI GS Supply Voltage (VCC) ................................................ 6V Input Voltage Driver ....................................... – 0.3V to V CC + 0.3V Receiver ............................................... – 25V to 25V Digital Input ............................... – 0.3V to VCC + 0.3V Output Voltage Driver .................................................... – 25V to 25V 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 .................... 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C U W U PACKAGE/ORDER I FOR ATIO TOP VIEW RX EN 1 20 ON/OFF C1 + 2 19 VCC V+ C1 – 3 18 GND 4 17 TR1 OUT C2 + 5 16 RX1 IN C2 – 6 15 RX1 OUT 7 14 TR1 IN 8 13 TR2 IN V– TR2 OUT RX2 IN ORDER PART NUMBER 9 NC 10 RX EN 1 18 ON/OFF C1+ 2 17 VCC V+ 3 16 GND C1– 4 15 TR1 OUT C2+ 5 14 RX1 IN C2 – 6 13 RX1 OUT V– 7 12 TR1 IN TR2 OUT 8 11 TR2 IN RX2 IN 9 10 RX2 OUT LTC1384CG 12 RX2 OUT 11 NC ORDER PART NUMBER TOP VIEW LTC1384CN LTC1384CS N PACKAGE S PACKAGE 18-LEAD PLASTIC DIP 18-LEAD PLASTIC SOL G PACKAGE 20-LEAD SSOP TJMAX = 125°C, θJA = 56°C/W TJMAX = 125°C, θJA = 135°C/W Consult factory for Industrial and Military grade parts. DC ELECTRICAL CHARACTERISTICS VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, VON/OFF = VCC, EN = 0V, unless otherwise noted. PARAMETER CONDITIONS Any Driver Output Voltage Swing 3k to GND Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Any Receiver Input Voltage Thresholds Hysteresis Input Resistance Output Voltage 2 MIN TYP ● ● 5.0 – 5.0 Input Low Level (VOUT = High) Input High Level (VOUT = Low) VIN = VCC VIN = 0V VOUT = 0V Shutdown or VCC = 0V (Note 3), VOUT = ±20V ● ● 2.0 7.0 – 6.5 1.4 1.4 Input Low Threshold Input High Threshold ● ● 0.8 ● 0.1 3 – 10V ≤ VIN ≤ 10V Output Low, IOUT = – 1.6mA (VCC = 5V) Output High, IOUT = 160µA (VCC = 5V) Positive Negative ● ● – 20 ±12 ±10 ● ● ● 3.0 1.3 1.7 0.4 5 0.2 3.2 MAX 0.8 5 – 40 ±500 2.4 1 7 0.4 UNITS V V V V µA µA mA µA V V V kΩ V V LTC1384 DC ELECTRICAL CHARACTERISTICS VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, VON/OFF = VCC, EN = 0V, unless otherwise noted. PARAMETER Output Short-Circuit Current CONDITIONS Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V EN = VCC, 0V ≤ VOUT ≤ VCC Output Leakage Current Power Supply Generator V + Output Voltage MIN – 15 10 ● IOUT = 0mA IOUT = 8mA IOUT = 0mA IOUT = – 8mA Shutdown to Turn-On V – Output Voltage Supply Rise Time Power Supply VCC Supply Current Supply Leakage Current (VCC) Digital Input Threshold Low Digital Input Threshold High ● ● ● 2.0 ● PARAMETER Slew Rate UNITS mA mA µA 10 V V V V ms 0.22 35 1.4 1.4 0.5 50 0.8 TYP 8 5 2 2 0.3 0.3 MAX 30 mA µA V V VCC = 5V, C1 = C2 = C3 = C4 = 0.1µF, unless otherwise noted. CONDITIONS RL = 3k, CL = 51pF RL = 3k, CL = 2500pF t HLD (Figure 1) t LHD (Figure 1) t HLR (Figure 2) t LHR (Figure 2) Driver Propagation Delay (TTL to RS232) Receiver Propagation Delay (RS232 to TTL) MAX 8.0 7.5 – 8.0 – 7.0 0.2 No Load (Note 2) Shutdown (Note 3) AC CHARACTERISTICS TYP – 40 20 1 MIN 3 ● ● ● ● The ● denotes specifications which apply over the operating temperature range of 0°C ≤ TA ≤ 70°C. Note 1: Absolute maximum ratings are those values beyond which the life of the device may be impaired. UNITS V/µs V/µs µs µs µs µs 3.5 3.5 0.8 0.8 Note 2: Supply current is measured with driver and receiver outputs unloaded. Note 3: Measurements made in the Shutdown mode are performed with VON/OFF = 0V. U W TYPICAL PERFORMANCE CHARACTERISTICS Receiver Input Thresholds vs Temperature Driver Output Voltage vs Temperature DRIVER OUTPUT VOLTAGE (V) 6 OUTPUT HIGH VCC = 5V 2.0 4 2 0 –2 OUTPUT LOW VCC = 4.5V –6 VTH 1.8 1.6 VTL 1.4 1.0 20 30 40 50 TEMPERATURE (°C) 60 30 25 20 15 10 5 –8 10 35 1.2 VCC = 5V 0 VCC = 5V RL = 3k CL = 2500pF 2 DRIVERS ACTIVE 40 VCC = 4.5V –4 45 SUPPLY CURRENT (mA) RL = 3k 8 Supply Current vs Data Rate 2.2 THRESHOLD VOLTAGE (V) 10 70 LTC1384 • TPC01 0 10 40 30 50 20 TEMPERATURE (˚C) 60 70 LTC1384 • TPC02 0 0 25 50 75 100 125 DATA RATE (kBAUD) 150 175 LTC1384 • TPC03 3 LTC1384 U W TYPICAL PERFORMANCE CHARACTERISTICS Driver Short-Circuit Current vs Temperature 18 16 16 14 12 2 DRIVERS LOADED RL = 3k 10 8 1 DRIVER LOADED RL = 3k 6 4 2 Receiver Short-Circuit Current vs Temperature 50 SHORT-CIRCUIT CURRENT (mA) 18 SHORT-CIRCUIT CURRENT (mA) SUPPLY CURRENT (mA) VCC Supply Current vs Temperature – 14 ISC 12 ISC+ 10 8 6 4 40 ISC– 30 20 ISC+ 2 0 0 0 10 20 30 40 50 TEMPERATURE (°C) 60 70 10 0 LTC1384 • TPC04 10 20 30 40 50 TEMPERATURE (°C) 60 70 0 LTC1384 • TPC05 Driver Leakage in Shutdown vs Temperature 10 30 20 50 40 TEMPERATURE (°C) 60 70 LTC1384 • TPC06 Driver Output Waveforms Receiver Output Waveforms 45 DRIVER OUTPUT RL = 3k CL = 2500pF LEAKAGE CURRENT (µA) 40 35 30 25 RECEIVER OUTPUT CL = 51pF DRIVER OUTPUT RL = 3k VOUT = –20V INPUT 20 INPUT 15 10 VOUT = 20V 5 LTC1384 • TPC08 0 0 10 30 20 40 50 TEMPERATURE (°C) 60 70 LTC1384 • TPC07 4 LTC1384 • TPC09 LTC1384 U U U PI FU CTIO S VCC: 5V Input Supply Pin. This pin should be decoupled with a 0.1µF ceramic capacitor. GND: Ground Pin. ON/OFF: TTL/CMOS Compatible Shutdown Pin. A logic low puts the device in the Shutdown mode independent of the EN pin. The supply current of the device drops to 35µA (two receivers alive) and both driver outputs are forced into three-state. EN: TTL/CMOS Compatible Receiver Enable Pin. A logic high forces the receiver outputs into three-state. A logic low enables the receiver outputs. V +: Positive Supply Output (RS232 Drivers). V + ≅ 2VCC – 2V. This pin requires an external capacitor C = 0.1µF for charge storage. The capacitor may be tied to ground or VCC. With multiple devices, the V + and V – pins may share a common capacitor. For large numbers of devices, increasing the size of the shared common storage capacitors is recommended to reduce ripple. V –: Negative Supply Output (RS232 Drivers). V – ≅ – (2VCC – 2V). This pin requires an external capacitor C = 0.1µF for charge storage. 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 –. To maintain charge pump efficiency, the capacitor’s effective series resistance should be less than 2Ω. TR IN: RS232 Driver Input Pins. Inputs are TTL/CMOS compatible. The inputs of unused drivers can be left unconnected since 300k input pull-up resistors to VCC are included on chip. To minimize power consumption, the internal driver pull-up resistors are disconnected from VCC in the Shutdown mode. TR OUT: Driver Outputs at RS232 Voltage Levels. Outputs are in a high impedance state when in the Shutdown or VCC = 0V. The driver outputs are protected against ESD to ±10kV for human body model discharges. RX IN: Receiver Inputs. These pins can be forced to ±25V without damage. The receiver inputs are protected against ESD to ±10kV for human body model discharges. Each receiver provides 0.4V of hysteresis for noise immunity. RX OUT: Receiver Outputs with TTL/CMOS Voltage Levels. A logic high at EN puts the outputs into three-state. U W W SWITCHI G TI E WAVEFOR S DRIVER INPUT VCC 1.4V 1.4V 0V V+ DRIVER OUTPUT 0V 0V t LHD V– t HLD VCC 1.7V RX INPUT RX OUTPUT 1.3V 0V 2.4V 0.8V t LHR t HLR 0V LTC1384 • F02 LTC1384 • F01 Figure 1. Driver Propagation Delay Timing VCC Figure 2. Receiver Propagation Delay Timing 5 LTC1384 TEST CIRCUITS Receiver Timing Test Load Driver Timing Test Load DRIVER INPUT DRIVER OUTPUT RX OUTPUT RX INPUT DRIVER 51pF RX 51pF 3k LTC1384 • TA04 LTC1384 • TA03 ESD Test Circuit 0.1µF 2 17 4 3 5 0.1µF LOGIC INPUT 6 LTC1384 VCC 0.1µF 7 0.1µF VCC 300k 15 12 232 OUTPUT VCC 300k LOGIC INPUT LOGIC OUTPUT LOGIC OUTPUT ON/OFF 11 8 13 14 5k 10 18 9 5k LTC1384 • TA04 6 16 232 OUTPUT 232 INPUT 232 INPUT RS232 LINE PINS PROTECTED TO ±10kV LTC1384 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. G Package 20-Lead SSOP 0.278 – 0.289* (7.07 – 7.33) 20 19 18 17 16 15 14 13 12 11 0.301 – 0.311 (7.65 – 7.90) 0.045 (1.14) 1 2 3 4 5 6 7 8 9 10 0.045 (1.14) 0.205 – 0.212* (5.20 – 5.38) 0.068 – 0.078 (1.73 – 1.99) 0° – 8° 0.005 – 0.009 (0.13 – 0.22) 0.0256 (0.65) BSC 0.022 – 0.037 (0.55 – 0.95) 0.002 – 0.008 (0.05 – 0.21) 0.010 – 0.015 (0.25 – 0.38) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 20SSOP 0294 N Package 18-Lead Plastic DIP 0.905 (22.860) MAX 18 17 16 15 14 13 12 11 10 1 2 3 4 5 6 7 8 9 0.260 ± 0.010 (6.604 ± 0.254) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( +0.025 0.325 –0.015 8.255 +0.635 –0.381 ) 0.130 ± 0.005 (3.302 ± 0.127) 0.045 – 0.065 (1.143 – 1.651) 0.015 (0.381) MIN 0.065 (1.651) TYP 0.125 (3.175) MIN 0.045 ± 0.015 (1.143 ± 0.381) 0.100 ± 0.010 (2.540 ± 0.254) 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. 0.018 ± 0.003 (0.457 ± 0.076) N18 0392 7 LTC1384 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. S Package 18-Lead Plastic SOL 0.447 – 0.463 (11.354 – 11.760) (NOTE 2) 18 17 16 15 14 13 12 11 10 0.394 – 0.419 (10.007 – 10.643) SEE NOTE 0.005 (0.127) RAD MIN 1 0.291 – 0.299 (7.391 – 7.595) (NOTE 2) 0.010 – 0.029 × 45° (0.254 – 0.737) 2 3 0.093 – 0.104 (2.362 – 2.642) 4 5 6 7 8 9 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. 2. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 8 Linear Technology Corporation SOL18 0392 LT/GP 0594 10K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977 LINEAR TECHNOLOGY CORPORATION 1994