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| LT1137A Advanced Low Power 5V RS232 Transceiver with Small Capacitors FEATURES s s s s s s s s s s DESCRIPTIO s s s s ESD Protection over 10kV Uses Small Capacitors: 0.1F, 0.2F 1A Supply Current in SHUTDOWN Pin Compatible with LT1137 Operates to 120k Baud CMOS Comparable Low Power: 60mW Operates from a Single 5V Supply Easy PC Layout: Flowthrough Architecture Rugged Bipolar Design Outputs Assume a High Impedance State When Off or Powered Down Improved Protection: RS232 I/O Lines Can Be Forced to 30V without Damage Output Overvoltage Does Not Force Current Back into Supplies Absolutely No Latch-up Available in SO Package The LT1137A is a three-driver, five-receiver RS232 transceiver, pin compatible with the LT1137, offering performance improvements and two SHUTDOWN modes. The LT1137A's charge pump is designed for extended compliance, and can deliver over 40mA of load current. Supply current is typically 12mA, competitive with similar CMOS devices. An advanced driver output stage operates up to 120k baud while driving heavy capacitive loads. The LT1137A is fully compliant with all EIA-RS232 specifications. Special bipolar construction techniques protect the drivers and receivers beyond the fault conditions stipulated for RS232. Driver outputs and receiver inputs can be shorted to 30V without damaging the device or the power supply generator. In addition, the RS232 I/O pins are resilient to multiple 10kV ESD strikes. The transceiver has two SHUTDOWN modes. One mode disables the drivers and the charge pump, the other shuts down all circuitry. While shut down, the drivers and receivers assume high impedance output states. APPLICATI s s S Notebook Computers Palmtop Computers TYPICAL APPLICATI + 0.1F 2 x 0.1F V+ 5V VCC 1 2 3 4 DRIVER OUT RX IN DRIVER OUT TO LINE RX IN RX IN RX IN DRIVER OUT RX IN ON/OFF = 5V 5 6 7 8 9 10 11 12 13 14 LT1137A 28 27 25 24 23 22 21 20 19 18 17 16 15 26 V- 0.1F 2 x 0.1F RECEIVER OUTPUT CL = 50pF DRIVER IN RX OUT DRIVER IN RX OUT RX OUT RX OUT DRIVER IN RX OUT GND DRIVER DISABLE LT1137 * TA01 LT1137A * TA02 + + TO LOGIC DRIVER R OUTPUT RL = 3k CL = 2500pF INPUT U Output Waveforms + UO UO 1 LT1137A ABSOLUTE (Note 1) TOP VIEW AXI U RATI GS PACKAGE/ORDER I FOR ATIO V+ C1+ C1- 1 3 4 28 V- 27 C2 - 26 C2+ 25 DRIVER IN 24 RX OUT 23 DRIVER IN 22 RX OUT 21 RX OUT 20 RX OUT 19 DRIVER IN 18 RX OUT 17 GND 16 DRIVER DISABLE 15 NC S PACKAGE 28-LEAD SOL Supply Voltage (VCC) ................................................ 6V V + ........................................................................ 13.2V V - (Note 7) .......................................................... - 6.5V Input Voltage Driver ........................................................... V - to V + Receiver ............................................... - 30V to 30V Output Voltage Driver .................................................... - 30V to 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 LT1137AC............................................... 0C to 70C LT1137AI........................................... - 40C to 85C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C ORDER PART NUMBER LT1137ACN LT1137ACS LT1137ACG LT1137AIN LT1137AIS 5V VCC 2 DRIVER OUT 5 RX IN 6 DRIVER OUT 7 RX IN 8 RX IN 9 RX IN 10 DRIVER OUT 11 RX IN 12 ON/OFF 13 NC 14 N PACKAGE 28-LEAD PLASTIC DIP G PACKAGE 28-LEAD SSOP TJMAX = 150C, JA = 56C/ W (N) TJMAX = 150C, JA = 85C/ W (S) TJMAX = 150C, JA = 96C/ W (G) Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS PARAMETER Power Supply Generator V + Output V - Output Supply Current (VCC) Supply Current When OFF (VCC) Supply Rise Time SHUTDOWN to Turn-On ON/OFF Pin Thresholds ON/OFF Pin Current Driver Disable Pin Thresholds Driver Disable Pin Current Oscillator Frequency CONDITIONS (Note 2) MIN TYP 8.6 - 7.2 12 1 4 2.0 0.2 1.4 1.4 1.4 1.4 130 MAX UNITS V V mA A mA ms ms V V A V V A kHz (Note 3) SHUTDOWN (Note 4) DRIVER DISABLE C1, C2, C +, C - = 1F, C +, C - = 0.1F, C1, C2 = 0.2F Input Low Level (Device SHUTDOWN) Input High Level (Device Enabled) 0V VON/OFF 5V Input Low Level (Drivers Enabled) Input High Level (Drivers Disabled) 0V VDRIVER DISABLE 5V q q 17 10 q q q q q q 0.8 80 0.8 500 2.4 -15 2.4 -10 2 U W U U WW W LT1137A ELECTRICAL CHARACTERISTICS PARAMETER Any Driver Output Voltage Swing Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Slew Rate Propagation Delay Any Receiver Input Voltage Thresholds Hysteresis Input Resistance Output Voltage Output Leakage Current Output Short-Circuit Current Propagation Delay CONDITIONS Load = 3k to GND (Note 2) MIN Positive Negative q q q q q q TYP 7.5 - 6.3 1.4 1.4 5 17 10 15 15 0.6 0.5 1.3 1.7 0.4 5 0.2 4.2 1 - 20 20 250 350 MAX UNITS V V V V A mA A V/s V/s s s V V V k V V A mA mA ns ns 5.0 Input Low Level (VOUT = High) Input High Level (VOUT = Low) 0.8V VIN 2V VOUT = 0V SHUTDOWN VOUT = 25V (Note 4) RL = 3k, CL = 51pF RL = 3k, CL = 2500pF Output Transition tHL High to Low (Note 5) Output Transition tLH Low to High Input Low Threshold (VOUT = High) Input High Threshold (VOUT = Low) VIN = 10V Output Low, IOUT = - 1.6mA Output High, IOUT = 160A (VCC = 5V) SHUTDOWN (Note 4) 0 VOUT VCC Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition tLH Low to High - 5.0 0.8 20 100 30 1.3 1.3 2.0 4 q q q q q q 0.8 0.1 3 3.5 2.4 1.0 7 0.4 10 - 10 600 600 10 The q denotes specifications which apply over the operating temperature range (0C TA 70C for commercial grade, and - 40C TA 85C for industrial grade). 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. Note 3: Supply current is measured with driver and receiver outputs unloaded and the driver inputs tied high. Note 4: Supply current and leakage current measurements in SHUTDOWN are performed with VON/OFF = 0.1V. Supply current measurements using DRIVER DISABLE are performed with VDRIVER DISABLE = 3V. 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). Note 7: Absolute maximum externally applied voltage. Internal charge pump may force a larger value on this pin. 3 LT1137A TYPICAL PERFOR A CE CHARACTERISTICS Driver Output Voltage 10 8 DRIVER OUTPUT VOLTAGE (V) RL = 3k OUTPUT HIGH THRESHOLD VOLTAGE (V) 6 4 2 0 -2 -4 -6 -8 -10 -55 -25 2.25 2.00 1.75 1.50 1.25 1.00 0.75 INPUT LOW INPUT HIGH SUPPLY CURRENT (mA) VCC = 5.5V VCC = 5V VCC = 4.5V VCC = 4.5V VCC = 5V VCC = 5.5V OUTPUT LOW 50 25 0 75 TEMPERATURE (C) 100 125 Supply Current in SHUTDOWN 100 5 10 THRESHOLD VOLTAGE (V) SUPPLY CURRENT (mA) SUPPLY CURRENT (A) 1 0.1 -55 -25 75 0 25 50 TEMPERATURE (C) On/Off Thresholds 3.0 2.5 THRESHOLD VOLTAGE (V) 40 35 SUPPLY CURRENT (mA) 30 25 20 15 10 5 LEAKAGE CURRENT ( A) 2.0 1.5 1.0 ON THRESHOLD OFF THRESHOLD 0.5 0 -55 -25 50 25 75 0 TEMPERATURE (C) 4 UW LT1137A * TPC01 Receiver Input Thresholds 3.00 2.75 2.50 60 50 40 30 20 10 80 70 Supply Current vs Data Rate 3DRIVERS ACTIVE RL = 3k CL = 2500pF 0.50 -55 -25 50 25 0 75 TEMPERATURE (C) 100 125 0 0 25 75 50 100 DATA RATE (kBAUD) 125 150 LT1137A * TPC02 LT1137A * TPC03 Supply Current in DRIVER DISABLE 3.0 2.5 2.0 1.5 1.0 0.5 Driver Disable Threshold 4 3 2 1 100 125 0 -55 -25 50 25 0 75 TEMPERATURE (C) 100 125 0 -55 -25 50 25 75 0 TEMPERATURE (C) 100 125 LT1137A * TPC04 LT1137A * TPC05 LT1137A * TPC06 Supply Current 100 Driver Leakage in SHUTDOWN 3DRIVERS LOADED R L = 3k 2DRIVERS LOADED R L = 3k 1DRIVER LOADED R L = 3k NO LOAD 10 1 VOUT = 30V VOUT = -30V 100 125 0 -55 -25 50 25 0 75 TEMPERATURE (C) 100 125 0.1 -55 -25 50 25 0 75 TEMPERATURE (C) 100 125 LT1137A * TPC07 LT1137A * TPC08 LT1137A * TPC09 LT1137A TYPICAL PERFOR A CE CHARACTERISTICS Driver Short-Circuit Current 30 SHORT-CIRCUIT CURRENT (mA) 50 SHORT-CIRCUIT CURRENT (mA) 25 ISC + 20 15 ISC - 10 5 0 -55 -25 50 25 75 0 TEMPERATURE (C) SHUTDOWN to Driver Output DRIVER OUTPUT HIGH RL = 3k 10 5 0 DRIVER - 5 OUTPUT LOW RL = 3k - 10 ON/OFF PIN DRIVER OUTPUT RL = 3k CL = 2500pF DRIVER OUTPUT RL = 3k PI FU CTIO S VCC: 5V Input Supply Pin. Supply current drops to zero in the SHUTDOWN mode. This pin should be decoupled with a 0.1F 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: TTL/CMOS Compatible Operating Mode Control. A logic low puts the device in the SHUTDOWN mode which reduces input supply current to zero and places all of the drivers and receivers in high impedance state. A logic high fully enables the transceiver. DRIVER DISABLE: This pin provides an alternate control for the charge pump and RS232 drivers. A logic high on this pin shuts down the charge pump and places all drivers in a high impedance state. Receivers remain active under these conditions. Floating the driver disable pin or driving it to a logic low level fully enables the transceiver. A logic low on the On/Off pin supersedes the state of the Driver Disable pin. Supply current drops to 4mA when in DRIVER DISABLE mode. V +: Positive Supply Output (RS232 Drivers). V + 2VCC - 1.5V. This pin requires an external charge storage capacitor C 0.1F, 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. For large numbers of transceivers, increasing the size of the shared common storage capacitors is recommended to reduce ripple. UW Receiver Short-Circuit Current 40 ISC - 30 ISC + 20 10 100 125 0 -55 -25 50 25 0 75 TEMPERATURE (C) 100 125 LT1137A * TPC10 LT1137A * TPC11 Driver Output Waveforms INPUT LT1137A * TPC12 LT1137A * TPC13 U U U 5 LT1137A PI FU CTIO S V -: Negative Supply Output (RS232 Drivers). V - - (2VCC - 2.5V). This pin requires an external charge storage capacitor C 0.1F. V - is short-circuit proof for 30 seconds. C1+, C1-, C2+, C2 -: Commutating Capacitor Inputs. These pins require two external capacitors C 0.2F: 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 2. For C 1F, low ESR tantalum capacitors work well in this application, although small value ceramic capacitors may be used with a minimal reduction in charge pump compliance. In applications where larger positive voltages are available, such as 12V, C1 may be omitted and the positive voltage may be connected directly to the C1+ pin. In this mode of operation, the V + pin should be decoupled with a 0.1F ceramic capacitor. DRIVER IN: RS232 Driver Input Pins. These inputs are TTL/CMOS compatible. Inputs should not be allowed to float. Tie unused inputs to VCC. DRIVER 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, VCC = 0V, or when the driver disable pin is active. Outputs are fully short-circuit 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 10kV for human body model discharges. RX IN: 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. RX 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 SHUTDOWN mode. ESD PROTECTIO 0.2F DRIVER 1 OUT RX1 IN DRIVER 2 OUT RS232 LINE PINS PROTECTED TO 10kV RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN ON/OFF 4 5 6 7 8 9 10 11 12 13 14 25 24 23 22 21 20 19 18 17 16 15 DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT RX3 OUT RX4 OUT DRIVER 3 IN RX5 OUT GND DRIVER DISABLE LT1137A * ESD TC 6 + 0.1F 0.1F + 3 26 + The RS232 line inputs of the LT1137A 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 LT1137A 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. U U U U ESD Test Circuit 1 V+ 5V VCC 2 28 LT1137A 27 V- 0.1F 0.2F + + LT1137A TYPICAL APPLICATIO S Operation Using 5V and 12V Power Supplies + 0.1F 5V VCC + 0.01F 0.01F C1- DRIVER OUT RX IN DRIVER OUT TO LINE RX IN RX IN RX IN DRIVER OUT RX IN ON/0FF = 5V 4 5 6 7 8 9 10 11 12 13 14 25 24 23 22 21 20 19 18 17 16 15 DRIVER IN RX OUT DRIVER IN RX OUT RX OUT RX OUT DRIVER IN RX OUT GND DRIVER DISABLE TO LOGIC Typical Mouse Driving Application + 0.1F MOUSE 2 x 0.1F V+ LOGIC (1) DCD DSR RX RTS OPTICS V- TX CTS DTR (5) (9) RI V+ 1 2 3 4 5 6 7 8 9 LT1137A 25 DRIVER 1 IN 24 RX1 OUT 23 DRIVER 2 IN 22 RX2 OUT 21 RX3 OUT 20 RX4 OUT 19 DRIVER 3 IN 18 RX5 OUT 17 GND 16 DRIVER DISABLE 15 DRIVER 1 OUT RX1 IN DRIVER 2 OUT RX2 IN RX3 IN RX4 IN 10 DRIVER 3 OUT 11 RX5 IN 12 ON/OFF 13 14 DB9 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. + + 26 LOGIC "0" LOGIC "0" MOUSE DATA LOGIC "1" LT1137A * TA04 + 5V VCC + 12V V + C1+ 3 26 2 x 0.1F LT1137A * TA03 28 27 + U V+ VCC 1 2 LT1137A 28 27 V- 0.1F V- 2 x 0.1F 0.1F 7 LT1137A PACKAGE DESCRIPTIO 0.600 - 0.625 (15.240 - 15.875) 0.020 (0.508) TYP 0.130 0.005 (3.302 0.127) 95 5 0.009 - 0.015 (0.229 - 0.381) +0.025 0.625 -0.015 +0.635 15.87 -0.381 0.020 (0.508) MIN ( ) 0.125 (3.175) MIN 0.035 - 0.080 (0.889 - 2.032) 0.100 0.010 (2.540 0.254) 0.291 - 0.299 (7.391 - 7.595) 0.005 (0.127) RAD MIN 0.010 - 0.029 x 45 (0.254 - 0.737) 0 - 8 TYP 0.050 0.014 - 0.019 0.009 - 0.013 (1.270) (0.356 - 0.482) (0.229 - 0.330) SEE NOTE TYP 0.016 - 0.050 (0.406 - 1.270) NOTE: 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. 0.093 - 0.104 (2.362 - 2.642) 0.205 - 0.212 (5.20 - 5.38) PARTING LINE 0.005 - 0.009 (0.13 - 0.22) 0.022 - 0.037 (0.55 - 0.95) 0 - 8 0.0256 (0.65) BSC 0.010 - 0.015 (0.25 - 0.38) 0.045 (1.14) 0.002 - 0.008 (0.05 - 0.21) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 U Dimensions in inches (millimeters) unless otherwise noted. N Package 28-Lead Plastic DIP 0.045 - 0.055 (1.143 - 1.651) 0.070 (1.778) TYP 28 27 26 25 24 23 1.455 (36.957) MAX 22 21 20 19 18 17 16 15 0.505 - 0.560 (12.827 - 14.224) 0.018 0.003 (0.457 0.076) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 S Package 28-Lead SOL 0.037 - 0.045 (0.940 - 1.143) 0.697 - 0.712 (17.70 - 18.08) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0.004 - 0.012 (0.102 - 0.305) SEE NOTE 0.394 - 0.419 (10.007 - 10.643) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 G Package 28-Lead SSOP 0.397 - 0.407 (10.07 - 10.33) 0.066 - 0.070 (1.68 - 1.78) 0.068 - 0.078 (1.73 - 1.99) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0.301 - 0.311 (7.65 - 7.90) 0.045 (1.14) LT/GP 0294 5K REV A * PRINTED IN USA (c) LINEAR TECHNOLOGY CORPORATION 1994 |
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