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| LT1341 5V RS232 Transceiver with One Receiver Active in SHUTDOWN FEATURES s s s s s s s s s s s s DESCRIPTIO s s One Receiver Remains Active While in SHUTDOWN ESD Protection Over 10kV Uses Small Capacitors: 0.1F, 0.2F 60A Supply Current in SHUTDOWN Pin Compatible with LT1137A 120kBaud Operation for RL = 3k, CL = 2500pF 250kBaud Operation for RL = 3k, CL = 1000pF 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 Absolutely No Latch-Up Available in SSOP Package The LT1341 is an advanced low power three-driver, fivereceiver RS232 transceiver. Included on the chip is a shutdown pin for reducing supply current to near zero. During SHUTDOWN one receiver remains active to detect incoming RS232 signals, for example, to wake up a system. All other receivers and the drivers assume high impedance states during SHUTDOWN. The DRIVER DISABLE function provides additional control of operating mode. When DRIVER DISABLE is high the charge pump and drivers turn off. Receivers continue to operate during DRIVER DISABLE. New ESD structures on the chip allow the LT1341 to survive multiple 10kV strikes, eliminating the need for costly TransZorbs(R) on the RS232 line pins. The LT1341 is fully compliant with all EIA RS232 specifications and operates in excess of 120kbaud even driving heavy capacitive loads. TransZorb is a registered trademark of General Instruments, GSI APPLICATI s s S Notebook Computers Palmtop Computers TYPICAL APPLICATI + 0.1F 2 x 0.1F V+ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 LT1341 VCC 28 V - 27 25 24 23 22 21 20 19 0.1F 26 2 x 0.1F DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT RX3 OUT RX4 OUT TO LOGIC DRIVER 1 OUT RX1 IN DRIVER 2 OUT TO LINE RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN (LOW-Q) ON/OFF NC DRIVER 3 IN 18 RX5 OUT (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC + + RECEIVER OUTPUT CL = 50pF DRIVER R OUTPUT RL = 3k CL = 2500pF INPUT RING DETECT IN CONTROLLER OR PROCESSOR SHUTDOWN CONTROL OUT LT1341 * TA01 U Output Waveforms LT1341 * TA02 + UO UO 1 LT1341 ABSOLUTE (Note 1) AXI U RATI GS PACKAGE/ORDER I FOR ATIO TOP VIEW V+ 1 5V VCC 2 C1+ 3 C1- 4 DRIVER 1 OUT 5 RX1 IN 6 DRIVER 2 OUT 7 RX2 IN 8 RX3 IN 9 RX4 IN 10 DRIVER 3 OUT 11 RX5 IN (LOW-Q) 12 ON/OFF 13 NC 14 G PACKAGE 28-LEAD SSOP 28 V - 27 C2 - 26 C2+ 25 DRIVER 1 IN 24 RX1 OUT 23 DRIVER 2 IN 22 RX2 OUT 21 RX3 OUT 20 RX4 OUT 19 DRIVER 3 IN RX5 OUT 18 (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC N PACKAGE 28-LEAD PLASTIC DIP Supply Voltage (VCC) ................................................ 6V V + ........................................................................ 13.2V V - ...................................................................... -13.2V 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 LT1341C ................................................. 0C to 70C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C ORDER PART NUMBER LT1341CG LT1341CN LT1341CS S PACKAGE 28-LEAD SOL TJMAX = 125C, JA = 96C/ W (G) TJMAX = 125C, JA = 56C/ W (N) TJMAX = 125C, JA = 85C/ W (S) Consult factory for Industrial and 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 14 0.06 3 0.2 1.4 1.4 1.4 1.4 130 MAX UNITS V V mA mA mA ms V V A V V A kHz (Note 3) SHUTDOWN (Note 4) DRIVER DISABLE C1 = C2 = 0.2F, C + = C - = 0.1F 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 17 0.150 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 LT1341 ELECTRICAL CHARACTERISTICS PARAMETER Any Driver Output Voltage Swing Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Data Rate Slew Rate Propagation Delay Any Receiver Input Voltage Thresholds Hysteresis Input Resistance Output Leakage Current Receivers 1 Through 4 Output Voltage Output Short-Circuit Current Propagation Delay Receiver 5 (Low-IQ RX) Output Voltage Output Short-Circuit Current Propagation Delay CONDITIONS Load = 3k to GND (Note 2) MIN Positive Negative q q q q q TYP 7.3 - 6.5 1.4 1.4 5 17 10 MAX UNITS V V V V A mA A kBaud kBaud V/s V/s s s V V V k A V V mA mA ns ns V V mA mA s s 5 Input Low Level (VOUT = High) Input High Level (VOUT = Low) 0.8V VIN 2V VOUT = 0V SHUTDOWN VOUT = 30V (Note 4) RL = 3k, CL = 2500pF RL = 3k, CL = 1000pF 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) -5 0.8 20 100 2 9 q 120 250 15 6 0.6 0.5 0.8 q 30 1.3 1.3 0.1 3 SHUTDOWN (Note 4) 0 VOUT VCC Output Low, IOUT = - 1.6mA Output High, IOUT = 160A (VCC = 5V) Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition tLH Low to High Output Low, IOUT = - 500A Output High, IOUT = 160A (VCC = 5V) Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition tLH Low to High q q q 1.3 1.7 0.4 5 1 0.2 4.2 - 20 20 250 350 0.2 4.2 -4 4 1 1 2.4 1.0 7 10 0.4 - 10 600 600 0.4 -2 3 3 3.5 10 q q 3.5 2 The q denotes specifications which apply over the full operating temperature range (0C TA 70C for commercial 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 as the average over several charge pump cycles. C + = C - = 0.1F, C1 = C2 = 0.2F. All outputs are open with all driver inputs tied high. Note 4: Supply current and leakage 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). 3 LT1341 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 150 125 SUPPLY CURRENT (A) SUPPLY CURRENT (mA) THRESHOLD VOLTAGE (V) 100 75 50 25 0 -55 -25 50 25 75 0 TEMPERATURE (C) On/Off Thresholds 3.0 2.5 THRESHOLD VOLTAGE (V) SUPPLY CURRENT (mA) 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 LT1341 * TPC01 Receiver Input Thresholds 3.00 2.75 2.50 Supply Current vs Data Rate 80 70 60 50 40 30 20 10 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 LT1341 * TPC02 LT1341 * TPC03 Supply Current in DRIVER DISABLE 5 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 LT1341 * TPC04 LT1341 * TPC05 LT1341 * TPC06 Supply Current 40 35 30 25 20 15 10 5 3DRIVERS LOADED R L = 3k 2DRIVERS LOADED R L = 3k 1DRIVER LOADED R L = 3k NO LOAD Driver Leakage in SHUTDOWN 100 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 LT1341 * TPC07 LT1341 * TPC08 LT1341 * TPC09 LT1341 TYPICAL PERFOR A CE CHARACTERISTICS Driver Short-Circuit Current 30 SHORT-CIRCUIT CURRENT (mA) 50 25 ISC + 20 15 ISC - 10 5 0 -55 -25 SHORT-CIRCUIT CURRENT (mA) 50 25 75 0 TEMPERATURE (C) Receiver Output Waveforms DRIVER OUTPUT RL = 3k RX5 OUTPUT CL = 50pF RX1 TO RX4 OUTPUT CL = 50pF INPUT PI FU CTIO S VCC: 5V Input Supply Pin. This pin should be decoupled with a 0.1F ceramic capacitor close to the package pin. Insufficient supply bypassing can lead to low output drive levels and erratic charge pump operation. GND: Ground Pin. ON/OFF: A TTL/CMOS logic low puts the device in the low power SHUTDOWN mode. All of the drivers and four receivers go to a high impedance state. Receiver RX5 remains active while the transceiver is in SHUTDOWN. The transceiver consumes only 60A of supply current while in SHUTDOWN. 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. All receivers remain active under these conditions. Floating the driver disable pin or driving it to a logic low level fully enables the transceiver. Supply current drops to 3mA when in DRIVER DISABLE mode. A logic low on the On/Off pin supersedes the state of the Driver Disable pin. 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 storage capacitors is recommended to reduce ripple. UW Receiver Short-Circuit Current 40 RX1 TO RX4 ISC - 30 RX1 TO RX4 ISC + RX5 ISC - 20 10 RX5 ISC + 0 -55 -25 100 125 50 25 0 75 TEMPERATURE (C) 100 125 LT1341 * TPC10 LT1341 * TPC11 Driver Output Waveforms DRIVER OUTPUT RL = 3k CL = 2500pF INPUT LT1341 * TPC12 LT1341 * TPC13 U U U 5 LT1341 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. To reduce supply ripple, increase the size of the storage capacitor. With multiple transceivers, the V + and V - pins may be paralleled into common filter capacitors. 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 -. 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. When a 12V supply is available, C1 may be omitted. Connect the 12V supply to C1+ and V +. The 12V supply should be decoupled with a 0.1F ceramic capacitor. DRIVER IN: RS232 Driver Input Pins. These inputs are TTL/CMOS compatible. Tie unused inputs to VCC. DRIVER OUT: Driver Outputs at RS232 Voltage Levels. 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 VOUT = V - + 30V to VOUT = 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. 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, including LOW-Q RX OUT, are fully short-circuit protected to ground or VCC with the power on, off, or in SHUTDOWN mode. LOW Q-CURRENT RX IN: Low Power Receiver Input. This special receiver remains active when the part is in SHUTDOWN mode, consuming typically 60A. This receiver has the same input and protection characteristics as the other receivers. LOW Q-CURRENT RX OUT: Low Power Receiver Output. This pin produces the same TTL/CMOS output voltage levels with slightly decreased speed and short-circuit current. 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 (LOW-Q) ON/OFF NC 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 (LOW-Q) GND DRIVER DISABLE NC LT1341 * ESD TC 6 + 0.1F 0.1F + 3 26 + The RS232 line inputs of the LT1341 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 LT1341 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 V+ 1 2 LT1341 28 27 V- 0.1F 0.2F + + 5V VCC LT1341 TYPICAL APPLICATIO S Operation Using 5V and 12V Power Supplies + 0.1F 0.1F C1- DRIVER 1 OUT RX1 IN DRIVER 2 OUT TO LINE RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN ON/0FF = 5V NC 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 NC LT1341 * TA03 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 LT1341 25 DRIVER 1 IN 24 22 20 18 17 16 15 RX1 OUT 23 DRIVER 2 IN RX2 OUT 21 RX3 OUT RX4 OUT 19 DRIVER 3 IN RX5 OUT GND DRIVER DISABLE NC DRIVER 1 OUT RX1 IN DRIVER 2 OUT RX2 IN RX3 IN RX4 IN 10 DRIVER 3 OUT 11 RX5 IN 12 ON/OFF NC 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" LT1341 * TA04 + 5V VCC + 12V V + C1+ 3 26 2 x 0.1F TO LOGIC 28 V - 27 2 x 0.1F 0.1F + 5V VCC U V+ VCC 1 2 LT1341 28 27 V- 0.1F 7 LT1341 PACKAGE DESCRIPTIO 0.205 - 0.212* (5.20 - 5.38) 0 - 8 0.005 - 0.009 (0.13 - 0.22) 0.022 - 0.037 (0.55 - 0.95) 0.0256 (0.65) BSC 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). 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 0.600 - 0.625 (15.240 - 15.875) 0.130 0.005 (3.302 0.127) 0.015 (0.381) MIN 0.045 - 0.065 (1.143 - 1.651) 0.009 - 0.015 (0.229 - 0.381) ( +0.025 0.625 -0.015 +0.635 15.87 -0.381 ) 0.125 (3.175) MIN 0.035 - 0.080 (0.889 - 2.032) 0.100 0.010 (2.540 0.254) 0.005 (0.127) RAD MIN 0.291 - 0.299 (7.391 - 7.595) (NOTE 2) 0.093 - 0.104 0.010 - 0.029 x 45 (2.362 - 2.642) (0.254 - 0.737) 0 - 8 TYP 0.050 (1.270) TYP 0.009 - 0.013 (0.229 - 0.330) NOTE 1 0.016 - 0.050 (0.406 - 1.270) 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 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. G Package 28-Lead SSOP 0.397 - 0.407* (10.07 - 10.33) 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) N Package 28-Lead Plastic DIP 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 0.697 - 0.712 (17.70 - 18.08) (NOTE 2) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0.037 - 0.045 (0.940 - 1.143) 0.014 - 0.019 (0.356 - 0.482) 0.004 - 0.012 (0.102 - 0.305) NOTE 1 0.394 - 0.419 (10.007 - 10.643) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 LT/GP 0593 10K REV 0 (c) LINEAR TECHNOLOGY CORPORATION 1993 |
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