LT1341 5V RS232 Transceiver with One Receiver Active in Shutdown U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT®1341 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. One Receiver Remains Active While in Shutdown ESD Protection Over ±10kV Uses Small Capacitors: 0.1µF, 0.2µF 60µA 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 Latchup Available in SSOP Package 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® 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. UO APPLICATI ■ ■ S Notebook Computers Palmtop Computers , LTC and LT are registered trademarks of Linear Technology Corporation. TransZorb is a registered trademark of General Instruments, GSI UO TYPICAL APPLICATI Output Waveforms V+ 0.1µF VCC 2 × 0.1µF 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 1 28 V – 2 27 3 LT1341 25 5 24 6 23 7 22 8 21 9 20 10 19 11 12 13 14 2 × 0.1µF 26 4 RECEIVER OUTPUT CL = 50pF 0.1µF DRIVER 1 IN RX1 OUT DRIVER ROUTPUT RL = 3k CL = 2500pF DRIVER 2 IN RX2 OUT RX3 OUT TO LOGIC RX4 OUT DRIVER 3 IN 18 RX5 OUT (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC INPUT RING DETECT IN µCONTROLLER OR µPROCESSOR LT1341 • TA02 SHUTDOWN CONTROL OUT LT1341 • TA01 1 LT1341 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 .................................................... – 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 ................................................. 0°C to 70°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C ORDER PART NUMBER TOP VIEW V+ 1 28 V– 5V VCC 2 27 C2 – C1+ 3 26 C2+ C1– 4 25 DRIVER 1 IN DRIVER 1 OUT 5 24 RX1 OUT RX1 IN 6 23 DRIVER 2 IN DRIVER 2 OUT 7 22 RX2 OUT RX2 IN 8 21 RX3 OUT RX3 IN 9 20 RX4 OUT RX4 IN 10 19 DRIVER 3 IN RX5 OUT 18 (LOW-Q) 17 GND 16 DRIVER DISABLE 15 NC DRIVER 3 OUT 11 RX5 IN (LOW-Q) 12 ON/OFF 13 NC 14 LT1341CG LT1341CNW LT1341CSW G PACKAGE NW PACKAGE 28-LEAD PLASTIC SSOP 28-LEAD (WIDE) PDIP SW PACKAGE 28-LEAD (WIDE) PLASTIC SO TJMAX = 125°C, θJA = 96°C/ W (G) TJMAX = 125°C, θJA = 56°C/ W (NW) TJMAX = 125°C, θJA = 85°C/ W (SW) 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 2 (Note 2) CONDITIONS (Note 3) Shutdown (Note 4) Driver Disable C1 = C2 = 0.2µF, C + = C – = 0.1µF Input Low Level (Device Shut Down) Input High Level (Device Enabled) 0V ≤ VON/OFF ≤ 5V Input Low Level (Drivers Enabled) Input High Level (Drivers Disabled) 0V ≤ VDRIVER DISABLE ≤ 5V MIN 8.6 –7 14 0.06 3 0.2 ● ● ● ● ● ● ● TYP 2.4 –15 2.4 –10 1.4 1.4 1.4 1.4 MAX UNITS 17 0.150 V V mA mA mA ms 0.8 80 0.8 500 130 V V µA V V µA kHz LT1341 ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS Any Driver Output Voltage Swing Load = 3k to GND Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Data Rate (Note 7) 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 (Note 2) Positive Negative 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 ● ● ● ● TYP 5 7.3 – 6.5 1.4 1.4 5 ±17 10 2 ● ±9 ● MAX 4 0.8 ● Shutdown (Note 4) 0 ≤ VOUT ≤ VCC ● Output Low, IOUT = – 1.6mA Output High, IOUT = 160µA (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 = – 500µA Output High, IOUT = 160µA (VCC = 5V) Sinking Current, VOUT = VCC Sourcing Current, VOUT = 0V Output Transition tHL High to Low (Note 6) Output Transition tLH Low to High ● ● 0.1 3 3.5 10 3.5 2 UNITS 15 6 0.6 0.5 1.3 1.3 V V V V µA mA µA kBaud kBaud V/µs V/µs µs µs 1.3 1.7 0.4 5 1 2.4 1.0 7 10 V V V kΩ µA –5 0.8 20 100 120 250 Input Low Threshold (VOUT = High) Input High Threshold (VOUT = Low) The ● denotes specifications which apply over the full operating temperature range (0°C ≤ TA ≤ 70°C 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 – = 0.1µF, C1 = C2 = 0.2µF. 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. MIN 0.2 4.2 – 20 20 250 350 0.2 4.2 –4 4 1 1 30 0.4 – 10 600 600 0.4 –2 3 3 V V mA mA ns ns V V mA mA µs µs 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: Data rate operation guaranteed by slew rate, short-circuit current and propagation delay tests. 3 LT1341 U W TYPICAL PERFOR A CE CHARACTERISTICS Driver Output Voltage RL = 3k 6 OUTPUT HIGH 2.75 VCC = 5.5V VCC = 5V VCC = 4.5V 4 2 0 VCC = 4.5V VCC = 5V VCC = 5.5V –2 –4 –6 –8 50 25 0 75 TEMPERATURE (°C) 100 2.50 2.25 2.00 INPUT HIGH 1.75 1.50 INPUT LOW 1.25 1.00 50 25 0 75 TEMPERATURE (°C) LT1341 • TPC01 50 40 30 20 100 0 125 0 Supply Current in Driver Disable 4 2.5 THRESHOLD VOLTAGE (V) 125 SUPPLY CURRENT (mA) 3.0 50 3 2 1 25 0 –55 –25 50 25 75 0 TEMPERATURE (°C) 100 50 25 0 75 TEMPERATURE (°C) 2.0 1.5 1.0 100 0 –55 –25 125 50 25 75 0 TEMPERATURE (°C) LT1341 • TPC05 LT1341 • TPC04 100 125 LT1341 • TPC06 Supply Current ON/OFF Thresholds 3.0 150 0.5 0 –55 –25 125 125 DRIVER DISABLE Threshold 5 75 75 50 100 DATA RATE (kBAUD) LT1341 • TPC03 150 100 25 LT1341 • TPC02 Supply Current in Shutdown SUPPLY CURRENT (µA) 60 10 0.50 –55 –25 125 3DRIVERS ACTIVE RL = 3k CL = 2500pF 70 0.75 OUTPUT LOW –10 –55 –25 Supply Current vs Data Rate 80 SUPPLY CURRENT (mA) DRIVER OUTPUT VOLTAGE (V) 8 Receiver Input Thresholds 3.00 THRESHOLD VOLTAGE (V) 10 Driver Leakage in Shutdown 100 40 35 ON THRESHOLD 1.5 1.0 OFF THRESHOLD 0.5 0 –55 –25 3DRIVERS LOADED R L = 3k 25 2DRIVERS LOADED R L = 3k 20 1DRIVER LOADED R L = 3k 15 NO LOAD 10 10 1 VOUT = 30V VOUT = –30V 5 50 25 75 0 TEMPERATURE (°C) 100 125 LT1341 • TPC07 4 30 LEAKAGE CURRENT( µA) 2.0 SUPPLY CURRENT (mA) THRESHOLD VOLTAGE (V) 2.5 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1341 • TPC08 0.1 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1341 • TPC09 LT1341 U W TYPICAL PERFOR A CE CHARACTERISTICS Driver Short-Circuit Current Receiver Short-Circuit Current 50 25 SHORT-CIRCUIT CURRENT (mA) SHORT-CIRCUIT CURRENT (mA) 30 ISC+ 20 15 ISC– 10 5 0 –55 –25 50 25 75 0 TEMPERATURE (°C) 100 125 40 RX1 TO RX4 ISC– 30 RX1 TO RX4 ISC+ RX5 ISC– 20 10 RX5 ISC+ 0 –55 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1341 • TPC11 LT1341 • TPC10 Driver Output Waveforms Receiver Output Waveforms DRIVER OUTPUT RL = 3k RX5 OUTPUT CL = 50pF RX1 TO RX4 OUTPUT CL = 50pF DRIVER OUTPUT RL = 3k CL = 2500pF INPUT INPUT LT1341 • TPC12 LT1341 • TPC13 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 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 60µA 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 ≥ 0.1µF, 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. For large numbers of transceivers, increasing the size of the storage capacitors is recommended to reduce ripple. 5 LT1341 U U U PI FU CTIO S V –: Negative Supply Output (RS232 Drivers). V – ≈ –(2VCC – 2.5V). This pin requires an external charge storage capacitor C ≥ 0.1µF. 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 ≥ 0.2µF: one from C1+ to C1–, and another from C2 + to C2 –. The capacitor’s effective series resistance should be less than 2Ω. For C ≥ 1µF, 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 0.1µF 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 over- drive 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 60µA. 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. U ESD PROTECTIO 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. ESD Test Circuit V+ 5V VCC 0.1µF 2 LT1341 3 26 0.2µF 4 25 5 24 6 23 7 22 8 21 9 20 10 19 11 18 12 17 13 16 14 15 RX1 IN DRIVER 2 OUT RX2 IN RX3 IN RX4 IN DRIVER 3 OUT RX5 IN (LOW-Q) ON/OFF NC V– 27 0.1µF DRIVER 1 OUT RS232 LINE PINS PROTECTED TO ±10kV 28 1 0.1µF 0.2µF 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 LT1341 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 0.397 – 0.407* (10.07 – 10.33) 0.205 – 0.212** (5.20 – 5.38) 0.068 – 0.078 (1.73 – 1.99) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0° – 8° 0.0256 (0.65) BSC 0.010 – 0.015 (0.25 – 0.38) 0.005 – 0.009 0.022 – 0.037 (0.13 – 0.22) (0.55 – 0.95) 0.301 – 0.311 (7.65 – 7.90) 0.002 – 0.008 (0.05 – 0.21) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 G28 SSOP 0694 NW Package 28-Lead PDIP (Wide 0.600) (LTC DWG # 05-08-1520) 0.150 ± 0.005 (3.810 ± 0.127) 0.600 – 0.625 (15.240 – 15.875) 0.070 (1.778) TYP 0.045 – 0.065 (1.143 – 1.651) 1.455* (36.957) MAX 28 27 26 25 24 23 22 21 20 19 18 17 16 1 2 3 4 5 6 7 8 9 10 11 12 13 0.015 (0.381) MIN 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.625 –0.015 15.87 +0.889 –0.381 ) 15 0.505 – 0.560* (12.827 – 14.224) 0.125 (3.175) MIN 0.018 ± 0.003 (0.457 ± 0.076) 0.035 – 0.080 (0.889 – 2.032) 0.100 ± 0.010 (2.540 ± 0.254) 14 N28 1197 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) SW Package 28-Lead Plastic Small Outline (Wide 0.300) (LTC DWG # 05-08-1620) 0.291 – 0.299** (7.391 – 7.595) 0.010 – 0.029 × 45° 0.093 – 0.104 (2.362 – 2.642) (0.254 – 0.737) 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° – 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 0.394 – 0.419 (10.007 – 10.643) NOTE 1 0.004 – 0.012 (0.102 – 0.305) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 S28 (WIDE) 0996 *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. 7 LT1341 U TYPICAL APPLICATIO S Operation Using 5V and 12V Power Supplies V+ VCC 1 + C1+ 3 26 0.1µF C1– 4 25 5 24 6 23 7 22 8 21 9 20 10 19 11 18 12 17 13 16 14 15 5V VCC 12V V 0.1µF 2 DRIVER 1 OUT RX1 IN DRIVER 2 OUT RX2 IN TO LINE RX3 IN RX4 IN DRIVER 3 OUT RX5 IN ON/0FF = 5V NC 28 LT1341 V– 27 0.1µF 2 × 0.1µF DRIVER 1 IN RX1 OUT DRIVER 2 IN RX2 OUT TO LOGIC RX3 OUT RX4 OUT DRIVER 3 IN RX5 OUT GND DRIVER DISABLE NC LT1341 • TA03 Typical Mouse Driving Application V+ 0.1µF 5V VCC MOUSE 2 × 0.1µF (1) OPTICS 24 DCD RX1 IN 6 RX1 OUT 23 DRIVER 2 IN DSR DRIVER 2 OUT 7 22 RX RX2 IN 8 RX2 OUT 21 RX3 OUT RTS RX3 IN 9 20 RX4 IN 10 RX4 OUT 19 DRIVER 3 IN DRIVER 3 OUT 11 18 RX5 IN 12 17 13 16 14 15 RI ON/OFF NC 0.1µF 2 × 0.1µF 25 DRIVER 1 IN DTR (5) 26 5 CTS (9) 27 3 4 TX V– 2 LT1341 DRIVER 1 OUT V+ LOGIC 28 V – 1 LOGIC “0” LOGIC “0” MOUSE DATA LOGIC “1” RX5 OUT GND DRIVER DISABLE NC DB9 LT1341 • TA04 RELATED PARTS PART NUMBER LT1137A LTC1334 LTC1347 LT1780/LT1781 8 DESCRIPTION 3 Driver/5 Receiver RS232 Transceiver RS232/RS485 Multiprotocol Transceiver 3 Driver/5 Receiver Micropower RS232 Transceiver 2 Driver/2 Receiver RS232 Transceivers Linear Technology Corporation COMMENTS ±15kV ESD Protection ±15kV ESD Protection 1341fa LT/TP 1098 2K REV A • 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