DESCRIPTIO Supply Current: 500µA Supply Current Shutdown: 0.2µA S

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DESCRIPTIO Supply Current: 500µA Supply Current Shutdown: 0.2µA S

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LTC1348 3.3V/5.0V Power RS232 3-Driver/5-Receiver Transceiver
DESCRIPTIO
Supply Current: 500µA Supply Current Shutdown: 0.2µA Supply Current Receiver Alive Mode: 15µA Protection over ±10kV Operates from Single 3.3V Supply Operates 120kBaud with 0.1µF Flying Capacitors Three-State Outputs High Impedance When Output Overvoltage Does Force Current Back into Supplies RS232 Lines Forced ±25V Without Damage Flowthrough Architecture
LTC1348 3-driver/5-receiver RS232 transceiver with very supply current. charge pump only requires five 0.1µF capacitors. LTC1348 provides full RS232 output levels when operated over wide supply range 3.0V 5.5V transceiver operates four modes: Normal, Receiver Disable, Receiver Alive Shutdown. Normal Receiver Disable mode, only 500µA load condition. Shutdown mode, supply current further reduced 0.2µA. Receiver Alive mode, five receivers kept alive supply current 15µA. RS232 outputs assume high impedance state Shutdown Receiver Alive mode with power off. receiver outputs assume high impedance state Receiver Disable with power off. LTC1348 fully compliant with data rate overvoltage RS232 specifications. transceiver operates 120kbaud with drivers loaded with 1000pF, Both driver outputs receiver inputs forced ±25V without damage survive multiple ±10kV strikes.
registered trademarks Linear Technology Corporation.
APPLICATI
Notebook Computers Palmtop Computers Printers Portable Instruments
TYPICAL APPLICATI
0.1µF 0.1µF 0.1µF LTC1348
3-Drivers/5-Receivers with Shutdown
0.1µF DR_EN RX_EN
LT1348 TA01
0.1µF
1200 1000
QUIESCENT CURRENT (µA)
3.3V
QUIESCENT CURRENT SHUTDOWN CURRENT
Supply Current
SHUTDOWN CURRENT (µA)
TEMPERATURE (°C)
LT1348 TA02
LTC1348 ABSOLUTE RATI
PACKAGE/ORDER ATIO
VIEW DR_EN RX_EN PACKAGE 28-LEAD PLASTIC WIDE PACKAGE 28-LEAD PLASTIC SSOP
(Note Supply Voltage (VCC) Input Voltage Driver 0.3V 0.3V Receiver Driver/Receiver Enable 0.3V 0.3V Output Voltage Driver Receiver 0.3V 0.3V Short-Circuit Duration Driver Output Indefinite Receiver Output Indefinite Operating Temperature Range 70°C Storage Temperature Range 65°C 150°C Lead Temperature (Soldering, sec). 300°C
ORDER PART NUMBER LTC1348CG LTC1348CSW
TJMAX 125°C, 96°C/W TJMAX 125°C, 85°C/W (SW)
Consult factory Industrial Military grade parts.
ELECTRICAL CHARACTERISTICS
3.3V, 0.1µF, unless otherwise noted.
PARAMETER Driver Output Voltage Swing Logic Input Voltage Level Logic Input Current Output Short-Circuit Current Output Leakage Current Receiver Input Voltage Thresholds CONDITIONS Positive Negative
UNITS
Input Level (VOUT High) Input High Level (VOUT Low) VOUT Shutdown (Note Receiver Alive (Note VOUT ±20V Input Threshold (Receiver Alive Mode) Input Threshold (Normal Mode) Input High Threshold (Normal Mode) Normal Mode ±10V Output Low, IOUT 1.6mA (VCC 3.3V) Output High, IOUT 160µA (VCC 3.3V) Sinking Current, VOUT Shutdown (Note VOUT
±500
Hysteresis Input Resistance Output Voltage Output Short-Circuit Current Output Leakage Current
LTC1348
ELECTRICAL CHARACTERISTICS
3.3V, 0.1µF, unless otherwise noted.
PARAMETER Power Supply Generator Output Voltage Output Voltage Supply Rise Time Power Supply Supply Current Supply Leakage Current (VCC) Driver/Receiver Enable Threshold Driver/Receiver Enable Threshold High CONDITIONS IOUT IOUT IOUT IOUT Shutdown Turn-On Load (Note 3.3V Receiver Alive Mode (Note 3.3V Shutdown (Note 3.3V 3.3V
15.0
UNITS
30.0
ELECTRICAL CHARACTERISTICS
3.3V 0.1µF, unless otherwise noted.
PARAMETER Maximum Data Rate Slew Rate Driver Propagation Delay (TTL RS232) Receiver Propagation Delay (RS232 TTL) CONDITIONS 1000pF, Driver Switching 51pF 2500pF (Figure (Figure (Figure (Normal Mode) (Figure (Normal Mode) tHLR (Figure (Receiver Alive Mode) tLHR (Figure (Receiver Alive Mode)
UNITS kbps V/µs V/µs
denotes specifications which apply over operating temperature range 70°C. Note Absolute maximum ratings those values beyond which life device impaired. Note Supply current measured with driver receiver outputs unloaded. VDR_EN VRX_EN VCC.
Note Supply current measurement Shutdown performed with VDR_EN VRX_EN Note Supply current measurement Receiver Alive mode performed with VDR_EN VRX_EN VCC.
LTC1348
TYPICAL PERFORMANCE CHARACTERISTICS
Driver Output Voltage High/Low Load Capacitance (CL)
DRIVER OUTPUT VOLTAGE HIGH/LOW 250kbps 120kbps 64kbps OUTPUT HIGH 3.3V 0.1µF FLYING CAPACITORS DRIVERS LOADED DRIVER DRIVEN OUTPUT 64kbps 20kbps 250kbps 120kbps 20kbps
DRIVER OUTPUT VOLTAGE HIGH/LOW
SUPPLY CURRENT (mA)
3000 4000 1000 2000 LOAD CAPACITANCE (pF)
Driver Output Voltage High/Low Temperature (°C)
DRIVER OUTPUT VOLTAGE HIGH/LOW
3.3V OUTPUT HIGH
SHORT-CIRCUIT CURRENT (mA)
LEAKAGE CURRENT (µA)
DRIVERS LOADED WITH
OUTPUT 3.3V
TEMPERATURE (°C)
Driver Output Voltage High/Low Load Capacitance (CL)
Supply Current Driver Data Rate
OUTPUT LOADED 2500pF
120kbps
64kbps OUTPUT HIGH 20kbps
3.3V 0.1µF FLYING CAPACITORS DRIVERS DRIVEN LOADED OUTPUT 120kbps 64kbps 20kbps 3000 4000 1000 2000 LOAD CAPACITANCE (pF) 5000
LTC1348
OUTPUT LOADED 2500pF
3.3V DRIVER DATA RATE
5000
LTC1348
LTC1348
Driver Short-Curcuit Current Temperature (°C)
3.3V TEMPERATURE (°C) ISC+ ISC-
Driver Leakage SHUTDOWN Temperature (°C)
3.3V
VOUT -20V
VOUT
TEMPERATURE (°C)
LTC1348
LTC1348 LTC1348
With 3.3V Driver Outputs Loaded with 1000pF. Driven 250kbps
DRIVEN DRIVER OUTPUT
DRIVER INPUT
LTC1348
LTC1348
CTIO
VCC: 3.3V Input Supply Pin. This should decoupled with 0.1µF ceramic capacitor. GND: Ground Pin. RX_EN: TTL/CMOS Compatible Enable Pin. Refer Table functional description. DR_EN: TTL/CMOS Compatible Enable Pin. Refer Table functional description. Positive Supply Output (RS232 Drivers). This requires external capacitor 0.1µF charge storage. capacitor tied ground VCC. With multiple devices, pins paralleled into common capacitors. large numbers devices, increasing size shared common storage capacitors recommended reduce ripple. Negative Supply Output (RS232 Drivers). This requires external capacitor 0.1µF charge storage. C1+, C1-, C2+, C2-, C3+, C3-: Commutating Capacitor Inputs. These pins require three external capacitors 0.1µF: from C1-, another from another from C3-. maintain charge pump
Table Functional Description
MODE Shutdown ENABLE ENABLE DRIVERS Drivers Shutdown. Driver Outputs Assume High Impedance. Driver Pull-Up Resistors Disconnect From VCC. Drivers Alive. Drivers Shutdown. Driver Outputs Three-State. Driver Pull-Up Resistors Disconnect From VCC. Drivers Alive. RECEIVERS Receivers Shutdown. Receiver Outputs Assume High Impedance. 0.2µA
Receiver Disable Receiver Alive
Normal
efficiency, capacitor's effective series resistance should less than Ceramic capacitors recommended. RS232 Driver Input Pins. Inputs TTL/CMOS compatible. inputs unused drivers left unconnected since 300k input pull-up resistors included chip. minimize power consumption, internal driver pull-up resistors disconnected from Shutdown Receiver Alive mode. OUT: Driver Outputs RS232 Voltage Levels. Outputs high impedance state when Shutdown, Receiver Alive mode driver outputs protected against ±10kV human body model discharges. Receiver Inputs. These pins forced ±25V without damage. receiver inputs protected against ±10kV human body model discharges. Each receiver provides 0.4V hysteresis noise immunity. Receiver Alive mode receivers have hysteresis. OUT: Receiver Outputs with TTL/CMOS Voltage Levels. Outputs high impedance state when Shutdown Receiver Disable mode allow data line sharing.
Receiver Outputs Three-State. Receivers Alive.
500µA 15µA
Receivers Alive.
500µA
LTC1348
SWITCHI WAVEFOR
DRIVER INPUT DRIVER OUTPUT 1.4V 1.4V
LTC1348
Figure Driver Propagation Delay Timing
TEST CIRCUITS
DRIVER INPUT DRIVER OUTPUT DRIVER 51pF
LTC1348
Figure Driver Timing Test Load
OUTPUT INPUT 51pF
LTC1348
Figure Receiver Timing Test Load
APPLICATIONS INFORMATION
Power Supply LTC1348 includes on-board voltage-tripling charge pump capable generating from single 3.3V supply. This allows LTC1348 drivers provide guaranteed RS232-compliant voltage levels with 3.3V supply. With outputs loaded with LTC1348 typically swing with voltages 2.85V. will meet ±3.7V EIA562 levels with supply voltages 2.2V. charge pump requires three external flying capacitors operate; 0.1µF ceramic capacitors adequate most applications. applications requiring extremely high data rates abnormally heavy output loads, 0.33µF flying capacitors recommended. Bypass output capacitor values should match those flying capacitors capacitors should mounted close package possible.
INPUT OUTPUT
1.7V
1.3V 2.4V
LTC1348
0.8V
Figure Receiver Propagation Delay Timing
Test Circuit
0.1µF 0.1µF 0.1µF 0.1µF
LT1348
LTC1348
0.1µF 0.1µF DR_EN RX_EN
RS232 LINE PINS PROTECTED ±10kV
LTC1348 APPLICATIONS INFORMATION
High Data Rates LTC1348 maintains true RS232 minimum driver output even high data rates. Figure shows test circuit with wires connecting test chips. Both chips from 3.3V supplies. Figure shows typical line waveforms with three drivers, loaded with 1000pF toggling simultaneously 120kbaud. Figure shows
0.1µF 0.1µF 0.1µF LTC1348 0.1µF DR_EN RX_EN
LTC1348
0.1µF
1000pF
0.1µF 0.1µF
LTC1348
0.1µF 0.1µF DRIVER DRIVER DRIVER DR_EN RX_EN
LT1348
0.1µF 1000pF 1000pF
Figure Data Rate Evaluation Circuit
LTC1348
Information furnished Linear Technology Corporation believed accurate reliable. However, responsibility assumed use. Linear Technology Corporation makes representation that interconnection circuits described herein will infringe existing patent rights.
same circuit with single 1000pF/3k loaded driver driven 250kbaud, other drivers loaded toggling. This closely approximates actual behavior RS232 serial port, with only driver (TX) driven high speed other drivers (RTS DTR) driven relatively data rate Under same conditions, LTC1348 fast 350kbaud still meet EIA562 (±3.7V) minimum driver output levels.
DRIVER OUTPUT
RECEIVER OUTPUT
DRIVER INPUT
Figure Driver Test Result 120kbps
DRIVER OUTPUT
RECEIVER OUTPUT
DRIVER INPUT
Figure Driver Test Results 250kbps
LTC1348
PACKAGE DESCRIPTION
0.205 0.212* (5.20 5.38)
0.005 0.009 (0.13 0.22)
0.022 0.037 (0.55 0.95)
*THESE DIMENSIONS INCLUDE MOLD FLASH PROTRUSIONS. MOLD FLASH PROTRUSIONS SHALL EXCEED 0.006 INCH (0.15mm).
0.005 (0.127)
0.291 0.299 (7.391 7.595) (NOTE 0.010 0.029 (0.254 0.737)
0.093 0.104 (2.362 2.642)
0.009 0.013 (0.229 0.330)
NOTE 0.016 0.050 (0.406 1.270)
0.050 (1.270) 0.014 0.019 (0.356 0.482)
NOTE: IDENT, NOTCH CAVITIES BOTTOM PACKAGES MANUFACTURING OPTIONS. PART SUPPLIED WITH WITHOUT OPTIONS.
RELATED PARTS
PART NUMBER LT1137A LTC1327 LT1330 LT1331 LTC1347 DESCRIPTION 3-DR/5-RX RS232 Transceiver 3-DR/5-RX RS562 Transceiver 3-DR/5-RX RS232 3-DR/5-RX RS232/RS562 Transceiver 3-DR/5-RX Micropower RS232 Transceiver COMMENTS ±15kV IEC-801-2 Protection 3.3V Operation Logic Interface RS232 RS562 Operation Receivers Active Shutdown
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, 95035-7487
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977
Dimensions inches (millimeters) unless otherwise noted. Package 28-Lead Plastic SSOP
0.397 0.407* (10.07 10.33)
0.068 0.078 (1.73 1.99) 0.301 0.311 (7.65 7.90)
0.0256 (0.65)
0.010 0.015 (0.25 0.38)
0.002 0.008 (0.05 0.21)
28SSOP 0694
Package 28-Lead Plastic
0.697 0.712 (17.70 18.08) (NOTE 0.037 0.045 (0.940 1.143)
NOTE
0.394 0.419 (10.007 10.643)
0.004 0.012 (0.102 0.305)
SOL28 0392
THESE DIMENSIONS INCLUDE MOLD FLASH PROTRUSIONS. MOLD FLASH PROTRUSIONS SHALL EXCEED 0.006 INCH (0.15mm).
LT/GP 0695 PRINTED
LINEAR TECHNOLOGY CORPORATION 1994

DESCRIPTIO Supply Current: 500µA Supply Current Shutdown: 0.2µA S

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