LTC2803 LINER [Linear Technology], LTC2803 Datasheet
LTC2803
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LTC2803 Summary of contents
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FeaTures Four RS232 and Two RS485 Transceivers 5.5V Supply Voltage n 20Mbps RS485 and 500kbps RS232 n Automatic Selection of Integrated RS485 (120Ω) n and RS232 (5kΩ) Termination Resistors Half-/Full-Duplex RS485 Switching n Logic Loopback Mode n ...
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LTC2872 absoluTe MaxiMuM raTings (Note 1) Input Supplies ..................................................... –0. Generated Supplies V ................................................ ......................................................... 0.3V to –7. – V ..............................................................15V ........................................... –0. ...
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T SYMBOL PARAMETER Power Supply V Supply Voltage Operating Range CC V Logic Supply Voltage Operating Range L V Supply Current in Shutdown Mode CC V Supply Current in RS485 Transceiver Mode ...
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LTC2872 elecTrical characTerisTics temperature range, otherwise specifications are at T SYMBOL PARAMETER RS232 Driver V Output Low Voltage OLD V Output High Voltage OHD Three-State (High Impedance) Output Current Output Short-Circuit Current RS232 Receiver Input Threshold Voltage Input Hysteresis Output ...
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T noted. V ≤ SYMBOL PARAMETER RS485 AC Characteristics Maximum Data Rate t Driver Propagation Delay PLHD485 t PHLD485 Driver Propagation Delay Difference |t – PLHD485 ...
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LTC2872 Typical perForMance characTerisTics V Supply Current vs Supply CC Voltage in Shutdown Mode 30 25 H/F HIGH 20 15 H/F LOW 3.5 4 4.5 5 INPUT VOLTAGE (V) 2872 G01 V Supply Current CC vs ...
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Typical perForMance characTerisTics RS485 Receiver Propagation Delay vs Temperature 3. 3. ...
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LTC2872 pin FuncTions V (Pins 1, 21, 31): Input Supply (3.0V to 5.5V). Tie all CC three pins together and connect 2.2µF capacitor between VCC and GND. V (Pin 35): Logic Supply (1.7V to 5.5V) for the receiver L outputs, ...
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FuncTions DXEN1 (Pin 10): Drivers #1 Enable. A logic low disables the RS232 and RS485 drivers in transceiver #1, leaving their outputs in a Hi-Z state. A logic high enables the RS232 or RS485 drivers in transceiver #1, depending ...
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LTC2872 block DiagraM 1.7V TO 5.5V (≤ 0.1µ H/F 16 FEN TRANSCEIVER # DXEN 10 RXEN1 9 CONTROL TE485_1 LOGIC 11 485/232_1 13 DY1 7 DZ1 8 LOOPBACK PATH RA1 37 RB1 38 ...
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TesT circuiTs Y + GND DY OR DRIVER – Figure 1. RS485 Driver DC Characteristics Figure 3. RS485 Receiver Input Current and Resistance (Note DRIVER DIFF ...
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LTC2872 TesT circuiTs DRIVER GND DXEN C L Figure 5. RS485 Driver Enable and Disable Timing Measurements ± RECEIVER CM B ± ...
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TesT circuiTs RECEIVER – TE485 + V B – Figure 8. RS485 Termination Resistance and Timing Measurements (Note 5) DRIVER INPUT Figure 9. RS232 Driver Timing and Slew Rate Measurements ...
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LTC2872 TesT circuiTs RECEIVER RECEIVER INPUT OUTPUT RECEIVER OUTPUT –3V OR +3V RXEN 14 RECEIVER 1.5V INPUT t PHLR232 C L 90% RECEIVER OUTPUT 10% Figure 11. RS232 Receiver Timing Measurements RXEN R ½ GND ...
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FuncTion Tables Table 1. Shutdown and Fast Enable Modes 485/232_1 AND RXEN1 AND DXEN1 AND FEN 485/232_2 RXEN2 DXEN2 Table 2. Mode Selection Table for a Given Port (FEX = X) 485/232 RXEN DXEN ...
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LTC2872 FuncTion Tables Table 5. RS485 Driver Mode for a Given Port (485/232 = 1, TE485 = 0) DXEN DY CONDITIONS Fault Fault Fault X X Thermal Fault Table 6. RS485 ...
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Overview The LTC2872 is a flexible multiprotocol transceiver sup- porting RS485/RS422 and RS232 protocols. It can be powered from a single 3.0V to 5.5V supply with optional logic interface supply as low as 1.7V. An integrated DC/ DC ...
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LTC2872 applicaTions inForMaTion Inrush Current and Supply Overshoot Precaution In certain applications fast supply slew rates are gener- ated when power is connected than 4.5V and its rise time is faster than 10μs, the pins V and SW ...
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RA RISING THRESHOLD SHIFTS IF SIGNAL IS IN WINDOW > ~2µs TO SUPPORT FAILSAFE –80mV –50mV 0V Figure 15. RS485 Receiver Input Threshold Characteristics with Typical Values Shown The benefit of this dual threshold architecture is that it ...
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LTC2872 applicaTions inForMaTion Selectable RS485 Termination Proper cable termination is important for good signal fidel- ity. When the cable is not terminated with its characteristic impedance, reflections cause waveform distortion. The LTC2872 offers integrated switchable 120Ω termination resistors between the ...
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At frequencies below 100kbps, the maximum cable length is determined by DC resistance in the cable. In this ex- ample, a cable longer than 4000ft will attenuate the signal at the far end to less than what can ...
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LTC2872 Typical applicaTions state. External components necessary for operation are not shown LTC2872 485/232_1 485/232_2 LB DY1 Y1 DZ1 Z1 RA1 A1 RB1 B1 DY2 Y2 DZ2 Z2 RA2 A2 RB2 B2 PORT 1: RS232 PORT 2: RS232 ...
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Typical applicaTions state. External components necessary for operation are not shown. ½ LTC2872 V L TE485 DZ H/F MASTER ½ LTC2872 V L TE485 DZ H 5.5V 1. ½ ...
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LTC2872 Typical applicaTions state. External components necessary for operation are not shown. OUTPUT Figure 26. RS485 Receiver with 4-Way Selectable Inputs 5.5V 1. Logic input pins not shown are tied ...
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Typical applicaTions state. External components necessary for operation are not shown. LTC2872 RA1 OUT1 RXEN1 S1 RA2 OUT2 RXEN2 5.5V 1. Logic input pins not shown are tied to a ...
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LTC2872 Typical applicaTions state. External components necessary for operation are not shown. RS232 RS232 OUT 5.5V 1. Logic input pins not shown are tied to a valid logic CC L ...
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DescripTion Please refer to http://www.linear.com/designtools/packaging/ 5.50 ± 0.05 4.10 ± 0.05 3.00 REF 5.00 ± 0.10 PIN 1 TOP MARK (SEE NOTE 6) 7.00 ± 0.10 NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE M0-220 VARIATION WHKD 2. DRAWING ...
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