LTC2871IFE#PBF Linear Technology, LTC2871IFE#PBF Datasheet

IC, RS232-RS485 TXRX, 200MBPS, 5.5V, TSSOP-38

LTC2871IFE#PBF

Manufacturer Part Number
LTC2871IFE#PBF
Description
IC, RS232-RS485 TXRX, 200MBPS, 5.5V, TSSOP-38
Manufacturer
Linear Technology
Datasheet

Specifications of LTC2871IFE#PBF

Device Type
Transceiver
No. Of Drivers
2
Supply Voltage Range
3V To 5.5V
Driver Case Style
TSSOP
No. Of Pins
38
Operating Temperature Range
-40°C To +85°C
Rohs Compliant
Yes
Ic Interface Type
RS232, RS485

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LTC2871IFE#PBF
Manufacturer:
Linear Technology
Quantity:
135
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APPLICATIONS
TYPICAL APPLICATIONS
FEATURES
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RS232
One RS485 and Two RS232 Transceivers
3V to 5.5V Supply Voltage
20Mbps RS485 and 500kbps RS232
Automatic Selection of Integrated RS485 (120Ω)
and RS232 (5kΩ)Termination Resistors
Half-/Full-Duplex RS485 Switching
High ESD: ±26kV (LTC2870), ±16kV (LTC2871)
Logic Loopback Mode
1.7V to 5.5V Logic Interface
Supports Up to 256 RS485 Nodes
RS485 Receiver Failsafe Eliminates UART Lockup
Available in 28-Pin 4mm × 5mm QFN and
TSSOP (LTC2870), and 38-Pin 5mm × 7mm QFN
and TSSOP (LTC2871)
Flexible RS232/RS485/RS422 Interface
Software Selectable Multiprotocol Interface Ports
Point-of-Sale Terminals
Cable Repeaters
Protocol Translators
RS485
1.7V TO V
Automatic Termination Selection
Protocol Switching with
CC
V
485/232
DY
DZ
RA
RB
L
LTC2870
V
CC
3V TO 5.5V
Y
A
B
Z
TERMINATION
OFF
RS485
1.7V TO V
ON
RS485 Termination Switching
Simultaneous Protocols and
CC
V
TE485
DI
RO
DIN1
ROUT1
DIN2
ROUT2
L
LTC2871
DESCRIPTION
The LTC
tiprotocol transceivers, supporting RS232, RS485, and
RS422 protocols, operating on a single 3V to 5.5V supply.
The LTC2870 can be configured as two RS232 single-ended
transceivers or one RS485 differential transceiver on shared
I/O lines. The LTC2871 offers independent control of two
RS232 transceivers and one RS485 transceiver, each on
dedicated I/O lines.
Pin-controlled integrated termination resistors allow
for easy interface reconfiguration, eliminating external
resistors and control relays. Half-duplex switches allow
four-wire and two-wire RS485 configurations. Loopback
mode steers the driver inputs to the receiver outputs for
diagnostic self-test.The RS485 receivers support up to
256 nodes per bus, and feature full failsafe operation for
floating, shorted or terminated inputs.
An integrated DC/DC boost converter uses a small induc-
tor and one capacitor, eliminating the need for multiple
supplies for driving RS232 levels.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
RS232/RS485 Multiprotocol
120Ω
120Ω
DOUT1
DOUT2
Integrated Termination
®
RIN1
RIN2
2870/LTC2871 are robust pin-configurable mul-
V
CC
3V TO 5.5V
Y
A
B
Z
LTC2870/LTC2871
Transceivers with
FULL
DUPLEX
RS485
1.7V TO V
HALF
RS485 Duplex Switching
CC
V
DI,
DY
H/F
RO,
RB
L
LTC2870,
LTC2871
28701 TA01
V
CC
3V TO 5.5V
Y
Z
A
B
28701f
1

Related parts for LTC2871IFE#PBF

LTC2871IFE#PBF Summary of contents

Page 1

... RS232 levels. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Simultaneous Protocols and RS485 Termination Switching 1 ...

Page 2

LTC2870/LTC2871 ABSOLUTE MAXIMUM RATINGS Input Supplies ..................................................... –0. Generated Supplies V ................................................ ......................................................... 0.3V to –7. – V ..............................................................15V ........................................... –0. CAP ............................................. ...

Page 3

... LTC2870IFE#PBF LTC2870IFE#TRPBF LTC2870CUFD#PBF LTC2870CUFD#TRPBF LTC2870IUFD#PBF LTC2870IUFD#TRPBF LTC2871CFE#PBF LTC2871CFE#TRPBF LTC2871IFE#PBF LTC2871IFE#TRPBF LTC2871CUHF#PBF LTC2871CUHF#TRPBF LTC2871IUHF#PBF LTC2871IUHF#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: ...

Page 4

LTC2870/LTC2871 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at 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 Transceiver Mode ...

Page 5

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER R Terminating Resistor TERM 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 ...

Page 6

LTC2870/LTC2871 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER RS485 AC Characteristics Maximum Data Rate t Driver Propagation Delay PLHD485 t PHLD485 Driver Propagation Delay Difference |t – PLHD485 PHLD485 t Driver Skew (Y to ...

Page 7

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) 28701 G01 V Supply Current CC vs RS232 ...

Page 8

LTC2870/LTC2871 TYPICAL PERFORMANCE CHARACTERISTICS RS485 Receiver Propagation Delay vs Temperature 3. 3. ...

Page 9

TYPICAL PERFORMANCE CHARACTERISTICS RS232 Driver Outputs Enabling and Disabling DX232 DOUT1 FEN = 1 5V/DIV DOUT2 DOUT1 FEN = 0 DOUT2 28701 G19 40μs/DIV TOP CURVES: FAST ENABLE DX232 BOTTOM CURVES: SHUTDOWN DX232 PIN FUNCTIONS LTC2870 LTC2870 LTC2871 PIN NAME ...

Page 10

LTC2870/LTC2871 PIN FUNCTIONS LTC2870 LTC2870 LTC2871 PIN NAME QFN TSSOP QFN DOUT1 23 DOUT2 485/232 4 7 RXEN 5 8 DXEN 6 9 ...

Page 11

BLOCK DIAGRAM 1.7V TO 5.5V (≤ V 0.1μF DXEN RXEN TE485 CONTROL H/F LOGIC 485/232 FEN LOOPBACK PATH RA RB LTC2870 ) 3V TO 5.5V CC 10μH 2.2μ PULSE-SKIPPING RT232 BOOST REGULATOR RT485 ...

Page 12

LTC2870/LTC2871 BLOCK DIAGRAM 1.7V TO 5.5V (≤ V 0.1μF DX232 DX485 RX232 RX485 CONTROL TE485 LOGIC H/F CH2 FEN LB DIN1 DI DIN2 LOOPBACK PATH ROUT1 RO ROUT2 12 LTC2871 10μH 2.2μ ...

Page 13

TEST CIRCUITS Y + GND DY/DI OR DRIVER – Figure 1. RS485 Driver DC Characteristics Figure 3. RS485 Receiver Input Current and Resistance (Note 5) Y DY/DI R DRIVER DIFF GND OR ...

Page 14

LTC2870/LTC2871 TEST CIRCUITS DY/DI OR DRIVER GND Z R DXEN/DX485 C L Figure 5. RS485 Driver Enable and Disable Timing Measurements ± RECEIVER CM B ± Figure 6. ...

Page 15

TEST CIRCUITS RECEIVER – B TE485 + – Figure 8. RS485 Termination Resistance and Timing Measurements (Note 5) DRIVER INPUT Figure 9. RS232 Driver Timing and Slew Rate Measurements DXEN/DX232 V AB ...

Page 16

LTC2870/LTC2871 TEST CIRCUITS RECEIVER RECEIVER INPUT OUTPUT RECEIVER OUTPUT –3V OR +3V RXEN/RX232 16 RECEIVER 1.5V INPUT t PHLR232 C L 90% RECEIVER OUTPUT 10% Figure 11. RS232 Receiver Timing Measurements RXEN/ R ½V L RX232 L GND OR V ...

Page 17

FUNCTION TABLES Table 1. LTC2870 Mode Selection Table RXEN FEN 485/232 DXEN ...

Page 18

LTC2870/LTC2871 FUNCTION TABLES Table 5. LTC2871 CH2 CONTROL RS232 RECEIVER INPUTS CH2 RX232 DX232 RIN1 Hi 5kΩ Hi 5kΩ 5kΩ Hi-Z 1 ...

Page 19

APPLICATIONS INFORMATION Overview The LTC2870 and LTC2871 are flexible multiprotocol trans- ceivers supporting RS485/RS422 and RS232 protocols. These parts can be powered from a single 3V to 5.5V supply with optional logic interface supply as low as 1.7V. An integrated ...

Page 20

LTC2870/LTC2871 APPLICATIONS INFORMATION Inrush Current and Supply Overshoot Precaution In certain applications fast supply slew rates are generated when power is connected. If the V than 4.5V and its rise time is faster than 10μs, the pins V and SW ...

Page 21

APPLICATIONS INFORMATION All devices also feature thermal shutdown protection that disables the drivers, receivers, and RS485 terminators in case of excessive power dissipation (see Note 6). RS485 Balanced Receiver with Full Failsafe Operation The LTC2870 and LTC2871 receivers use a ...

Page 22

LTC2870/LTC2871 APPLICATIONS INFORMATION Receiver Outputs The RS232 and RS485 receiver outputs are internally driven high ( low (to GND) with no external pull needed. When the receivers are disabled the output pin becomes Hi-Z with ...

Page 23

APPLICATIONS INFORMATION Logic Loopback A loopback mode connects the driver inputs to the re- ceiver outputs (non-inverting) for self test. This applies to both RS232 and RS485 transceivers. Loopback mode is entered when the LB pin is high and the ...

Page 24

LTC2870/LTC2871 TYPICAL APPLICATIONS 5.5V 1. Logic input pins not shown are tied to a valid logic state LTC2870 485/232 DXEN RXEN ...

Page 25

TYPICAL APPLICATIONS 5.5V 1. Logic input pins not shown are tied to a valid logic state LTC2870 RXEN DXEN TE485 H/F LB 485/232 RS RS 232 ...

Page 26

LTC2870/LTC2871 TYPICAL APPLICATIONS 5.5V 1. Logic input pins not shown are tied to a valid logic state LTC2871 CH2 H/F LB TE485 D R 485 DX485 ...

Page 27

TYPICAL APPLICATIONS 1. DXEN RXEN 485/232 H/F TE485 DY CONTROLLER Figure 38. LTC2870: Making Use of Shared I/O for Various Communication Configurations 1. DXEN RXEN ...

Page 28

LTC2870/LTC2871 TYPICAL APPLICATIONS V L CONTROLLER Figure 40. LTC2871: Various Communication Configurations V L CONTROLLER Figure 41. LTC2871: More Communication Configurations Using External Connections LTC2871 L CC RS232 DX232 FULL-DUPLEX ...

Page 29

TYPICAL APPLICATIONS 5.5V 1. Logic input pins not shown are tied to a valid logic state DX232 DX485 CH2 TE485 DI ROUT1 RXIN RIN1 RS232 ROUT1 ...

Page 30

LTC2870/LTC2871 TYPICAL APPLICATIONS LTC2871 DIN1 DOUT1 PORT 1 LOGIC ROUT1 INTERFACE DIN2 DOUT2 PORT 2A/2B LOGIC ROUT2 INTERFACE CH2 SELECT LINE 2A LTC2871 CH2 SELECT LINE 2B DIN2 DOUT2 ROUT2 DIN1 DOUT1 PORT 3 LOGIC ROUT1 INTERFACE Figure 44. RS232 ...

Page 31

TYPICAL APPLICATIONS 3V TO 5.5V 10μH 2.2μ 1. H/F 0.1μF TE485 DI RO DIN1 ROUT1 DIN2 ROUT2 1μF EE 1μF Figure 47. Typical Supply Connections with External Components Shown 3V ...

Page 32

LTC2870/LTC2871 PACKAGE DESCRIPTION 4.75 (.187) 6.60 ±0.10 4.50 ±0.10 SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 0.50 – 0.75 (.0035 – .0079) (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. ...

Page 33

PACKAGE DESCRIPTION 4.75 REF 6.60 ±0.10 4.50 REF SEE NOTE 4 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50* (.169 – .177) 0.09 – 0.20 0.50 – 0.75 (.0035 – .0079) (.020 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS 2. DIMENSIONS ...

Page 34

LTC2870/LTC2871 PACKAGE DESCRIPTION 4.50 ± 0.05 3.10 ± 0.05 2.50 REF 2.65 ± 0.05 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 5.00 ...

Page 35

... ALL DIMENSIONS ARE IN MILLIMETERS 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. UHF Package 38-Lead Plastic QFN (5mm × ...

Page 36

... Switchable, 120Ω Termination Resistor, 15kV ESD 1Mbps, 2500V RMS www.linear.com ● 3. 0.1μ 120Ω RO GND 28701 TA02 Isolation with Integrated DC/DC Converter, Integrated, Isolation with Integrated DC/DC Converter, ±10kV ESD LT 1210 • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2010 28701f ...

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