F81438
F81438
Single 5V RS232/RS422/RS485 Multiprotocol
Transceiver
Release Date: Jan, 2012
Version: V0.11P
Jan, 2012
V0.11P
F81438
F81438 Datasheet Revision History
Version
V0.10P
V0.11P
Date
2011/11
2012/01
Page
-
-
Revision History
Preliminary
Made Clarification and Correction
Delete 28-SOP Package
Update Pin 21 & 22 Description
Please note that all data and specifications are subject to change without notice. All the trade marks of products
and companies mentioned in this data sheet belong to their respective owners.
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of
these products can reasonably be expected to result in personal injury. Customers using or selling these products
for use in such applications do so at their own risk and agree to fully indemnify Fintek for any damages resulting
from such improper use or sales.
Jan, 2012
V0.11P
F81438
Table of Content
1
2
3
4
5
General Description ................................................................................................................................................. 4
Feature List.............................................................................................................................................................. 4
Pin Configuration ..................................................................................................................................................... 5
Pin Description ........................................................................................................................................................ 5
Function Description ................................................................................................................................................ 7
5.1
5.2
5.2.1
5.2.2
5.2.3
5.2.4
6
7
8
9
10
Mode Selection ............................................................................................................................................. 7
Mode Description.......................................................................................................................................... 8
Pure RS-232 (Mode 01) ............................................................................................................................ 8
RS-485 Driver Half Duplex (Mode 10) ...................................................................................................... 9
RS-485 Receiver Full Duplex (Mode 11) .................................................................................................. 9
Pure RS-422 Full Duplex (Mode 00) ....................................................................................................... 10
Electrical Characteristics Request ........................................................................................................................ 11
Ordering Information ............................................................................................................................................. 18
Top Marking Specification ..................................................................................................................................... 18
Package Spec. ...................................................................................................................................................... 19
Application Circuit .................................................................................................................................................. 20
Jan, 2012
V0.11P
F81438
1 General Description
The F81438 is programmable, monolithic multi-protocol transceiver device that contains RS-232
and RS-485 / RS-422 drivers and receivers. The F81438 can be reconfigured into four operating
modes including RS-232 only (3TX/5RX), one RS-485 (1TX/1RX) driver (TX) half duplex mode, one
RS-485 (1TX/1RX) receiver (RX) half duplex mode, and RS-422 (1TX/1RX) full duplex mode which
can be selected whenever you need by changing the logic state of the 2 mode selection pins. The
device can implement a dual-mode serial port, mixed mode ports or as an interface signal translator.
The extra charge pumps deliver true RS-232 driver output voltage from a single power supply at 5V.
A slew rate control pin configures driver outputs for either high data rate or slew-controlled data rates.
Slew-controlled outputs minimize the problems that caused by the reflections and ringing on long or
un-terminated cables.
All RS-485 receivers or transceivers feature high impedance which allow up to 256 transceivers
on a shared bus. When configured in RS-485/RS-422 mode, each driver may be individually enabled
or put into tri-state, simplifying use on shared buses or bidirectional communication. All receivers
have advanced failsafe protection to prevent oscillation when inputs are un - connected. In RS-232
mode each receiver input has a 5k
Ω
pull-down to ground. Differential Receivers will default to output
logic 1 if inputs are floating, shorted or open but terminated. All driver outputs and receiver inputs are
protected against ESD strikes up to ±15,000 volts (IEC 61000-4-2 Air Gap).
2 Feature List
5V Single Supply Operation
Robust ±15kV ESD Protection (IEC 61000-4-2 Air Gap)
Mixed RS-232 / RS-485 Modes
Adjustable Slew Rate for Minimize EMI Error
RS-485 Advance Failsafe on Open, Short or Terminated Lines
28 Pin TSSOP Packaging
Flexible 4 Operation Modes Selected by 2 Configuration Pins
One set of 3T5R RS-232 V.28 Drivers & Receivers
One Set of RS-485 Drivers (Half Duplex Configuration)
One Set of RS-485 Receivers (Half Duplex Configuration)
One set of RS-422 Driver & Receiver (Full Duplex Configuration)
4
Jan, 2012
V0.11P
F81438
3
Pin Configuration
4 Pin Description
AIN
AOUT
O
4
P
IN
t,pu 8uA
IN
t
- TTL level input pin.
- TTL level input pin, pull up 8uA.
- Input pin (Receiver).
- Output pin (Buffer driver).
- Output pin with 4mA driver.
- Power.
4.1. Power Pin
Pin
5
8
Pin Name
VCC
GND
Type
P
P
Description
5V power supply voltage input
GND.
5
Jan, 2012
V0.11P
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