Deutsch | Français | Italiano | 简体中文 | 繁體中文 | 日本語 | 한국어
Robust 3.3V/5V RS232/RS485 Multiprotocol Transceivers Provide Integrated Switchable Termination
MILPITAS, CA - December 08, 2010 - Linear Technology Corporation
introduces the LTC2870 and
LTC2871 multiprotocol
transceivers with switchable integrated termination for 3.3V and 5V
systems. RS485 systems require a termination resistor on the ends
of the communication bus to minimize signal reflections. Both the
LTC2870 and LTC2871 integrate pin-controlled termination resistors
that allow for easy interface reconfiguration, eliminating external
resistors and control relays. The termination resistors, when
enabled, are automatically switched on or out to match the
transceiver's protocol selection of RS232 or RS485. Both devices
also feature high ESD protection: ±26kV HBM (LTC2870) or ±16kV HBM
(LTC2871) on the transceiver bus pins, when powered off or
operating. The LTC2870 can be configured as two RS232 single-ended
transceivers or one RS485 differential transceiver on shared I/O
lines, whereas the LTC2871 offers independent control of two RS232
transceivers and one RS485 transceiver, each on dedicated I/O
lines. Both devices reduce component count for multiprotocol
networks and offer on-the-fly configurability.
The LTC2870 and LTC2871 are suitable for a wide variety of
applications, including software-selectable multiprotocol interface
ports, point-of-sale terminals, security cameras, cable repeaters
and protocol translators. An optional 1.7V to 5.5V logic supply
enables convenient digital interfacing, and an integrated DC/DC
boost converter eliminates the need for multiple supplies to drive
RS232 levels. Drivers and receivers can be independently disabled,
leaving them in a high impedance state, consuming only 9uA in a low
power shutdown mode. Aside from automatic termination selection,
both devices provide half- and full-duplex RS485 switching and a
logic loopback mode that steers the driver inputs to the receiver
outputs for diagnostic self-test and debug. Other protective
measures include high ESD of ±4kV or better on all pins, thermal
shutdown protection and a full failsafe RS485 receiver for
floating, shorted or terminated inputs that eliminates the need for
external network biasing resistors and UART lockup.
The LTC2870 is available in 28-pin 4mm x 5mm QFN and TSSOP
packages, and the LTC2871 is available in 38-pin 5mm x 7mm QFN and
TSSOP packages. Both devices are available today in production
quantities, priced starting at $5.00 each in 1,000 piece
quantities. Please visit www.linear.com/2870 for more product selection and
information.
|
Summary of Features: LTC2870/71
|
Simultaneous Protocols and |
