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SP338E
RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION
JANUARY 2019 REV. 1.0.2
GENERAL DESCRIPTION
The SP338 is an advanced multiprotocol transceiver
supporting RS-232, RS-485, and RS-422 serial
standards in a 40 pin QFN package. Integrated cable
termination and four configuration modes allow all
three protocols to be used interchangeably over a
single cable or connector with no additional switching
components. Full operation requires only four
external charge pump capacitors.
The RS-485/422 modes feature up to two drivers and
four receivers (2TX/4RX) in half, full, and mixed
duplex configurations. The RS-232 mode (3TX/5RX)
provides full support of all eight signals commonly
used with the DB9 RS-232 connector. A dedicated
diagnostic loopback mode is also provided.
The high speed drivers operate up to 20Mbps in RS-
485/422 modes, and up to 1Mbps in RS-232 mode.
All drivers can be slew limited to 250kbps in any
mode to minimize electromagnetic interference (EMI).
All transmitter outputs and receiver inputs feature
robust electrostatic discharge (ESD) protection to
±15kV Human Body Model (HBM) and ±8kV IEC-
61000-4-2 Contact. Each receiver output has full fail-
safe protection to avoid system lockup, oscillation, or
indeterminate states by defaulting to logic-high output
level when the inputs are open, shorted, or
terminated but undriven. No external biasing resistors
are required.
The RS-232 receiver inputs include a 5k pull-down
to ground. The RS-485/422 receiver inputs are high
impedance (>96k when termination is disabled),
allowing up to 256 devices on a single
communication bus (1/8th unit load).
The SP338 operates from a single power supply,
either 3.3V or 5V, with low idle current. The shutdown
mode consumes less than 10µA for low power
standby operation.
FEATURES
Pin selectable Cable Termination
No external resistors required for RS-485/422
termination and biasing
3.3V or 5V Single Supply Operation
Robust ESD Protection on bus pins
n±15kV Human Body Model (HBM)
n±8kV IEC 61000-4-2 (Contact)
Max Data Rate of 20Mbps in RS-485/422 Modes
and up to 1Mbps in RS-232 Modes
Pin selectable 250kbps Slew Limiting
3 Drivers, 5 Receivers RS-232/V.28
2 Drivers, 4 Receivers RS-485/422
nFull, Half, and Mixed Duplex Configurations
n1/8th Unit Load, up to 256 receivers on bus
RS-485/422 Enhanced Failsafe for open, shorted,
or terminated but idle inputs
Space saving 6mm x 6mm QFN-40 Package
Pin compatible with SP339E
TYPICAL APPLICATIONS
Dual Protocol Serial Ports (RS-232 or RS-485/422)
Industrial Computers
Industrial and Process Control Equipment
Point-Of-Sale Equipment
Networking Equipment
HVAC Controls Equipment
Building Security and Automation Equipment
ORDERING INFORMATION(1)
PART NUMBER OPERATING TEMPERATURE RANGE LEAD-FREE PACKAGE PACKAGING METHOD
SP338EER1-L
-40°C to +85°C Yes(2) 40-pin QFN
Tray
SP338EER1-L/TR Tape and Reel
NOTE:
1. Refer to www.exar.com/SP338E for most up-to-date Ordering Information.
2. Visit www.exar.com for additional information on Environmental Rating.