SP338E Datasheet, PDF (1/25 Pages) Exar Corporation – RS-232/RS-485/RS-422 TRANSCEIVER

SP338E
RS-232/RS-485/RS-422 TRANSCEIVER WITH INTERNAL TERMINATION
NOVEMBER 2011
REV. 1.0.0
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 5kΩ pull-down
to ground. The RS-485/422 receiver inputs are high
impedance (>96kΩ 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
■ ±15kV Human Body Model (HBM)
■ ±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
■ Full, Half, and Mixed Duplex Configurations
■ 1/8th 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
PART NUMBER
SP338EER1-L
SP338EER1-L/TR
SP338ECR1-L
SP338ECR1-L/TR
PACKAGE
40-pin QFN
40-pin QFN
40-pin QFN
40-pin QFN
OPERATING TEMPERATURE RANGE
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
DEVICE STATUS
Active
Active
Active
Active
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com