ISL81387_14 Datasheet, PDF (1/27 Pages) Intersil Corporation – ±15kV ESD Protected, 5V, Dual Protocol (RS-232/RS-485) Transceivers

±15kV ESD Protected, 5V, Dual Protocol
(RS-232/RS-485) Transceivers
ISL81387, ISL41387
These devices are BiCMOS interface ICs that are user
configured as either a single RS-422, RS-485 differential
transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver.
In RS-232 mode, the on-board charge pump generates RS-232
compliant ±5V Tx output levels, from a supply as low as 4.5V.
Four small 0.1µF capacitors are required for the charge pump.
The transceivers are RS-232 compliant, with the Rx inputs
handling up to 25V, and the Tx outputs handling ±12V.
In RS-485 mode, the transceivers support both the RS-485
and RS-422 differential communication standards. The
RS-485 receiver features "full fail-safe" operation, so the Rx
output remains in a high state if the inputs are open or shorted
together. The RS-485 transmitter supports up to three data
rates, two of which are slew rate limited for problem free
communications. The charge pump disables in RS-485 mode,
thereby saving power, minimizing noise, and eliminating the
charge pump capacitors.
Both RS-232, RS-485 modes feature loopback and shutdown
functions. The loopback mode internally connects the Tx
outputs to the corresponding Rx input, which facilitates the
implementation of board level self test functions. The outputs
remain connected to the loads during loopback, so connection
problems (e.g., shorted connectors or cables) can be detected.
The shutdown mode disables the Tx and Rx outputs, disables
the charge pump if in RS-232 mode, and places the IC in a low
current (35µA) mode.
The ISL41387 is a QFN packaged device that offers additional
functionality, including a lower speed and edge rate option
(115kbps) for EMI sensitive designs, or to allow longer bus
lengths. It also features a logic supply voltage pin (V_L) that sets
the V_OH level of logic outputs, and the switching points of logic
inputs, to be compatible with another supply voltage in mixed
voltage systems. The QFN's choice of active high or low Rx
enable pins increases design flexibility, allowing Tx/Rx
direction control via a single signal by connecting DEN and
RXEN together.
For a dual port version of these devices, please see the
ISL81334, ISL41334 datasheet.
Features
• 5V powered, user selectable RS-232 or RS-485, RS-422
interface port (two RS-232 transceivers or one RS-485,
RS-422 transceiver)
• ±15kV (HBM) ESD protected bus pins (RS-232 or RS-485)
• True flow-through pinouts simplify board layouts
• Pb-Free (RoHS compliant)
• Large (2.7V) differential V_OUT for improved noise immunity
in RS-485, RS-422 networks
• Full fail-safe (open/short) Rx in RS-485, RS-422 mode
• Loopback mode facilitates board self test functions
• User selectable RS-485 data rates . . . . . . . . . . . . . . 20Mbps
- Slew rate limited . . . . . . . . . . . . . . . . . . . . . . . . . . . 460kbps
- Slew rate limited (ISL41387 only) . . . . . . . . . . . . . 115kbps
• Fast RS-232 data rate . . . . . . . . . . . . . . . . . . . . up to 650kbps
• Low current shutdown mode . . . . . . . . . . . . . . . . . . . . . . 35µA
• QFN package saves board space (ISL41387 only)
• Logic supply pin (V_L) eases operation in mixed supply
systems (ISL41387 only)
Applications
• Gaming applications (e.g., slot machines)
• Single board computers
• Factory automation
• Security networks
• Industrial/process control networks
• Level translators (e.g., RS-232 to RS-422)
• Point of sale equipment
Related Literature
• AN1378, “Implementing a Three Pin, Half-Duplex, Dual
Protocol (RS-232/RS-485) Interface Using the ISL81387 or
ISL41387.”
PART
NUMBER
ISL81387
ISL41387
NO. OF
PORTS
1
1
TABLE 1. SUMMARY OF FEATURES
PACKAGE OPTIONS
RS-485 DATA RATE RS-232 DATA
(bps)
RATE (kbps)
20 Ld SOIC, 20 Ld SSOP
20M, 460k
650
40 Ld QFN (6mmx6mm) 20M, 460k, 115k
650
V_L PIN?
NO
YES
ACTIVE H or L Rx
ENABLE?
H
BOTH
LOW POWER
SHUTDOWN?
YES
YES
June 9, 2014
FN6201.4
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2005, 2007, 2014. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.