ISL81387 Datasheet, PDF (1/27 Pages) Intersil Corporation – ±15kV ESD Protected, Dual Protocol (RS-232/RS-485) Transceivers

®
Data Sheet
ISL81387, ISL41387
December 20, 2005
FN6201.1
±15kV ESD Protected, Dual Protocol
(RS-232/RS-485) Transceivers
These devices are BiCMOS interface ICs that are user
configured as either a single RS-422/485 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 failsafe" 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-232/485 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 (20µA) 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.
Features
• User Selectable RS-232 or RS-485/422 Interface Port
(Two RS-232 Transceivers or One RS-485/422
Transceiver)
• ±15kV (HBM) ESD Protected Bus Pins (RS-232 or
RS-485)
• Flow-Through Pinouts Simplify Board Layouts
• Pb-Free Plus Anneal Available (RoHS Compliant)
• Large (2.7V) Differential V_OUT for Improved Noise
Immunity in RS-485/422 Networks
• Full Failsafe (Open/Short) Rx in RS-485/422 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
For a dual port version of these devices, please see the
ISL81334/ISL41334 data sheet.
TABLE 1. SUMMARY OF FEATURES
PART
NUMBER
NO. OF
PORTS
PACKAGE OPTIONS
RS-485 DATA
RATE (bps)
RS-232 DATA
RATE (kbps)
V_L PIN?
ACTIVE H or L LOW POWER
Rx ENABLE? SHUTDOWN?
ISL81387
1
20 Ld SOIC, 20 Ld SSOP 20M, 460k
650
NO
H
YES
ISL41387
1
40 Ld QFN (6 x 6mm) 20M, 460k, 115k
650
YES
BOTH
YES
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2005. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.