The ISL81334, ISL41334 are two port interface ICs where
each port can be independently configured as a single
RS-485, RS-422 transceiver, or as a dual (2 Tx, 2 Rx) RS232 transceiver. With both ports set to the same mode, two
RS-485, RS-422 transceivers, or four RS-232 transceivers
are available.
If either port is in RS-232 mode, the onboard charge pump
generates RS-232 compliant ±5V Tx output levels from a
single VCC 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
receivers feature "full failsafe" operation, so the Rx outputs
remain in a high state if the inputs are open or shorted
together. The transmitters support up to three data rates, two
of which are slew rate limited for problem free
communications. The charge pump disables when both
ports are in RS-485 mode, thereby saving power, minimizing
noise, and eliminating the charge pump capacitors.
Both RS-232 and RS-485 modes feature loopback and
shutdown functions. Loopback internally connects the Tx
outputs to the corresponding Rx input, to facilitate board
level self test implementation. The outputs remain connected
to the loads during loopback, so connection problems (e.g.,
shorted connectors or cables) can be detected. Shutdown
mode disables the Tx and Rx outputs, disables the charge
pumps, and places the IC in a low current (µA) mode.
The ISL41334 is a QFN packaged device that includes two
additional user selectable, lower speed and edge rate
options for EMI sensitive designs, or to allow longer bus
lengths. It also features a logic supply pin (VL) that sets the
VOH level of logic outputs, and the switching points of logic
inputs, to be compatible with another supply voltage in mixed
voltage systems. The QFN also adds active low Rx enable
pins to increase design flexibility, allowing Tx/Rx direction
control, via a single signal per port, by connecting the
corresponding DE and RXEN pins together.

Features
• ±15kV (HBM) ESD Protected Bus Pins (RS-232 or
RS-485)
• Two Independent Ports, Each User Selectable for RS-232
(2 Transceivers) or RS-485, RS-422 (1 Transceiver)
• Single 5V (10% Tolerance) Supply
• Flow-Through Pinouts Simplify Board Layouts
• Pb-Free (RoHS Compliant)
• Large (2.7V) Differential VOUT for Improved Noise
Immunity in RS-485, RS-422 Networks
• Full Failsafe (Open/Short) Rx in RS-485, RS-422 Mode
• Loopback Mode Facilitates Board Self Test Functions
• User Selectable RS-485 Data Rates (ISL41334 Only)
- Fast Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Mbps
- Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps
- Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 115kbps
• Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 650kbps
• Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . .42µA
• QFN Package Saves Board Space (ISL41334 Only)
• Logic Supply Pin (VL) Eases Operation in Mixed Supply
Systems (ISL41334 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
• Dual Channel RS-485 Interfaces