ISL81334_14 Datasheet, PDF (1/28 Pages) Intersil Corporation – ±15kV ESD Protected, 5V, Two Port, Dual Protocol (RS-232/RS-485) Transceivers

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Data Sheet
ISL81334, ISL41334
November 21, 2007
FN6202.3
±15kV ESD Protected, 5V, Two Port, Dual
Protocol (RS-232/RS-485) Transceivers
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) RS-
232 transceiver. With both ports set to the same mode, two
RS-485, RS-422 transceivers, or four RS-232 transceivers
are available.
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
If either port is in RS-232 mode, the onboard charge pump
generates RS-232 compliant ±5V Tx output levels from a
single V_CC 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.
• Pb-Free (RoHS Compliant)
• Large (2.7V) Differential V_OUT 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
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 (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 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.
• 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 (V_L) 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
For a single port version of these devices, please see the
ISL81387, ISL41387 data sheet.
TABLE 1. SUMMARY OF FEATURES
NO. OF
PART NUMBER _PORTS
PACKAGE OPTIONS
RS-485 DATA
RATE (bps)
RS-232 DATA
RATE (kbps)
ACTIVE H or L LOW POWER
V_L PIN? _{Rx ENABLE? SHUTDOWN?}
ISL81334
2 28 Ld SOIC, 28 Ld SSOP
20M
650
NO
NONE
YES
ISL41334
2 40 Ld QFN (6mmx6mm) 20M, 460k, 115k
650
YES
L
YES
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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