ISL81334, ISL41334
®
Data Sheet
December 1, 2005
FN6202.0
±15kV ESD Protected, Two Port, Dual
Features
Protocol Trans ceivers
• ±15kV (HBM) ESD Protected Bus Pins (RS-232 or
RS-485)
The ISLX1334 are two port interface ICs where each port
can be independently configured as a single RS-485/422
transceiver, or as a dual (2 Tx, 2 Rx) RS-232 transceiver.
With both ports set to the same mode, two RS-485/422
transceivers, or four RS-232 transceivers are available.
• Two Independent Ports, Each User Selectable for RS-232
(2 Transceivers) or RS-485/422 (1 Transceiver)
• Flow-Through Pinouts Simplify Board Layouts
• Pb-Free Plus Anneal Available (RoHS Compliant)
If either port is in RS-232 mode, the onboard charge pump
• Large (2.7V) Differential V
for Improved Noise
generates RS-232 compliant ±5V Tx output levels from a
OUT
Immunity in RS-485/422 Networks
single V
supply as low as 4.5V. Four small 0.1µF
CC
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.
• Full Failsafe (Open/Short) Rx in RS-485/422 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
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.
• Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 650kbps
• Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . .42µA
• QFN Package Saves Board Space (ISL41334 Only)
• Logic Supply Pin (V ) Eases Operation in Mixed Supply
L
Systems (ISL41334 Only)
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.
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
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 ) that sets the
L
• Dual Channel RS-485 Interfaces
V
level of logic outputs, and the switching points of logic
OH
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 RE pins together.
For a single port version of these devices, please see the
ISL81387/ ISL41387 data sheet.
TABLE 1. SUMMARY OF FEATURES
NO. OF
PORTS
RS-485 DATA
RATE (bps)
RS-232 DATA
RATE (kbps)
ACTIVE H or L LOW POWER
Rx ENABLE? SHUTDOWN?
PART NUMBER
PACKAGE OPTIONS
V PIN?
L
ISL81334
ISL41334
2
2
28 Ld SOIC, 28 Ld SSOP
40 Ld QFN (6 x 6mm)
20M
650
650
NO
NONE
L
YES
YES
20M, 460k, 115k
YES
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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