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FXL4TD245

Low-Voltage Dual-Supply 4-Bit Signal Translator with Configurable Voltage Supplies and Signal Levels and 3-STATE Outputs and Independent Direction Controls

ON Semiconductor 

Truth Table

Inputs

OE T/R0 T/R1 T/R2 T/R3

Outputs

L L X X X B0 Data to A0 Output

L H X X X A0 Data to B0 Output

L X L X X B1 Data to A1 Output

L X H X X A1 Data to B1 Output

L X X L X B2 Data to A2 Output

L X X H X A2 Data to B2 Output

L X X X L B3 Data to A3 Output

L X X X H A3 Data to B3 Output

H X X X X 3-State

H = HIGH Voltage Level

L = LOW Voltage Level

X = Don't Care

Power-Up/Power-Down Sequencing

FXL translators offer an advantage in that either VCC

may be powered up first. This benefit derives from the

chip design. When either VCC is at 0 volts, outputs are in

a HIGH-Impedance state. The control inputs (T/Rn and

OE) are designed to track the VCCA supply. A pull-up

resistor tying OE to VCCA should be used to ensure that

bus contention, excessive currents, or oscillations do not

occur during power-up/power-down. The size of the pull-

up resistor is based upon the current-sinking capability of

the OE driver.

The recommended power-up sequence is the following:

1. Apply power to either VCC.

2. Apply power to the T/Rn inputs (Logic HIGH for A-to-B

operation; Logic LOW for B-to-A operation) and to the

respective data inputs (A Port or B Port). This may

occur at the same time as Step 1.

3. Apply power to other VCC.

4. Drive the OE input LOW to enable the device.

The recommended power-down sequence is the following:

1. Drive OE input HIGH to disable the device.

2. Remove power from either VCC.

3. Remove power from other VCC.

©2006 Fairchild Semiconductor Corporation

FXL4TD245 • Rev. 1.0.6

3

www.fairchildsemi.com

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