FXL2TD245 Datasheet, PDF(2/12 Page) Fairchild Semiconductor – Low Voltage Dual Supply 2-Bit Signal Translator with Configurable Voltage Supplies and Signal Levels 3-STATE Outputs and Independent

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FXL2TD245 Datasheet, PDF (2/12 Pages) Fairchild Semiconductor – Low Voltage Dual Supply 2-Bit Signal Translator with Configurable Voltage Supplies and Signal Levels 3-STATE Outputs and Independent

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Functional Diagram

VCCA

T/R0

T/R1

VCCB

Connection Diagram

B0 B1 OE T/R1

VCCB 10

5 GND

VCCA A0 A1 T/R0

(Top View)

Pin Assignment

Pin Number

Terminal Name

VCCA

T/R0

GND

T/R1

VCCB

Pin Descriptions

Pin Names

Description

Output Enable Input

T/Rn

VCCA

VCCB

Transmit/Receive Inputs

Side A Inputs or 3-STATE Outputs

Side B Inputs or 3-STATE Outputs

Side A Power Supply

Side B Power Supply

Truth Table

Inputs

OE T/R0 T/R1

Outputs

X B0 Data to A0 Output

L H X A0 Data to B0 Output

L B1 Data to A1 Output

H A1 Data to B1 Output

H 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 follow-

ing:

1. Drive OE input HIGH to disable the device.

2. Remove power from either VCC.

3. Remove power from other VCC.

FXL2TD245 Rev. 1.0.4

www.fairchildsemi.com

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