Datasheet

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DESCRIPTION/ORDERING INFORMATION (CONTINUED)
GQL OR ZQL PACKAGE
(TOP VIEW)
1 2 3 4
A
B
C
D
E
F
G
H
J
K
5 6
SN74LVCH16543A
16-BIT REGISTERED TRANSCEIVER
WITH 3-STATE OUTPUTS
SCAS317M – NOVEMBER 1993 – REVISED MARCH 2005
The A-to-B enable ( CEAB) input must be low to enter data from A or to output data from B. If CEAB is low and
LEAB is low, the A-to-B latches are transparent; a subsequent low-to-high transition of LEAB puts the A latches
in the storage mode. With CEAB and OEAB both low, the 3-state B outputs are active and reflect the data
present at the output of the A latches. Data flow from B to A is similar, but requires using the CEBA, LEBA, and
OEBA inputs.
To ensure the high-impedance state during power up or power down, OE should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
Inputs can be driven from either 3.3-V or 5-V devices. This feature allows the use of this device as a translator in
a mixed 3.3-V/5-V system environment.
This device is fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the outputs,
preventing damaging current backflow through the device when it is powered down.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level. Use of pullup or
pulldown resistors with the bus-hold circuitry is not recommended. The bus-hold circuitry is part of the input
circuit and is not disabled by OE or DIR.
TERMINAL ASSIGNMENTS
1 2 3 4 5 6
A 1 CEAB 1 LEAB 1 OEAB 1 OEBA 1 LEBA 1 CEBA
B 1A2 1A1 GND GND 1B1 1B2
C 1A4 1A3 V
CC
V
CC
1B3 1B4
D 1A6 1A5 GND GND 1B5 1B6
E 1A8 1A7 1B7 1B8
F 2A1 2A2 2B2 2B1
G 2A3 2A4 GND GND 2B4 2B3
H 2A5 2A6 V
CC
V
CC
2B6 2B5
J 2A7 2A8 GND GND 2B8 2B7
K 2 CEAB 2 LEAB 2 OEAB 2 OEBA 2 LEBA 2 CEBA
2