1. General description
The 74LVC646A consists of non-inverting bus transceiver circuits with 3-state outputs,
D-type flip-flops and control circuitry arranged for multiplexed transmission of data directly
from the internal registers. Data on the A or B bus is clocked in the internal registers, as
the appropriate clock (CPAB or CPBA) goes to a HIGH logic level. Output enable (OE
)
and direction (DIR) inputs are provided to control the transceiver function. In the
transceiver mode, data present at the high-impedance port may be stored in either the A
or B register, or in both. With the select source inputs (SAB and SBA), stored and
real-time (transparent mode) data can be multiplexed. The direction (DIR) input
determines which bus receives data when OE
is active (LOW). In the isolation mode (OE
= HIGH), A data may be stored in the B register and/or B data may be stored in the A
register. When an output function is disabled, the input function is still enabled and may be
used to store and transmit data. Only one of the two buses A or B may be driven at a time.
Inputs can be driven from either 3.3 V or 5 V devices. When disabled, up to 5.5 V can be
applied to the outputs. These features allow the use of these devices as translators in
mixed 3.3 V and 5 V applications.
2. Features and benefits
5 V tolerant inputs/outputs for interfacing with 5 V logic
Supply voltage range from 1.2 V to 3.6 V
CMOS low-power consumption
Direct interface with TTL levels
8-bit octal transceiver with D-type latch
Back-to-back registers for storage
Separate controls for data flow in each direction
Supports partial power-down applications; inputs/outputs are high-impedance when
V
CC
=0V
Complies with JEDEC standard:
JESD8-7A (1.65 V to 1.95 V)
JESD8-5A (2.3 V to 2.7 V)
JESD8-C/JESD36 (2.7 V to 3.6 V)
ESD protection:
HBM JESD22-A114F exceeds 2000 V
MM JESD22-A115-B exceeds 200 V
CDM JESD22-C101E exceeds 1000 V
Specified from 40 Cto+85C and 40 Cto+125C.
74LVC646A
Octal bus transceiver/register; 3-state
Rev. 5 — 28 March 2013 Product data sheet
