FEATURES
· Member of the Texas Instruments Widebus™
Family
· EPIC™ (Enhanced-Performance Implanted
CMOS) Submicron Process
· ESD Protection Exceeds 2000 V Per
MIL-STD-883, Method 3015; Exceeds 200 V
Using Machine Model (C = 200 pF, R = 0)
· Latch-Up Performance Exceeds 250 mA Per
JESD 17
· Bus Hold on Data Inputs Eliminates the Need
for External Pullup/Pulldown Resistors
· Package Options Include Plastic 300-mil
Shrink Small-Outline (DL), Thin Shrink
Small-Outline (DGG), and Thin Very
Small-Outline (DGV) Packages

DESCRIPTION
This 16-bit bus transceiver and register is designed
for 1.65-V to 3.6-V VCC operation.
The SN74ALVCH16646 can be used as two 8-bit
transceivers or one 16-bit transceiver. Data on the A
or B bus is clocked into the registers on the
low-to-high transition of the appropriate clock (CLKAB
or CLKBA) input. Figure 1 illustrates the four
fundamental bus-management functions that can be
performed with the SN74ALVCH16646.
Output-enable (OE) and direction-control (DIR) inputs
are provided to control the transceiver functions. In
the transceiver mode, data present at the
high-impedance port may be stored in either register
or in both. The select-control (SAB and SBA) inputs
can multiplex stored and real-time (transparent mode) data. The circuitry used for select control eliminates the
typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. DIR
determines which bus receives data when OE is low. In the isolation mode (OE high), A data may be stored in
one register and/or B data may be stored in the other 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, can be driven at a time.
To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level.
The SN74ALVCH16646 is characterized for operation from -40°C to 85°C.