FEATURES

· Member of the Texas Instruments Widebus™

Family

· Bus Hold on Data Inputs Eliminates the Need

for External Pullup/Pulldown Resistors

· Latch-Up Performance Exceeds 250 mA Per

JESD 17

· ESD Protection Exceeds JESD 22

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

DESCRIPTION/ORDERING INFORMATION

This 20-bit bus-interface flip-flop is designed for

1.65-V to 3.6-V VCC operation.

The SN74ALVCH16821 can be used as two 10-bit

flip-flops or one 20-bit flip-flop. The 20 flip-flops are

edge-triggered D-type flip-flops. On the positive

transition of the clock (CLK) input, the device

provides true data at the Q outputs.

A buffered output-enable (OE) input can be used to

place the ten outputs in either a normal logic state

(high or low logic levels) or the high-impedance state.

In the high-impedance state, the outputs neither load

nor drive the bus lines significantly. The

high-impedance state and increased drive provide the

capability to drive bus lines without need for interface

or pullup components.

OE does not affect the internal operation of the

flip-flops. Old data can be retained or new data can

be entered while the outputs are in the

high-impedance state.

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 holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors

with the bus-hold circuitry is not recommended.