Controlled Baseline

− One Assembly/Test Site, One Fabrication

Site

Extended Temperature Performance of

−55°C to 125°C

Enhanced Diminishing Manufacturing

Sources (DMS) Support

Enhanced Product-Change Notification

Qualification Pedigree†

4.5-V to 5.5-V VCC Operation

Inputs Accept Voltages to 5.5 V

Max tpd of 10 ns at 5 V

Inputs Are TTL-Voltage Compatible

description/ordering information

This 8-bit latch features 3-state outputs designed specifically for driving highly capacitive or relatively

low-impedance loads. The device is particularly suitable for implementing buffer registers, I/O ports,

bidirectional bus drivers, and working registers.

The eight latches are D-type transparent latches. When the latch-enable (LE) input is high, the Q outputs follow

the data (D) inputs. When LE is taken low, the Q outputs are latched at the logic levels set up at the D inputs.

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

in bus-organized systems without need for interface or pullup components.

OE does not affect the internal operations of the latches. 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.