Description
74F398 Quad 2-Port Register
DESCRIPTION
The 74F398 and 74F399 are the logical equivalent of a quad 2-input multiplexer feeding into four edge-triggered flip-flops. A common Select input determines which of two 4-bit words is accepted. The
selected data enters the flip-flops on the rising edge of the clock.
The 74F399 is the 16-pin version of the 74F398, with only the true (Qn) outputs of the flip-flops available.
The 74F398 and 74F399 are high speed quad 2-port registers. They select 4 bits of data from either of two sources (Ports) under control of a common select input (S). The selected data is transferred to a 4-bit output register synchronous with the Low-to-High transition of the Clock input (CP). The 4-bit D-type output register is fully edge-triggered. The Data inputs (I0n, I1n) and Select input (S) must be stable only a setup time prior to and hold time after the Low-to-High transition of the Clock input for predictable operation. The 74F398 has both Q and Q outputs.
The 74F399 is the 16-pin version of the 74F398, with only the true (Qn) outputs of the flip-flops available.
The 74F398 and 74F399 are high speed quad 2-port registers. They select 4 bits of data from either of two sources (Ports) under control of a common select input (S). The selected data is transferred to a 4-bit output register synchronous with the Low-to-High transition of the Clock input (CP). The 4-bit D-type output register is fully edge-triggered. The Data inputs (I0n, I1n) and Select input (S) must be stable only a setup time prior to and hold time after the Low-to-High transition of the Clock input for predictable operation. The 74F398 has both Q and Q outputs.
FEATURES
•Select inputs from two data sources
•Fully positive edge-triggered
•Both True and Complementary outputs–74F399
