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SN74LS399 - QUAD 2-PORT REGISTER

Download the SN74LS399 datasheet PDF. This datasheet also covers the SN74LS398D variant, as both devices belong to the same quad 2-port register family and are provided as variant models within a single manufacturer datasheet.

General Description

The SN54 / 74LS398 and SN54 / 74LS399 are high-speed Quad 2-Port Registers.

They select four bits of data from two sources (Ports) under the control of a common Select Input (S).

Key Features

  • both Q and Q inputs, while the SN54/ 74LS399 has only Q outputs.
  • Select From Two Data Sources.
  • Fully Positive Edge-Triggered Operation.
  • Both True and Complemented Outputs on SN54/ 74LS398.
  • Input Clamp Diodes Limit High-Speed Termination Effects.

📥 Download Datasheet

Note: The manufacturer provides a single datasheet file (SN74LS398D_MotorolaInc.pdf) that lists specifications for multiple related part numbers.

📁 Similar Datasheet

Part Number Description Manufacturer
SN74LS399 QUADRUPLE 2-INPUT MULTIPLEXER Texas Instruments
SN74LS399N QUADRUPLE 2-INPUT MULTIPLEXER Texas Instruments
SN74LS390 DUAL 4-BIT DECADE AND BINARY COUNTERS Texas Instruments
SN74LS393 DUAL 4-BIT DECADE AND BINARY COUNTERS Texas Instruments
SN74LS393 Dual 4-Stage Binary Counter ON Semiconductor

Other Datasheets by Motorola Semiconductor (now NXP Semiconductors)

Part Number Description
SN74LS390 DUAL DECADE COUNTER / DUAL 4-STAGE BINARY COUNTER
SN74LS393 DUAL DECADE COUNTER / DUAL 4-STAGE BINARY COUNTER
SN74LS395 4-BIT SHIFT REGISTER
SN74LS398 QUAD 2-PORT REGISTER
SN74LS398D QUAD 2-PORT REGISTER

Full PDF Text Transcription (Reference)

The following content is an automatically extracted verbatim text from the original manufacturer datasheet and is provided for reference purposes only.

View original datasheet text
QUAD 2-PORT REGISTER The SN54 / 74LS398 and SN54 / 74LS399 are Quad 2-Port Registers. They are the logical equivalent of a quad 2-input multiplexer followed by a quad 4-bit edge-triggered register. A Common Select input selects between two 4-bit input ports (data sources). The selected data is transferred to the output register on the LOW-to-HIGH transition of the Clock input. The SN54/ 74LS398 features both Q and Q inputs, while the SN54/ 74LS399 has only Q outputs.