This is a document about quadruple 1-of-2 data selectors/multiplexers, including models SN54ALS157A, SN54ALS158, SN74ALS157A, SN74ALS158, and SN74AS157. These products have buffered inputs and outputs, provide full data selection, and have a separate control input. The document describes the operating temperature range and data output type for each model.
The SN54ALS157A, SN54ALS158, SN74ALS157A, SN74ALS158, SN74AS157 and SN74AS158 are quad 1‑of‑2 data selectors/multiplexers that route a 4‑bit word from one of two sources to four outputs, with a separate strobe input. They feature buffered inputs and outputs, and the ALS variants provide true data while the AS variants provide inverted data to reduce propagation delay.
The devices are offered in multiple package types (plastic D, J, and N packages, as well as small‑outline and ceramic options) and are rated for operation over a wide temperature range (‑55 °C to 125 °C for the SN54 series). Electrical specifications include a supply voltage of 4.5 V–5.5 V, high‑level input voltage of 2 V, low‑level input voltage of 0.7 V, and output currents up to ±0.4 mA (high) and 4 mA (low).
| Supply voltage (VCC) | 4.5 V – 5.5 V |
|---|---|
| High‑level input voltage (VIH) | 2 V |
| Low‑level input voltage (VIL) | 0.7 V |
The recommended supply voltage is 4.5 V to 5.5 V.