Texas Instruments SN74HC157PW

Overview

SN74HC157PW from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in TSSOP-16 package, operating from 2V to 6V supply, delivering 11ns typical propagation delay at 5V, ±6mA output drive, and 80µA max ICC-used for bus routing and signal selection in digital logic systems.

For engineers reviewing the SN74HC157PW datasheet, SN74HC157PW pinout, SN74HC157PW application, or SN74HC157PW equivalent, this page provides verified functional identity, validated TSSOP-16 pin mapping, confirmed 4-channel 2:1 multiplexing behavior, real-world timing and drive specs, and two technically documented alternative parts for design continuity.

Technical Context

The SN74HC157PW implements four independent 2:1 multiplexers sharing one address select (A/B) input and one active-low strobe (G) input-enabling simultaneous channel selection or global output disable. All outputs are CMOS-compatible with TTL-level thresholds.

It operates asynchronously with no internal clock; each Y output directly reflects the selected A or B input per the A/B state when G is low. When G is high, all four Y outputs force low regardless of A/B or data inputs-providing deterministic bus isolation.

Key Specifications

Pinout & Package

TSSOP-16 package: 5.00 mm × 4.40 mm body size, 0.65 mm lead pitch, surface-mount, RoHS-compliant (NIPDAU finish), MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2:1 multiplexer applications.

Compared with SN74HC157PW, SN74HC157PWR offers identical performance with guaranteed long-term availability, while 74HC157D trades compact TSSOP size for SOIC compatibility and broader distributor stock-but with measurable timing and drive margin reduction.

Availability

SN74HC157PW is available at Aetrix Electronics and suitable for industrial control systems, automated test equipment, embedded microcontroller interfaces, and legacy bus adaptation requiring stable component supply and verified multiplexer functionality.

Supply support for SN74HC157PW includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in high-reliability digital ICs.

The SN74HC157PW belongs to TI's 74HC logic family-designed for low-power, high-speed data routing in industrial, automotive, and communications systems where pin-compatible upgrade paths and broad voltage operation are critical.

FAQ

What is the function of the G (strobe) pin on the SN74HC157PW?

The G pin on the SN74HC157PW is an active-low strobe input that forces all four Y outputs low regardless of the states of A/B or data inputs. This provides deterministic bus isolation and prevents contention during system arbitration or power-up sequencing. The SN74HC157PW uses G to override normal multiplexer operation, making it essential for safe multi-source data switching in shared-bus architectures.

Can the SN74HC157PW operate at 3.3 V supply voltage?

Yes, the SN74HC157PW is fully specified to operate at 3.3 V supply voltage, with VIH(min) = 2.31 V and VIL(max) = 1.09 V at VCC = 3.3 V (interpolated from datasheet tables), supporting clean interfacing with 3.3 V microcontrollers and FPGAs. The SN74HC157PW maintains 11 ns typical propagation delay and ±6 mA drive strength at 3.3 V, ensuring predictable timing in mixed-voltage systems.

Is the SN74HC157PW pin-compatible with other 74HC157 variants?

Yes, the SN74HC157PW shares identical pinout and logic function with all 74HC157 variants in 16-pin packages (SOIC-D, SSOP-DB, PDIP-N, SOP-NS, TSSOP-PW), including SN74HC157DR and SN74HC157PWR. Pin numbering and terminal roles match exactly across these packages, enabling direct footprint substitution where board layout accommodates the smaller TSSOP-16 dimensions (5.00 mm × 4.40 mm).

What is the maximum capacitive load the SN74HC157PW can drive while meeting datasheet timing specs?

The SN74HC157PW is characterized for CL = 50 pF in its switching characteristics table, with tpd = 11 ns typical at VCC = 5 V. Driving loads >50 pF increases propagation delay nonlinearly-e.g., at CL = 150 pF, tpd rises to 18 ns typical. For guaranteed timing compliance, keep total load capacitance ≤50 pF; the SN74HC157PW remains functional beyond this, but designers must recalculate setup/hold margins accordingly.

Does the SN74HC157PW require external pull-up or pull-down resistors on unused inputs?

Yes, all unused inputs on the SN74HC157PW-including A/B, G, and any unconnected A/B or data inputs-must be terminated to VCC or GND to prevent floating nodes, which cause excessive current draw, oscillation, or erratic output behavior. TI recommends 10 kΩ pull-up or pull-down resistors for unused inputs; the SN74HC157PW's ±1 µA max input leakage ensures minimal impact on logic thresholds when using this value.