Texas Instruments SN74HC157PWT

Overview

SN74HC157PWT from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in a 16-pin TSSOP package, operating from 2V to 6V supply, with 11ns typical propagation delay at 5V, ±6mA output drive, and 80µA max ICC. It routes four independent 2:1 data paths under shared A/B address and active-low strobe (G) control, used in digital bus switching and logic-level signal routing.

For engineers reviewing the SN74HC157PWT datasheet, SN74HC157PWT pinout, SN74HC157PWT application, or SN74HC157PWT equivalent, this page delivers verified functional identity, confirmed TSSOP-16 pin mapping, real-world timing and drive specs, and two validated alternative parts for multiplexer-based designs requiring 2:1 selection per channel.

Technical Context

The SN74HC157PWT implements four independent CMOS 2:1 multiplexers sharing one address select (A/B) input and one active-low strobe (G) input. All outputs go low when G is high, enabling synchronous enable/disable of all channels. Each Y output reflects the selected A or B input without latching or clocking.

It uses high-speed silicon-gate CMOS technology with TTL-compatible inputs, supports asynchronous operation across −40°C to +85°C, and features standard CMOS input impedance with ≤1µA max input current and 10pF typical input capacitance - ensuring compatibility with both CMOS and legacy TTL logic families.

Key Specifications

Pinout & Package

TSSOP-16 package (PW), 5.00 mm × 4.40 mm body size, 0.65 mm lead pitch, surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC157PWT, SN74HC158PWR offers inverted output behavior for specific logic architectures, while 74LVC157PW delivers superior speed and drive in 3.3V domains but sacrifices 5V input tolerance - making SN74HC157PWT the optimal choice for mixed-voltage, industrial-temperature, and legacy-TTL-compatible designs.

Availability

SN74HC157PWT is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, and legacy-system upgrades requiring stable component supply and long-term obsolescence management.

Supply support for SN74HC157PWT 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 delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74HC157PWT belongs to TI's HC logic family, designed for high-noise-immunity, low-power, pin-compatible replacements of legacy TTL multiplexers in space-constrained industrial and instrumentation applications.

FAQ

What is the function of the G pin on the SN74HC157PWT?

The G pin on the SN74HC157PWT is an active-low strobe input. When G is high, all four Y outputs are forced low regardless of the states of A/B or data inputs. When G is low, the multiplexer operates normally, routing either A or B inputs to each Y output based on the A/B select signal. This enables synchronized channel enable/disable in bus arbitration or time-multiplexed systems.

Can SN74HC157PWT operate reliably at 3.3V supply?

Yes, SN74HC157PWT operates reliably at 3.3V supply. Its specified 2V–6V range includes 3.3V, and electrical characteristics such as VIH(min) = 2.31V and VIL(max) = 0.99V at VCC = 3.3V ensure full compatibility with standard 3.3V CMOS logic. Propagation delay is 14ns typical at 3.3V, supporting >30MHz operation in properly terminated circuits.

Is SN74HC157PWT pin-compatible with other TSSOP-16 multiplexers?

SN74HC157PWT is pin-compatible with SN74HC158PWR and SN74HC257PWR within the same HC family - sharing identical TSSOP-16 pinout for A/B, G, VCC, GND, and all data I/Os. However, SN74HC158PWR inverts outputs and SN74HC257PWR uses active-high enable, so functional substitution requires logic-level verification.

What is the maximum capacitive load SN74HC157PWT can drive while meeting datasheet timing specs?

SN74HC157PWT is characterized for CL = 50pF in its switching specifications - propagation delay and transition time values (e.g., 11ns tpd at 5V) are guaranteed only up to this load. Driving >50pF increases tpd nonlinearly; for example, at CL = 150pF and VCC = 5V, tpd rises to 32ns. For critical timing paths, keep total load ≤50pF via short traces and minimal fanout.

Does SN74HC157PWT require external pull-up or pull-down resistors on unused inputs?

Yes, SN74HC157PWT requires all unused inputs (A/B, G, or any A/B data lines) to be terminated to either VCC or GND - floating CMOS inputs cause increased ICC, oscillation, and ESD susceptibility. A 10kΩ pull-up or pull-down resistor is recommended for unconnected inputs, especially when driven intermittently, to maintain defined logic states and ensure stable operation per TI's SCBA004 guidelines.