Texas Instruments SN74HC157DBR

Overview

SN74HC157DBR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in SSOP-16 package, operating from 2V to 6V supply, delivering 11ns typical propagation delay at 6V, ±6mA output drive, and 80µA max ICC - used for bus selection and signal routing in digital logic systems.

For engineers reviewing the SN74HC157DBR datasheet, SN74HC157DBR pinout, SN74HC157DBR application, or SN74HC157DBR equivalent, this page provides verified functional identity, validated SSOP-16 pin mapping, confirmed 2–6V operation range, real-world timing specs (tpd = 11ns typ @6V), and two technically documented alternative parts for multiplexer-based design reuse.

Technical Context

The SN74HC157DBR implements four independent 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 channel enable/disable across all four channels. It uses high-speed silicon-gate CMOS technology with TTL-compatible inputs.

Each channel selects between two data inputs (A or B) based on A/B state, with output Y reflecting the selected input when G is low. Input transition time must be ≤400ns at 6V to avoid oscillation or excess power draw, and unused inputs must be tied to VCC or GND - not left floating.

Key Specifications

Pinout & Package

SN74HC157DBR is housed in a 16-pin SSOP (Shrink Small Outline Package) with 0.65mm lead pitch, 6.20mm × 5.30mm body size, and surface-mount compatibility for automated PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC157DBR, SN74LV157AIPW offers faster speed at 3.3V but sacrifices 5V input tolerance, while 74HC257D,653 delivers identical performance in SOIC-16 - making it ideal for cost-sensitive or through-hole prototyping use cases without sacrificing timing or drive capability.

Availability

SN74HC157DBR is available at Aetrix Electronics and suitable for industrial control panels, microcontroller I/O expansion, digital test equipment, and legacy system interface adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant SSOP packaging.

Supply support for SN74HC157DBR 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 SN74HC157DBR belongs to TI's 74HC logic family - designed for general-purpose digital signal routing in industrial, automotive, and communications systems where speed, low power, and wide supply voltage tolerance are critical.

FAQ

What is the maximum recommended capacitive load for SN74HC157DBR?

The SN74HC157DBR is characterized for CL ≤ 50pF in its switching specifications. While larger loads can be driven, exceeding 50pF increases propagation delay and transition time - for example, tpd rises from 11ns to 32ns at 6V with CL = 150pF. For optimal timing compliance in high-speed designs, keep total output capacitance at or below 50pF including trace and receiver input capacitance.

Does SN74HC157DBR support 3.3V operation?

Yes, SN74HC157DBR fully supports 3.3V operation within its 2V–6V supply range. At VCC = 3.3V, it delivers guaranteed VIH = 2.31V, VIL = 0.99V, and tpd ≈ 18ns (typ) with CL = 50pF - making it compatible with standard 3.3V CMOS and mixed-voltage systems without level translation.

Can unused inputs on SN74HC157DBR be left floating?

No - all unused inputs on SN74HC157DBR must be terminated to either VCC or GND. Floating CMOS inputs cause excessive current draw, potential oscillation, and increased EMI. TI explicitly recommends using 10kΩ pull-up or pull-down resistors for unconnected inputs to ensure stable logic states and reliable device operation.

What is the function of the G (strobe) pin on SN74HC157DBR?

The G pin on SN74HC157DBR is an active-low strobe that overrides all channel selections: when G = HIGH, all four Y outputs are forced LOW regardless of A/B state or input data. This enables synchronized channel blanking, bus contention prevention, or power-aware gating - a key feature distinguishing SN74HC157DBR from non-strobed multiplexers like SN74HC158.

Is SN74HC157DBR pin-compatible with SN74HC257?

Yes, SN74HC157DBR and SN74HC257 share identical logic function, pinout, and electrical specifications - both are quadruple 2:1 multiplexers with A/B select and active-low G strobe. However, SN74HC157DBR is in SSOP-16 package while SN74HC257 is typically offered in SOIC-16; physical compatibility depends on footprint alignment, not functional mismatch.