Texas Instruments SN74HCS151DR

Overview

SN74HCS151DR from Texas Instruments is an 8-to-1 CMOS data selector/multiplexer with Schmitt-trigger inputs, operating across 2V–6V supply, delivering ±7.8mA output drive at 6V, and supporting –40°C to +125°C ambient temperature. It routes one of eight digital inputs (D0–D7) to complementary outputs Y and W under address control (A/B/C) and active-low strobe (G), used in industrial I/O expansion and sensor signal routing.

For engineers reviewing the SN74HCS151DR datasheet, SN74HCS151DR pinout, SN74HCS151DR application, or SN74HCS151DR equivalent, key selection criteria include Schmitt-trigger noise immunity, dual complementary outputs, wide VCC range compatibility, and SOIC-16 package suitability for legacy PCB layouts.

Technical Context

The SN74HCS151DR implements asynchronous 8:1 multiplexing using full binary decoding of address lines A, B, C to select one of eight data inputs. Its strobe (G) input forces Y low and W high when high, overriding all address and data states.

All inputs feature Schmitt-trigger architecture with hysteresis (ΔVT = 0.29–1.29V depending on VCC), enabling reliable operation with slow-rising signals and rejecting noise up to ±0.65V peak-to-peak. Outputs are balanced CMOS push-pull with matched sourcing/sinking capability.

Key Specifications

Pinout & Package

SN74HCS151DR is supplied in a 16-pin SOIC (D) package measuring 9.90mm × 3.90mm, with gull-wing leads and standard JEDEC MS-012AC footprint. Thermal performance includes RθJA = 122.2°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-to-1 multiplexer applications.

Compared with SN74HC151DR and CD74HCT151M, the SN74HCS151DR uniquely combines wide-VCC operation, Schmitt-trigger noise immunity, and complementary outputs-making it the only option suitable for mixed-voltage, electrically noisy, or low-power always-on applications without additional support components.

Availability

SN74HCS151DR is available at Aetrix Electronics and suitable for industrial automation, automotive subsystems, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74HCS151DR 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 company headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and logic products for industrial, automotive, and communications markets.

The SN74HCS151DR belongs to TI's HCS logic family, engineered for high-noise environments and wide-supply applications where reliability and signal integrity outweigh raw speed requirements.

FAQ

What is the function of the G (strobe) pin on the SN74HCS151DR?

The G pin on the SN74HCS151DR is an active-high strobe that overrides all address and data inputs: when G is HIGH, Y is forced LOW and W is forced HIGH regardless of A/B/C or D0–D7 states. This enables synchronous blanking of outputs during address transitions or system reset events. The SN74HCS151DR uses this pin to prevent glitching during multiplexer reconfiguration, ensuring clean signal handover in real-time control loops.

Can the SN74HCS151DR operate at 3.3V supply voltage?

Yes, the SN74HCS151DR operates reliably across 2V–6V, including 3.3V nominal supplies. At 3.3V, its typical propagation delay is 12ns, VOH is ≥3.2V (IOH = –6mA), and VOL is ≤0.18V (IOL = 6mA). Input thresholds scale proportionally: VT+ ≈ 1.71V and VT– ≈ 1.71V – 0.82V = 0.89V, providing 0.82V hysteresis for noise rejection. The SN74HCS151DR maintains full functionality and specifications at 3.3V without derating.

Does the SN74HCS151DR require external pull-up or pull-down resistors on unused inputs?

Unused inputs on the SN74HCS151DR must be terminated to a defined logic level-either VCC or GND-to prevent floating states that cause increased ICC and potential oscillation. While Schmitt-trigger inputs tolerate slow edges, they do not eliminate the need for DC biasing. A 10kΩ resistor is recommended for pull-up/pull-down networks to limit leakage-induced voltage drift. Leaving inputs unconnected violates the SN74HCS151DR absolute maximum ratings and risks erratic behavior in production systems.

How does the SN74HCS151DR differ from standard HC-series multiplexers like SN74HC151?

The SN74HCS151DR differs from SN74HC151 primarily through integrated Schmitt-trigger inputs (providing 0.29–1.29V hysteresis), lower ICC (0.1µA vs. 2µA typical), and enhanced noise immunity-enabling direct interface with slow or noisy signals like mechanical switches or long-wire sensors. Unlike the SN74HC151, the SN74HCS151DR does not require external RC filters or debouncing circuits, reducing BOM cost and PCB area while improving system-level reliability in harsh environments.

Is the SN74HCS151DR pin-compatible with other 16-pin 8-to-1 multiplexers?

Yes, the SN74HCS151DR shares identical pinout and function mapping with SN74HC151DR, CD74HCT151M, and SN74LS151N across all 16 pins-including D0–D7, A/B/C, G, Y, W, VCC, and GND. This allows drop-in replacement in existing SOIC-16 footprints. However, electrical differences (e.g., Schmitt-trigger inputs, VCC range, drive strength) require validation of timing margins and noise environment before substitution. The SN74HCS151DR retains full pin compatibility while adding functional enhancements.