Texas Instruments SN74HCS151QPWRQ1

Overview

SN74HCS151QPWRQ1 from Texas Instruments is an AEC-Q100 Grade 1 qualified automotive 8-to-1 CMOS multiplexer with Schmitt-trigger inputs, operating from 2V to 6V supply, delivering ±7.8mA output drive at 6V and featuring typical ICC of 100nA for ultra-low-power data routing in engine control units and body electronics.

For engineers reviewing the SN74HCS151QPWRQ1 datasheet, SN74HCS151QPWRQ1 pinout, SN74HCS151QPWRQ1 application, or SN74HCS151QPWRQ1 equivalent, key selection criteria include Schmitt-trigger noise immunity (ΔVT = 1.02V typ at 4.5V), propagation delay ≤12ns (typ) at 4.5V, TSSOP-16 wettable flanks for AOI-compatible solder joint inspection, and automotive-grade thermal robustness up to +125°C ambient.

Technical Context

The SN74HCS151QPWRQ1 implements a single 8:1 data selector with complementary Y (non-inverted) and W (inverted) outputs, controlled by three binary address inputs (A, B, C) and an active-low strobe (G). Its asynchronous operation ensures Y reflects the selected D_n input immediately upon valid address and strobe assertion.

Schmitt-trigger inputs provide hysteresis (VT+ − VT− = 0.82V typ at 4.5V), enabling reliable operation with slow-rising/falling signals and rejecting noise up to ±0.41V peak-to-peak. The device uses balanced CMOS push-pull outputs capable of sourcing/sinking 7.8mA at 6V while maintaining VOH ≥ 5.4V and VOL ≤ 0.33V under load.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00mm × 4.40mm) with wettable flanks for automated optical inspection of solder joints; 0.65mm lead pitch; exposed thermal pad not present in TSSOP variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV151AQPWRQ1 and MC74HC151ADTR2G, the SN74HCS151QPWRQ1 uniquely combines automotive qualification, Schmitt-trigger noise immunity, and ultra-low quiescent current-making it the only option that satisfies simultaneous requirements for under-hood deployment, EMI resilience, and battery-sensitive operation.

Availability

SN74HCS151QPWRQ1 is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment interfaces, and ADAS sensor hubs requiring stable component supply across automotive production lifecycles.

Supply support for SN74HCS151QPWRQ1 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, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The SN74HCS151QPWRQ1 belongs to TI's automotive-qualified HCS logic family, designed specifically for robust signal routing in electrically noisy, thermally demanding vehicle subsystems where reliability and long-term supply stability are critical.

FAQ

What is the maximum capacitive load the SN74HCS151QPWRQ1 can drive while meeting datasheet timing specifications?

The SN74HCS151QPWRQ1 is characterized for switching performance with a 50pF load. While it can drive larger capacitances, propagation delay and transition time degrade beyond this value. For designs requiring guaranteed tpd ≤12ns (typ) and tt ≤9ns (typ) at 4.5V, keep total output node capacitance-including trace, probe, and receiver input-≤50pF. Exceeding this may necessitate buffer insertion or layout optimization. The SN74HCS151QPWRQ1 datasheet specifies CL = 50pF in all switching characteristics tables.

Does the SN74HCS151QPWRQ1 require external pull-up or pull-down resistors on unused address inputs?

No, external resistors are not required on unused address inputs of the SN74HCS151QPWRQ1 because its Schmitt-trigger inputs tolerate floating conditions without excessive current draw-but TI strongly recommends tying unused inputs to VCC or GND to prevent undefined logic states and potential oscillation. The SN74HCS151QPWRQ1 internal input structure avoids the high ICC seen in standard CMOS when inputs hover near threshold, yet deterministic biasing remains essential for functional reliability in automotive systems.

Can the Y and W outputs of the SN74HCS151QPWRQ1 be paralleled to increase drive strength?

Yes, the Y and W outputs of the SN74HCS151QPWRQ1 can be wired in parallel to double the effective output current drive, provided both are driven by identical logic states-i.e., only when G is low and the selected D_n is stable. Since W is the logical inverse of Y, paralleling them directly would cause contention. To safely parallel, use only Y outputs from multiple SN74HCS151QPWRQ1 devices synchronized to the same address and strobe, or invert one W output externally before combining. The SN74HCS151QPWRQ1 output stage supports this configuration within its ±35mA absolute maximum rating per pin.

Is the thermal pad on the SN74HCS151QPWRQ1 package electrically connected, and how should it be handled in layout?

The SN74HCS151QPWRQ1 is supplied in TSSOP-16 (PW) packaging, which does not include an exposed thermal pad-only the WBQB (WQFN) variant has one. Therefore, no thermal pad connection is required or possible for SN74HCS151QPWRQ1. Layout focus should instead be on minimizing VCC/GND loop inductance via a 0.1µF ceramic capacitor placed directly between pins 16 and 8, and ensuring short, direct traces for address and strobe lines to reduce noise coupling. The SN74HCS151QPWRQ1 TSSOP footprint matches industry-standard 16-pin SOIC land patterns except for lead profile.

How does the SN74HCS151QPWRQ1 behave when the strobe (G) input is held high?

When the strobe (G) input of the SN74HCS151QPWRQ1 is held high, the device enters disabled state: the Y output is forced low and the W output is forced high, irrespective of the states of address inputs (A, B, C) or data inputs (D0–D7). This override function provides fail-safe output control in safety-critical automotive logic paths. The SN74HCS151QPWRQ1 maintains this behavior across its full operating voltage (2V–6V) and temperature (–40°C to +125°C) range, with no additional current penalty-ICC remains at 100nA typical even during forced-output mode.