Texas Instruments SN74HCS157QWBQBRQ1

Overview

SN74HCS157QWBQBRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified quadruple 2-to-1 CMOS multiplexer with Schmitt-trigger inputs, operating from 2 V to 6 V, delivering ±7.8-mA output drive at 6 V and typical ICC of 100 nA - used for data routing in engine control units, ADAS sensor interfaces, and body electronics.

For engineers reviewing the SN74HCS157QWBQBRQ1 datasheet, SN74HCS157QWBQBRQ1 pinout, SN74HCS157QWBQBRQ1 application, or SN74HCS157QWBQBRQ1 equivalent, key selection criteria include its wettable-flank WQFN-16 package, –40°C to +125°C ambient operation, Schmitt-trigger noise immunity, and shared A/B + G control architecture across four independent channels.

Technical Context

The SN74HCS157QWBQBRQ1 implements four independent 2:1 multiplexers sharing a common address select (A/B) and active-low strobe (G) input; all outputs go low when G is high, regardless of A/B or data inputs. Its asynchronous logic operates without internal clocks or state machines.

Schmitt-trigger inputs provide hysteresis (ΔVT = 0.6 V min at 6 V), enabling reliable operation with slow-rising/falling signals and rejecting noise up to ±0.3 V peak-to-peak. Outputs feature balanced CMOS push-pull drivers capable of sourcing/sinking ±7.8 mA at 6 V while maintaining VOL ≤ 0.33 V and VOH ≥ 5.4 V under load.

Key Specifications

Pinout & Package

SN74HCS157QWBQBRQ1 uses a 16-pin wettable-flank WQFN (WBQB) package measuring 3.60 mm × 2.60 mm with exposed thermal pad. Wettable flanks enable reliable AOI inspection of solder fillets on QFN side walls.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCS157PWQ1 and SN74LV157AQPWRQ1, SN74HCS157QWBQBRQ1 uniquely combines wettable-flank packaging, Grade 1 temperature rating, and Schmitt-trigger inputs - making it the only option qualified for safety-critical, high-noise, high-temperature automotive multiplexing without design compromises.

Availability

SN74HCS157QWBQBRQ1 is available at Aetrix Electronics and suitable for engine control units, ADAS sensor interfaces, and body electronics requiring stable component supply across automotive production lifecycles.

Supply support for SN74HCS157QWBQBRQ1 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 designing analog and embedded processing chips for automotive, industrial, and consumer applications, with over 90 years of innovation in precision electronics.

The SN74HCS157QWBQBRQ1 belongs to TI's automotive-qualified HCS logic family, engineered specifically for robust signal routing in harsh-temperature, high-reliability vehicle subsystems where noise immunity and long-term supply stability are critical.

FAQ

What is the maximum operating frequency of the SN74HCS157QWBQBRQ1?

The SN74HCS157QWBQBRQ1 supports a maximum switching frequency of 29 MHz at 6 V and –40°C to +125°C ambient temperature, as specified in the switching characteristics table. This performance enables real-time data selection in engine timing and camera interface applications without introducing timing jitter or metastability.

Does the SN74HCS157QWBQBRQ1 require external pull-up or pull-down resistors on unused inputs?

Unused inputs on the SN74HCS157QWBQBRQ1 must be terminated to VCC or GND - either directly or via resistor - to prevent floating states. While Schmitt-trigger inputs tolerate slow edges, unconnected pins can cause undefined logic states and increased dynamic current consumption. A 10-kΩ resistor is commonly used for default HIGH or LOW biasing.

Can the SN74HCS157QWBQBRQ1 drive capacitive loads greater than 50 pF?

The SN74HCS157QWBQBRQ1 is characterized for 50-pF loads per output; exceeding this value increases propagation delay and transition time, potentially violating timing budgets. For loads >50 pF, add series resistance or buffer stages. The device's ±7.8-mA drive strength helps mitigate rise/fall time degradation but does not eliminate timing margin erosion at higher capacitance.

How does the strobe (G) pin function in the SN74HCS157QWBQBRQ1?

The G pin on the SN74HCS157QWBQBRQ1 is an active-low strobe that forces all four Y outputs low regardless of A/B address or data inputs. This enables synchronous blanking of multiplexed signals - for example, disabling sensor data during ADC conversion windows or muting display interface lines during power-state transitions.

Is the thermal pad on the SN74HCS157QWBQBRQ1 package required to be connected to ground?

The thermal pad on the SN74HCS157QWBQBRQ1 WBQB package may be connected to GND or left floating - it must not be tied to any other signal or supply. Connecting to GND improves thermal dissipation (R_θJB = 66.4°C/W) and provides additional grounding for noise suppression, but is not mandatory for functional operation per TI's mechanical guidelines.