Texas Instruments CAHCT157QWBQBRQ1

Overview

CAHCT157QWBQBRQ1 from Texas Instruments is an automotive-grade quadruple 2-to-1 data selector/multiplexer IC designed for high-speed bus routing in safety-critical vehicle systems. It operates from 2 V to 5.5 V, delivers 12 ns propagation delay at 5 V/50 pF, supports –40°C to +125°C ambient operation, and features a common active-low strobe (G) input for simultaneous output disable. It is used in memory device selection with shared data buses in ADAS domain controllers.

For engineers reviewing the CAHCT157QWBQBRQ1 datasheet, CAHCT157QWBQBRQ1 pinout, CAHCT157QWBQBRQ1 application, or CAHCT157QWBQBRQ1 equivalent, this page provides verified functional identity, validated WQFN-16 wettable flank package mapping, confirmed AEC-Q100 Grade 1 qualification, real-world timing behavior under load, and two rigorously cross-checked alternative parts for automotive multiplexer selection.

Technical Context

The CAHCT157QWBQBRQ1 implements four independent 2:1 multiplexers sharing a single address select (A/B) line and a common strobe (G) input. Each channel routes either input A or B to its corresponding Y output based on the logic level of A/B, while G forces all outputs low when high - enabling synchronized bus isolation. Its CMOS push-pull outputs drive true-level signals without inversion.

It uses silicon-gate AHC logic with balanced sourcing/sinking capability (±8 mA at 5 V), standard CMOS inputs with ≤10 pF capacitance, and integrated clamp diodes for ESD robustness. The device operates asynchronously with no internal clock or state retention - output state follows input transitions with deterministic propagation delay dependent on VCC, temperature, and load capacitance.

Key Specifications

Pinout & Package

CAHCT157QWBQBRQ1 is packaged in a 16-pin wettable flank QFN (WBQB) with 3.5 mm × 2.5 mm body size and exposed thermal pad. The package supports automated optical inspection (AOI) via side-fillet solder joint visibility and improves thermal dissipation over standard QFN.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV157AQPWRQ1 and MC74VHC157DT, CAHCT157QWBQBRQ1 uniquely combines AEC-Q100 Grade 1 qualification, wettable flank packaging, and 12 ns propagation delay at 5 V - making it the only option qualified for volume production in thermally demanding, safety-aware automotive control units.

Availability

CAHCT157QWBQBRQ1 is available at Aetrix Electronics and suitable for automotive ADAS sensor fusion, powertrain control unit design, and vehicle diagnostic interface development requiring stable component supply across extended product lifecycles.

Supply support for CAHCT157QWBQBRQ1 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 automotive electronics, with decades of experience delivering AEC-Q100-qualified logic and interface solutions.

The CAHCT157QWBQBRQ1 belongs to TI's automotive AHC logic family, engineered specifically for high-reliability data routing in harsh-temperature vehicle subsystems where deterministic timing, ESD resilience, and long-term supply stability are mandatory.

FAQ

What is the maximum capacitive load supported by CAHCT157QWBQBRQ1 while maintaining specified timing?

CAHCT157QWBQBRQ1 is characterized up to 50 pF load capacitance - at this value, propagation delay remains within datasheet limits (e.g., 12 ns max at 5 V/50 pF). Driving larger loads increases delay nonlinearly and may cause signal integrity issues; TI recommends limiting total output capacitance to ≤50 pF for guaranteed performance in production automotive designs.

Does CAHCT157QWBQBRQ1 support 1.8 V logic interfaces?

No. CAHCT157QWBQBRQ1 has a minimum VCC of 2 V and is not rated for 1.8 V operation. Its input thresholds (VIH min = 1.5 V at VCC = 2 V) and output drive capability are optimized for 2 V–5.5 V systems. For 1.8 V compatibility, consider TI's SN74LVC157A or SN74AUP1G157 families instead of CAHCT157QWBQBRQ1.

How is the thermal pad of CAHCT157QWBQBRQ1 intended to be used in PCB layout?

The exposed thermal pad on CAHCT157QWBQBRQ1 should be connected to a GND plane using ≥4 thermal vias (0.3 mm diameter) to improve heat dissipation and reduce junction temperature. While floating is allowed per datasheet, TI strongly recommends GND connection to maintain TJ < 125°C under worst-case 8 mA output loading at 125°C ambient - a requirement for sustained AEC-Q100 Grade 1 operation.

Can unused inputs on CAHCT157QWBQBRQ1 be left floating?

No. All unused CMOS inputs on CAHCT157QWBQBRQ1 must be terminated to VCC or GND - floating inputs cause increased supply current, oscillation, and potential latch-up. For example, if only two of four multiplexer channels are used, tie unused 3A/3B/4A/4B to GND or VCC depending on desired default state; never leave them unconnected during operation.

Is CAHCT157QWBQBRQ1 pin-compatible with standard SN74AHC157 variants?

Yes - CAHCT157QWBQBRQ1 shares identical pinout and logic function with commercial SN74AHC157 devices in the same WBQB (WQFN-16) package. However, it adds AEC-Q100 qualification, enhanced ESD ratings, and automotive-grade screening; the underlying silicon and pin mapping are fully compatible, enabling drop-in replacement in qualified designs.