Texas Instruments SN74LVC2G157DCTRG4

Overview

SN74LVC2G157DCTRG4 from Texas Instruments is a single 2-line to 1-line data selector multiplexer in an 8-pin SSOP package, supporting 1.65-V to 5.5-V V_CC, delivering true and complementary outputs (Y and Y), with 6 ns max propagation delay at 3.3 V and ±24-mA output drive - used for signal routing in sensor interface and embedded control systems.

For engineers reviewing the SN74LVC2G157DCTRG4 datasheet, SN74LVC2G157DCTRG4 pinout, SN74LVC2G157DCTRG4 application, or SN74LVC2G157DCTRG4 equivalent, key selection criteria include I_off support for live insertion, 5.5-V tolerant inputs enabling level translation, low 10-µA ICC quiescent current, and NanoFree™-compatible SSOP packaging for space-constrained PCBs.

Technical Context

The SN74LVC2G157DCTRG4 implements a positive-logic 2:1 multiplexer with active-low common strobe (G) controlling output enable: when G = HIGH, both outputs are forced to static states (Y = LOW, Y = HIGH); when G = LOW, the A/B select input routes either A or B to Y (true) and Y (complement). It uses standard CMOS inputs and balanced high-drive push-pull outputs.

Its I_off circuitry disables outputs during partial power-down, blocking back-current flow when V_CC = 0, while 5.5-V input tolerance allows down-translation from higher-voltage domains (e.g., 5-V sensors) into 1.8-V or 3.3-V logic domains without external level shifters.

Key Specifications

Pinout & Package

SN74LVC2G157DCTRG4 is housed in an 8-pin SSOP (DCT) package measuring 2.95 mm × 2.80 mm, optimized for automated assembly and thermal performance (R_θJA = 192°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC2G157DCTRG4, SN74LVC1G157DBVR saves board area but sacrifices design flexibility by omitting Y; 74LVC2G157GM,115 offers identical functionality in a smaller, leadless package better suited for fine-pitch automated assembly - both require validation of thermal derating and signal integrity in high-speed routing.

Availability

SN74LVC2G157DCTRG4 is available at Aetrix Electronics and suitable for barcode scanners, field transmitters, e-book controllers, and embedded PC I/O expansion requiring stable component supply, long-term lifecycle assurance, and industrial-temperature qualification.

Supply support for SN74LVC2G157DCTRG4 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 decades of expertise in high-reliability interface and signal-path ICs.

The SN74LVC2G157DCTRG4 belongs to TI's LVC logic family - engineered for low-voltage operation, mixed-signal compatibility, and robustness in industrial and portable electronics where power efficiency and voltage translation are critical.

FAQ

What is the function of the G (strobe) pin on the SN74LVC2G157DCTRG4?

The G pin is an active-low common strobe that globally enables or disables multiplexing. When G = HIGH, Y is forced LOW and Y is forced HIGH regardless of A/B or data inputs - effectively disabling signal routing. When G = LOW, the device operates normally, passing the selected input (A or B) to Y and its complement to Y. This provides synchronous gating for time-critical control sequences in the SN74LVC2G157DCTRG4.

Does the SN74LVC2G157DCTRG4 support level translation between 5-V and 3.3-V logic domains?

Yes. The SN74LVC2G157DCTRG4 accepts input voltages up to 5.5 V independent of V_CC, allowing it to interface directly with 5-V sensors or peripherals while operating at 3.3 V or even 1.8 V. Its outputs swing rail-to-rail (V_CC/GND), so when V_CC = 3.3 V, the SN74LVC2G157DCTRG4 outputs are compatible with 3.3-V receivers - making it a bidirectional voltage translator for the A, B, and A/B control lines.

Can unused inputs on the SN74LVC2G157DCTRG4 be left floating?

No. All unused inputs (A, B, A/B, or G) on the SN74LVC2G157DCTRG4 must be terminated to either V_CC or GND using a pull-up or pull-down resistor - typically 10 kΩ - to prevent undefined logic states, oscillation, or excessive ICC. Floating CMOS inputs can cause shoot-through current and unpredictable output behavior, violating the SN74LVC2G157DCTRG4's recommended operating conditions.

What is the maximum capacitive load the SN74LVC2G157DCTRG4 can drive while maintaining specified timing?

The SN74LVC2G157DCTRG4 is characterized for loads ≤50 pF in its switching specifications. While it can drive up to 70 pF without damage, exceeding 50 pF may increase propagation delay beyond the 6 ns (max at 3.3 V) spec and degrade edge rates. For reliable timing compliance in high-speed applications, keep total load capacitance - including trace, probe, and receiver input - at or below 50 pF per output of the SN74LVC2G157DCTRG4.

How does the I_off feature protect the SN74LVC2G157DCTRG4 during partial power-down?

The I_off circuitry in the SN74LVC2G157DCTRG4 automatically disables all outputs when V_CC = 0 or near-zero, preventing current from flowing backward into the powered-down device from live system buses. This protects against latch-up and damage during hot-swap events or staged power sequencing - a critical capability confirmed in the SN74LVC2G157DCTRG4 datasheet and validated per JESD 78 Class II latch-up standards.