Texas Instruments CD74ACT157E

Overview

CD74ACT157E from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in PDIP-16 package, operating at 4.5V–5.5V V_CC, with ±24mA output drive, balanced propagation delays (t_PLH/t_PHL ≤ 9.5ns), and TTL-voltage-compatible inputs. It enables synchronous 4-bit bus selection in digital control logic, data routing, and address decoding circuits.

For engineers reviewing the CD74ACT157E datasheet, CD74ACT157E pinout, CD74ACT157E application, or CD74ACT157E equivalent, key selection criteria include its 16-pin DIP footprint, active-low strobe (G) for global output disable, CMOS push-pull outputs with 2kV HBM ESD rating, and guaranteed operation across –55°C to 125°C industrial temperature range.

Technical Context

The CD74ACT157E implements four independent 2:1 multiplexers sharing a common address select (A/B) and active-low strobe (G) input. Each Y output reflects the selected A or B input when G is high; all outputs force low when G is low - enabling synchronized channel enable/disable without external gating logic.

Its TTL-compatible CMOS inputs accept VIH ≥ 2.0V and VIL ≤ 0.8V under 4.5V–5.5V supply, while push-pull outputs deliver VOH ≥ 3.7V at I_OH = –24mA and VOL ≤ 0.5V at I_OL = 24mA, supporting fanout to 15 F-series devices. Propagation delay matching between channels ensures deterministic timing in parallel data paths.

Key Specifications

Pinout & Package

Packaged in 16-pin plastic dual in-line package (PDIP-N), body size 19.31mm × 6.35mm, with through-hole mounting and industry-standard 0.3" width.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT157N, CD74ACT157E offers identical performance and sourcing; versus CD74HC157E, it delivers 3× higher output current and >2× faster propagation - critical for driving terminated lines or interfacing with legacy TTL loads.

Availability

CD74ACT157E is available at Aetrix Electronics and suitable for industrial control logic, digital test equipment, legacy system bus expansion, and embedded microcontroller peripheral routing requiring stable component supply across extended temperature ranges.

Supply support for CD74ACT157E 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 heritage in high-reliability logic families.

The CD74ACT157E belongs to TI's Advanced CMOS (ACT) logic series, engineered for speed/power optimization in 5V systems where TTL compatibility, robust ESD tolerance, and precise timing matching are essential.

FAQ

What is the maximum capacitive load the CD74ACT157E can drive while maintaining specified timing?

The CD74ACT157E is characterized for CL = 50 pF in its switching characteristics table. While it can drive larger loads, performance (propagation delay, rise/fall times) degrades beyond this value. For reliable operation within datasheet limits, keep total output capacitance ≤ 50 pF - including trace, probe, and receiver input capacitance. Exceeding this may cause timing violations in high-speed bus applications using CD74ACT157E.

Can unused inputs on the CD74ACT157E be left floating?

No - all unused inputs on the CD74ACT157E must be terminated to either V_CC or GND. Floating TTL-compatible CMOS inputs cause excessive power consumption, oscillation, and potential device damage due to undefined internal node voltages. A 10 kΩ pull-up or pull-down resistor is recommended for inputs that may be inactive during certain modes, ensuring stable logic levels and preventing noise coupling into CD74ACT157E.

Does the CD74ACT157E support hot insertion or live insertion into a powered system?

No - CD74ACT157E is not designed for hot insertion. Its absolute maximum ratings specify that V_CC must be applied before or simultaneously with input signals. Applying inputs before V_CC risks exceeding IIK clamp current limits (±20 mA), potentially damaging internal protection diodes. Always power the CD74ACT157E supply first, then apply logic signals - especially critical in backplane or modular systems using CD74ACT157E.

How does the strobe (G) pin affect output behavior when held low?

When the G pin is held low, all four Y outputs (1Y–4Y) are forced to logic low regardless of the states of A/B or any A/B inputs. This overrides normal multiplexer operation and provides hardware-level output disable - useful for bus contention avoidance, power sequencing, or safe state initialization. The CD74ACT157E maintains this behavior across its full –55°C to 125°C temperature range without timing penalty.

Is the CD74ACT157E RoHS compliant and lead-free?

Yes - the CD74ACT157E is RoHS compliant and features lead-free (NIPDAU) termination per the TI Packaging Information Addendum. It meets EU Directive 2011/65/EU requirements and carries "Yes" in the RoHS column for all active orderable variants, including CD74ACT157E. No lead-based solder or finishes are used in its PDIP-N package construction or plating.