Texas Instruments CD74ACT157MG4

Overview

CD74ACT157MG4 from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in SOIC-16 package, operating at 4.5V–5.5V V_CC, with ±24mA output drive, balanced propagation delays, and TTL-voltage-compatible inputs. It routes four independent 2:1 data paths under shared address (A/B) and active-low strobe (G) control, used in digital bus switching and logic-level multiplexing.

For engineers reviewing the CD74ACT157MG4 datasheet, CD74ACT157MG4 pinout, CD74ACT157MG4 application, or CD74ACT157MG4 equivalent, key selection criteria include its 2.4ns minimum t_PLH/t_PHL at –55°C to 125°C, 156pF power dissipation capacitance, SCR-latchup-resistant CMOS process, and MIL-STD-883-compliant 2kV ESD protection.

Technical Context

The CD74ACT157MG4 implements four independent 2:1 multiplexers sharing one address input (A/B) and one active-low output enable (G), enabling synchronous selection across all channels. Its CMOS push-pull outputs provide symmetrical sourcing/sinking capability up to ±24mA per channel, supporting fanout to 15 F-series devices.

It operates asynchronously with no internal clock; output Y equals selected input A or B when G is high, and forces all Y outputs low when G is low. Input thresholds are TTL-compatible (V_IL = 0.8V, V_VIH = 2.0V), and unused inputs must be tied to V_CC or GND to prevent oscillation and excess power draw.

Key Specifications

Pinout & Package

CD74ACT157MG4 is supplied in a 16-pin SOIC (D) package measuring 9.90mm × 6.00mm (body: 9.90mm × 3.90mm), with gull-wing leads and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT157N, CD74ACT157MG4 offers identical functionality and qualification, making it a drop-in alternative; versus 74VHC157N, CD74ACT157MG4 provides higher drive strength, wider temperature support, and guaranteed TTL compatibility-critical for legacy system upgrades and harsh-environment deployments.

Availability

CD74ACT157MG4 is available at Aetrix Electronics and suitable for industrial control systems, aerospace data acquisition, and automotive engine management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74ACT157MG4 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 CD74ACT157MG4 belongs to TI's Advanced CMOS (ACT) logic series, engineered for high-speed, low-power operation in mission-critical industrial and defense systems where TTL compatibility and latchup immunity are mandatory.

FAQ

What is the maximum operating temperature range for CD74ACT157MG4?

The CD74ACT157MG4 is rated for operation from –55°C to +125°C, meeting extended industrial and military temperature requirements. This specification is validated per TI's characterization testing and applies to all SOIC-packaged variants including CD74ACT157MG4. Operation outside this range may result in parametric degradation or permanent damage.

Does CD74ACT157MG4 require external pull-up or pull-down resistors on its inputs?

Yes - all unused inputs of CD74ACT157MG4 must be terminated to either V_CC or GND to prevent floating states that cause excessive current draw and potential oscillation. TI explicitly recommends 10kΩ resistors for un-driven inputs; direct connection is acceptable if the input is permanently inactive. The A/B, G, and data inputs all follow this rule.

Can CD74ACT157MG4 drive a 50pF load while maintaining specified timing?

Yes - CD74ACT157MG4 switching characteristics (t_PLH, t_PHL) are characterized with C_L = 50pF, and TI confirms full compliance with datasheet timing specs under this condition. Driving larger capacitive loads will increase propagation delay and may violate setup/hold margins; layout best practices recommend keeping trace capacitance ≤50pF.

Is CD74ACT157MG4 pin-compatible with older CD74HC157 devices?

No - CD74ACT157MG4 and CD74HC157 share the same pinout and logic function but differ electrically: CD74ACT157MG4 has TTL-compatible inputs (V_IH = 2.0V), ±24mA drive, and –55°C to +125°C rating, whereas CD74HC157 uses CMOS thresholds (V_IH = 3.15V at 4.5V) and ±4mA drive. Direct substitution requires validation of input voltage levels and load requirements.

What is the purpose of the G (strobe) pin on CD74ACT157MG4?

The G pin on CD74ACT157MG4 is an active-low output enable that forces all four Y outputs low regardless of the A/B address state. This provides a hardware-controlled disable function for bus isolation or safe-state assertion - for example, during system reset or fault conditions. When G is high, normal multiplexing proceeds; when G is low, all outputs are driven low.