Texas Instruments CD74HC137PWE4

Overview

CD74HC137PWE4 from Texas Instruments is a high-speed CMOS 3-to-8 line decoder/demultiplexer with address latches, designed for memory address decoding and data routing. It features active-low outputs, dual output enables (OE0, OE1), latch enable (LE), three binary select inputs (A0–A2), and operates from 2V to 6V with propagation delay of 31ns (typ) at VCC = 6V, CL = 15pF.

For engineers reviewing the CD74HC137PWE4 datasheet, CD74HC137PWE4 pinout, CD74HC137PWE4 application, or CD74HC137PWE4 equivalent, key selection criteria include latch-controlled output isolation, cascading support via two enable inputs, wide temperature range (−55°C to +125°C), low power consumption versus LSTTL, and compatibility with both CMOS and TTL input logic levels.

Technical Context

The CD74HC137PWE4 implements a 3-bit address latch followed by a 1-of-8 decoder, where LE latches A0–A2 to freeze output state independently of subsequent input changes. Output selection is determined by the latched address, and outputs remain stable until LE transitions again.

Two independent output enables (OE0 and OE1) provide hierarchical control: OE1 must be low and OE0 must be low for any output to activate; this dual-enable structure simplifies multi-stage cascading and supports demultiplexing when one enable serves as data input while the other remains asserted.

Key Specifications

Pinout & Package

TSSOP-16 package (PW), 4.4mm × 5.0mm body, 0.65mm pitch, 1.2mm max height, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-to-8 decoder with latch applications.

Compared with CD74HC237PW, the CD74HC137PWE4 provides native active-low outputs ideal for direct chip-select use, while SN74LV138APWR offers lower voltage operation but eliminates latch-based timing margin - making CD74HC137PWE4 preferable for systems requiring glitch-free output hold during address updates.

Availability

CD74HC137PWE4 is available at Aetrix Electronics and suitable for industrial automation, aerospace avionics, and automotive ECU designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC137PWE4 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 ICs, with decades of heritage in high-reliability logic families.

The CD74HC137PWE4 belongs to TI's HC-series high-speed CMOS logic family, engineered for low-power, high-noise-immunity digital control in mission-critical systems operating across extreme temperatures.

FAQ

What is the maximum clock frequency supported by the CD74HC137PWE4?

The CD74HC137PWE4 does not operate on a clock signal - it is a combinational logic device with latch control. Its speed is defined by propagation delay: 31ns (typ) at VCC = 6V and CL = 15pF. Maximum usable toggle rate depends on system setup/hold timing and load capacitance, but address changes can be reliably latched at frequencies up to ~10MHz in typical PCB layouts with proper decoupling.

Does the CD74HC137PWE4 require external pull-up resistors on its outputs?

No, the CD74HC137PWE4 does not require external pull-up resistors. Its outputs are push-pull CMOS drivers capable of actively sourcing and sinking current (±25mA). Pull-ups are unnecessary unless interfacing with open-drain systems - which is not the intended use case for CD74HC137PWE4's active-low outputs.

Can the CD74HC137PWE4 be used as a demultiplexer, and how is that configured?

Yes, the CD74HC137PWE4 can function as a 1-to-8 demultiplexer. Configure by holding OE1 low (active), using OE0 as the data input signal, and applying the 3-bit channel address to A0–A2. When OE0 is high, all outputs remain high (inactive); when OE0 is low, the addressed output (Y0–Y7) goes low - effectively routing the OE0 logic level to one of eight destinations.

What is the purpose of the Latch Enable (LE) pin on the CD74HC137PWE4?

The Latch Enable (LE) pin on the CD74HC137PWE4 controls whether the device operates in transparent or latched mode. When LE is low, outputs follow A0–A2 in real time. When LE transitions high, the current A0–A2 values are captured and held - decoupling outputs from further address changes until LE is pulsed again. This prevents glitches during bus transitions and enables synchronous decoding.

Is the CD74HC137PWE4 compatible with 3.3V logic systems?

Yes, the CD74HC137PWE4 is fully compatible with 3.3V logic systems. Its HC-family specification guarantees operation from 2V to 6V, and input thresholds scale with VCC: at VCC = 3.3V, VIH ≈ 2.3V (min) and VIL ≈ 1.0V (max). Outputs swing rail-to-rail, providing 3.3V-compatible high/low levels when powered from 3.3V.