Texas Instruments CD74HC137PWT

Overview

CD74HC137PWT 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 across –55°C to 125°C.

For engineers reviewing the CD74HC137PWT datasheet, CD74HC137PWT pinout, CD74HC137PWT application, or CD74HC137PWT equivalent, this device is selected for robust industrial decoding where latch isolation, low-power CMOS performance, and wide temperature operation are critical - especially in legacy-compatible systems requiring HC logic voltage thresholds and TTL fanout compatibility.

Technical Context

The CD74HC137PWT implements a 3-bit address latch followed by an active-low 1-of-8 decoder. Latch Enable (LE) controls transparency vs. latched operation: when LE is low, outputs follow A0–A2; when LE goes high, the current address is latched and outputs remain stable despite input changes. This supports asynchronous address hold during memory access cycles.

Two independent Output Enable inputs (OE0 and OE1) allow cascading of multiple devices and flexible demultiplexing configurations. OE1 must be low and OE0 used as data input to achieve demux mode, with the selected Yx output driven low - a behavior confirmed exclusively for CD74HC137/CD74HCT137 variants per truth table and functional description.

Key Specifications

Pinout & Package

CD74HC137PWT is housed in a 16-pin TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, 4.4 mm width, and 1.2 mm max height - optimized for high-density PCB layouts and automated surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC237PWT and CD74HCT137PWR, the CD74HC137PWT uniquely balances wide supply flexibility (2V–6V), active-low output polarity, and industrial temperature range - making it optimal for new designs requiring backward compatibility with LS-family timing while supporting modern low-voltage operation.

Availability

CD74HC137PWT is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O expansion, bus demultiplexing, and legacy logic replacement requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC137PWT 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 over 90 years of innovation in high-reliability components.

The CD74HC137PWT belongs to TI's High-Speed CMOS Logic family, engineered for industrial and aerospace applications demanding wide temperature operation, low power, and pin-compatible upgrades from bipolar TTL logic.

FAQ

What is the maximum operating voltage for CD74HC137PWT?

The CD74HC137PWT supports a supply voltage range of 2V to 6V DC, with absolute maximum rating at 7V. Operation above 6V violates the HC logic specification and risks parametric failure or accelerated wear-out. At 6V, propagation delay is minimized (31 ns typ), and noise immunity remains at 30% of VCC - making 5V or 6V optimal for performance-critical applications.

Does CD74HC137PWT support demultiplexing functionality?

Yes, CD74HC137PWT supports demultiplexing by using OE0 as the data input while holding OE1 low and applying address bits A0–A2. In this configuration, the selected Yx output mirrors the OE0 logic state (active-low), enabling 1-to-8 serial-to-parallel conversion. This mode is explicitly defined in the datasheet truth table and functional diagram for CD74HC137/CD74HCT137 variants.

Is CD74HC137PWT pin-compatible with CD74HC237PWT?

Yes, CD74HC137PWT and CD74HC237PWT share identical TSSOP-16 packaging, pinout, and terminal assignments. The sole functional difference is output polarity: CD74HC137PWT drives selected outputs low, while CD74HC237PWT drives them high. No PCB changes are required for substitution, but downstream logic must accommodate the inverted output behavior.

What is the purpose of the Latch Enable (LE) input on CD74HC137PWT?

The Latch Enable (LE) input on CD74HC137PWT controls whether the A0–A2 address inputs are transparent to the outputs (LE = low) or latched (LE = high). When LE transitions high, the current address is captured and held, freezing Y0–Y7 states regardless of subsequent A0–A2 changes - critical for glitch-free memory chip selection during CPU read/write cycles.

Can CD74HC137PWT operate reliably at –55°C?

Yes, CD74HC137PWT is fully specified and tested for operation from –55°C to +125°C. Its electrical parameters - including propagation delay, output drive strength, and input thresholds - are guaranteed across this full range per the Absolute Maximum Ratings and Operating Conditions tables. This makes CD74HC137PWT suitable for aerospace, military, and outdoor industrial deployments without derating.