Texas Instruments CD74HC237NSR

Overview

CD74HC237NSR 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-high 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 CD74HC237NSR datasheet, CD74HC237NSR pinout, CD74HC237NSR application, or CD74HC237NSR equivalent, this page delivers verified electrical specs, SOP-16 package details, truth table behavior, propagation delay (13ns @ 5V/15pF), fanout capability (10 LSTTL loads), and real-world demultiplexing use cases in industrial control and instrumentation systems.

Technical Context

The CD74HC237NSR implements a 3-bit address latch followed by an active-high 1-of-8 decoder. Its LE input latches A0–A2 on rising edge, isolating outputs from subsequent address changes - enabling stable output selection during bus arbitration or memory access cycles.

Demultiplexing is achieved by using A0–A2 to select one of eight outputs while routing data through OE0 or OE1 (with the other held low). Unlike the '137 variant, the '237 asserts the selected output high (Yn = H), making it suitable for active-high enable logic in peripheral selection and signal distribution.

Key Specifications

Pinout & Package

SOP-16 (NS package), 2.00 mm max height, 16-pin surface-mount small outline package with gull-wing leads; RoHS-compliant, NIPDAU lead finish, MSL Level-1, tape-and-reel (2000 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC137NSR, the CD74HC237NSR provides native active-high output polarity critical for direct enable control, while SN74HC237N offers identical functionality in through-hole form - both preserve latch timing, fanout, and temperature range but differ in physical integration and interface compatibility.

Availability

CD74HC237NSR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive ECU memory mapping, and medical imaging subsystem control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC237NSR 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.

The CD74HC237NSR belongs to TI's HC-series high-speed CMOS logic family, engineered for low-power, high-noise-immunity digital interfacing in harsh-environment applications including aerospace, energy infrastructure, and transportation systems.

FAQ

What is the maximum clock frequency supported by CD74HC237NSR?

The CD74HC237NSR does not operate on a clock signal - it is a combinational logic device with no internal clock. Its maximum usable frequency depends on propagation delay and system setup/hold timing. At VCC = 5V and CL = 15pF, tPLH/tPHL is 13ns typical, supporting address transition rates up to ~38 MHz in transparent mode and lower in latched configurations due to LE timing constraints. Always verify timing margins using the full truth table and switching specifications in the TI datasheet SCHS146F.

Does CD74HC237NSR support 3.3V logic levels?

Yes, CD74HC237NSR fully supports 3.3V operation: its HC-family specification guarantees correct function from 2V to 6V, with VIH(min) = 1.5V and VIL(max) = 0.5V at VCC = 3.3V - comfortably exceeding standard 3.3V CMOS thresholds (VIH ≥ 2.0V, VIL ≤ 0.8V). Input leakage remains ≤±1µA, and output drive strength meets 10 LSTTL load requirements at 3.3V.

How does the latch enable (LE) function work in CD74HC237NSR?

In CD74HC237NSR, LE is a positive-edge-triggered latch control. When LE is low, outputs follow A0–A2 in real time (transparent mode). On the rising edge of LE, the current A0–A2 values are captured and held, freezing Y0–Y7 output states regardless of subsequent address changes - essential for glitch-free bus decoding during multiplexed address/data transfers. LE must meet minimum pulse width (9ns @ 6V) and setup/hold timing relative to address inputs.

Can CD74HC237NSR be used as a demultiplexer?

Yes, CD74HC237NSR can function as a 1-to-8 demultiplexer. Configure A0–A2 as select lines, hold OE1 low, and apply data to OE0 - the selected Yn output mirrors OE0's logic level. This exploits the device's dual enable architecture and eliminates need for external gating. Note that only one output is active per cycle (active-high), matching classic demux behavior. Truth table section "'HC237, 'HCT237" in SCHS146F confirms this mode.

What is the thermal resistance (θJA) of the SOP-16 (NS) package for CD74HC237NSR?

The junction-to-ambient thermal resistance θJA for CD74HC237NSR in the SOP-16 (NS) package is 64°C/W, as specified in the Absolute Maximum Ratings table of the TI datasheet SCHS146F. This value assumes standard JEDEC high-K board conditions (2S2P). For thermally constrained designs, derate power dissipation accordingly - maximum junction temperature is 150°C, and operating ambient must stay within –55°C to +125°C limits.