Texas Instruments SN74HCS237PWR

Overview

SN74HCS237PWR from Texas Instruments is a 3-to-8 line decoder/demultiplexer with latched address inputs, Schmitt-trigger inputs, and dual strobe control (G0 active-high, G1 active-low). It operates from 2 V to 6 V, delivers ±7.8-mA output drive at 6 V, and supports industrial temperature range (–40°C to +125°C). It enables memory device selection on shared data buses by decoding 3-bit addresses into one-of-eight chip-select signals.

For engineers reviewing the SN74HCS237PWR datasheet, SN74HCS237PWR pinout, SN74HCS237PWR application, or SN74HCS237PWR equivalent, key selection criteria include latch-enable functionality for address retention, Schmitt-trigger noise immunity for slow/industrial inputs, output drive strength under load, thermal performance in TSSOP-16, and compatibility with 3.3-V and 5-V logic systems.

Technical Context

The SN74HCS237PWR implements a CMOS-based 3:8 decoder with integrated address latches controlled by an active-low LE input: when LE is low, it decodes A2–A0 in real time; when LE is high, outputs retain prior decoded state regardless of address changes. Two independent strobes-G0 (active-high) and G1 (active-low)-gate all outputs to low simultaneously, enabling cascading and demultiplexing.

Schmitt-trigger inputs provide hysteresis (ΔVT = 0.6 V min at 6 V), allowing robust operation with slow-rising signals and noise rejection up to ±1.6 V peak-to-peak. Outputs are balanced CMOS push-pull with VOH ≥ 5.4 V and VOL ≤ 0.33 V at 6 V/7.8 mA, supporting direct interfacing with standard logic loads without external pull-ups.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm), thermally enhanced for surface-mount assembly in space-constrained PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCS138PWR and CD74HC237M96, the SN74HCS237PWR uniquely combines latched addressing, Schmitt-trigger noise immunity, and TSSOP thermal efficiency-making it optimal for dynamic, noise-prone, space-constrained embedded systems requiring reliable one-of-eight selection.

Availability

SN74HCS237PWR is available at Aetrix Electronics and suitable for memory address decoding, industrial I/O expansion, automotive body control, and test equipment signal routing requiring stable component supply across extended temperature ranges and mixed-voltage designs.

Supply support for SN74HCS237PWR 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 logic solutions for industrial, automotive, and communications markets.

The SN74HCS237PWR belongs to TI's HCS logic family-designed for high-noise environments and wide-supply applications where reliability, low power, and robust input conditioning are critical.

FAQ

What is the function of the LE pin on the SN74HCS237PWR?

The LE (Latch Enable) pin on the SN74HCS237PWR is an active-low control that determines whether the device operates in real-time decode mode or latched mode. When LE is low, the outputs respond immediately to changes on A2–A0. When LE is high, the internal address latches retain their last decoded state, maintaining output stability despite address bus fluctuations. This behavior is explicitly defined in the Function Table (Table 8-1) and confirmed across all operating conditions in the datasheet.

Does the SN74HCS237PWR support 3.3-V operation?

Yes, the SN74HCS237PWR fully supports 3.3-V operation within its recommended supply range of 2 V to 6 V. At 3.3 V, it delivers typical VOH ≥ 3.2 V and VOL ≤ 0.25 V under 6-mA load, meets timing specs (tpd ≤ 14 ns), and maintains Schmitt-trigger hysteresis (ΔVT ≥ 0.4 V), ensuring interoperability with standard 3.3-V CMOS logic families without level translation.

Can unused inputs on the SN74HCS237PWR be left floating?

No, unused inputs on the SN74HCS237PWR must not be left floating. The datasheet mandates termination to VCC or GND (Section 9.2.1.2 and Layout Guidelines) to prevent undefined logic states, increased dynamic current, and potential oscillation. Schmitt-trigger inputs reduce sensitivity to noise but do not eliminate the risk of metastability or excessive ICC when held near switching thresholds.

What is the maximum capacitive load the SN74HCS237PWR can drive while meeting datasheet timing specs?

The SN74HCS237PWR is characterized for CL = 50 pF in all timing specifications (Sections 6.6–6.7). While larger loads may be driven, propagation delay and transition time degrade beyond this value. For guaranteed timing compliance-including tpd ≤ 17 ns at 2 V-the load capacitance must remain ≤ 50 pF, including trace, probe, and input capacitance of downstream devices as specified in Figure 7-1.

How does the SN74HCS237PWR differ from the SN74HC237 in terms of latch behavior?

The SN74HCS237PWR uses an active-low LE input, whereas legacy SN74HC237 variants used active-high LE. This polarity reversal-documented in Revision History (Page 2)-ensures correct latching behavior: LE high holds the address, LE low enables real-time decoding. This change was implemented to improve noise immunity and align with industry-standard latch enable conventions in modern logic families.