SN74HC138DB

Overview

The SN74HC138DB is a single 3-to-8 line decoder/demultiplexer from the Texas Instruments SN74HC series. It operates within a supply voltage range of 2 V to 6 V and features a 16-pin SSOP package. The device provides eight low-active outputs selected by three binary address inputs. Key electrical parameters include a propagation delay of 45 ns, an output drive capability of ±5.2 mA, and a maximum power dissipation of 320 mW. It functions reliably across an operating temperature range of -40°C to +85°C.

Feature Summary

• Provides one circuit for decoding three binary inputs into eight distinct active-low outputs
• Integrates three enable inputs (two low-active, one high-active) to simplify system expansion and reduce external logic requirements
• Designed for high-performance memory decoding and data routing applications with minimal system delay impact

Applications

• High-performance memory decoding systems
• Data routing and transmission networks
• Industrial control logic circuits

Procurement Notes

Verify the specific package variant, as SN74HC138DB typically denotes the SSOP-16 form factor. Confirm RoHS compliance status and moisture sensitivity level (MSL 1) prior to assembly. Ensure the design accommodates the 2V to 6V operating range and check for any obsolescence notices or lifecycle changes from the manufacturer before finalizing procurement plans.

Selection Notes

Select this component when a standard CMOS 3-to-8 decoder is required in a compact surface-mount package. The SN74HC138DB offers compatibility with LSTTL loads and supports cascading for larger decoding schemes. Consider the SSOP footprint constraints and verify that the 45 ns propagation delay meets the timing requirements of the target application.

Part Context

This part belongs to the Texas Instruments SN74HC family of high-speed CMOS logic devices. The SN74HC138 series is widely used for address decoding and signal distribution. The 'DB' suffix specifically identifies the 16-lead Shrink Small Outline Package (SSOP), distinguishing it from SOIC or DIP variants within the same logical function family.

Replacement Considerations

SN74HC138DR (SOIC-16), SN74HC138PWR (TSSOP-16), SN74HC138DBR (SSOP-16). Verify pinout compatibility and package dimensions before substitution.