CD74HC4538MT Equivalent & Substitute Parts

Part Overview

The CD74HC4538MT is a monostable multivibrator logic IC manufactured by Texas Instruments, housed in a 16-SOIC surface mount package. This component features dual independent circuits with Schmitt trigger inputs, operating across a 2V to 6V supply range with a 21 ns propagation delay. The part is designated as Last Time Buy, indicating discontinued production status. Identifying equivalent and substitute parts is necessary to ensure design continuity and maintain supply chain flexibility for applications requiring monostable multivibrator functionality.

Substiute Parts

CD74HC4538MT

Texas InstrumentsIn Stock: 4018CD74HC4538MT Datasheet

Current PartRFQ

CD74HC4538M96

Texas InstrumentsIn Stock: 18296CD74HC4538M96 Datasheet

MFR RecommendedRFQ

74HC4538D,653

Nexperia USA Inc.In Stock: 230374HC4538D,653 Datasheet

MFR RecommendedRFQ

74HC4538D-Q100,118

Nexperia USA Inc.In Stock: 349774HC4538D-Q100,118 Datasheet

MFR RecommendedRFQ

MC74HC4538ADG

onsemiIn Stock: 1226MC74HC4538ADG Datasheet

MFR RecommendedRFQ

MC74HC4538ADR2G

onsemiIn Stock: 15678MC74HC4538ADR2G Datasheet

MFR RecommendedRFQ

NLV74HC4538ADR2G

onsemiIn Stock: 3807NLV74HC4538ADR2G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the CD74HC4538MT is determined by the following critical parameters:

Primary Compatibility Criteria:

• Logic type: Monostable multivibrator
• Independent circuits: 2
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Supply voltage range: 2 V to 6 V
• Output current: 5.2 mA (both high and low)
• Mounting type: Surface mount
• RoHS compliance: ROHS3 Compliant

Secondary Considerations:

• Propagation delay: 21 ns (primary specification)
• Schmitt trigger input: Yes (preferred for noise immunity)
• Operating temperature range: -55°C to 125°C (preferred for extended range)
• Product status: Active status preferred over obsolete

Substitute parts are grouped based on adherence to these parameters. Parts with identical electrical specifications and package dimensions are direct equivalents. Parts with extended propagation delays (25 ns or 30 ns) or reduced temperature ranges (-40°C to 125°C) are functional substitutes with minor performance trade-offs.

Parameter Comparison

Engineering Selection Recommendations

Preferred Primary Substitute: CD74HC4538M96

CD74HC4538M96 is the recommended direct substitute. Manufactured by Texas Instruments, it maintains identical electrical specifications to the CD74HC4538MT, including 21 ns propagation delay, Schmitt trigger input, and -55°C to 125°C operating range. The part is in Active product status with 18,213 units in stock, ensuring supply continuity. The only difference is packaging format (Cut Tape & Digi-Reel® versus Tape & Reel), which does not affect electrical performance or PCB compatibility.

Secondary Substitutes with Performance Trade-offs:

MC74HC4538ADR2G (onsemi) is an Active substitute maintaining Schmitt trigger input and extended temperature range (-55°C to 125°C). The 30 ns propagation delay represents a 43% increase over the original specification and may impact timing-critical applications. This part is suitable for applications with relaxed timing requirements.

74HC4538D,653 and 74HC4538D-Q100,118 (Nexperia) are Active substitutes with 25 ns propagation delay and reduced operating temperature range (-40°C to 125°C). Both lack Schmitt trigger input, reducing noise immunity. These parts are suitable for applications operating within the narrower temperature range and where Schmitt trigger functionality is not required.

Avoid:

MC74HC4538ADG and NLV74HC4538ADR2G are designated Obsolete and should not be selected for new designs despite technical compatibility.

Frequently Asked Questions (FAQ)

Q: Can CD74HC4538M96 be used as a direct replacement for CD74HC4538MT?

A: Yes. CD74HC4538M96 is electrically and functionally identical to CD74HC4538MT. Both are manufactured by Texas Instruments with identical propagation delay (21 ns), Schmitt trigger input, and operating temperature range (-55°C to 125°C). The difference in packaging format (Cut Tape & Digi-Reel® versus Tape & Reel) does not affect circuit performance or PCB footprint compatibility.

Q: What is the impact of using a substitute with 25 ns or 30 ns propagation delay instead of 21 ns?

A: Propagation delay determines the time required for the output to respond to input changes. A 25 ns delay represents a 19% increase; a 30 ns delay represents a 43% increase. Applications with timing-critical functions may experience altered pulse widths or timing margins. Verify that the application's timing budget accommodates the extended delay before substitution.

Q: Why do some substitutes lack Schmitt trigger input?

A: Schmitt trigger input provides hysteresis, improving noise immunity and signal integrity on noisy input lines. Parts without Schmitt trigger input (74HC4538D,653 and 74HC4538D-Q100,118) are functionally equivalent for clean input signals but may exhibit instability in high-noise environments. Select based on input signal quality requirements.

Q: What is the significance of the -40°C to -55°C temperature range difference?

A: The CD74HC4538MT operates from -55°C to 125°C, while some substitutes (74HC4538D,653 and 74HC4538D-Q100,118) operate from -40°C to 125°C. Applications requiring operation below -40°C must use parts with the extended lower temperature specification. Verify application temperature requirements before substitution.

Q: Are Nexperia 74HC4538D parts suitable for automotive applications?

A: 74HC4538D-Q100,118 carries AEC-Q100 automotive qualification, making it suitable for automotive-grade applications. 74HC4538D,653 does not carry automotive qualification. Verify application requirements before selecting between these variants.

Q: Can I use an Obsolete part as a substitute?

A: MC74HC4538ADG and NLV74HC4538ADR2G are designated Obsolete. While technically compatible, obsolete parts present supply chain risk and should not be selected for new designs. Use Active status parts (CD74HC4538M96, MC74HC4538ADR2G, 74HC4538D,653, or 74HC4538D-Q100,118) to ensure long-term availability.