CD4538BCN Equivalent & Substitute Parts

Part Overview

The CD4538BCN is a monostable multivibrator IC manufactured by onsemi, designed for precision timing and pulse generation applications. This 16-pin DIP package device features dual independent circuits with 100 ns propagation delay and operates across a 3V to 15V supply range. The product is currently classified as obsolete, making identification of compatible substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

CD4538BCN

onsemiIn Stock: 2277CD4538BCN Datasheet

Current PartRFQ

CD14538BE

Texas InstrumentsIn Stock: 26614CD14538BE Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the CD4538BCN is determined by the following critical parameters:

• Logic Type & Circuit Configuration: Must be monostable multivibrator with 2 independent circuits
• Propagation Delay: 100 ns specification
• Package & Mounting: 16-DIP through-hole package (0.300", 7.62mm)
• Operating Temperature Range: -55°C to 125°C
• Supply Voltage Compatibility: Minimum 3V operation required; upper limit tolerance varies by substitute

The CD14538BE from Texas Instruments satisfies all substitution criteria. While it introduces enhanced features (Schmitt Trigger Input capability) and expanded supply voltage range (3V to 18V), these represent functional improvements that maintain backward compatibility with CD4538BCN applications.

Parameter Comparison

Engineering Selection Recommendations

The CD14538BE is a direct functional substitute for the CD4538BCN. Selection should be based on the following factors:

Product Availability: The CD4538BCN is obsolete with limited remaining inventory. The CD14538BE maintains active production status with significantly higher stock availability (26,529 pcs vs. 2,215 pcs), ensuring supply chain continuity.

Regulatory Compliance: The CD14538BE carries ROHS3 compliance certification, meeting current environmental and material restriction standards. This is particularly relevant for new designs or systems requiring compliance documentation.

Electrical Compatibility: Both devices operate within identical propagation delay and temperature specifications. The CD14538BE's expanded supply voltage range (18V maximum vs. 15V) provides additional design margin without compromising existing applications. Output current specifications differ slightly (6.8 mA vs. 8.8 mA), which is acceptable for standard logic-level applications but should be verified for high-current output requirements.

Enhanced Features: The CD14538BE includes Schmitt Trigger input capability, providing improved noise immunity compared to the original CD4538BCN. This enhancement is transparent to existing designs and beneficial for noisy environments.

Frequently Asked Questions (FAQ)

Q: Can CD14538BE directly replace CD4538BCN in existing designs?

A: Yes. Both devices share identical logic type, circuit configuration, propagation delay, temperature range, and 16-DIP package. The CD14538BE is electrically compatible and can be substituted without circuit modification.

Q: What is the significance of the Schmitt Trigger input in CD14538BE?

A: Schmitt Trigger input provides hysteresis, improving noise rejection on input signals. This is an enhancement that does not affect compatibility with designs using standard logic inputs. Existing circuits will function identically.

Q: Are there supply voltage considerations when substituting?

A: The CD14538BE supports 3V to 18V operation, compared to CD4538BCN's 3V to 15V range. This expanded range is backward compatible. If your design operates at 15V or below, no adjustment is required. Higher voltage applications can now utilize the extended range.

Q: How do output current specifications affect substitution?

A: CD14538BE output current (6.8 mA) is lower than CD4538BCN (8.8 mA). For standard logic-level loads, this difference is negligible. Applications requiring maximum output current should verify that 6.8 mA meets load requirements before substitution.

Q: What packaging considerations apply?

A: Both devices use identical 16-DIP through-hole packages (0.300", 7.62mm). No PCB layout or socket modifications are necessary. Direct pin-for-pin substitution is possible.

Q: Does RoHS3 compliance affect circuit operation?

A: No. RoHS3 compliance indicates material composition standards and does not alter electrical performance or functionality. It reflects manufacturing process compliance with environmental regulations.