CD4538BCWM Equivalent & Substitute Parts

Part Overview

The CD4538BCWM is a monostable multivibrator logic IC manufactured by onsemi, housed in a 16-SOIC package with 100 ns propagation delay. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The CD4538BCWM belongs to the 4000B logic series and operates across a wide supply voltage range of 3 V to 15 V, supporting industrial and consumer-grade applications requiring precision timing and pulse generation.

Key Parameters

Parameter	Value
Manufacturer Part Number	CD4538BCWM
Manufacturer	onsemi
Logic Type	Monostable Multivibrator
Independent Circuits	2
Propagation Delay	100 ns
Current - Output High, Low	8.8 mA, 8.8 mA
Voltage - Supply	3 V ~ 15 V
Operating Temperature	-55°C ~ 125°C
Package / Case	16-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the CD4538BCWM is determined by the following critical parameters:

Logic Type & Circuit Count: All substitutes must be monostable multivibrators with 2 independent circuits
Package Compatibility: 16-SOIC surface mount package (physical dimensions must accommodate PCB layout)
Propagation Delay: 100 ns or faster (95 ns or 40 ns variants are acceptable)
Supply Voltage Range: Minimum 3 V to 15 V overlap required
Output Current Capability: 6.8 mA to 8.8 mA range acceptable
Operating Temperature: -55°C to 125°C range required
Schmitt Trigger Input: Present in most active substitutes (not present in CD4538BCWM)

Substitute parts are grouped by manufacturer and product status. Direct equivalents maintain identical electrical specifications. Similar parts offer enhanced performance (faster propagation delay, wider voltage range) or specialized qualifications (automotive-grade).

Parameter Comparison

Part Number	Manufacturer	Propagation Delay	Supply Voltage	Output Current (High/Low)	Schmitt Trigger	Product Status	Package Width
CD4538BCWM	onsemi	100 ns	3 V ~ 15 V	8.8 mA / 8.8 mA	No	Obsolete	7.50 mm
MC14538BDWG	onsemi	95 ns	3 V ~ 18 V	8.8 mA / 8.8 mA	Yes	Active	7.50 mm
MC14538BDWR2G	onsemi	95 ns	3 V ~ 18 V	8.8 mA / 8.8 mA	Yes	Active	7.50 mm
NLV14538BDWR2G	onsemi	95 ns	3 V ~ 18 V	8.8 mA / 8.8 mA	Yes	Not For New Designs	7.50 mm
CD14538BM	Texas Instruments	100 ns	3 V ~ 18 V	6.8 mA / 6.8 mA	Yes	Discontinued at DiGi Electronics	3.90 mm
CD14538BM96	Texas Instruments	100 ns	3 V ~ 18 V	6.8 mA / 6.8 mA	Yes	Active	3.90 mm
CD14538BMT	Texas Instruments	100 ns	3 V ~ 18 V	6.8 mA / 6.8 mA	Yes	Discontinued at DiGi Electronics	3.90 mm
CD14538BNSR	Texas Instruments	100 ns	3 V ~ 18 V	6.8 mA / 6.8 mA	Yes	Active	5.30 mm
HEF4538BT,653	Nexperia USA Inc.	40 ns	3 V ~ 15 V	3.4 mA / 3.4 mA	No	Active	3.90 mm

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility)

MC14538BDWG and MC14538BDWR2G (onsemi) are the preferred direct substitutes. Both maintain identical output current specifications (8.8 mA), offer faster propagation delay (95 ns vs. 100 ns), and extend supply voltage range to 18 V. Both are active products with ROHS3 compliance. MC14538BDWG is packaged in tube format; MC14538BDWR2G is supplied in cut tape and digi-reel format for automated assembly.

Secondary Substitutes (Electrical Equivalence with Packaging Variation)

CD14538BM96 (Texas Instruments) is an active product with identical 100 ns propagation delay and matching supply voltage range (3 V ~ 18 V). Output current is reduced to 6.8 mA, which remains within acceptable limits for most applications. Package width is narrower (3.90 mm vs. 7.50 mm), requiring PCB layout verification. ROHS3 compliant with unlimited moisture sensitivity.

CD14538BNSR (Texas Instruments) provides the same electrical performance as CD14538BM96 with an intermediate package width (5.30 mm). This part is actively produced and supplied in tape and reel format.

Alternative for Performance-Critical Applications

HEF4538BT,653 (Nexperia USA Inc.) offers significantly faster propagation delay (40 ns) and is actively produced. Supply voltage range matches the original (3 V ~ 15 V). Output current is reduced to 3.4 mA. This part is suitable only for applications where reduced output current is acceptable and faster timing is beneficial.

Not Recommended for New Designs

NLV14538BDWR2G carries automotive qualification (AEC-Q100) but is marked "Not For New Designs," indicating end-of-life status despite current inventory availability.

Frequently Asked Questions (FAQ)

Q: Can I directly replace CD4538BCWM with MC14538BDWG?

A: Yes. MC14538BDWG is a direct functional substitute with identical output current (8.8 mA), matching operating temperature range (-55°C to 125°C), and compatible supply voltage overlap (3 V ~ 15 V). The faster propagation delay (95 ns vs. 100 ns) is a performance improvement. Schmitt trigger input is present in MC14538BDWG but absent in CD4538BCWM; this does not prevent substitution in standard monostable applications.

Q: What is the difference between MC14538BDWG and MC14538BDWR2G?

A: Both parts are electrically identical. The difference is packaging format: MC14538BDWG is supplied in tube format for manual handling; MC14538BDWR2G is supplied in cut tape and digi-reel format for automated pick-and-place assembly. Select based on assembly process requirements.

Q: Can I use CD14538BM96 as a substitute?

A: Yes, with output current verification. CD14538BM96 maintains 100 ns propagation delay and extends supply voltage to 18 V. Output current is reduced from 8.8 mA to 6.8 mA. This is acceptable for applications where output current demand does not exceed 6.8 mA. Package width is narrower (3.90 mm vs. 7.50 mm); verify PCB layout compatibility before implementation.

Q: Is HEF4538BT,653 suitable for my application?

A: HEF4538BT,653 is suitable only if reduced output current (3.4 mA) and faster propagation delay (40 ns) are compatible with your circuit requirements. Supply voltage range is identical (3 V ~ 15 V). This part is not a direct replacement but an alternative for performance-critical timing applications with lower output current demands.

Q: What does "Discontinued at DiGi Electronics" mean for CD14538BM and CD14538BMT?

A: These parts are no longer actively distributed through DiGi Electronics but may remain available through other suppliers. Both are electrically equivalent to CD14538BM96 (same propagation delay and output current). For new production, CD14538BM96 is the recommended active alternative from Texas Instruments.

Q: Are all substitutes ROHS3 compliant?

A: Yes. All substitute parts listed carry ROHS3 compliance status. All are also REACH unaffected and classified under ECCN EAR99 and HTSUS 8542.39.0001.

Q: What is the moisture sensitivity difference between CD4538BCWM and its substitutes?

A: CD4538BCWM has MSL 1 (unlimited moisture sensitivity). Most onsemi and Texas Instruments substitutes also have MSL 1. NLV14538BDWR2G and MC14538BDWR2G have MSL 3 (168 hours), requiring controlled storage conditions. HEF4538BT,653 has MSL 1. Select based on storage and handling environment requirements.

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