CD214B-T40ALF Equivalent & Substitute Parts

Part Overview

The CD214B-T40ALF is a unidirectional transient voltage suppressor (TVS) diode manufactured by Bourns Inc., designed for general-purpose overvoltage protection in surface mount applications. This component features a 40V reverse standoff voltage with 64.5V maximum clamping voltage and 9.3A peak pulse current capability in the DO-214AA (SMB) package format. The part is classified as obsolete, necessitating identification of active equivalent and substitute components to maintain design continuity and ensure supply chain availability.

Key Parameters

Parameter	Value	Unit
Reverse Standoff Voltage (Typ)	40V	V
Breakdown Voltage (Min)	44.4V	V
Clamping Voltage (Max) @ Ipp	64.5V	V
Peak Pulse Current (10/1000µs)	9.3A	A
Peak Pulse Power	600W	W
Package / Case	DO-214AA, SMB	—
Operating Temperature Range	-55°C to 150°C	°C (TJ)
Unidirectional Channels	1	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the CD214B-T40ALF is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Reverse standoff voltage: 40V (±tolerance acceptable within standard TVS specifications)
Clamping voltage: 64.5V maximum at rated peak pulse current
Peak pulse current: 9.3A at 10/1000µs waveform
Package format: DO-214AA (SMB) surface mount
Unidirectional configuration: Single channel
Peak pulse power rating: 600W minimum

Substitution Categories:

Direct Equivalents maintain identical electrical specifications and package format, enabling pin-for-pin replacement without circuit modification.

Similar Substitutes exhibit comparable voltage and current ratings within acceptable engineering tolerances but may have minor variations in clamping voltage or peak pulse current specifications. These parts are functionally equivalent for general-purpose transient suppression applications.

Extended Range Substitutes provide higher voltage ratings or current capabilities, suitable for applications requiring enhanced protection margins but compatible with the same package footprint and mounting interface.

Parameter Comparison

Part Number	Manufacturer	VWM (Typ) V	Breakdown (Min) V	Clamp (Max) V	Ipp (10/1000µs) A	Package	Status	Temp Range °C
CD214B-T40ALF	Bourns Inc.	40	44.4	64.5	9.3	DO-214AA, SMB	Obsolete	-55 to 150
SMBJ40A	MDD	40	44.4	64.5	9.3	DO-214AA, SMB	Active	-50 to 150
P6SMB47A-M3/52	Vishay General Semiconductor	40.2	44.7	64.8	9.3	DO-214AA, SMB	Active	-65 to 150
P6SMB47A-M3/5B	Vishay General Semiconductor	40.2	44.7	64.8	9.3	DO-214AA, SMB	Active	-65 to 150
P6SMB51A-M3/52	Vishay General Semiconductor	43.6	48.5	70.1	8.6	DO-214AA, SMB	Active	-65 to 150
P6SMB51A-M3/5B	Vishay General Semiconductor	43.6	48.5	70.1	8.6	DO-214AA, SMB	Active	-65 to 150
P6SMB56A-M3/52	Vishay General Semiconductor	47.8	53.2	77	7.8	DO-214AA, SMB	Active	-65 to 150
P6SMB56A-M3/5B	Vishay General Semiconductor	47.8	53.2	77	7.8	DO-214AA, SMB	Active	-65 to 150
SM6T47AY	STMicroelectronics	40	44.4	84	48 (8/20µs)	DO-214AA, SMB	Active	-55 to 150

Engineering Selection Recommendations

Direct Replacement (Preferred): The SMBJ40A from MDD provides identical electrical specifications to the CD214B-T40ALF with active product status. This component maintains the 40V reverse standoff voltage, 64.5V clamping voltage, and 9.3A peak pulse current rating. The operating temperature range extends from -50°C to 150°C, which covers the original -55°C lower limit with a 5°C variance acceptable for most general-purpose applications. ROHS3 compliance and MSL 1 rating ensure environmental and moisture handling compatibility.

Near-Equivalent Substitutes: The Vishay P6SMB47A-M3/52 and P6SMB47A-M3/5B (TransZorb® series) offer marginally higher voltage specifications (40.2V standoff, 64.8V clamp) with identical 9.3A peak pulse current. These components provide extended operating temperature range (-65°C to 150°C) and are suitable for applications requiring enhanced low-temperature performance. The 0.3V increase in clamping voltage remains within acceptable tolerance for general-purpose transient suppression.

Higher Protection Margin Substitutes: The Vishay P6SMB51A and P6SMB56A series provide progressively higher voltage ratings (43.6V and 47.8V standoff respectively) with corresponding increases in clamping voltage. These components are applicable when circuit design permits higher protection thresholds or when enhanced overvoltage margin is required. Peak pulse current ratings decrease proportionally (8.6A and 7.8A respectively) due to the higher voltage classification.

Automotive-Grade Alternative: The STMicroelectronics SM6T47AY maintains the 40V standoff voltage with enhanced peak pulse current capability (48A at 8/20µs waveform). This component carries AEC-Q101 automotive qualification and is suitable for applications requiring automotive-grade reliability. The significantly higher clamping voltage (84V) indicates a different pulse waveform specification and should be evaluated for circuit compatibility.

All recommended substitutes maintain DO-214AA (SMB) package compatibility, ROHS3 compliance, and MSL 1 moisture sensitivity rating, ensuring direct mechanical and environmental compatibility with the original design.

Frequently Asked Questions (FAQ)

Q: Can SMBJ40A directly replace CD214B-T40ALF without circuit modification? A: Yes. The SMBJ40A maintains identical reverse standoff voltage (40V), clamping voltage (64.5V), and peak pulse current (9.3A) specifications. The 5°C difference in minimum operating temperature (-50°C versus -55°C) is acceptable for applications not requiring extended low-temperature operation. Pin configuration and DO-214AA package format are identical, enabling direct substitution.

Q: What is the difference between P6SMB47A and P6SMB51A series substitutes? A: The P6SMB47A series maintains the 40V standoff voltage class with 64.8V clamping voltage, closely matching the original CD214B-T40ALF specifications. The P6SMB51A series operates at a higher voltage class (43.6V standoff, 70.1V clamp) with reduced peak pulse current (8.6A). Selection depends on circuit voltage tolerance requirements; P6SMB47A is preferred for direct replacement, while P6SMB51A is suitable when higher protection thresholds are acceptable.

Q: Are P6SMB47A-M3/52 and P6SMB47A-M3/5B interchangeable? A: Yes. Both variants maintain identical electrical specifications and package format. The designation suffix indicates different packaging configurations (tape & box variants). Electrical performance and pin compatibility are equivalent; selection is based on procurement and assembly requirements.

Q: Why does SM6T47AY have significantly higher peak pulse current (48A)? A: The SM6T47AY specifies peak pulse current at an 8/20µs waveform, whereas the CD214B-T40ALF and other substitutes use the 10/1000µs standard waveform. These represent different transient pulse profiles; the 8/20µs waveform is shorter duration, resulting in higher peak current capability for the same power dissipation. Direct current comparison between different waveform specifications is not valid.

Q: Can higher voltage-rated substitutes (P6SMB51A, P6SMB56A) be used in place of CD214B-T40ALF? A: These components are functionally compatible but provide higher protection thresholds. The P6SMB51A (43.6V standoff) and P6SMB56A (47.8V standoff) will not trigger transient suppression until higher voltage levels are reached. Use only if circuit design permits the higher activation voltage or when enhanced overvoltage margin is required.

Q: What compliance certifications are maintained across all substitutes? A: All recommended substitutes maintain ROHS3 compliance and MSL 1 (unlimited moisture sensitivity) rating. The SM6T47AY additionally carries AEC-Q101 automotive qualification. REACH compliance status varies by manufacturer; verify specific requirements for your application region.

Q: Is the DO-214AA package format consistent across all substitutes? A: Yes. All listed substitutes use the DO-214AA (SMB) surface mount package format, ensuring mechanical and footprint compatibility. Pin configuration and soldering requirements remain identical to the original CD214B-T40ALF.

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