CD214L-T18ALF Equivalent & Substitute Parts

Part Overview

The CD214L-T18ALF is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Bourns Inc., designed for general-purpose overvoltage protection in surface mount applications. This component features an 18V reverse standoff voltage with a 29.2V maximum clamping voltage and 102.8A peak pulse current capability in a DO-214AB (SMC) package. The part is currently obsolete, making equivalent and substitute parts necessary for ongoing design support and production requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	CD214L-T18ALF
Manufacturer	Bourns Inc.
Category	Transient Voltage Suppressors (TVS)
Type	Zener, Unidirectional
Voltage - Reverse Standoff (Typ)	18V
Voltage - Breakdown (Min)	20V
Voltage - Clamping (Max) @ Ipp	29.2V
Current - Peak Pulse (10/1000µs)	102.8A
Power - Peak Pulse	3000W (3kW)
Package / Case	DO-214AB, SMC
Operating Temperature	-55°C ~ 150°C (TJ)
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the CD214L-T18ALF are categorized based on electrical parameter compatibility within the TVS diode classification. The primary substitution criteria are:

Critical Parameters for Substitution:

Voltage - Reverse Standoff: 18V (±tolerance)
Voltage - Clamping (Max) @ Ipp: 29.2V
Package / Case: DO-214AB, SMC
Unidirectional Zener type
Surface mount mounting type

Substitution Categories:

Direct Equivalents maintain identical electrical specifications (18V standoff, 29.2V clamping, 102.8A peak pulse, 3000W power rating) with active product status and full compliance certifications.

Compatible Alternatives share the core voltage parameters (18V standoff, 29.2V clamping) and DO-214AB package but differ in peak pulse current or power dissipation ratings. These parts are suitable when application requirements permit lower current handling or when higher power ratings are acceptable.

Limited Compatibility Parts maintain voltage specifications but operate outside the standard temperature range or have reduced peak pulse current ratings. Selection requires verification of application thermal and current requirements.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Operating Temperature	Product Status	RoHS Status
CD214L-T18ALF	Bourns Inc.	18V	29.2V	102.8A	3000W	-55°C ~ 150°C	Obsolete	ROHS3 Compliant
SMLJ18A	Bourns Inc.	18V	29.2V	102.8A	3000W	-55°C ~ 150°C	Active	ROHS3 Compliant
5.0SMDJ18A	Taiwan Semiconductor Corporation	18V	29.2V	172A	5000W	-55°C ~ 175°C	Active	ROHS3 Compliant
5.0SMDJ18A-T7	Littelfuse Inc.	18V	29.2V	172A	5000W	-65°C ~ 150°C	Active	ROHS3 Compliant
SMCJ18A	MDD	18V	29.2V	51.4A	1500W	-50°C ~ 150°C	Active	ROHS3 Compliant
SMCJ18A-TP	Micro Commercial Co	18V	29.2V	51.4A	1500W	-55°C ~ 175°C	Active	ROHS3 Compliant
SMDJ18A	Alpha & Omega Semiconductor Inc.	18V	29.2V	102.8A	3000W	-55°C ~ 150°C	Active	ROHS3 Compliant
SMDJ18A-HR	Littelfuse Inc.	18V	29.2V	102.7A	3000W	-65°C ~ 150°C	Active	ROHS3 Compliant
SMLJ18A-TP	Micro Commercial Co	18V	29.2V	102.8A	3000W	-55°C ~ 175°C	Active	ROHS3 Compliant
TPSMC20A	Littelfuse Inc.	17.1V	27.7V	54.9A	1500W	-55°C ~ 150°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Direct Equivalents):

SMLJ18A (Bourns Inc.) and SMDJ18A (Alpha & Omega Semiconductor Inc.) are the preferred direct substitutes. Both maintain identical electrical specifications to the CD214L-T18ALF with 18V standoff voltage, 29.2V clamping voltage, 102.8A peak pulse current, and 3000W power dissipation. Both are active products with ROHS3 compliance and MSL 1 rating, ensuring long-term availability and supply chain stability.

Extended Temperature Range Alternatives:

SMLJ18A-TP (Micro Commercial Co) and 5.0SMDJ18A-T7 (Littelfuse Inc.) provide extended upper operating temperature limits (-55°C to 175°C and -65°C to 150°C respectively) compared to the original specification. These are suitable for applications requiring enhanced thermal performance while maintaining equivalent voltage and current specifications.

Higher Power Capability:

5.0SMDJ18A (Taiwan Semiconductor Corporation) offers increased peak pulse current (172A) and power dissipation (5000W) with identical voltage parameters. This part is applicable when circuit protection requirements exceed the original 3000W specification.

Reduced Current Rating:

SMCJ18A (MDD) and SMCJ18A-TP (Micro Commercial Co) maintain voltage specifications but provide reduced peak pulse current (51.4A) and power dissipation (1500W). These are suitable for applications with lower transient current requirements.

Limited Compatibility:

TPSMC20A (Littelfuse Inc.) operates at 17.1V standoff and 27.7V clamping voltage, representing a deviation from the original 18V/29.2V specification. This part is not recommended as a direct substitute without circuit re-evaluation.

Frequently Asked Questions (FAQ)

Q: Can SMLJ18A directly replace CD214L-T18ALF in existing designs?

A: Yes. SMLJ18A maintains identical electrical specifications (18V standoff, 29.2V clamping, 102.8A peak pulse, 3000W power) and DO-214AB package. Both are Zener unidirectional TVS diodes with equivalent performance characteristics. The primary difference is product status: SMLJ18A is active while CD214L-T18ALF is obsolete.

Q: What is the difference between 3000W and 5000W rated parts?

A: Power rating indicates the maximum transient energy the device can dissipate during a 10/1000µs pulse. The 5.0SMDJ18A series (5000W) provides higher transient energy handling capability. Selection depends on the actual transient energy present in the application circuit. If the circuit generates transients exceeding 3000W, the higher-rated part is required.

Q: Are parts with different peak pulse current ratings interchangeable?

A: Peak pulse current rating indicates the maximum current the device can conduct during transient suppression. Parts with lower ratings (51.4A in SMCJ18A) are suitable only if circuit transient currents remain below that threshold. Parts with higher ratings (172A in 5.0SMDJ18A) provide additional margin. Verify application transient current requirements before selecting a substitute with different current rating.

Q: What does the temperature range difference mean for substitution?

A: Operating temperature range specifies the junction temperature limits for reliable device operation. SMLJ18A-TP (-55°C to 175°C) provides extended high-temperature capability compared to the original (-55°C to 150°C). This is beneficial in high-ambient or high-power applications. Lower temperature limits do not affect substitution if the application operates within the specified range.

Q: Why is TPSMC20A not recommended as a substitute?

A: TPSMC20A operates at 17.1V standoff and 27.7V clamping voltage, deviating from the CD214L-T18ALF specification of 18V standoff and 29.2V clamping. These voltage differences affect circuit protection thresholds and may result in inadequate overvoltage suppression. This part requires circuit re-evaluation and is not a direct substitute.

Q: Does packaging format (Tape & Reel vs. bulk) affect electrical performance?

A: No. Packaging format affects handling, storage, and assembly processes but does not alter electrical characteristics. Parts designated with "-TP" or "-TR" indicate Tape & Reel packaging for automated assembly. Bulk packaged parts have identical electrical performance. Selection depends on manufacturing process requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance, ensuring compatibility with environmental and regulatory requirements equivalent to the original CD214L-T18ALF.

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