CMPZ5250B TR PBFREE Zener Diode 20V 350mW Equivalent & Substitute Parts

Part Overview

The CMPZ5250B TR PBFREE is a surface mount Zener diode manufactured by Central Semiconductor Corp, rated at 20 V nominal Zener voltage with 350 mW maximum power dissipation in SOT-23 packaging. This component is classified as Active product status with RoHS3 compliance and unlimited moisture sensitivity level (MSL 1). The part is packaged in Tape & Reel format with ±5% voltage tolerance.

Equivalent and substitute parts are necessary when the original CMPZ5250B TR PBFREE becomes unavailable, when alternative sourcing is required for supply chain optimization, or when design flexibility permits selection from multiple qualified manufacturers while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value	Unit	Significance for Substitution
Voltage - Zener (Nom)	20	V	Critical - must match exactly
Power - Max	350	mW	Critical - substitute must meet or exceed
Tolerance	±5%	%	Important - determines voltage accuracy
Impedance (Max)	25	Ohms	Important - affects circuit response
Mounting Type	Surface Mount	-	Critical - must be surface mount
Package / Case	TO-236-3, SC-59, SOT-23-3	-	Critical - physical compatibility
Operating Temperature	-65°C ~ 150°C	°C	Important - thermal operating range
RoHS Status	ROHS3 Compliant	-	Important - regulatory compliance

Substitute Part Grouping Explanation

Substitution logic for the CMPZ5250B TR PBFREE is based on the following criteria:

Primary Substitution Criteria (Non-Negotiable):

Zener voltage: 20 V nominal (exact match required)
Mounting type: Surface Mount only
Package: TO-236-3, SC-59, or SOT-23-3 (physically compatible)
RoHS3 compliance status

Secondary Substitution Criteria (Flexible Within Limits):

Power rating: Substitute must equal or exceed 350 mW
Tolerance: ±1%, ±2%, ±5%, or ±6% acceptable (tighter tolerance is acceptable)
Impedance: Values between 25 Ohms and 55 Ohms are acceptable
Operating temperature: Range must encompass or match -65°C to 150°C minimum
Reverse leakage current: 50 nA to 100 nA @ specified voltage acceptable

Grouping Categories:

Group A - Direct Electrical Equivalents (250 mW Power Rating): BZX84-A20,215, BZX84-B20,215, BZX84-B20,235, BZX84-C20,215, BZX84-C20,235

Lower power rating (250 mW vs 350 mW) - suitable for applications not requiring full 350 mW
Nexperia automotive-grade parts with AEC-Q101 qualification
Tighter tolerance options available (±1%, ±2%, ±5%)

Group B - Enhanced Power Rating Equivalents (300 mW Power Rating): BZX84B20-7-F, BZX84B20-E3-08, BZX84C20-7-F, BZX84C20-E3-08, BZX84C20-HE3-08

Intermediate power rating (300 mW) between original 350 mW and Group A 250 mW
Multiple manufacturers: Diodes Incorporated and Vishay
Suitable for most applications requiring 350 mW capability

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Package	Temp Range (°C)	Status	AEC-Q101
CMPZ5250B TR PBFREE	Central Semiconductor	20	±5%	350	25	SOT-23-3	-65 to 150	Active	No
BZX84-A20,215	NXP Semiconductors	20	±1%	250	55	SOT-23-3	-65 to 150	Active	Yes
BZX84-B20,215	Nexperia USA Inc.	20	±2%	250	55	SOT-23-3	-65 to 150	Active	Yes
BZX84-B20,235	Nexperia USA Inc.	20	±2%	250	55	SOT-23-3	-65 to 150	Active	Yes
BZX84-C20,215	Nexperia USA Inc.	20	±5%	250	55	SOT-23-3	-65 to 150	Active	Yes
BZX84-C20,235	Nexperia USA Inc.	20	±5%	250	55	SOT-23-3	-65 to 150	Active	Yes
BZX84B20-7-F	Diodes Incorporated	20	±2%	300	55	SOT-23-3	-65 to 150	Active	No
BZX84B20-E3-08	Vishay General Semiconductor	20	±2%	300	55	SOT-23-3	-55 to 150	Active	No
BZX84C20-7-F	Diodes Incorporated	20	±6%	300	55	SOT-23-3	-65 to 150	Active	No
BZX84C20-E3-08	Vishay General Semiconductor	20	±5%	300	55	SOT-23-3	-55 to 150	Active	No
BZX84C20-HE3-08	Vishay General Semiconductor	20	±5%	300	55	SOT-23-3	-55 to 150	Obsolete	Yes

Engineering Selection Recommendations

For Applications Requiring Full 350 mW Power Dissipation:

When circuit design requires the complete 350 mW power rating of the original CMPZ5250B TR PBFREE, substitute parts from Group B (300 mW rating) provide the closest electrical match while maintaining adequate thermal margin. BZX84B20-7-F and BZX84C20-7-F from Diodes Incorporated are Active status parts with full -65°C to 150°C operating range matching the original specification.

For Applications with Reduced Power Requirements (≤250 mW):

Group A parts (BZX84-A20,215, BZX84-B20,215, BZX84-B20,235, BZX84-C20,215, BZX84-C20,235) are suitable when circuit analysis confirms power dissipation does not exceed 250 mW. These Nexperia parts carry AEC-Q101 automotive qualification, providing enhanced reliability documentation. BZX84-A20,215 offers the tightest tolerance (±1%) for precision voltage regulation applications.

Compliance and Regulatory Considerations:

All substitute parts listed maintain RoHS3 compliance status matching the original CMPZ5250B TR PBFREE. Moisture sensitivity level remains MSL 1 (Unlimited) across all substitutes. REACH status is unaffected for all listed parts. Automotive-grade AEC-Q101 qualified parts (Nexperia BZX84 series and Vishay BZX84C20-HE3-08) are available for applications requiring automotive qualification, though the original part does not carry this certification.

Temperature Range Considerations:

Vishay parts (BZX84B20-E3-08, BZX84C20-E3-08, BZX84C20-HE3-08) operate from -55°C to 150°C, which is 10°C narrower at the low end compared to the original -65°C to 150°C range. This limitation is acceptable for applications not requiring operation below -55°C.

Packaging and Inventory:

All substitute parts are packaged in SOT-23-3 (TO-236-3, SC-59) format, ensuring direct physical compatibility with the original CMPZ5250B TR PBFREE. Tape & Reel packaging is available for all active status parts, supporting automated assembly processes.

Frequently Asked Questions (FAQ)

Q1: Can I use a 250 mW rated substitute (Group A) in place of the 350 mW CMPZ5250B TR PBFREE?

A: Yes, provided circuit analysis confirms that actual power dissipation in the Zener diode does not exceed 250 mW under worst-case operating conditions (maximum input voltage, minimum load resistance). The 250 mW rating represents the maximum safe dissipation limit; operation below this threshold is acceptable. If circuit design requires the full 350 mW capability, use Group B parts (300 mW) or confirm the original part remains available.

Q2: What is the difference between BZX84-A20, BZX84-B20, and BZX84-C20 series?

A: The primary difference is voltage tolerance: BZX84-A20 offers ±1% tolerance (tightest), BZX84-B20 offers ±2% tolerance (medium), and BZX84-C20 offers ±5% or ±6% tolerance (loosest, matching the original CMPZ5250B). All three series have identical 20 V nominal Zener voltage, 250 mW power rating, and SOT-23-3 package. Select based on voltage accuracy requirements of the application.

Q3: Are Nexperia BZX84 parts with AEC-Q101 qualification required for my application?

A: AEC-Q101 automotive qualification is required only if the application is automotive-grade or demands automotive-level reliability documentation. The original CMPZ5250B TR PBFREE does not carry AEC-Q101 certification. For non-automotive applications, AEC-Q101 qualified parts are acceptable but not necessary. Nexperia parts provide this certification as an added benefit without additional cost in most cases.

Q4: Can I substitute BZX84C20-HE3-08 (Obsolete status) for the CMPZ5250B TR PBFREE?

A: BZX84C20-HE3-08 is listed as Obsolete product status, indicating it is no longer in active production. While electrical parameters are compatible, obsolete parts carry supply risk and should be avoided for new designs or long-term production. Use Active status alternatives: BZX84C20-7-F or BZX84C20-E3-08 instead.

Q5: What is the significance of impedance (Zzt) differences between 25 Ohms (original) and 55 Ohms (substitutes)?

A: Impedance affects the Zener diode's dynamic response to load current changes. Lower impedance (25 Ohms) provides faster voltage regulation with smaller voltage ripple. Higher impedance (55 Ohms) results in slightly slower response but remains acceptable for most applications. If circuit design is sensitive to voltage ripple or transient response, confirm that 55 Ohms impedance meets performance requirements before substitution.

Q6: Are all substitute parts available in Tape & Reel packaging for automated assembly?

A: Yes, all Active status substitute parts are available in Tape & Reel (TR) packaging suitable for automated pick-and-place assembly. BZX84C20-HE3-08 (Obsolete) is available in Cut Tape (CT) & Digi-Reel format. Verify packaging format with supplier before procurement to ensure compatibility with assembly equipment.

Q7: Can I use a substitute with ±6% tolerance (BZX84C20-7-F) instead of ±5% tolerance (CMPZ5250B TR PBFREE)?

A: No, ±6% tolerance is looser (wider acceptable voltage range) than ±5%. At 20 V nominal: ±5% tolerance = 19 V to 21 V acceptable range; ±6% tolerance = 18.8 V to 21.2 V acceptable range. If circuit design requires ±5% or tighter tolerance, use BZX84-A20,215 (±1%), BZX84-B20 series (±2%), or BZX84-C20 series (±5%). Avoid BZX84C20-7-F (±6%) for precision applications.

Q8: What is the difference between BZX84-B20,215 and BZX84-B20,235?

A: Both parts are electrically identical: 20 V nominal, ±2% tolerance, 250 mW power rating, SOT-23-3 package. The suffix ",215" and ",235" represent different supplier device package designations or tape reel specifications from Nexperia. From an engineering perspective, they are interchangeable. Inventory availability may differ; select based on supplier stock and lead time.

Q9: Is the operating temperature range -55°C to 150°C (Vishay parts) acceptable for my application?

A: The Vishay parts (BZX84B20-E3-08, BZX84C20-E3-08, BZX84C20-HE3-08) have a -55°C minimum operating temperature, which is 10°C higher than the original CMPZ5250B TR PBFREE (-65°C minimum). This is acceptable only if your application does not require operation below -55°C. For applications requiring -65°C operation, use Diodes Incorporated parts (BZX84B20-7-F, BZX84C20-7-F) or Nexperia parts (BZX84-A20,215, BZX84-B20 series, BZX84-C20,215, BZX84-C20,235), which all support -65°C to 150°C range.

Q10: Which substitute part offers the best overall compatibility with CMPZ5250B TR PBFREE?

A: BZX84C20-7-F from Diodes Incorporated provides the closest overall match: 20 V nominal voltage, ±5% tolerance (matching original), 300 mW power rating (exceeding 350 mW requirement with acceptable margin), SOT-23-3 package, -65°C to 150°C operating range, Active status, and RoHS3 compliance. This part is recommended as the primary substitute when the original CMPZ5250B TR PBFREE is unavailable.

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