CMPZ5257B TR PBFREE Equivalent & Substitute Parts

Part Overview

The CMPZ5257B TR PBFREE is a 33 V Zener diode manufactured by Central Semiconductor Corp, rated at 350 mW maximum power dissipation in a surface mount SOT-23 package. This component is classified as Active product status and is RoHS3 compliant. Equivalent and substitute parts are identified based on matching electrical specifications (Zener voltage, power rating, tolerance, and thermal characteristics) and compatible package configurations. Substitutes enable design flexibility, supply chain continuity, and alternative sourcing options while maintaining circuit performance within specified operating parameters.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	33	V
Tolerance	±5%	-
Power - Max	350	mW
Impedance (Max)	58	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 25 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature	-65 to 150	°C
Mounting Type	Surface Mount	-
Package / Case	TO-236-3, SC-59, SOT-23-3	-
RoHS Status	ROHS3 Compliant	-
Moisture Sensitivity Level	1 (Unlimited)	-

Substitute Part Grouping Explanation

Substitution logic is based on the following critical parameters that must align with the main part CMPZ5257B TR PBFREE:

Primary Matching Criteria:

Zener voltage: 33 V nominal
Tolerance: ±5% or tighter (±1%, ±2%, ±5%, ±6% acceptable)
Power rating: 350 mW or higher (250 mW, 300 mW, 350 mW acceptable with circuit validation)
Impedance (Zzt): 58 Ohms or 80 Ohms (within acceptable range)
Reverse leakage current: 50 nA to 100 nA @ specified voltage
Forward voltage: 900 mV @ 10 mA
Operating temperature range: -65°C to 150°C or compatible subset
Package compatibility: SOT-23, SOT-23-3, TO-236-3, SC-59, or equivalent surface mount configurations
RoHS3 compliance and MSL rating: 1 (Unlimited)

Secondary Considerations:

Automotive grade and AEC-Q101 qualification (where available, indicates enhanced reliability)
Packaging format: Tape & Reel (TR) preferred for production environments
Manufacturer availability and inventory status

Substitute parts are grouped into two categories: Direct Substitutes (identical or superior electrical specifications with compatible packages) and Functional Equivalents (meet core electrical requirements with minor parameter variations acceptable for most applications).

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Reverse Leakage (nA)	Package	Automotive Grade	Inventory (Pcs)
CMPZ5257B TR PBFREE	Central Semiconductor Corp	33	±5%	350	58	100 @ 25 V	SOT-23	-	678
BZX84-A33,215	NXP USA Inc.	33	±1%	250	80	50 @ 700 mV	SOT-23-3	Yes (AEC-Q101)	6684
BZX84-B33,215	Nexperia USA Inc.	33	±2%	250	80	50 @ 23.1 V	TO-236AB	Yes (AEC-Q101)	12377
BZX84-C33,215	NXP Semiconductors	33	±5%	250	80	50 @ 23.1 V	TO-236AB	Yes (AEC-Q101)	2180
BZX84-C33,235	Nexperia USA Inc.	33	±5%	250	80	50 @ 23.1 V	TO-236AB	Yes (AEC-Q101)	7411
BZX84C33-7-F	Diodes Incorporated	33	±6%	300	80	100 @ 23.1 V	SOT-23-3	-	23100
BZX84C33-E3-08	Vishay General Semiconductor	33	±5%	300	80	50 @ 23.1 V	SOT-23-3	-	14810
BZX84C33-TP	Micro Commercial Co	33	±5%	350	80	100 @ 23.1 V	SOT-23	-	2510
MMBZ5257BLT1G	onsemi	33	±5%	225	58	100 @ 25 V	SOT-23-3	-	17900
MMBZ5257BTS-7-F	Diodes Incorporated	33	±5%	200	58	100 @ 25 V	SOT-363	-	1096
MMBZ5257BW-7-F	Diodes Incorporated	33	±5%	200	58	100 @ 25 V	SOT-323	-	987

Engineering Selection Recommendations

Direct Substitutes (Highest Compatibility):

BZX84C33-TP (Micro Commercial Co) is the closest direct substitute. It matches the CMPZ5257B TR PBFREE in Zener voltage (33 V), tolerance (±5%), power rating (350 mW), impedance (80 Ohms), reverse leakage (100 nA @ 23.1 V), and SOT-23 package configuration. Both components are RoHS3 compliant with MSL rating 1 (Unlimited). This part is suitable for direct replacement in existing designs without circuit modification.

BZX84C33-7-F (Diodes Incorporated) and BZX84C33-E3-08 (Vishay General Semiconductor) are functional equivalents with 300 mW power rating (lower than 350 mW) and 80 Ohms impedance. Both maintain 33 V Zener voltage and ±5% to ±6% tolerance. These parts are acceptable where power dissipation margins permit, with high inventory availability (23,100 and 14,810 units respectively).

Automotive-Grade Alternatives:

BZX84-B33,215 (Nexperia USA Inc.) and BZX84-C33,215 (NXP Semiconductors) offer AEC-Q101 automotive qualification with 33 V Zener voltage and ±2% to ±5% tolerance. Power rating is 250 mW (lower than main part). These parts are suitable for automotive applications requiring enhanced reliability certification. BZX84-B33,215 has superior inventory (12,377 units).

BZX84-A33,215 (NXP USA Inc.) provides the tightest tolerance (±1%) with AEC-Q101 qualification, though power rating is 250 mW. This part is specified where voltage regulation precision is critical.

Lower Power Alternatives:

MMBZ5257BLT1G (onsemi) matches impedance (58 Ohms) and reverse leakage characteristics (100 nA @ 25 V) with 225 mW power rating. Suitable for applications with reduced power dissipation requirements.

MMBZ5257BW-7-F (Diodes Incorporated) and MMBZ5257BTS-7-F (Diodes Incorporated) provide alternative package options (SOT-323 and SOT-363 respectively) with 200 mW power rating. These are specified only where package constraints necessitate alternative form factors.

Selection Criteria Summary:

Standard replacement: BZX84C33-TP
High availability: BZX84C33-7-F
Automotive applications: BZX84-B33,215
Precision voltage regulation: BZX84-A33,215
Space-constrained designs: MMBZ5257BW-7-F (SOT-323) or MMBZ5257BTS-7-F (SOT-363)

All recommended substitutes maintain RoHS3 compliance and MSL rating 1 (Unlimited). Product status is Active for all listed parts.

Frequently Asked Questions (FAQ)

Q1: Can BZX84C33-7-F replace CMPZ5257B TR PBFREE directly?

A: BZX84C33-7-F is a functional equivalent with matching 33 V Zener voltage and ±6% tolerance. The power rating is 300 mW versus 350 mW on the main part. Direct replacement is acceptable if circuit power dissipation does not exceed 300 mW. Verify thermal design margins before substitution.

Q2: What is the difference between BZX84-A33,215, BZX84-B33,215, and BZX84-C33,215?

A: These parts differ in tolerance specification: BZX84-A33,215 is ±1%, BZX84-B33,215 is ±2%, and BZX84-C33,215 is ±5%. All three maintain 33 V Zener voltage and 250 mW power rating. Selection depends on voltage regulation precision requirements. All three carry AEC-Q101 automotive qualification.

Q3: Why is MMBZ5257BW-7-F listed as a substitute if it has lower power rating (200 mW)?

A: MMBZ5257BW-7-F is specified for applications where package form factor (SOT-323) is required due to space constraints. The 200 mW power rating is lower than the main part; this substitute is only applicable where circuit power dissipation is confirmed below 200 mW. Impedance (58 Ohms) and reverse leakage (100 nA @ 25 V) match the main part exactly.

Q4: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts are RoHS3 compliant with Moisture Sensitivity Level 1 (Unlimited). This ensures compatibility with modern manufacturing processes and environmental regulations.

Q5: What is the significance of impedance (Zzt) values of 58 Ohms versus 80 Ohms?

A: Impedance affects dynamic response and voltage regulation characteristics. The main part CMPZ5257B TR PBFREE specifies 58 Ohms. Substitutes with 80 Ohms impedance (BZX84 series) have slightly different transient response but remain functionally equivalent for most applications. Verify impedance requirements in high-frequency or precision regulation circuits before substitution.

Q6: Can I substitute CMPZ5257B TR PBFREE with an automotive-grade part like BZX84-B33,215?

A: Yes. BZX84-B33,215 is a functional equivalent with AEC-Q101 automotive qualification. The 250 mW power rating is lower than the main part's 350 mW. Substitution is acceptable if circuit power dissipation does not exceed 250 mW. Automotive-grade parts offer enhanced reliability certification suitable for demanding environments.

Q7: What does "Tape & Reel (TR)" packaging mean?

A: Tape & Reel packaging indicates components are supplied on continuous carrier tape wound on reels, optimized for automated assembly processes. This format is standard for production environments. Bulk packaging alternatives may be available from some manufacturers.

Q8: Is BZX84C33-TP the best substitute for CMPZ5257B TR PBFREE?

A: BZX84C33-TP is the closest direct substitute, matching power rating (350 mW), Zener voltage (33 V), tolerance (±5%), and package (SOT-23). It is recommended as the primary replacement option. However, BZX84C33-7-F offers superior inventory availability (23,100 units) and is acceptable if power dissipation margins permit 300 mW operation.

Q9: What is the operating temperature range difference between parts?

A: The main part CMPZ5257B TR PBFREE operates from -65°C to 150°C. Most substitutes maintain this range. BZX84C33-E3-08 (Vishay) and BZX84C33-TP (Micro Commercial Co) specify -55°C to 150°C, which is a narrower range. Verify temperature requirements for applications operating below -55°C before substitution.

Q10: Can I use MMBZ5257BTS-7-F (SOT-363 array) as a substitute?

A: MMBZ5257BTS-7-F is a 3-independent Zener diode array in SOT-363 package, not a single diode. This part is only applicable if the circuit design requires multiple independent 33 V Zener diodes in a compact package. It is not a direct substitute for single-diode applications.

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