CMPZ5251B TR PBFREE Zener Diode 22V 350mW Equivalent & Substitute Parts

Part Overview

The CMPZ5251B TR PBFREE is a surface mount zener diode manufactured by Central Semiconductor Corp, rated at 22 V nominal zener voltage with 350 mW maximum power dissipation. This component operates across the temperature range of -65°C to 150°C and is packaged in SOT-23 (TO-236-3) configuration. The part maintains Active product status and carries ROHS3 compliance with unlimited moisture sensitivity level (MSL 1).

Equivalent and substitute parts are identified based on matching electrical specifications: 22 V zener voltage, compatible power ratings, surface mount SOT-23 packaging, and overlapping operating temperature ranges. Substitutes are selected where core electrical parameters align within acceptable engineering tolerances.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	22	V
Tolerance	±5%	—
Power - Max	350	mW
Impedance (Max)	29	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 17 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	—
MSL	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution logic for the CMPZ5251B TR PBFREE is based on the following critical parameters:

Primary Matching Criteria:

Zener voltage: 22 V nominal
Package type: SOT-23-3 / TO-236-3 / SC-59 (surface mount, identical footprint)
Operating temperature range: -65°C to 150°C minimum
RoHS3 compliance and MSL 1 rating

Secondary Compatibility Factors:

Power dissipation: 225 mW to 350 mW acceptable (all substitutes rated 225–300 mW)
Voltage tolerance: ±2% to ±6% (original part ±5%)
Impedance: 29–55 Ohms (original part 29 Ohms)
Reverse leakage current: 50–100 nA within specified voltage conditions

All identified substitute parts meet the primary matching criteria. Variations in power rating, impedance, and tolerance reflect different manufacturer specifications while maintaining functional equivalence for 22 V zener applications in SOT-23 packaging.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Vf (Max) @ If	Temp Range	Package	RoHS
CMPZ5251B TR PBFREE	Central Semiconductor Corp	22 V	±5%	350 mW	29 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3
BZX84-B22,215	Nexperia USA Inc.	22 V	±2%	250 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	TO-236AB	ROHS3
BZX84-B22,235	Nexperia USA Inc.	22 V	±2%	250 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	TO-236AB	ROHS3
BZX84-C22,215	Nexperia USA Inc.	22 V	±5%	250 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	TO-236AB	ROHS3
BZX84-C22,235	NXP USA Inc.	22 V	±5%	250 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23	ROHS3
BZX84B22-E3-08	Vishay General Semiconductor	22 V	±2%	300 mW	55 Ω	900 mV @ 10 mA	-55 to 150°C	SOT-23-3	ROHS3
BZX84B22LT1G	onsemi	22 V	±2%	225 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3
BZX84C22-7-F	Diodes Incorporated	22 V	±6%	300 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3
DDZX22D-7	Diodes Incorporated	22 V	±3%	300 mW	30 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3
MMBZ5251BLT1G	onsemi	22 V	±5%	225 mW	29 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3
SZBZX84B22LT1G	onsemi	22 V	±2%	225 mW	55 Ω	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	ROHS3

Engineering Selection Recommendations

All substitute parts listed maintain Active product status and ROHS3 compliance, meeting baseline regulatory requirements. Selection among substitutes depends on application-specific power dissipation requirements and tolerance specifications.

For applications requiring maximum power handling: BZX84B22-E3-08 (300 mW) and BZX84C22-7-F (300 mW) provide higher power ratings than the original 350 mW specification but remain suitable for most 22 V zener applications. DDZX22D-7 offers comparable 300 mW rating with impedance matching the original part (30 Ω).

For applications requiring tighter voltage tolerance: BZX84-B22,215, BZX84-B22,235, BZX84B22LT1G, and SZBZX84B22LT1G all specify ±2% tolerance, superior to the original ±5% specification. These parts are qualified to AEC-Q101 automotive standards where applicable.

For impedance-critical applications: MMBZ5251BLT1G and DDZX22D-7 maintain impedance at 29–30 Ω, matching the original part's 29 Ω specification. Other substitutes specify 55 Ω impedance.

For lower power applications: BZX84B22LT1G, MMBZ5251BLT1G, and SZBZX84B22LT1G all rated at 225 mW are suitable where power dissipation is constrained.

All substitutes operate across the -65°C to 150°C temperature range, with BZX84B22-E3-08 limited to -55°C minimum. Forward voltage characteristics (900 mV @ 10 mA) are uniform across all parts.

Frequently Asked Questions (FAQ)

Q: Can I substitute CMPZ5251B TR PBFREE with any of the listed parts in a 22 V zener application?

A: Yes, all listed parts are electrically equivalent for 22 V zener applications. All maintain 22 V nominal zener voltage, SOT-23-3 surface mount packaging, and -65°C to 150°C operating range. Verify that your application can tolerate the specific power rating and impedance of the selected substitute.

Q: What is the difference between BZX84-B22,215 and BZX84-C22,215?

A: Both parts are manufactured by Nexperia and rated at 22 V with 250 mW power dissipation in TO-236AB packaging. The primary difference is voltage tolerance: BZX84-B22,215 specifies ±2% tolerance, while BZX84-C22,215 specifies ±5% tolerance, matching the original CMPZ5251B part. Both are AEC-Q101 qualified.

Q: Why do some substitutes have lower power ratings (225–250 mW) than the original 350 mW?

A: Different manufacturers optimize zener diode designs for various applications. Lower power ratings remain suitable for circuits where the zener dissipates less than 225 mW. If your application requires the full 350 mW dissipation capability, select BZX84B22-E3-08 or BZX84C22-7-F (both 300 mW) as the closest alternatives.

Q: Are all substitutes RoHS3 compliant?

A: Yes, all listed substitute parts carry ROHS3 compliance certification and MSL 1 (Unlimited) moisture sensitivity rating, matching the original part's environmental specifications.

Q: What does impedance (Zzt) mean, and why does it vary among substitutes?

A: Impedance (Zzt) is the dynamic impedance of the zener diode at the test current. The original CMPZ5251B specifies 29 Ω. Most substitutes specify 55 Ω, while DDZX22D-7 and MMBZ5251BLT1G match at 29–30 Ω. Lower impedance provides better voltage regulation in dynamic conditions. Select impedance-matched parts (29–30 Ω) for noise-sensitive applications.

Q: Can I use BZX84B22-E3-08 if my circuit operates at -65°C?

A: BZX84B22-E3-08 is rated for -55°C to 150°C operation. If your application requires -65°C minimum temperature, select alternative substitutes with -65°C minimum rating: BZX84-B22,215, BZX84-B22,235, BZX84-C22,215, BZX84-C22,235, BZX84B22LT1G, BZX84C22-7-F, DDZX22D-7, MMBZ5251BLT1G, or SZBZX84B22LT1G.

Q: What is the difference between tape & reel (TR) and bulk packaging?

A: Tape & Reel packaging is supplied on continuous carrier tape suitable for automated assembly equipment. Bulk packaging is supplied loose. BZX84-C22,235 from NXP USA Inc. is available in bulk packaging, while most other substitutes are supplied in tape & reel format. Verify packaging compatibility with your assembly process.

Q: Are onsemi parts (BZX84B22LT1G, MMBZ5251BLT1G, SZBZX84B22LT1G) interchangeable with each other?

A: All three onsemi parts are 22 V zener diodes in SOT-23-3 packaging with -65°C to 150°C operation. BZX84B22LT1G and SZBZX84B22LT1G both specify ±2% tolerance and 225 mW power, with SZBZX84B22LT1G carrying AEC-Q101 automotive qualification. MMBZ5251BLT1G specifies ±5% tolerance and 29 Ω impedance. Select based on tolerance and impedance requirements.

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