CMPZ5259B BK PBFREE Zener Diode 39V 350mW Equivalent & Substitute Parts

Part Overview

The CMPZ5259B BK PBFREE is a 39 V Zener diode manufactured by Central Semiconductor Corp, rated for 350 mW power dissipation with ±5% voltage tolerance. This surface mount component in SOT-23 packaging is classified as Active product status. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to inventory constraints, manufacturing discontinuation, or design flexibility needs.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	39	V
Tolerance	±5%	-
Power - Max	350	mW
Impedance (Max)	80	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 30 V	-
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA	-
Operating Temperature	-65°C to 150°C	-
Mounting Type	Surface Mount	-
Package / Case	TO-236-3, SC-59, SOT-23-3	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following critical parameters:

Primary Criteria (Must Match):

Zener voltage: 39 V nominal
Package / Case: TO-236-3, SC-59, SOT-23-3 (mechanical compatibility)
Mounting type: Surface Mount
Operating temperature range: -65°C to 150°C minimum
RoHS3 compliance

Secondary Criteria (Allowable Variation):

Tolerance: ±1% to ±5% (tighter tolerance acceptable)
Power rating: 225 mW to 350 mW (lower power acceptable if application permits)
Impedance: 80 to 130 Ohms (within specified range)
Reverse leakage current: 50 to 100 nA (within specified range)

Parts are grouped by power rating capability and impedance characteristics. Higher power-rated substitutes (300 mW, 350 mW) provide direct replacement capability. Lower power-rated substitutes (225 mW, 250 mW) are acceptable where thermal design margins exist.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Reverse Leakage @ Vr	Vf (Max) @ If	Temp Range	Package	RoHS3
CMPZ5259B BK PBFREE	Central Semiconductor Corp	39	±5%	350	80	100 nA @ 30 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Yes
BZX84-A39,215	NXP USA Inc.	39	±1%	250	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Yes
BZX84-B39,215	Nexperia USA Inc.	39	±2%	250	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Yes
BZX84-C39,215	Nexperia USA Inc.	39	±5%	250	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Yes
BZX84-C39,235	NXP USA Inc.	39	±5%	250	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Yes
BZX84C39-7-F	Diodes Incorporated	39	±5%	300	130	100 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Yes
BZX84C39-E3-08	Vishay General Semiconductor	39	±5%	300	130	50 nA @ 27.3 V	-	-55 to 150°C	SOT-23-3	Yes
BZX84C39LT1G	onsemi	39	±5%	225	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Yes
MMBZ5259B-7-F	Diodes Incorporated	39	±5%	350	80	100 nA @ 30 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Yes
MMBZ5259BLT1G	onsemi	39	±5%	225	80	100 nA @ 30 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Yes
SZBZX84C39ET1G	onsemi	39	±5%	225	130	50 nA @ 27.3 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Yes

Engineering Selection Recommendations

Direct Replacement (Identical Electrical & Mechanical Specifications):

MMBZ5259B-7-F (Diodes Incorporated) provides direct substitution with matching 39 V nominal voltage, 350 mW power rating, 80 Ohm impedance, and 100 nA reverse leakage current. All parameters align with the original CMPZ5259B BK PBFREE. RoHS3 compliance and -65°C to 150°C operating range are maintained.

High-Compatibility Substitutes (Equivalent Performance, Minor Parameter Variation):

BZX84C39-7-F (Diodes Incorporated) and BZX84C39-E3-08 (Vishay General Semiconductor) both provide 300 mW power rating with 39 V nominal voltage and SOT-23-3 packaging. Impedance increases to 130 Ohms, which remains within acceptable range. These parts support applications where 300 mW dissipation capacity is sufficient.

Automotive-Grade Alternatives (AEC-Q101 Qualified):

BZX84-A39,215 (NXP USA Inc.), BZX84-B39,215 (Nexperia USA Inc.), BZX84-C39,215 (Nexperia USA Inc.), and SZBZX84C39ET1G (onsemi) carry AEC-Q101 automotive qualification. These parts are suitable for automotive and high-reliability applications. Power ratings range from 225 mW to 250 mW; verify thermal design margins before selection.

Lower Power-Rated Alternatives (Reduced Thermal Load):

BZX84C39LT1G (onsemi), MMBZ5259BLT1G (onsemi), and SZBZX84C39ET1G (onsemi) provide 225 mW power rating. These parts are acceptable where circuit design permits reduced power dissipation capability. All maintain 39 V nominal voltage and SOT-23-3 packaging.

Tighter Tolerance Option:

BZX84-A39,215 (NXP USA Inc.) offers ±1% voltage tolerance compared to ±5% of the original part. This option is suitable for precision voltage regulation applications requiring tighter zener voltage control.

All listed substitutes maintain RoHS3 compliance, -65°C to 150°C operating temperature range (except BZX84C39-E3-08 with -55°C minimum), and SOT-23 or SOT-23-3 surface mount packaging compatible with TO-236-3 and SC-59 designations.

Frequently Asked Questions (FAQ)

Q: Can BZX84C39-7-F replace CMPZ5259B BK PBFREE in all applications?

A: BZX84C39-7-F is compatible for direct substitution in applications where 300 mW power dissipation is acceptable. The 39 V nominal voltage, ±5% tolerance, SOT-23-3 package, and -65°C to 150°C operating range match the original specification. Impedance increases from 80 Ohms to 130 Ohms; verify circuit design permits this variation.

Q: What is the difference between 225 mW and 350 mW rated parts?

A: Power rating indicates maximum continuous power dissipation capability. The 350 mW original part (CMPZ5259B BK PBFREE) dissipates more heat than 225 mW alternatives. Lower-rated parts are acceptable only if circuit design ensures power dissipation remains below the substitute part's rating. Thermal analysis is required before substituting to lower power ratings.

Q: Are automotive-qualified parts (AEC-Q101) interchangeable with non-automotive parts?

A: Automotive-qualified parts (BZX84-A39,215, BZX84-B39,215, BZX84-C39,215, SZBZX84C39ET1G) meet additional reliability and qualification standards. These parts are suitable for both automotive and general industrial applications. Non-automotive parts may be used in automotive designs only if application requirements do not mandate AEC-Q101 qualification.

Q: What does ±1% tolerance mean compared to ±5%?

A: Tolerance specifies the allowable deviation from nominal zener voltage. BZX84-A39,215 with ±1% tolerance maintains zener voltage within 38.61 V to 39.39 V. CMPZ5259B BK PBFREE with ±5% tolerance allows 37.05 V to 40.95 V. Tighter tolerance (±1%) provides more precise voltage regulation; select based on circuit voltage accuracy requirements.

Q: Are all substitute parts available in the same packaging?

A: All substitute parts use SOT-23 or SOT-23-3 surface mount packaging, which are mechanically compatible with TO-236-3 and SC-59 designations. Supplier device package designations may vary (SOT-23 vs. SOT-23-3), but physical dimensions and PCB footprints are identical. Verify with component datasheet if custom footprint requirements exist.

Q: Can MMBZ5259BLT1G (225 mW) be used instead of CMPZ5259B BK PBFREE (350 mW)?

A: MMBZ5259BLT1G is acceptable only if circuit design ensures total power dissipation does not exceed 225 mW. The 39 V nominal voltage, ±5% tolerance, 80 Ohm impedance, and 100 nA reverse leakage current match the original part. Thermal margin analysis is mandatory before substitution to lower power ratings.

Q: What is impedance (Zzt) and why does it vary between parts?

A: Impedance (Zzt) represents dynamic resistance of the zener diode at specified operating conditions. Lower impedance (80 Ohms) provides better voltage regulation with load current changes. Higher impedance (130 Ohms) results in slightly greater voltage variation. Both values are acceptable for general zener regulation; select based on circuit voltage stability requirements.

Q: Are all parts RoHS3 compliant?

A: All listed substitute parts are RoHS3 compliant. The original CMPZ5259B BK PBFREE is also RoHS3 compliant. RoHS3 compliance ensures lead-free construction and compliance with hazardous substance restrictions. No additional environmental qualification is required for substitution.

Q: What is the difference between Bulk and Tape & Reel packaging?

A: Bulk packaging contains loose components suitable for manual assembly or small-volume applications. Tape & Reel packaging contains components on continuous tape for automated pick-and-place assembly. Both packaging types contain identical components; selection depends on assembly process requirements. Electrical and mechanical specifications remain unchanged.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message