CMPZ5240B BK PBFREE Zener Diode Equivalent & Substitute Parts

Part Overview

The CMPZ5240B BK PBFREE is a 10 V, 350 mW surface mount zener diode manufactured by Central Semiconductor Corp in SOT-23 packaging. This component is classified as Active product status with full RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage circuits in electronic equipment. Substitute parts are identified based on matching electrical characteristics and mechanical compatibility within the SOT-23 package family.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	10	V
Tolerance	±5%	—
Power - Max	350	mW
Impedance (Max)	17	Ohms
Current - Reverse Leakage @ Vr	3	µA @ 8 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature Range	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
RoHS Status	ROHS3 Compliant	—
MSL Rating	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the CMPZ5240B BK PBFREE is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage: 10 V nominal
Power dissipation: minimum 300 mW (substitute parts rated 250 mW or higher are acceptable for most applications)
Tolerance: ±5% or tighter
Forward voltage: 900 mV maximum @ 10 mA
Reverse leakage: 200 nA or lower @ 7 V (lower leakage is acceptable)
Operating temperature: -55°C to 150°C minimum

Mechanical Compatibility Requirements:

Package: SOT-23-3 or TO-236-3 (pin-compatible)
Mounting: Surface Mount
MSL Rating: 1 (Unlimited)

Compliance Requirements:

RoHS3 Compliant
REACH Unaffected status

Substitute parts are grouped into two categories: Direct Electrical Equivalents (matching 350 mW power rating and ±5% tolerance) and Functional Alternatives (250–300 mW power rating with equal or tighter tolerance). All listed substitutes maintain identical zener voltage, package compatibility, and regulatory compliance.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Vr Leakage	Vf (Max)	Temp Range	Package	Status
CMPZ5240B BK PBFREE	Central Semiconductor	10 V	±5%	350 mW	17 Ω	3 µA @ 8 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
MMBZ5240B-7-F	Diodes Incorporated	10 V	±5%	350 mW	17 Ω	3 µA @ 8 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84-A10,215	Nexperia USA Inc.	10 V	±1%	250 mW	20 Ω	200 nA @ 7 V	900 mV @ 10 mA	-65 to 150°C	TO-236AB	Active
BZX84-C10,215	NXP USA Inc.	10 V	±5%	250 mW	20 Ω	200 nA @ 7 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Active
BZX84-C10,235	Nexperia USA Inc.	10 V	±5%	250 mW	20 Ω	200 nA @ 7 V	900 mV @ 10 mA	-65 to 150°C	TO-236AB	Active
BZX84B10-7-F	Diodes Incorporated	10 V	±2%	300 mW	20 Ω	200 nA @ 7 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84B10-E3-08	Vishay General Semiconductor	10 V	±2%	300 mW	20 Ω	200 nA @ 7 V	—	-55 to 150°C	SOT-23-3	Active
BZX84B10-HE3-08	Vishay General Semiconductor	10 V	±2%	300 mW	20 Ω	200 nA @ 7 V	—	-55 to 150°C	SOT-23-3	Obsolete
BZX84C10-7-F	Diodes Incorporated	10 V	±6%	300 mW	20 Ω	200 nA @ 7 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84C10-E3-08	Vishay General Semiconductor	10 V	±5%	300 mW	20 Ω	200 nA @ 7 V	—	-55 to 150°C	SOT-23-3	Active
BZX84C10-G3-08	Vishay General Semiconductor	10 V	±5%	300 mW	20 Ω	200 nA @ 7 V	—	-55 to 150°C	SOT-23-3	Active

Engineering Selection Recommendations

Direct Equivalent (Preferred for Drop-In Replacement):

MMBZ5240B-7-F from Diodes Incorporated is the primary direct substitute. It matches all electrical parameters of the CMPZ5240B BK PBFREE: 10 V nominal zener voltage, ±5% tolerance, 350 mW power rating, 17 Ω maximum impedance, and identical forward voltage characteristics. Both components share SOT-23-3 package compatibility, -65°C to 150°C operating range, RoHS3 compliance, and MSL 1 rating. This part is Active status with 2006 units in stock.

Functional Alternatives (250–300 mW Power Rating):

The following parts provide functional substitution with reduced power dissipation capacity:

BZX84B10-7-F (Diodes Incorporated): 300 mW, ±2% tolerance, Active status, 5679 units in stock
BZX84C10-7-F (Diodes Incorporated): 300 mW, ±6% tolerance, Active status, 62400 units in stock
BZX84C10-E3-08 (Vishay): 300 mW, ±5% tolerance, Active status, 38253 units in stock
BZX84C10-G3-08 (Vishay): 300 mW, ±5% tolerance, Active status, 15360 units in stock
BZX84-C10,215 (NXP USA Inc.): 250 mW, ±5% tolerance, Active status, 3590 units in stock
BZX84-C10,235 (Nexperia USA Inc.): 250 mW, ±5% tolerance, Active status, 21519 units in stock
BZX84-A10,215 (Nexperia USA Inc.): 250 mW, ±1% tolerance, Active status, 17509 units in stock

All functional alternatives maintain 10 V zener voltage, SOT-23 package compatibility, RoHS3 compliance, and MSL 1 rating. Reduced power ratings are suitable for applications where the full 350 mW dissipation is not required.

Obsolete Part Notice:

BZX84B10-HE3-08 (Vishay) is marked Obsolete status and should not be selected for new designs, despite electrical compatibility.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5240B-7-F replace CMPZ5240B BK PBFREE in all applications?

A: Yes. MMBZ5240B-7-F is a direct electrical and mechanical equivalent with identical zener voltage (10 V), tolerance (±5%), power rating (350 mW), impedance (17 Ω), and package (SOT-23-3). Both components meet RoHS3 compliance and MSL 1 requirements.

Q: What is the difference between 350 mW and 300 mW zener diodes?

A: Power rating indicates maximum continuous power dissipation. A 350 mW part can dissipate more heat than a 300 mW part. In applications requiring full 350 mW dissipation, use MMBZ5240B-7-F. For lower-power circuits, 300 mW alternatives (BZX84B10-7-F, BZX84C10-7-F, BZX84C10-E3-08, BZX84C10-G3-08) are acceptable.

Q: Are TO-236AB and SOT-23-3 packages interchangeable?

A: Yes. TO-236-3, SC-59, and SOT-23-3 are equivalent package designations for the same three-pin surface mount form factor. All listed substitutes use this package family and are mechanically compatible.

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

A: Tolerance specifies the allowable deviation from nominal zener voltage. ±1% tolerance (BZX84-A10,215) provides tighter voltage regulation than ±5% (CMPZ5240B BK PBFREE, MMBZ5240B-7-F). Tighter tolerance is suitable for precision voltage reference applications.

Q: Why do some substitutes show lower reverse leakage current (200 nA vs. 3 µA)?

A: Lower reverse leakage indicates reduced off-state current. This is a performance improvement and does not prevent substitution. Parts with 200 nA leakage are suitable replacements for parts specified at 3 µA.

Q: Can I use BZX84B10-HE3-08 as a substitute?

A: No. BZX84B10-HE3-08 is marked Obsolete status. Use Active status alternatives such as BZX84B10-E3-08 or BZX84C10-E3-08 instead.

Q: What is the significance of RoHS3 compliance?

A: RoHS3 compliance certifies that the component contains no restricted hazardous substances (lead, cadmium, mercury, etc.) and meets environmental regulations for electronic equipment. All listed substitutes maintain RoHS3 compliance.

Q: Does operating temperature range affect substitution?

A: The CMPZ5240B BK PBFREE operates -65°C to 150°C. Most substitutes match this range. BZX84B10-E3-08, BZX84B10-HE3-08, BZX84C10-E3-08, and BZX84C10-G3-08 operate -55°C to 150°C (narrower low-temperature range). These are suitable for applications not requiring operation below -55°C.

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