MMBZ5256B-TP Zener Diode Equivalent & Substitute Parts

Part Overview

The MMBZ5256B-TP is a 30 V, 350 mW surface mount zener diode manufactured by Micro Commercial Co in SOT-23 packaging. This component is classified as Active and is ROHS3 compliant. Equivalent and substitute parts are identified based on matching electrical specifications, package compatibility, and regulatory compliance. Alternative part numbers are necessary when the primary part experiences supply constraints, when different packaging formats are required for manufacturing processes, or when alternative manufacturers provide identical electrical performance within specified tolerances.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	30	V
Tolerance	±5	%
Power - Maximum	350	mW
Impedance (Maximum)	49	Ohms
Current - Reverse Leakage @ 23 V	100	nA
Voltage - Forward (Maximum) @ 10 mA	900	mV
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount
Package / Case	SOT-23-3

Substitute Part Grouping Explanation

Substitution of the MMBZ5256B-TP is determined by the following critical parameters:

Electrical Equivalence Criteria:

Zener voltage: 30 V nominal with ±5% tolerance
Maximum power dissipation: 350 mW or greater
Impedance (maximum): 49 Ohms
Reverse leakage current: 100 nA @ 23 V
Forward voltage: 900 mV maximum @ 10 mA

Package Compatibility:

Primary package: SOT-23-3 (TO-236-3, SC-59)
Alternative package: SOT-323 (SC-70) for space-constrained applications with reduced power rating

Regulatory Compliance:

ROHS3 compliant
REACH unaffected
ECCN: EAR99

Parts are grouped into two categories: Upgrade Substitutes (identical electrical specifications with enhanced operating temperature range) and Similar Substitutes (same zener voltage and tolerance with different package and power rating).

Parameter Comparison

Parameter	MMBZ5256B-TP (Main)	MMBZ5256B-7-F (Upgrade)	MMBZ5256BW-7-F (Similar)
Manufacturer	Micro Commercial Co	Diodes Incorporated	Diodes Incorporated
Voltage - Zener (Nominal)	30 V	30 V	30 V
Tolerance	±5%	±5%	±5%
Power - Maximum	350 mW	350 mW	200 mW
Impedance (Maximum)	49 Ohms	49 Ohms	49 Ohms
Current - Reverse Leakage @ 23 V	100 nA	100 nA	100 nA
Voltage - Forward (Maximum) @ 10 mA	900 mV	900 mV	900 mV
Operating Temperature Range	-55 to 150°C	-65 to 150°C	-65 to 150°C
Package / Case	SOT-23-3	SOT-23-3	SOT-323
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

MMBZ5256B-7-F (Upgrade Substitute): This part is a direct electrical equivalent with identical power rating (350 mW) and impedance specifications. The operating temperature range extends to -65°C, providing enhanced low-temperature performance compared to the main part. Both parts use SOT-23-3 packaging, ensuring mechanical and thermal compatibility. ROHS3 compliance and REACH unaffected status match the original specification. This substitute is suitable for applications requiring identical electrical performance with extended temperature capability.

MMBZ5256BW-7-F (Similar Substitute): This part maintains the same zener voltage (30 V), tolerance (±5%), and impedance (49 Ohms) as the main part. The maximum power rating is reduced to 200 mW, requiring circuit design verification for applications operating at the upper power limits of the original specification. The package format changes to SOT-323 (SC-70), which is physically smaller and suitable for space-constrained PCB layouts. Operating temperature range extends to -65°C. ROHS3 compliance and REACH unaffected status are maintained. This substitute is applicable only when power dissipation does not exceed 200 mW and when SOT-323 package dimensions are compatible with the target application.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5256B-7-F be used as a direct replacement for MMBZ5256B-TP?

A: Yes. Both parts have identical zener voltage (30 V), tolerance (±5%), power rating (350 mW), impedance (49 Ohms), and forward voltage specifications. Both use SOT-23-3 packaging. The MMBZ5256B-7-F offers an extended operating temperature range (-65°C to 150°C versus -55°C to 150°C). Regulatory compliance is equivalent.

Q: When should MMBZ5256BW-7-F be selected instead of MMBZ5256B-TP?

A: MMBZ5256BW-7-F should be selected when PCB space constraints require the smaller SOT-323 package and when the circuit design operates with maximum power dissipation not exceeding 200 mW. The zener voltage and tolerance remain identical. Verify that the reduced power rating is compatible with the application before selection.

Q: Are there package compatibility issues between SOT-23-3 and SOT-323?

A: Yes. SOT-23-3 and SOT-323 are different package formats with different footprints, pin spacing, and thermal characteristics. SOT-323 is physically smaller. PCB layout and thermal design must be verified for compatibility. These packages are not interchangeable without PCB redesign.

Q: Do all substitute parts meet the same regulatory requirements?

A: Yes. MMBZ5256B-TP, MMBZ5256B-7-F, and MMBZ5256BW-7-F are all ROHS3 compliant and REACH unaffected. ECCN classification (EAR99) and HTSUS code (8541.10.0050) are identical across all parts.

Q: What is the impact of the extended temperature range in MMBZ5256B-7-F?

A: MMBZ5256B-7-F operates from -65°C to 150°C, compared to -55°C to 150°C for MMBZ5256B-TP. The extended low-temperature capability provides additional margin for applications operating in cold environments. This does not affect high-temperature performance, which remains identical at 150°C maximum.

Q: Can MMBZ5256BW-7-F handle the same power dissipation as the main part?

A: No. MMBZ5256BW-7-F has a maximum power rating of 200 mW, while MMBZ5256B-TP is rated for 350 mW. Applications requiring sustained power dissipation above 200 mW must use MMBZ5256B-TP or MMBZ5256B-7-F. Exceeding the 200 mW limit in MMBZ5256BW-7-F will result in component failure.

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