MMSZ5255B-TP Zener Diode 28V 500mW Equivalent & Substitute Parts

Part Overview

The MMSZ5255B-TP is a 28 V, 500 mW surface mount zener diode manufactured by Micro Commercial Co in SOD-123 package. This component is classified as Active and maintains full RoHS3 compliance. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage circuits across industrial and commercial applications. Equivalent and substitute parts are identified to support design flexibility, supply chain continuity, and application-specific performance requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	28	V
Power - Maximum	500	mW
Tolerance	±5%	—
Impedance (Maximum)	44	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 21 V
Voltage - Forward (Maximum) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-123	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of zener diodes is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Zener voltage (Vz): 28 V nominal
Maximum power dissipation: 500 mW
Package type: SOD-123 surface mount
Mounting compatibility: Surface mount technology
Regulatory compliance: RoHS3 and REACH status

Secondary Compatibility Factors:

Tolerance specification (±2%, ±3%, ±5%)
Impedance (Zzt) maximum value
Reverse leakage current characteristics
Forward voltage characteristics
Operating temperature range

Substitute parts are grouped into two categories: Direct Substitutes (identical electrical parameters and tolerance) and Parametric Equivalents (same core specifications with variations in tolerance or impedance within acceptable engineering margins).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Reverse Leakage (nA)	Vf Max (mV)	Temp Range (°C)	Inventory (Pcs)
MMSZ5255B-TP	Micro Commercial Co	28	±5%	500	44	100 @ 21 V	900 @ 10 mA	-55 to 150	1,139
DDZ28-7	Diodes Incorporated	28	±3%	500	55	50 @ 23 V	900 @ 10 mA	-65 to 150	3,400
MMSZ5255B-7-F	Diodes Incorporated	28	±5%	500	44	100 @ 21 V	900 @ 10 mA	-65 to 150	8,950
MMSZ5255BT1G	onsemi	28	±5%	500	44	100 @ 21 V	900 @ 10 mA	-55 to 150	35,300
MMSZ5255C-E3-08	Vishay General Semiconductor - Diodes Division	28	±2%	500	44	100 @ 21 V	—	-55 to 150	14,827
SZMMSZ5255BT1G	onsemi	28	±5%	500	44	100 @ 21 V	900 @ 10 mA	-55 to 150	17,100

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical and Mechanical Specifications):

MMSZ5255B-7-F (Diodes Incorporated) is a direct substitute for MMSZ5255B-TP. Both components share identical zener voltage, power rating, tolerance, impedance, and forward voltage characteristics. MMSZ5255B-7-F provides an extended lower operating temperature limit (-65°C versus -55°C) and higher inventory availability (8,950 units). This part is suitable for applications requiring the same electrical performance with enhanced low-temperature operation.

Parametric Equivalents (Core Specifications Match with Tolerance or Impedance Variations):

MMSZ5255BT1G (onsemi) is a parametric equivalent with identical electrical performance to MMSZ5255B-TP across all critical parameters. This part offers the highest inventory availability (35,300 units) and is classified under the MMSZ52xxxT1G series. Selection is appropriate for high-volume applications where supply continuity is prioritized.

SZMMSZ5255BT1G (onsemi) is an automotive-grade parametric equivalent qualified to AEC-Q101 standard. This part maintains identical electrical specifications to MMSZ5255B-TP and is designated for automotive and mission-critical applications requiring automotive-level reliability qualification.

MMSZ5255C-E3-08 (Vishay General Semiconductor - Diodes Division) is a parametric equivalent with tighter tolerance specification (±2% versus ±5%). This part is suitable for applications requiring improved voltage accuracy and is available in substantial inventory (14,827 units).

DDZ28-7 (Diodes Incorporated) is a parametric equivalent with improved tolerance (±3%) and lower reverse leakage current (50 nA @ 23 V versus 100 nA @ 21 V). This part provides extended operating temperature range (-65°C to 150°C) and higher impedance (55 Ohms). Selection is appropriate for precision voltage regulation applications requiring lower leakage characteristics.

All substitute parts maintain RoHS3 compliance, REACH unaffected status, and surface mount SOD-123 package compatibility. All parts are classified as Active products.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5255B-TP be replaced with DDZ28-7?

A: Yes. Both components share identical 28 V zener voltage and 500 mW power rating in SOD-123 package. DDZ28-7 offers improved tolerance (±3% versus ±5%) and lower reverse leakage current. The impedance difference (55 Ohms versus 44 Ohms) and extended temperature range (-65°C to 150°C) are within acceptable substitution parameters for most applications.

Q: What is the difference between MMSZ5255BT1G and SZMMSZ5255BT1G?

A: Both parts are manufactured by onsemi and share identical electrical specifications. SZMMSZ5255BT1G is automotive-grade and qualified to AEC-Q101 standard, making it suitable for automotive and safety-critical applications. MMSZ5255BT1G is the commercial-grade equivalent. Selection depends on application requirements and automotive qualification necessity.

Q: Is MMSZ5255C-E3-08 suitable for high-precision voltage reference applications?

A: Yes. MMSZ5255C-E3-08 features ±2% tolerance, which is tighter than the ±5% tolerance of MMSZ5255B-TP. This improved accuracy makes it suitable for applications requiring precise voltage regulation. All other electrical parameters remain equivalent.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain RoHS3 compliance and REACH unaffected status, consistent with MMSZ5255B-TP regulatory requirements.

Q: Can these parts be used interchangeably in PCB designs?

A: Yes. All substitute parts use identical SOD-123 surface mount package and footprint. Direct PCB layout and assembly compatibility is maintained across all listed alternatives without design modification.

Q: Which substitute part offers the best supply availability?

A: MMSZ5255BT1G (onsemi) provides the highest inventory availability at 35,300 units, followed by SZMMSZ5255BT1G at 17,100 units and MMSZ5255C-E3-08 at 14,827 units.

Q: What is the temperature range difference between MMSZ5255B-TP and MMSZ5255B-7-F?

A: MMSZ5255B-TP operates from -55°C to 150°C, while MMSZ5255B-7-F extends the lower limit to -65°C. Both maintain the same 150°C upper limit. MMSZ5255B-7-F is suitable for applications requiring enhanced low-temperature performance.

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