1N4757AW-TP Zener Diode 51V 1W Equivalent & Substitute Parts

Part Overview

The 1N4757AW-TP is a surface mount Zener diode rated at 51 V nominal voltage with 1 W maximum power dissipation in SOD-123 packaging. Manufactured by Micro Commercial Co, this component is classified as obsolete. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute components maintain the core electrical specifications while offering improved availability and active product support.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	51	V
Tolerance	±5%	—
Power - Max	1	W
Impedance (Max)	95	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 38.8 V
Voltage - Forward (Max) @ If	1.2	V @ 200 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-123	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the 1N4757AW-TP is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 51 V nominal
Operating temperature range: -55°C to 150°C minimum
Mounting type: Surface Mount
Package compatibility: SOD-123 or SOD-123F variants
RoHS3 compliance

Secondary Compatibility Factors:

Tolerance: ±5% or tighter (±2% acceptable)
Power rating: 1 W or greater
Impedance: 95 to 125 Ohms maximum
Reverse leakage current: 5 µA to 100 nA @ specified voltage

Substitute parts are grouped into two categories:

Category 1 - Direct Equivalent (Active Status): DFLZ51-TP maintains identical electrical specifications and 1 W power rating with SOD-123F packaging variant.

Category 2 - Functional Equivalents (Lower Power Rating): BZT52 series (Vishay), MMSZ5262 series (Vishay), and CMHZ5262B (Central Semiconductor) provide 410 mW to 500 mW power ratings. These parts satisfy applications where the full 1 W capability is not required while maintaining voltage regulation performance across the specified temperature range.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power Max	Zzt (Max)	Package	Status
1N4757AW-TP	Micro Commercial Co	51 V	±5%	1 W	95 Ω	SOD-123	Obsolete
DFLZ51-TP	Micro Commercial Co	51 V	±5%	1 W	95 Ω	SOD-123F	Active
BZT52B51-E3-08	Vishay General Semiconductor	51 V	±2%	410 mW	100 Ω	SOD-123	Active
BZT52B51-E3-18	Vishay General Semiconductor	51 V	±2%	410 mW	100 Ω	SOD-123	Active
BZT52B51-G3-08	Vishay General Semiconductor	51 V	±2%	410 mW	100 Ω	SOD-123	Active
BZT52B51-G3-18	Vishay General Semiconductor	51 V	±2%	410 mW	100 Ω	SOD-123	Active
BZT52C51-E3-08	Vishay General Semiconductor	51 V	±5%	410 mW	100 Ω	SOD-123	Active
BZT52C51-E3-18	Vishay General Semiconductor	51 V	±5%	410 mW	100 Ω	SOD-123	Active
CMHZ5262B TR PBFREE	Central Semiconductor Corp	51 V	±5%	500 mW	125 Ω	SOD-123	Active
MMSZ5262B-E3-08	Vishay General Semiconductor	51 V	±5%	500 mW	125 Ω	SOD-123	Active
MMSZ5262B-E3-18	Vishay General Semiconductor	51 V	±5%	500 mW	125 Ω	SOD-123	Active

Engineering Selection Recommendations

For Direct Replacement with Identical Specifications:

DFLZ51-TP is the primary substitute for 1N4757AW-TP. Both components are manufactured by Micro Commercial Co, maintain 51 V nominal voltage, ±5% tolerance, 1 W power rating, and -55°C to 150°C operating temperature range. DFLZ51-TP is currently in active production status with 847 pieces in stock. The SOD-123F package variant is mechanically and electrically compatible with SOD-123 footprints. Both parts are ROHS3 compliant with MSL 1 rating.

For Applications with Reduced Power Dissipation Requirements:

BZT52C51-E3-08 and BZT52C51-E3-18 (Vishay) provide 410 mW power rating with ±5% tolerance matching the original specification tolerance. These parts maintain 51 V nominal voltage and SOD-123 packaging. With 15,110 and 717 pieces respectively in stock, availability is excellent. ROHS3 compliance and MSL 1 rating are maintained.

MMSZ5262B-E3-08 and MMSZ5262B-E3-18 (Vishay) offer 500 mW power rating with ±5% tolerance. These components provide intermediate power capability between the 410 mW BZT52 series and the 1 W original specification. Stock levels are 15,780 and 821 pieces respectively.

For Tighter Voltage Tolerance Requirements:

BZT52B51-E3-08, BZT52B51-E3-18, BZT52B51-G3-08, and BZT52B51-G3-18 (Vishay) provide ±2% tolerance with 410 mW power rating. These parts are suitable for applications requiring improved voltage regulation accuracy. All variants maintain 51 V nominal voltage and SOD-123 packaging with active product status and ROHS3 compliance.

For Extended Operating Temperature Range:

CMHZ5262B TR PBFREE (Central Semiconductor) operates from -65°C to 150°C, extending the lower temperature limit by 10°C compared to the original specification. This component provides 500 mW power rating with ±5% tolerance and 51 V nominal voltage in SOD-123 packaging. Stock availability is 11,501 pieces.

All recommended substitutes maintain ROHS3 compliance and MSL 1 moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage processes.

Frequently Asked Questions (FAQ)

Q: Can BZT52 series diodes with 410 mW rating replace the 1N4757AW-TP in all applications?

A: BZT52 series substitution is valid for applications where power dissipation does not exceed 410 mW. The 1N4757AW-TP is rated for 1 W maximum power dissipation. Applications requiring the full 1 W capability must use DFLZ51-TP or MMSZ5262B series (500 mW) as alternatives. Verify circuit power requirements before selection.

Q: What is the difference between BZT52B51 and BZT52C51 variants?

A: The primary difference is voltage tolerance. BZT52B51 series provides ±2% tolerance, while BZT52C51 series provides ±5% tolerance. Both maintain 51 V nominal voltage, 410 mW power rating, and SOD-123 packaging. Selection depends on voltage regulation accuracy requirements in the application.

Q: Are the SOD-123 and SOD-123F packages interchangeable?

A: SOD-123F is a variant of SOD-123 packaging. Both packages are mechanically and electrically compatible for PCB footprint purposes. DFLZ51-TP uses SOD-123F packaging while maintaining full compatibility with SOD-123 design specifications.

Q: Why do some substitute parts have different impedance values?

A: Impedance variation (95 to 125 Ohms maximum) reflects manufacturing differences between component series. All values remain within acceptable ranges for 51 V Zener diode operation. Impedance differences do not affect basic voltage regulation function across the specified operating temperature range.

Q: What does the "-E3-08" and "-E3-18" suffix indicate in part numbers?

A: These suffixes denote packaging configuration and tape reel specifications. "-E3-08" and "-E3-18" refer to different tape and reel formats for automated assembly. Both configurations contain identical electrical components and are functionally equivalent.

Q: Is CMHZ5262B TR PBFREE suitable for applications requiring the full 1 W power rating?

A: CMHZ5262B TR PBFREE is rated for 500 mW maximum power dissipation, which is below the 1 W specification of the original 1N4757AW-TP. This component is suitable for applications with power dissipation up to 500 mW. For full 1 W capability, use DFLZ51-TP.

Q: Do all substitute parts maintain the same operating temperature range?

A: Most substitutes operate from -55°C to 150°C, matching the original specification. CMHZ5262B TR PBFREE extends the lower limit to -65°C. Verify specific temperature requirements for your application before final component selection.

Q: Are all recommended substitutes ROHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and MSL 1 moisture sensitivity rating, ensuring compatibility with standard manufacturing processes and environmental requirements.

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