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1N4745A-TP Zener Diode Equivalent & Substitute Parts
Part Overview
The 1N4745A-TP is a 16 V, 1 W Zener diode in DO-41G axial through-hole package manufactured by Micro Commercial Co. This component is classified as obsolete, though 739 pieces remain in stock as new original inventory. The part operates across a temperature range of -65°C to 200°C and maintains ±5% voltage tolerance with a maximum impedance of 16 Ohms. Due to its obsolete status, equivalent and substitute parts from active manufacturers provide viable alternatives for new designs and ongoing production requirements.
Substiute Parts
Key Parameters
| Parameter | Value | Unit |
|---|---|---|
| Voltage - Zener (Nominal) | 16 | V |
| Power - Maximum | 1 | W |
| Tolerance | ±5% | — |
| Impedance (Maximum) | 16 | Ohms |
| Current - Reverse Leakage @ Vr | 5 | µA @ 12.2 V |
| Voltage - Forward (Maximum) @ If | 1.2 | V @ 200 mA |
| Operating Temperature Range | -65 to 200 | °C |
| Mounting Type | Through Hole | — |
| Package / Case | DO-204AL, DO-41, Axial | — |
Substitute Part Grouping Explanation
Substitution of the 1N4745A-TP is determined by the following critical parameters: nominal Zener voltage (16 V), power dissipation capability (1 W minimum), voltage tolerance (±5%), impedance characteristics (16 Ohms maximum), reverse leakage current (5 µA @ 12.2 V), forward voltage drop (1.2 V @ 200 mA), and through-hole axial mounting configuration. Parts are grouped into three categories based on these criteria:
Category 1: Direct Electrical Equivalents (1 W Power Rating) Parts matching all primary electrical specifications with 1 W power rating and identical or compatible operating temperature ranges. These include 1N4745AP-TP, 1N4745A (Lumimax), 1N4745A,133 (NXP), and 1N4745AP/TR8 (Microchip).
Category 2: Enhanced Performance Substitutes (Higher Power Rating) Parts exceeding the 1 W specification with improved thermal characteristics. These include 1N4745A-TR (Vishay, 1.3 W), BZX85B16-TAP (Vishay, 1.3 W), BZX85B16-TR (Vishay, 1.3 W), and BZX85C16 (Taiwan Semiconductor, 1.3 W).
Category 3: Higher Power Alternatives (3 W and Above) Parts designed for applications requiring significantly greater power dissipation. These include 1N5072 (Microchip, 3 W) and 1N5353B/TR8 (Microchip, 5 W). These parts are suitable only when circuit design permits larger package dimensions and thermal characteristics.
Parameter Comparison
| Part Number | Manufacturer | Vz (V) | Power (W) | Tolerance | Zzt (Ohms) | Ir @ Vr (µA) | Vf @ If (V) | Temp Range (°C) | Package | Status |
|---|---|---|---|---|---|---|---|---|---|---|
| 1N4745A-TP | Micro Commercial Co | 16 | 1 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -65 to 200 | DO-41G | Obsolete |
| 1N4745AP-TP | Micro Commercial Co | 16 | 1 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -65 to 150 | DO-41 | Active |
| 1N4745A | Lumimax Optoelectronic | 16 | 1 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -65 to 200 | DO-41G | Active |
| 1N4745A,133 | NXP USA Inc. | 16 | 1 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -65 to 200 | DO-41 | Active |
| 1N4745AP/TR8 | Microchip Technology | 16 | 1 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -65 to 150 | DO-204AL (DO-41) | Active |
| 1N4745A-TR | Vishay General Semiconductor | 16 | 1.3 | ±5% | 16 | 5 @ 12.2 | 1.2 @ 200 mA | -55 to 175 | DO-204AL (DO-41) | Active |
| BZX85B16-TAP | Vishay General Semiconductor | 16 | 1.3 | ±2% | 15 | 500 nA @ 12 | 1.2 @ 200 mA | -55 to 175 | DO-204AL (DO-41) | Active |
| BZX85B16-TR | Vishay General Semiconductor | 16 | 1.3 | ±2% | 15 | 500 nA @ 12 | 1.2 @ 200 mA | -55 to 175 | DO-204AL (DO-41) | Active |
| BZX85C16 | Taiwan Semiconductor | 16 | 1.3 | ±5% | 15 | 500 nA @ 12 | 1.2 @ 10 mA | -65 to 200 | DO-204AL (DO-41) | Active |
| 1N5072 | Microchip Technology | 16 | 3 | ±5% | 7 | 5 @ 12.2 | — | -65 to 175 | Axial | Active |
| 1N5353B/TR8 | Microchip Technology | 16 | 5 | ±5% | 2.5 | 1 µA @ 11.5 | 1.2 @ 1 A | -65 to 150 | T-18 Axial | Active |
Engineering Selection Recommendations
For Direct Replacement (1 W Applications)
The 1N4745A from Lumimax Optoelectronic Technology provides the closest functional equivalent to the obsolete 1N4745A-TP. This part maintains identical electrical specifications, operating temperature range (-65°C to 200°C), and DO-41G package configuration. With 280,199 pieces in active stock, supply continuity is assured. RoHS compliance status is confirmed.
The 1N4745A,133 from NXP USA Inc. offers an alternative with identical electrical performance and active product status. This part is available in bulk packaging with 2,150 pieces in stock. Operating temperature extends to 200°C, matching the original specification.
The 1N4745AP-TP from Micro Commercial Co maintains the same manufacturer lineage as the original part. This active variant differs only in operating temperature range (-65°C to 150°C) and packaging format (Tape & Reel). Selection of this part is appropriate when the reduced upper temperature limit (150°C versus 200°C) is acceptable for the application.
For Enhanced Thermal Performance (1.3 W Applications)
The 1N4745A-TR from Vishay General Semiconductor provides 30% increased power dissipation (1.3 W) while maintaining 16 V Zener voltage and ±5% tolerance. This part carries AEC-Q101 automotive qualification and ROHS3 compliance. The operating temperature range is -55°C to 175°C. With 24,686 pieces in stock, availability is strong.
The BZX85C16 from Taiwan Semiconductor Corporation offers 1.3 W power rating with identical 16 V Zener voltage and ±5% tolerance. This part extends the operating temperature range to -65°C to 200°C, matching the original specification. ROHS3 compliance is confirmed. Impedance is reduced to 15 Ohms, providing improved voltage regulation characteristics.
The BZX85B16-TAP and BZX85B16-TR from Vishay General Semiconductor are identical variants differing only in packaging format (Cut Tape). Both provide 1.3 W power rating, 16 V Zener voltage, and ±2% tolerance (tighter than the original ±5%). AEC-Q101 automotive qualification is included. Operating temperature range is -55°C to 175°C.
For Higher Power Applications (3 W and Above)
The 1N5072 from Microchip Technology provides 3 W power dissipation with 16 V Zener voltage and ±5% tolerance. This part features reduced impedance (7 Ohms) for improved regulation. Operating temperature range is -65°C to 175°C. Selection is appropriate only when circuit board space permits the larger axial package and thermal design accommodates the increased power capability.
The 1N5353B/TR8 from Microchip Technology provides 5 W power dissipation with 16 V Zener voltage and ±5% tolerance. This part features significantly reduced impedance (2.5 Ohms) and lower reverse leakage current (1 µA @ 11.5 V). The T-18 axial package is substantially larger than DO-41. Selection is appropriate only for applications requiring maximum power dissipation and improved regulation characteristics.
Compliance and Certification Considerations
All recommended substitute parts maintain ROHS3 compliance and REACH unaffected status, consistent with the original 1N4745A-TP. Parts designated with AEC-Q101 qualification (Vishay BZX85 series) are suitable for automotive applications requiring formal qualification documentation. Parts without explicit automotive qualification are suitable for general industrial and consumer applications.
Frequently Asked Questions (FAQ)
Q: Can the 1N4745AP-TP be used as a direct replacement for the 1N4745A-TP?
A: The 1N4745AP-TP is electrically equivalent with identical Zener voltage (16 V), power rating (1 W), tolerance (±5%), and impedance (16 Ohms). The primary difference is the reduced operating temperature range (-65°C to 150°C versus -65°C to 200°C). This part is suitable for replacement when the application does not require operation above 150°C. Packaging format differs (Tape & Reel versus bulk), which may affect procurement and assembly processes.
Q: What is the difference between the 1N4745A from Lumimax and the 1N4745A,133 from NXP?
A: Both parts are electrically identical with 16 V Zener voltage, 1 W power rating, ±5% tolerance, and -65°C to 200°C operating range. The differences are manufacturer identity and packaging format. Lumimax supplies in DO-41G package with 280,199 pieces in stock. NXP supplies in bulk packaging with 2,150 pieces in stock. Selection depends on procurement requirements and assembly compatibility.
Q: When should the 1.3 W variants (BZX85C16, 1N4745A-TR) be selected over the 1 W equivalents?
A: The 1.3 W variants provide 30% additional power dissipation capability. Selection is appropriate when circuit analysis indicates power dissipation approaching or exceeding 1 W under worst-case conditions. The 1.3 W variants also feature reduced impedance (15 Ohms versus 16 Ohms), providing marginally improved voltage regulation. These parts are backward compatible with 1 W designs and do not require circuit modification.
Q: What is the significance of the ±2% tolerance in the BZX85B16 series compared to the ±5% tolerance of the 1N4745A?
A: The ±2% tolerance in BZX85B16 parts provides tighter Zener voltage control compared to the ±5% tolerance of the original 1N4745A-TP. This tighter tolerance is beneficial in applications requiring precise voltage regulation. However, the original design was validated with ±5% tolerance, so the tighter tolerance of BZX85B16 parts does not introduce compatibility issues. Applications requiring ±5% tolerance can use either specification.
Q: Are the higher power variants (1N5072 at 3 W, 1N5353B/TR8 at 5 W) suitable for direct substitution?
A: The 1N5072 and 1N5353B/TR8 maintain the 16 V Zener voltage and ±5% tolerance, making them electrically compatible. However, these parts feature significantly different package sizes (larger axial packages) and reduced impedance values. Direct substitution requires verification that circuit board layout accommodates the larger package dimensions and that the reduced impedance does not introduce unintended circuit behavior. These parts are suitable for new designs or when circuit board space permits the larger package.
Q: What packaging formats are available for the substitute parts?
A: Substitute parts are available in the following packaging formats: DO-41G (Lumimax 1N4745A), DO-41 (Micro Commercial 1N4745AP-TP, NXP 1N4745A,133), DO-204AL (DO-41) (Vishay 1N4745A-TR, Vishay BZX85B16 series, Taiwan Semiconductor BZX85C16, Microchip 1N4745AP/TR8), Axial (Microchip 1N5072), and T-18 Axial (Microchip 1N5353B/TR8). The original 1N4745A-TP uses DO-41G package. Most substitutes use DO-41 or DO-204AL (DO-41) packages, which are mechanically and electrically compatible. Larger packages (Axial, T-18) require circuit board layout verification.
Q: Which substitute parts carry automotive qualification?
A: The Vishay BZX85B16-TAP and BZX85B16-TR parts carry AEC-Q101 automotive qualification. The Vishay 1N4745A-TR also carries AEC-Q101 qualification. These parts are suitable for automotive applications requiring formal qualification documentation. Other substitute parts do not carry explicit automotive qualification and are suitable for general industrial and consumer applications.
Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?
A: Cut Tape (CT) packaging provides components on continuous tape that is cut to length during assembly. Tape & Reel (TR) packaging provides components on continuous tape wound on a reel for automated assembly equipment. Both formats are compatible with standard surface-mount and through-hole assembly processes. Selection depends on assembly equipment capability and procurement preferences. The electrical and mechanical specifications are identical between CT and TR variants of the same part number.
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