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Diodes Incorporated ZM4738A-13
- Part No.:
- ZM4738A-13
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
ZM4738A-13.pdf
- Description:
- DIODE ZENER 8.2V 1W MELF
- Quantity:
- Payment:
- Shipping:
Inventory:5,108
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Product details
Overview
ZM4738A-13 from Diodes Incorporated is a 1.0W surface-mount Zener diode with nominal Zener voltage 8.2V ±5% at 31mA test current, 4.5Ω maximum Zener impedance at IZT, and 6.0mA maximum Zener current at 0.5V reverse bias; used for precision voltage regulation in power supply feedback loops and overvoltage protection circuits.
For engineers reviewing the ZM4738A-13 datasheet, ZM4738A-13 pinout, ZM4738A-13 application, or ZM4738A-13 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (170°C/W), surge current rating (550mA @ 8.3ms), MELF package compatibility, and discontinuation status requiring migration planning.
Technical Context
This discrete Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its 8.2V nominal Zener voltage is specified at 31mA DC test current (IZT), with sharp knee characteristics verified by dual-point Zener impedance measurement per DS18009 Rev. 4.
Thermal performance is defined by 170°C/W junction-to-ambient thermal resistance and derating curve (Fig. 1), supporting operation from –65°C to +200°C. The device uses glass-passivated MELF construction with solderable terminals compliant with MIL-STD-202, Method 208.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 8.2 V ±5% @ IZT = 31 mA - defines regulated output voltage in shunt regulator designs |
| Power Dissipation (Pd) | 1.0 W @ TA = 25°C - sets maximum continuous DC power handling before thermal derating |
| Zener Impedance (ZZT) | 4.5 Ω max @ IZT - determines AC voltage regulation stability under dynamic load changes |
| Surge Current (IZS) | 550 mA @ 8.3 ms - supports transient overvoltage clamping without failure |
| Reverse Leakage (IR) | 10 µA max @ VR = 0.5 V - ensures low standby current in high-impedance bias networks |
| Thermal Resistance (RJA) | 170 °C/W - quantifies self-heating impact on Zener voltage drift and reliability |
| Operating Temperature | –65°C to +200°C - enables use in automotive engine compartments and industrial environments |
Pinout & Package
Package: MELF (Metal Electrode Leadless Face), cylindrical glass-body surface-mount package with axial cathode band marking; dimensions A = 4.80–5.20 mm (length), B = 2.40–2.60 mm (diameter), C = 0.55 mm (lead diameter).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-biased Zener configuration |
| Cathode | Reverse breakdown terminal | Marked by band; connected to regulated voltage node in shunt regulator topologies |
Key Features
| Feature | Design Value |
|---|---|
| 1.0W Power Rating | Enables higher-current shunt regulation than 0.5W MELF Zeners, reducing need for parallel devices |
| ±5% VZ Tolerance | Supports tight voltage reference requirements in feedback networks without post-calibration |
| Sharp Knee Breakdown | Verified by dual-point Zener impedance testing to ensure stable regulation across operating range |
| MIL-STD-202 Solderability | Guarantees reliable reflow attachment in automated SMT assembly processes |
| –65°C to +200°C Range | Permits deployment in under-hood automotive and high-temp industrial control modules |
Applications
| Switch-Mode Power Supply Feedback | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Regulates error amplifier reference in isolated flyback converter feedback loop. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 8.2V threshold for optocoupler-driven primary-side control. Use Value: Maintains ±1% output voltage accuracy across line/load/temperature with minimal external components. | Use Scenario: Clamps analog sensor output to prevent ADC input overload during ESD events. IC Role / Device Role / Timing Role: Transient voltage suppressor protecting 0–10V industrial sensor interface against 1kV EFT bursts. Use Value: Limits peak voltage to ≤9.0V with <10ns response, preserving signal integrity and IC reliability. |
| Automotive Engine Control Unit (ECU) | Programmable Logic Controller (PLC) Input Module |
Use Scenario: Provides stable bias voltage for knock sensor amplifier in high-temperature engine bay. IC Role / Device Role / Timing Role: Precision Zener reference ensuring consistent gain calibration of piezoelectric sensor front-end. Use Value: Delivers <0.1%/°C voltage drift up to 150°C ambient, meeting AEC-Q101 thermal stability requirements. | Use Scenario: Sets threshold for 24V digital input detection in modular PLC backplane. IC Role / Device Role / Timing Role: Voltage clamp defining logic-high recognition level while absorbing induced surges on field wiring. Use Value: Withstands repeated 500A/8.3ms surges per IEC 61000-4-5, extending module service life in factory-floor environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAZ8.2-13 | Same 8.2V VZ, but DO-214AC package; 1.0W rating; 5Ω ZZT; 10µA IR @ 0.5V | Surface-mount footprint differs; higher thermal resistance (200°C/W); better surge robustness (600mA) | Select for legacy PCB redesign where DO-214AC layout exists and surge margin is critical |
| DFLZ8.2-7 | Same 8.2V VZ, SOD-123FL package; 0.5W rating; 7Ω ZZT; 5µA IR @ 0.5V | Lower power rating requires derating above 70°C; smaller footprint; tighter leakage spec | Select for space-constrained consumer electronics where 0.5W suffices and leakage <5µA is mandatory |
Compared with ZM4738A-13, SMAZ8.2-13 offers superior surge capability in a different package, while DFLZ8.2-7 trades power and impedance for miniaturization-neither matches the original's MELF thermal performance or 170°C/W RJA.
Availability
ZM4738A-13 is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor interfaces, automotive ECUs, and PLC input modules requiring stable component supply despite its discontinued status.
Supply support for ZM4738A-13 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.
The ZM47xxA series belongs to Diodes' legacy Zener diode product line, engineered specifically for high-reliability voltage reference and clamping in industrial and automotive power systems.
FAQ
Is ZM4738A-13 still in active production?
No, ZM4738A-13 is officially discontinued per Diodes Incorporated's DS18009 Rev. 4 datasheet, which explicitly states "DISCONTINUED Use SMAZ OR DFLZ Series". Aetrix Electronics maintains limited legacy stock and supports migration paths to SMAZ8.2-13 or DFLZ8.2-7.
What is the cathode identification method for ZM4738A-13?
The cathode is marked by a single black band located near one end of the cylindrical MELF glass body. When mounted horizontally on PCB, the banded end connects to the higher-potential node in reverse-bias Zener operation.
Can ZM4738A-13 replace ZM4737A or ZM4739A in existing designs?
Yes, with verification: ZM4737A (7.5V) and ZM4739A (9.1V) differ by ±0.9V nominal voltage. Substitution requires confirming that circuit tolerance (e.g., feedback divider ratio, clamping threshold) accommodates the 8.2V vs. 7.5V/9.1V shift and that power dissipation remains within 1.0W limit.
What is the maximum allowable ambient temperature at full 1.0W dissipation?
Per Fig. 1 (Power Derating Curve), full 1.0W dissipation is only rated at TA = 25°C. Above 25°C, linear derating applies: maximum power = 1.0W × (1 − (TA − 25)/170). At TA = 75°C, max power drops to 0.71W; at TA = 125°C, it falls to 0.41W.
ZM4738A-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Cut Tape (CT)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 8.2 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 4.5 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 6 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 200°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- MELF
ZM4738A-13 FAQ
1.How can I place an order for ZM4738A-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for ZM4738A-13 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ZM4738A-13 reliable?
The price and inventory of ZM4738A-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZM4738A-13 is usually 5 days.
3.What payment methods are accepted for ZM4738A-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZM4738A-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZM4738A-13?
ZM4738A-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZM4738A-13 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ZM4738A-13?
For technical support, including ZM4738A-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZM4738A-13 requirements.
6.How does Aetrix verify that ZM4738A-13 is sourced from the original manufacturer or authorized distributors?
All ZM4738A-13 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ZM4738A-13 meets industry standards.
7.What is the process for return or replacement of ZM4738A-13?
All ZM4738A-13 units undergo pre-shipment inspection (PSI). If there is an issue with ZM4738A-13, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ZM4738A-13 part is unused and in its original packaging.
Return procedure for ZM4738A-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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