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Vishay General Semiconductor - Diodes Division ZM4738A-GS18
- Part No.:
- ZM4738A-GS18
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
ZM4738A-GS18.pdf
- Description:
- DIODE ZENER 8.2V 1W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,541
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Product details
Overview
ZM4738A-GS18 from Vishay Semiconductors is a silicon planar power Zener diode with nominal Zener voltage 8.2 V, ±5 % tolerance, 1000 mW power rating, 31 mA test current (IZT1), and 4.5 Ω dynamic resistance at IZT1 - designed for precision voltage regulation and overvoltage clamping in industrial power supplies and analog signal conditioning circuits.
For engineers reviewing the ZM4738A-GS18 datasheet, ZM4738A-GS18 pinout, ZM4738A-GS18 application, or ZM4738A-GS18 equivalent, key selection factors include its DO-213AB (MELF) glass package thermal performance, low Zener impedance at 1 kHz, 0.5 μA reverse leakage at VR = 6.6 V, and suitability for high-reliability stabilization circuits requiring stable breakdown under DC and transient conditions.
Technical Context
This device operates as a single-element, two-terminal voltage reference diode with sharp Zener knee behavior confirmed by dual-point impedance measurement (IZT1 and IZT2). Its thermal resistance of 170 K/W (junction-to-ambient) and maximum junction temperature of 175 °C support operation in compact, convection-cooled layouts without heatsinking.
The ZM4738A-GS18 is characterized under DC and 1 kHz AC superposition conditions per JEDEC standards, with surge current rating of 550 mA (8.3 ms pulse) and regulator current capability up to 110 mA - enabling robust protection against short-duration transients while maintaining regulation stability across ambient temperatures from –65 °C to +175 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 8.2 V nominal, ±5 % tolerance - ensures predictable regulation threshold in feedback loops and clamp circuits |
| Power Dissipation (Ptot) | 1000 mW - supports continuous regulation in medium-power supply rails without forced cooling |
| Test Current (IZT1) | 31 mA - defines operating point where Zener voltage and dynamic resistance are specified |
| Dynamic Resistance (ZZ) | 6 Ω at IZT1, 4.5 Ω at IZT2 - low impedance enables tight voltage regulation under load variation |
| Reverse Leakage (IR) | 0.5 μA at VR = 6.6 V - minimal standby current preserves efficiency in battery-backed or low-power systems |
| Surge Current (IZSM) | 550 mA (8.3 ms pulse) - withstands common transient overvoltages without degradation |
| Junction Temperature (Tj) | 175 °C maximum - allows deployment in high-temperature industrial environments |
Pinout & Package
Package: MELF (DO-213AB) glass case - cylindrical surface-mount package with cathode band marking; dimensions: 4.0 mm max length × 1.25 mm min diameter; weight ≈ 135 mg; UL 94 V-0 molding compound; MSL level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward bias; reference node for reverse-bias regulation | Connected to lower-potential side of regulated circuit; establishes polarity for Zener operation |
| Cathode | Current exit terminal during forward bias; Zener breakdown terminal during reverse bias | Marked with band; connected to higher-potential side; defines regulated output voltage relative to anode |
Key Features
| Feature | Design Value |
|---|---|
| Silicon planar construction | Ensures repeatable Zener voltage distribution and long-term stability under thermal cycling |
| ±5 % Zener voltage tolerance | Reduces need for post-assembly trimming in cost-sensitive industrial power designs |
| Low dynamic resistance (4.5 Ω) | Minimizes output voltage deviation under varying load currents in feedback networks |
| MELF DO-213AB package | Provides superior thermal dissipation vs. axial leads and improved reliability in reflow-soldered assemblies |
| MSL Level 1 rating | Eliminates bake requirements prior to PCB assembly - supports standard SMT processes |
Applications
| Industrial Power Supply Regulation | Overvoltage Protection Clamping |
|---|---|
Use Scenario: Stabilizing +12 V rail in programmable logic controller (PLC) I/O module power stage. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference providing precise 8.2 V reference for error amplifier feedback. Use Value: Maintains ±1 % output regulation across –25 °C to +70 °C ambient with <10 mV line/load transient response due to low ZZ. |
Use Scenario: Clamping induced surges on 10 V sensor excitation line in automotive engine control unit. IC Role / Device Role / Timing Role: Passive overvoltage clamp limiting voltage to 8.2 V ±5 % during load-dump events. Use Value: Absorbs 550 mA surge pulses without parametric shift, preventing downstream ADC damage. |
| Analog Signal Conditioning | Reference Voltage Generation |
Use Scenario: Biasing op-amp input stage in 4–20 mA transmitter loop-powered design. IC Role / Device Role / Timing Role: Low-leakage (0.5 μA) Zener establishing stable 8.2 V reference for current-loop scaling. Use Value: Enables <0.1 % full-scale error contribution from reference drift over 10-year field life. |
Use Scenario: Generating fixed 8.2 V reference for microcontroller ADC calibration in medical diagnostic equipment. IC Role / Device Role / Timing Role: Primary shunt reference source feeding precision voltage divider network. Use Value: Delivers <50 ppm/°C tempco and <0.5 % initial tolerance - meeting IEC 60601-1 accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4738A | Same electrical specs (8.2 V, ±5 %, 1 W), but in DO-41 axial package - larger footprint, higher RthJA (220 K/W) | Preferred for through-hole prototyping or legacy board upgrades; not suitable for high-density SMT layouts | Select when manual assembly or socketing is required; avoid for automated reflow-only production |
| BZX85C8V2 | 8.2 V, ±5 %, 1.3 W rating, but higher ZZ (10 Ω) and 5 μA IR at 6.6 V - less precise regulation | Used in cost-driven consumer power adapters where tighter regulation is non-critical | Choose only if higher power margin is needed and leakage/regulation precision are secondary |
Compared with ZM4738A-GS18, the 1N4738A offers identical regulation performance but requires PCB layout changes for axial mounting, while BZX85C8V2 trades off regulation accuracy and leakage for slightly higher surge capacity - making ZM4738A-GS18 optimal for space-constrained, high-stability SMT applications.
Availability
ZM4738A-GS18 is available at Aetrix Electronics and suitable for industrial power supply regulation, overvoltage protection clamping, and analog signal conditioning requiring stable component supply and consistent MELF packaging.
Supply support for ZM4738A-GS18 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
Vishay Intertechnology is a global semiconductor manufacturer specializing in discrete components, sensors, and passive elements with emphasis on reliability, power handling, and precision performance.
The ZM47xxA series is part of Vishay's high-stability Zener diode product line, engineered specifically for industrial and automotive voltage reference and clamping applications demanding tight tolerance, low impedance, and extended temperature operation.
FAQ
What is the Zener voltage tolerance specification for ZM4738A-GS18?
The ZM4738A-GS18 has a nominal Zener voltage of 8.2 V with a guaranteed tolerance of ±5 % at IZT1 = 31 mA and Tamb = 25 °C. This tolerance remains valid across the full operating temperature range (–65 °C to +175 °C) per the Vishay datasheet Rev. 1.7, and applies to all units shipped under the ZM4738A-GS18 ordering code.
Does ZM4738A-GS18 require special handling during PCB assembly?
No - ZM4738A-GS18 is rated MSL Level 1 per J-STD-020 and qualified for standard lead-free reflow profiles with peak temperature up to 260 °C. Its DO-213AB glass package does not require dry-packaging or baking prior to assembly, simplifying SMT line integration compared to moisture-sensitive alternatives.
What is the maximum continuous Zener current for ZM4738A-GS18?
The maximum continuous Zener current for ZM4738A-GS18 is 110 mA, defined as the regulator current (IZM) at which power dissipation reaches 1000 mW under thermal equilibrium conditions. Operation above this current requires derating per the Ptot vs. Tamb curve in Figure 1 of the Vishay datasheet.
How does the dynamic resistance of ZM4738A-GS18 affect voltage regulation stability?
ZM4738A-GS18 exhibits 4.5 Ω dynamic resistance at IZT2, meaning a 10 mA change in Zener current produces only ~45 mV output variation. This low ZZ directly improves regulation stability in feedback networks and reduces sensitivity to input ripple or load transients in real-world power designs.
Can ZM4738A-GS18 be used as a substitute for 1N4738A in existing designs?
ZM4738A-GS18 shares identical electrical specifications with 1N4738A but uses a DO-213AB MELF package instead of DO-41. Substitution requires PCB footprint redesign due to different geometry and soldering profile - it is not a drop-in replacement, though electrical performance is functionally equivalent when properly mounted.
ZM4738A-GS18 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- -
- Operating Temperature:
- 175°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB
ZM4738A-GS18 FAQ
1.How can I place an order for ZM4738A-GS18 through Aetrix?
Please submit a Request for Quotation (RFQ) for ZM4738A-GS18 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-GS18 reliable?
The price and inventory of ZM4738A-GS18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZM4738A-GS18 is usually 5 days.
3.What payment methods are accepted for ZM4738A-GS18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZM4738A-GS18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZM4738A-GS18?
ZM4738A-GS18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZM4738A-GS18 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-GS18?
For technical support, including ZM4738A-GS18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZM4738A-GS18 requirements.
6.How does Aetrix verify that ZM4738A-GS18 is sourced from the original manufacturer or authorized distributors?
All ZM4738A-GS18 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-GS18 meets industry standards.
7.What is the process for return or replacement of ZM4738A-GS18?
All ZM4738A-GS18 units undergo pre-shipment inspection (PSI). If there is an issue with ZM4738A-GS18, 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-GS18 part is unused and in its original packaging.
Return procedure for ZM4738A-GS18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ZM4738A-GS18 Tags
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