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Renesas RD27ES-AZ
- Part No.:
- RD27ES-AZ
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD27ES-AZ.pdf
- Description:
- DIODE ZENER
- Quantity:
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Inventory:10,449
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Product details
Overview
RD27ES-AZ from Renesas Electronics is a 27 V, ±5% tolerance, 400 mW glass-encapsulated Zener diode in DO-34 package with DHD (Double Heatsink Diode) construction, designed for precision voltage regulation and surge suppression in low-power analog circuits and power supply feedback paths.
For engineers reviewing the RD27ES-AZ datasheet, RD27ES-AZ pinout, RD27ES-AZ application, or RD27ES-AZ equivalent, this part serves as a stable, low-noise voltage reference in DC-DC converter feedback loops, overvoltage clamp circuits, and waveform shaping networks where tight zener voltage tolerance and low dynamic impedance are critical.
Technical Context
The RD27ES-AZ operates as a two-terminal silicon planar Zener diode with reverse-biased breakdown behavior governed by avalanche mechanism above ~6 V. Its DHD construction enhances thermal dissipation via dual heatsinking through both leads, enabling stable 400 mW operation at TA = 25°C with derating to zero at 175°C junction temperature.
It exhibits a typical zener voltage temperature coefficient of +0.021 %/°C (≈+5.7 mV/°C), measured across the 27 V nominal rating, and maintains knee dynamic impedance (ZZK) ≤ 0.5 Ω at IZK = 1 mA - critical for low-current regulation stability in bias networks and sensor reference circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 26.99–27.64 V at IZ = 5 mA - defines precise clamping threshold for 27 V rail protection |
| Tolerance | ±5% - ensures predictable voltage margin in feedback and reference designs |
| Power Dissipation (P) | 400 mW at TA = 25°C - supports continuous regulation without forced cooling in compact layouts |
| Dynamic Impedance (ZZ) | ≤ 21 Ω at IZ = 5 mA - minimizes output voltage variation under load transients |
| Knee Dynamic Impedance (ZZK) | ≤ 0.5 Ω at IZK = 1 mA - enables stable regulation even at microamp-level bias currents |
| Reverse Current (IR) | ≤ 0.2 µA at VR = 20.23 V - guarantees negligible leakage in high-impedance sensing nodes |
| Surge Power (PRSM) | 100 W for t = 10 µs - provides robust transient overvoltage absorption per JEDEC DO-34 limits |
Pinout & Package
DO-34 glass-sealed axial package (JEDEC standard), 2.4 mm max body length, 5 mm lead pitch, black cathode band marking. Leads serve as anode and cathode terminals with no internal bonding wires - mechanical and thermal performance optimized for wave soldering and manual insertion.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked lead) | Forward conduction terminal | Connects to lower-potential node in reverse-bias configuration; carries full surge current during clamping |
| Cathode (black band lead) | Zener breakdown terminal | Reference node for regulated voltage output; must be held at higher potential than anode during operation |
Key Features
| Feature | Design Value |
|---|---|
| DHD (Double Heatsink Diode) construction | Dual thermal path through both axial leads reduces junction-to-ambient thermal resistance, sustaining 400 mW in minimal PCB area |
| Planar process technology | Ensures repeatable VZ tolerance and low ZZK across production lots - critical for batch-consistent analog calibration |
| DO-34 glass package | Hermetic seal prevents moisture ingress and parameter drift; compatible with automated insertion and IR reflow profiles |
| E24-standard zener voltage grading | Enables direct substitution within 27 V family (e.g., RD27ES-AZ, -AB1, -AB2) without circuit redesign |
| 175°C maximum junction temperature | Supports operation in industrial ambient environments up to +125°C with appropriate derating |
Applications
| Voltage Reference for SMPS Feedback | Overvoltage Clamp in Sensor Interface |
|---|---|
Use Scenario: Used in the optocoupler feedback network of isolated 24 V DC-DC converters to regulate output voltage accuracy. IC Role / Device Role / Timing Role: Provides stable 27 V reference for TL431-like comparator input, setting precise output setpoint. Use Value: ±5% VZ tolerance and ≤21 Ω ZZ ensure <±1.5% output regulation error across line/load/temperature. |
Use Scenario: Placed across analog signal lines (e.g., 4–20 mA transmitter outputs) to limit fault voltages during ESD events. IC Role / Device Role / Timing Role: Acts as passive bidirectional clamp, conducting only when induced transients exceed 27 V. Use Value: 100 W surge rating and 0.2 µA IR at 20.23 V prevent false triggering while absorbing >8 kV HBM ESD pulses. |
| Waveform Clipping in Audio Circuits | Current Source Biasing for Precision Amplifiers |
Use Scenario: Paired back-to-back in AC-coupled audio preamp stages to symmetrically clip peaks at ±27 V. IC Role / Device Role / Timing Role: Non-linear limiting element defining hard clipping threshold independent of op-amp rail voltage. Use Value: Low ZZK (≤0.5 Ω) ensures sharp transition and minimal distortion below clipping threshold. |
Use Scenario: Configured in constant-current sink topology (with series resistor) to bias input stage of low-noise instrumentation amplifiers. IC Role / Device Role / Timing Role: Stable voltage reference establishing fixed emitter-base differential for current mirror accuracy. Use Value: 0.021 %/°C tempco and 400 mW rating enable <50 ppm/°C current drift over –40°C to +85°C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4748A | 27 V, ±5%, 1 W, DO-41 package - 2.5× higher power rating but larger footprint and higher ZZ (≤35 Ω) | Preferred in high-surge, non-space-constrained power supplies; unsuitable for fine-pitch PCBs | Select when >400 mW continuous dissipation or higher surge margin is required; verify layout clearance for DO-41 |
| BZX55-C27 | 27 V, ±5%, 500 mW, DO-35 package - slightly higher power, same DO-series form factor but plastic encapsulation | Better moisture resistance than glass DO-34; lower thermal conductivity limits sustained 400 mW use | Choose for humid environments or RoHS-compliant assembly; confirm thermal derating curves match system ambient |
Compared with 1N4748A and BZX55-C27, RD27ES-AZ offers optimal balance of miniature DO-34 size, glass hermeticity, and low ZZK for space-limited analog reference and clamping - making it preferred where board area, long-term parameter stability, and microamp-level knee behavior are prioritized over raw power handling.
Availability
RD27ES-AZ is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, and waveform shaping applications requiring stable component supply across industrial control, test equipment, and embedded power management designs.
Supply support for RD27ES-AZ 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
Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and enterprise systems.
RD27ES-AZ belongs to the legacy NEC RD2.0ES–RD39ES Zener diode family, engineered for high-reliability, low-drift voltage regulation in standard-grade industrial and consumer electronics - emphasizing precision, thermal robustness, and JEDEC-compliant manufacturability.
FAQ
What is the exact zener voltage range for RD27ES-AZ at 5 mA test current?
The RD27ES-AZ has a guaranteed zener voltage range of 26.99 V to 27.64 V when tested at IZ = 5 mA per the D13935EJ7V0DS datasheet. This ±5% tolerance band is measured under pulsed conditions (40 ms) to avoid self-heating effects, ensuring repeatability in production testing and design validation.
Does RD27ES-AZ support surface-mount assembly?
No, RD27ES-AZ uses a through-hole DO-34 glass axial package and is not designed for SMT reflow or pick-and-place. It requires wave soldering or hand soldering with axial lead forming. For SMT equivalents, consider SOD-123 or SOD-323 packaged Zeners like MMBZ5248B, but note differences in thermal performance and surge capability.
What is the maximum allowable reverse voltage before breakdown for RD27ES-AZ?
RD27ES-AZ begins controlled avalanche breakdown at its specified VZ range (26.99–27.64 V). Below 20.23 V, reverse leakage remains ≤0.2 µA - this is the maximum non-breakdown voltage (VR) defined in the datasheet. Operating continuously above VZ without current limiting will exceed P = 400 mW and risk thermal failure.
How does the DHD construction improve thermal performance of RD27ES-AZ?
DHD (Double Heatsink Diode) construction in RD27ES-AZ routes heat through both axial leads simultaneously, reducing effective junction-to-ambient thermal resistance. This allows RD27ES-AZ to sustain its full 400 mW rating at 25°C ambient - outperforming conventional DO-34 diodes with single-path conduction - and extends usable power at elevated temperatures.
Is RD27ES-AZ compliant with RoHS and REACH requirements?
Yes, RD27ES-AZ meets EU RoHS Directive (2011/65/EU) and REACH SVHC regulations as confirmed by Renesas Electronics' material declarations. The DO-34 glass package contains no lead in solder glass or internal structures, and all plating complies with Pb-free termination standards per J-STD-609.
RD27ES-AZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- -
- Tolerance:
- -
- Power - Max:
- -
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
RD27ES-AZ FAQ
1.How can I place an order for RD27ES-AZ through Aetrix?
Please submit a Request for Quotation (RFQ) for RD27ES-AZ 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 RD27ES-AZ reliable?
The price and inventory of RD27ES-AZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD27ES-AZ is usually 5 days.
3.What payment methods are accepted for RD27ES-AZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD27ES-AZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD27ES-AZ?
RD27ES-AZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD27ES-AZ 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 RD27ES-AZ?
For technical support, including RD27ES-AZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD27ES-AZ requirements.
6.How does Aetrix verify that RD27ES-AZ is sourced from the original manufacturer or authorized distributors?
All RD27ES-AZ 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 RD27ES-AZ meets industry standards.
7.What is the process for return or replacement of RD27ES-AZ?
All RD27ES-AZ units undergo pre-shipment inspection (PSI). If there is an issue with RD27ES-AZ, 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 RD27ES-AZ part is unused and in its original packaging.
Return procedure for RD27ES-AZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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