My Inquiry
My Account
Renesas RD20F-T8-AZ
- Part No.:
- RD20F-T8-AZ
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD20F-T8-AZ.pdf
- Description:
- DIODE ZENER
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
RD20F-T8-AZ from Renesas Electronics is a 1 W planar silicon zener diode with nominal zener voltage of 20 V (B3 grade: 19.59–20.84 V), dynamic impedance of 14 Ω at 20 mA, and temperature coefficient of +15 mV/°C. It features DO-41 glass-sealed DHD (Double Heatsink Diode) packaging, operates up to 175°C junction temperature, and is used for precision voltage regulation and surge absorption in industrial power supplies.
For engineers reviewing the RD20F-T8-AZ datasheet, RD20F-T8-AZ pinout, RD20F-T8-AZ application, or RD20F-T8-AZ equivalent, this page delivers verified electrical specs, JEDEC DO-41 terminal mapping, thermal derating curves, real-world clipping/limiter use cases, and two validated alternative zeners with voltage tolerance and impedance trade-offs.
Technical Context
This device is a single-junction, planar-diffused zener diode optimized for stable reverse-biased operation at 20 V. Its DO-41 package provides double heatsink thermal path via axial leads and glass body, enabling 1 W continuous dissipation at 25°C ambient with defined derating above 50°C.
The RD20F-T8-AZ exhibits a positive temperature coefficient (+15 mV/°C typical), indicating increasing VZ with temperature-critical for biasing circuits requiring thermal stability. Its 14 Ω dynamic impedance at IZ = 20 mA ensures low output impedance in shunt regulator configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 19.59–20.84 V (B3 grade, tested at 40 ms after power-on; defines regulation window under load) |
| Power Dissipation (P) | 1.0 W at TA = 25°C; derates linearly to zero at 150°C ambient per Figure 1 |
| Dynamic Impedance (ZZ) | 14 Ω max at IZ = 20 mA; determines output voltage ripple sensitivity in shunt regulators |
| Reverse Current (IR) | ≤10 μA at VR = 15 V; ensures low leakage in standby or high-impedance sensing nodes |
| Junction Temperature (Tj) | −65 to +175°C; supports operation in industrial environments without forced cooling |
| Surge Reverse Power (PRSM) | 400 W for t = 10 μs (non-repetitive); enables transient overvoltage clamping in input protection stages |
| Thermal Resistance (Rth) | 150°C/W (transient, t = 1 s); informs PCB copper area requirements for thermal management |
Pinout & Package
RD20F-T8-AZ uses JEDEC DO-41 glass-encapsulated axial package with cathode indicated by black band. Leads are tinned copper-clad steel, suitable for wave or hand soldering. Package dimensions: Ø3.0 mm max body diameter, 25 mm min lead length, 5 mm max overall length.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / reference ground node in shunt configuration | Connected to system ground or lower-potential rail; carries forward current up to 200 mA |
| Cathode | Zener breakdown terminal / regulated output node | Connected to voltage source via series resistor; maintains stable 20 V across load when reverse-biased |
Key Features
| Feature | Design Value |
|---|---|
| E24-standardized voltage grading | B3 tolerance (±3.2% at 20 V) enables interchangeability within standard resistor/zener design libraries |
| Planar-type glass seal | Hermetic DO-41 construction ensures long-term reliability in humid or chemically aggressive industrial enclosures |
| Double Heatsink Diode (DHD) structure | Enhanced thermal path reduces junction-to-ambient resistance by ~25% vs. standard DO-41, supporting higher sustained power |
| Positive temperature coefficient | +15 mV/°C allows predictable VZ drift compensation in temperature-critical bias networks |
| 10 μs surge rating | Withstands 400 W transients-sufficient for IEC 61000-4-5 Level 3 surge immunity in AC/DC front-ends |
Applications
| Industrial Power Supply Regulation | Overvoltage Protection Clamping |
|---|---|
Use Scenario: Stabilizing 24 V DC bus in programmable logic controller (PLC) backplane power distribution. IC Role / Device Role / Timing Role: Shunt regulator maintaining precise 20 V reference for analog sensor signal conditioning circuitry. Use Value: 14 Ω ZZ limits output variation to <±15 mV under 50 mA load step, ensuring ADC reference stability. |
Use Scenario: Protecting microcontroller I/O pins from ESD and lightning-induced surges on RS-485 communication lines. IC Role / Device Role / Timing Role: Fast-acting clamp diverting >1 kV transients away from sensitive interface ICs. Use Value: 400 W/10 μs surge rating absorbs IEC 61000-4-2 contact discharge energy without degradation. |
| Waveform Limiting in Signal Conditioning | Constant-Current Bias Generation |
Use Scenario: Constraining op-amp output swing to ±20 V in audio preamplifier test equipment. IC Role / Device Role / Timing Role: Bidirectional limiter using two RD20F-T8-AZ diodes in anti-parallel configuration. Use Value: Matched B3-grade VZ tolerance ensures symmetrical clipping thresholds within ±0.25 V. |
Use Scenario: Setting bias current for laser diode driver in fiber-optic transceiver modules. IC Role / Device Role / Timing Role: Zener-based current source delivering 20 mA with <1% drift over −40 to +85°C. Use Value: +15 mV/°C γZ enables predictable current scaling with temperature, simplifying calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4744A (ON Semiconductor) | 20 V nominal, ±5% tolerance (wider than RD20F-T8-AZ B3), 22 Ω ZZ at 25 mA, DO-41 package | Higher impedance increases output ripple; wider tolerance reduces precision in multi-rail systems | Select when cost sensitivity outweighs regulation accuracy; verify thermal margin due to higher ZZ loss |
| BZX85C20 (Nexperia) | 20 V nominal, ±5% tolerance, 30 Ω ZZ at 5 mA, DO-41, 1.3 W rating | Lower test current (5 mA vs. 20 mA) yields higher apparent ZZ; higher P rating requires larger heatsinking | Prefer for low-current biasing where 5 mA operation suffices; avoid in 20 mA+ shunt regulator roles |
Compared with RD20F-T8-AZ, the 1N4744A offers broader availability but sacrifices 1.5× higher dynamic impedance and looser voltage tolerance, while the BZX85C20 trades off test-current relevance and thermal efficiency for slightly higher power headroom-neither is pin-compatible nor drop-in, but both serve as functional alternatives in non-critical regulation roles.
Availability
RD20F-T8-AZ is available at Aetrix Electronics and suitable for industrial power supply regulation, overvoltage protection clamping, and waveform limiting applications requiring stable component supply, consistent parametric performance, and long-lifecycle support.
Supply support for RD20F-T8-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 formed in 2010 through the merger of NEC Electronics and Renesas Technology, specializing in microcontrollers, analog, and power devices for industrial, automotive, and infrastructure markets.
The RD20F-T8-AZ belongs to Renesas' legacy "RD" series of planar zener diodes, designed specifically for high-reliability voltage reference and transient suppression in industrial control and power conversion systems.
FAQ
What is the exact zener voltage range for RD20F-T8-AZ?
The RD20F-T8-AZ is specified as B3 grade, with a guaranteed zener voltage range of 19.59 V to 20.84 V at 20 mA test current and 40 ms post-power-on stabilization. This ±3.2% tolerance is tighter than standard ±5% zeners, making RD20F-T8-AZ suitable for applications demanding precise voltage references without trimming.
Does RD20F-T8-AZ have a positive or negative temperature coefficient?
RD20F-T8-AZ has a positive temperature coefficient of +15 mV/°C (typical), meaning its zener voltage increases with rising junction temperature. This behavior is confirmed in Figure 4 of the datasheet and is critical when designing temperature-compensated bias networks or selecting complementary devices for thermal drift cancellation.
What is the maximum surge power RD20F-T8-AZ can withstand?
RD20F-T8-AZ is rated for 400 W of non-repetitive surge reverse power at a pulse width of 10 μs (Figure 7). This capability enables robust transient voltage suppression in AC line inputs or communication port protection, provided the average power remains within the 1 W continuous limit and thermal recovery time is observed between events.
Is RD20F-T8-AZ compatible with automated PCB assembly processes?
Yes, RD20F-T8-AZ uses JEDEC DO-41 packaging with tinned axial leads fully compatible with wave soldering, selective soldering, and hand assembly. Its glass body withstands standard reflow profile thermal excursions when mounted off-board or used in hybrid assemblies, per Renesas' recommended process guidelines in Document No. D13936EJ5V0DS.
How does the DHD (Double Heatsink Diode) structure improve thermal performance of RD20F-T8-AZ?
The DHD structure in RD20F-T8-AZ enhances heat conduction from the silicon die through both axial leads and the glass body interface, reducing transient thermal impedance to 150°C/W at 1 s (Figure 8). This allows RD20F-T8-AZ to sustain higher average power in compact layouts compared to conventional DO-41 zeners, especially in natural-convection environments.
RD20F-T8-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:
- -
RD20F-T8-AZ FAQ
1.How can I place an order for RD20F-T8-AZ through Aetrix?
Please submit a Request for Quotation (RFQ) for RD20F-T8-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 RD20F-T8-AZ reliable?
The price and inventory of RD20F-T8-AZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD20F-T8-AZ is usually 5 days.
3.What payment methods are accepted for RD20F-T8-AZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD20F-T8-AZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD20F-T8-AZ?
RD20F-T8-AZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD20F-T8-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 RD20F-T8-AZ?
For technical support, including RD20F-T8-AZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD20F-T8-AZ requirements.
6.How does Aetrix verify that RD20F-T8-AZ is sourced from the original manufacturer or authorized distributors?
All RD20F-T8-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 RD20F-T8-AZ meets industry standards.
7.What is the process for return or replacement of RD20F-T8-AZ?
All RD20F-T8-AZ units undergo pre-shipment inspection (PSI). If there is an issue with RD20F-T8-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 RD20F-T8-AZ part is unused and in its original packaging.
Return procedure for RD20F-T8-AZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD20F-T8-AZ Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
