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Renesas RD39UM-T1-A
- Part No.:
- RD39UM-T1-A
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- 2-SMD, Gull Wing
- Datasheet:
-
RD39UM-T1-A.pdf
- Description:
- RD39UM-T1-A - ZENER DIODES 2PIN
- Quantity:
- Payment:
- Shipping:
Inventory:72,000
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Product details
Overview
RD39UM-T1-A from Renesas Electronics is a 2-pin Ultra Super Mini Mold surface-mount zener diode rated for 150 mW power dissipation, with a nominal zener voltage of 39 V (min 37.0 V, max 41.0 V at IZ = 2 mA), dynamic impedance of 30 Ω, and reverse current ≤2 µA at VR = 30 V. It serves as a precision voltage reference or surge absorber in low-power analog signal conditioning circuits.
For engineers reviewing the RD39UM-T1-A datasheet, RD39UM-T1-A pinout, RD39UM-T1-A application, or RD39UM-T1-A equivalent, this device is selected for stable 39 V clamping in compact DC bias networks, ESD protection paths, and waveform shaping stages where tight VZ tolerance (±5.1%) and low ZZ are critical under low-current operation.
Technical Context
This zener diode operates in reverse breakdown mode with sharp knee characteristics, optimized for constant-voltage regulation and transient suppression at low test currents (IZ = 2 mA). Its E24-standardized VZ value ensures compatibility with common reference design practices across consumer and industrial electronics.
The device uses an ultra-miniature molded package (2.1 × 1.3 × 0.7 mm) with cathode-indicated marking, enabling high-density PCB layouts. Thermal performance is characterized by transient thermal impedance curves up to 100 ms pulse width, supporting short-duration surge absorption per Fig. 6 (PRSM = 85 W at t = 10 µs).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 37.0–41.0 V at IZ = 2 mA - defines precise clamping threshold for 39 V nominal rail stabilization |
| Power Dissipation (P) | 150 mW at TA = 25 °C - sets maximum continuous DC power handling on standard FR-4 PCB |
| Dynamic Impedance (ZZ) | 30 Ω - indicates low AC impedance near operating point, minimizing voltage variation under load changes |
| Reverse Current (IR) | ≤2 µA at VR = 30 V - ensures minimal leakage in high-impedance bias networks |
| Surge Power (PRSM) | 85 W at t = 10 µs - supports single-pulse transient suppression without failure |
| Junction Temperature (Tj) | 150 °C - establishes upper thermal limit for reliability in sealed enclosures or elevated ambient conditions |
Pinout & Package
RD39UM-T1-A uses a 2-pin Ultra Super Mini Mold package (2.1 ± 0.1 mm × 1.3 ± 0.1 mm × 0.7 ± 0.1 mm) with cathode indicated by a band. No separate anode/cathode labeling beyond polarity marking; terminals are unidirectional and non-reversible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reference ground node | Connected to lower-potential side in reverse-biased configuration; forms return path for zener current |
| Cathode | Breakdown voltage terminal / Input clamp node | Marked with band; connected to protected node or voltage source to enable controlled reverse conduction at VZ |
Key Features
| Feature | Design Value |
|---|---|
| Sharp breakdown knee | Enables clean voltage clamping with minimal transition region-critical for accurate waveform clipping |
| E24-standard VZ | Ensures interoperability with industry-standard resistor and capacitor values in feedback and divider networks |
| Ultra-miniature SMD package | 2.1 × 1.3 mm footprint allows placement in space-constrained sensor modules and portable device power rails |
| Low leakage (IR ≤2 µA) | Maintains accuracy in high-impedance biasing applications such as op-amp reference inputs or comparator thresholds |
Applications
| Industrial Sensor Signal Conditioning | USB Port ESD Protection |
|---|---|
Use Scenario: Stabilizing reference voltage for 4–20 mA transmitter output stages in PLC analog I/O modules. IC Role / Device Role / Timing Role: Zener voltage reference providing fixed 39 V bias to current-regulating transistor base. Use Value: Tight VZ tolerance (±5.1%) and low ZZ (30 Ω) ensure <±0.2% output current drift over temperature and supply variation. |
Use Scenario: Secondary-level transient suppression on USB VBUS line in embedded host controllers. IC Role / Device Role / Timing Role: Low-capacitance shunt clamp absorbing ESD events before reaching USB PHY IC. Use Value: 85 W surge rating at 10 µs enables compliance with IEC 61000-4-2 Level 4 (±15 kV air) when combined with series impedance. |
| Audio Equipment DC Bias Networks | Programmable Logic Controller (PLC) Input Protection |
Use Scenario: Setting bias point for Class-A headphone amplifier output stage in portable DAC/amp designs. IC Role / Device Role / Timing Role: Precision voltage clamp defining quiescent operating point for MOSFET driver stage. Use Value: 150 mW rating supports continuous DC bias without thermal derating on 2-layer PCBs with minimal copper area. |
Use Scenario: Overvoltage protection for 24 V digital input channels in industrial control cabinets. IC Role / Device Role / Timing Role: Standoff clamp limiting transient spikes to safe levels before optocoupler input. Use Value: Cathode-marked polarity and 2-pin SMD form factor simplify automated assembly and reduce BOM count vs. discrete resistor-zener combos. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX55-C39 (ON Semiconductor) | Same VZ range (37–41 V), but 500 mW rating and DO-35 through-hole package | Requires PCB redesign for through-hole mounting; higher power enables higher continuous current but larger footprint | Select when board-level surge energy exceeds 85 W × 10 µs and manual rework is acceptable |
| MMSZ5267B (Diodes Inc.) | 39 V nominal, SOD-123 package (2.7 × 1.4 mm), 500 mW rating, ZZ = 70 Ω | Larger footprint and higher ZZ reduce precision in low-current references but improve thermal margin | Prefer for cost-sensitive production where 30 Ω ZZ is not required and 500 mW headroom justifies size increase |
Compared with RD39UM-T1-A, BZX55-C39 offers higher power but requires through-hole layout changes, while MMSZ5267B provides greater thermal robustness in a slightly larger SMD package at the expense of dynamic impedance-making RD39UM-T1-A optimal for space-constrained, low-leakage 39 V reference designs.
Availability
RD39UM-T1-A is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB port ESD protection, and audio equipment DC bias networks requiring stable component supply with full traceability and RoHS compliance.
Supply support for RD39UM-T1-A 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 Japanese semiconductor manufacturer specializing in microcontrollers, analog and power devices, and system-on-chip solutions for industrial, automotive, and consumer markets.
The RD2.0UM to RD39UM series was designed specifically for compact, low-power voltage regulation and transient suppression in space-constrained consumer and industrial electronics-emphasizing tight VZ tolerance, miniature packaging, and reliable low-current breakdown behavior.
FAQ
What is the zener voltage tolerance of RD39UM-T1-A?
The RD39UM-T1-A has a zener voltage range of 37.0 V to 41.0 V at IZ = 2 mA, corresponding to a ±5.1% tolerance around the nominal 39 V rating. This tolerance is defined per the E24 standard and verified under pulsed test conditions (40 ms), ensuring consistency across production lots for precision biasing applications.
Can RD39UM-T1-A be used in place of a 36 V zener diode?
No-RD39UM-T1-A is specified only for 39 V nominal operation and must not be substituted for 36 V zeners like RD36UM without circuit validation. The RD36UM has distinct VZ (34.0–38.0 V), ZZ (27 Ω), and IR limits; using RD39UM-T1-A would raise clamping voltage by ~3 V, potentially exceeding downstream component ratings.
What is the maximum continuous forward current for RD39UM-T1-A?
The RD39UM-T1-A supports a maximum forward current (IF) of 100 mA at TA = 25 °C. This rating applies only during forward conduction (anode positive relative to cathode); the device is intended for reverse-bias operation, and sustained forward current above 100 mA risks thermal damage even with brief exposure.
Does RD39UM-T1-A meet RoHS requirements?
Yes-RD39UM-T1-A complies with the EU RoHS Directive (2011/65/EU) as confirmed by Renesas Electronics' environmental compliance documentation. Lead-free soldering is supported, and the device contains no restricted substances above threshold limits, making it suitable for environmentally regulated consumer and industrial products.
How does the thermal performance of RD39UM-T1-A compare to larger-package zeners?
RD39UM-T1-A exhibits higher thermal resistance due to its Ultra Super Mini Mold package: transient thermal impedance reaches 833 °C/W at t = 1 ms on a glass-epoxy PCB (30 × 30 × 1.6 mm). Larger packages like DO-35 offer lower Zth, so RD39UM-T1-A requires careful layout-such as localized copper pours-to manage junction temperature rise during repetitive surges.
RD39UM-T1-A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 2-SMD, Gull Wing
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- -
- Tolerance:
- -
- Power - Max:
- -
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- -
- Voltage - Forward (Vf) (Max) @ If:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 2-Ultra Super Mini Mold
RD39UM-T1-A FAQ
1.How can I place an order for RD39UM-T1-A through Aetrix?
Please submit a Request for Quotation (RFQ) for RD39UM-T1-A 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 RD39UM-T1-A reliable?
The price and inventory of RD39UM-T1-A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD39UM-T1-A is usually 5 days.
3.What payment methods are accepted for RD39UM-T1-A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD39UM-T1-A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD39UM-T1-A?
RD39UM-T1-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD39UM-T1-A 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 RD39UM-T1-A?
For technical support, including RD39UM-T1-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD39UM-T1-A requirements.
6.How does Aetrix verify that RD39UM-T1-A is sourced from the original manufacturer or authorized distributors?
All RD39UM-T1-A 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 RD39UM-T1-A meets industry standards.
7.What is the process for return or replacement of RD39UM-T1-A?
All RD39UM-T1-A units undergo pre-shipment inspection (PSI). If there is an issue with RD39UM-T1-A, 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 RD39UM-T1-A part is unused and in its original packaging.
Return procedure for RD39UM-T1-A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD39UM-T1-A Tags
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