My Inquiry
My Account
Renesas RD3.9ES-T1
- Part No.:
- RD3.9ES-T1
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- -
- Datasheet:
-
RD3.9ES-T1.pdf
- Description:
- DIODE ZENER
- Quantity:
- Payment:
- Shipping:
Inventory:36,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
RD3.9ES-T1 from Renesas Electronics is a 3.9 V, 400 mW glass-encapsulated Zener diode in DO-34 package with DHD (Double Heatsink Diode) construction, ±5% zener voltage tolerance at 5 mA test current, and 5 Ω typical dynamic impedance-used for precision voltage regulation in low-power analog reference circuits.
For engineers reviewing the RD3.9ES-T1 datasheet, RD3.9ES-T1 pinout, RD3.9ES-T1 application, or RD3.9ES-T1 equivalent, this page delivers verified electrical specs, thermal behavior, surge capability, and real-world use cases for constant-voltage clamping, waveform shaping, and transient suppression in industrial control and consumer power supplies.
Technical Context
The RD3.9ES-T1 operates as a silicon planar Zener diode with sharp knee characteristics, optimized for stable reverse-biased breakdown at 3.9 V under 5 mA nominal test current. Its DHD construction enables enhanced thermal dissipation through dual heatsinking paths along the axial leads.
It exhibits a positive zener voltage temperature coefficient of +0.035 %/°C (≈1.4 mV/°C), confirmed by Fig. 9 in D13935EJ7V0DS, and supports non-repetitive surge reverse power up to 100 W for 10 µs pulses per Fig. 10-critical for ESD and line-transient protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.77–3.98 V at IZ = 5 mA - defines precise clamping threshold for 3.3 V system rail stabilization |
| Dynamic Impedance (ZZ) | 5 Ω max at IZ = 5 mA - ensures minimal output voltage variation under load current shifts |
| Power Dissipation (P) | 400 mW at TA = 25°C - sets maximum continuous DC power handling on standard PCB layouts |
| Surge Reverse Power (PRSM) | 100 W for t = 10 µs - enables robust transient absorption without failure in surge-prone interfaces |
| Junction Temperature (Tj) | 175°C max - allows operation in high-ambient environments like enclosed power adapters |
| Reverse Current (IR) | 5 µA max at VR = 0.5 V - guarantees low leakage in battery-backed or standby circuits |
| Package | DO-34 (JEDEC) - axial-leaded, glass-sealed, 2.4 mm body length, compatible with 5 mm pitch PCB insertion |
Pinout & Package
RD3.9ES-T1 uses a two-terminal DO-34 glass package with axial leads. Cathode is marked by a black band near one end. No internal circuitry or polarity-sensitive terminals beyond anode/cathode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node in reverse-bias regulation; carries forward current up to 150 mA |
| Cathode | Zener breakdown terminal | Marked with black band; connected to higher-potential node during voltage clamping; sustains 3.9 V reverse bias |
Key Features
| Feature | Design Value |
|---|---|
| DHD construction | Enables 400 mW continuous dissipation via dual thermal paths-reducing junction temperature rise by ~25% vs. standard DO-34 diodes |
| Planar process | Delivers tight VZ tolerance (±5%) and repeatable knee characteristics across production lots |
| DO-34 glass seal | Provides hermetic reliability and moisture resistance for long-term stability in humid environments |
| E24-standard VZ | Ensures compatibility with common resistor-divider networks and industry-standard reference designs |
Applications
| Industrial Sensor Reference | USB Port Overvoltage Clamp |
|---|---|
Use Scenario: Providing stable 3.9 V reference for 12-bit ADC in temperature sensor module operating from unregulated 5 V supply. IC Role / Device Role / Timing Role: Zener voltage reference diode regulating reference node against supply ripple and load transients. Use Value: Maintains <±0.5% reference accuracy over –40°C to +85°C due to low ZZ and predictable TC, enabling sub-1 LSB measurement error. | Use Scenario: Protecting USB 2.0 data lines (D+/D−) from ESD events exceeding IEC 61000-4-2 Level 4 (8 kV contact). IC Role / Device Role / Timing Role: Low-capacitance shunt clamp absorbing fast transients before they reach downstream PHY IC. Use Value: Limits voltage excursion to ≤4.2 V during 100 ns surges using 100 W/10 µs surge rating-preventing latch-up in USB transceivers. |
| LED Constant-Current Bias | AC Mains Surge Absorber |
Use Scenario: Setting bias point for high-brightness white LED string driven by linear current regulator in signage application. IC Role / Device Role / Timing Role: Zener-based current-sense reference establishing fixed voltage drop across sense resistor. Use Value: Delivers ±1.2% current regulation stability over input voltage range (4.5–5.5 V) due to 5 Ω ZZ and low IR. | Use Scenario: Suppressing 1 kV/µs line surges on 24 V AC control input of PLC I/O module. IC Role / Device Role / Timing Role: Primary surge absorber placed across input terminals ahead of bridge rectifier. Use Value: Clamps peak voltage to <4.5 V within 100 ns, limiting energy delivered to downstream TVS and protecting optocoupler input stage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4730A | 3.9 V nominal, 1 W rating, DO-41 package, 9 Ω ZZ, ±5% tolerance | Higher power but larger footprint; less suitable for space-constrained PCBs with 5 mm pitch | Choose when >400 mW continuous dissipation is required and board area permits DO-41 |
| BZX55-C3V9 | 3.9 V nominal, 500 mW rating, DO-35 package, 10 Ω ZZ, ±5% tolerance | Same voltage grade but plastic DO-35 lacks glass hermeticity and DHD thermal advantage | Prefer for cost-sensitive consumer designs where long-term humidity stability is secondary |
Compared with 1N4730A and BZX55-C3V9, RD3.9ES-T1 offers superior thermal performance in compact DO-34 form factor and lower dynamic impedance-making it optimal for precision, space-limited, and thermally demanding analog references where leakage and stability are critical.
Availability
RD3.9ES-T1 is available at Aetrix Electronics and suitable for industrial sensor references, USB port protection, LED biasing, and AC mains surge suppression requiring stable component supply and long-lifecycle support.
Supply support for RD3.9ES-T1 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, with global design and manufacturing infrastructure.
RD3.9ES-T1 belongs to the legacy NEC RD2.0ES–RD39ES Zener diode family, designed specifically for high-stability, low-power voltage reference and clamping in industrial and consumer equipment.
FAQ
What is the exact zener voltage range for RD3.9ES-T1 at 5 mA test current?
The RD3.9ES-T1 has a guaranteed zener voltage range of 3.77 V to 3.98 V when measured at IZ = 5 mA and TA = 25°C, per the "AB1" suffix row in the Electrical Characteristics table of datasheet D13935EJ7V0DS. This ±5% tolerance ensures predictable clamping behavior in precision analog circuits where RD3.9ES-T1 serves as a stable reference node.
Does RD3.9ES-T1 support surge protection, and what is its pulse rating?
Yes, RD3.9ES-T1 supports non-repetitive surge suppression with a rated surge reverse power (PRSM) of 100 W for pulse width t = 10 µs, as shown in Figure 10 of its datasheet. This capability makes RD3.9ES-T1 suitable for absorbing fast transients in interface protection circuits-provided peak pulse energy remains below 1 mJ (100 W × 10 µs), and ambient temperature stays within derated limits.
What is the thermal resistance and maximum junction temperature of RD3.9ES-T1?
RD3.9ES-T1 has a junction-to-ambient thermal resistance (RthJA) of approximately 375°C/W on a standard 7 mm² PCB (Fig. 7), and a maximum rated junction temperature (Tj) of 175°C. At 400 mW dissipation and 25°C ambient, junction temperature rises ~150°C-so RD3.9ES-T1 must be used with adequate copper area or airflow if ambient exceeds 40°C to avoid exceeding Tj limit.
Is RD3.9ES-T1 RoHS compliant and lead-free?
RD3.9ES-T1 was originally released prior to RoHS enforcement (2003 datasheet), and its DO-34 glass package contains leaded solder seals. Renesas does not list RD3.9ES-T1 as RoHS-compliant in current product databases. For new designs requiring RoHS compliance, consider modern alternatives such as BZX55C3V9 (lead-free DO-35) or SMAZ3V9-though RD3.9ES-T1 remains viable for legacy repair and non-RoHS markets.
How does the DHD (Double Heatsink Diode) construction improve RD3.9ES-T1 performance?
DHD construction in RD3.9ES-T1 provides two parallel thermal conduction paths from the silicon junction to each axial lead, reducing effective thermal resistance by ~20–25% versus conventional DO-34 diodes. This allows RD3.9ES-T1 to sustain full 400 mW dissipation at higher ambient temperatures and improves long-term parameter stability-especially critical when RD3.9ES-T1 is used in sealed enclosures or stacked PCB assemblies where airflow is limited.
RD3.9ES-T1 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:
- -
RD3.9ES-T1 FAQ
1.How can I place an order for RD3.9ES-T1 through Aetrix?
Please submit a Request for Quotation (RFQ) for RD3.9ES-T1 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 RD3.9ES-T1 reliable?
The price and inventory of RD3.9ES-T1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD3.9ES-T1 is usually 5 days.
3.What payment methods are accepted for RD3.9ES-T1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD3.9ES-T1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD3.9ES-T1?
RD3.9ES-T1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD3.9ES-T1 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 RD3.9ES-T1?
For technical support, including RD3.9ES-T1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD3.9ES-T1 requirements.
6.How does Aetrix verify that RD3.9ES-T1 is sourced from the original manufacturer or authorized distributors?
All RD3.9ES-T1 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 RD3.9ES-T1 meets industry standards.
7.What is the process for return or replacement of RD3.9ES-T1?
All RD3.9ES-T1 units undergo pre-shipment inspection (PSI). If there is an issue with RD3.9ES-T1, 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 RD3.9ES-T1 part is unused and in its original packaging.
Return procedure for RD3.9ES-T1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD3.9ES-T1 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…
