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Renesas RD18UJ-T1-A
- Part No.:
- RD18UJ-T1-A
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- 2-SMD, Gull Wing
- Datasheet:
-
RD18UJ-T1-A.pdf
- Description:
- RD18UJ-T1-A - LOW NOISE SHARP BR
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
RD18UJ-T1-A from Renesas Electronics is a 2-pin Ultra Super Mini Mold zener diode with nominal zener voltage of 17.24 V to 18.81 V (Class N2/N3), 150 mW power dissipation, low-noise operation, and sharp breakdown characteristics-designed for precision voltage reference and surge suppression in audio and instrumentation circuits.
For engineers reviewing the RD18UJ-T1-A datasheet, RD18UJ-T1-A pinout, RD18UJ-T1-A application, or RD18UJ-T1-A equivalent, key selection criteria include zener voltage tolerance (±3.1% for N2, ±2.9% for N3), dynamic impedance (≤200 Ω at Iz = 0.5 mA), reverse current limit (≤80 µA at VR = 13 V), and thermal derating above 25 °C ambient.
Technical Context
This device operates as a two-terminal voltage-regulating element relying on controlled reverse-biased avalanche breakdown. Its sharp knee characteristic enables stable clamping with minimal voltage variation under varying current loads between 0.1 mA and 5 mA.
The RD18UJ-T1-A exhibits a positive temperature coefficient (γz ≈ +0.04 %/°C at Vz ≈ 18 V), requiring thermal compensation in high-precision references. It is rated for junction temperatures up to 150 °C and supports transient surge power of 2.2 W for 10 µs pulses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (Vz) | 17.24–18.81 V (N2/N3 classes); defines stable regulation point under 0.5 mA test current |
| Power Dissipation (P) | 150 mW at TA = 25 °C; derates linearly above 25 °C per Fig. 1 |
| Reverse Current (IR) | ≤80 µA at VR = 13 V; ensures low leakage in standby or high-impedance bias networks |
| Dynamic Impedance (Zz) | ≤200 Ω at Iz = 0.5 mA; determines output voltage stability under load transients |
| Surge Power (PRSM) | 2.2 W for 10 µs pulse; enables transient overvoltage absorption without failure |
| Junction Temp (Tj) | 150 °C max; sets upper thermal limit for PCB layout and heatsinking decisions |
Pinout & Package
RD18UJ-T1-A uses a 2-pin Ultra Super Mini Mold package (SOD-323 equivalent footprint), with cathode indicated by a band. The package measures 1.3 ± 0.1 mm × 0.8 ± 0.1 mm × 0.7 ± 0.1 mm (L × W × H) and is surface-mount compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reference ground node in shunt regulator | Connected to circuit ground or lower-potential rail; carries forward current up to 100 mA |
| Cathode | Zener breakdown terminal / Regulated output node | Connected to input supply; maintains stable voltage relative to anode during reverse bias |
Key Features
| Feature | Design Value |
|---|---|
| Low noise operation | Enables use in audio signal paths and sensitive analog front-ends without introducing measurable ripple or hiss |
| Sharp breakdown knee | Minimizes transition region between conduction and cutoff-critical for accurate clipping and threshold detection |
| E24-standardized Vz | Ensures compatibility with standard resistor/capacitor value series in feedback and bias networks |
| 150 mW rating in ultra-miniature package | Supports space-constrained designs in portable instrumentation and compact audio modules |
Applications
| Audio Equipment Voltage Reference | Instrumentation Signal Clipping |
|---|---|
Use Scenario: Biasing op-amp input stages and setting reference levels in headphone amplifiers and DAC output buffers. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable DC offset independent of supply variation. Use Value: RD18UJ-T1-A's low noise and sharp knee prevent audible distortion while maintaining ±0.5% regulation across 0.2–2 mA load range. |
Use Scenario: Limiting peak amplitude in oscilloscope front-end attenuators and spectrum analyzer log amplifiers. IC Role / Device Role / Timing Role: Passive waveform clipper defining upper/lower signal bounds before ADC sampling. Use Value: RD18UJ-T1-A's consistent 17.24–18.81 V breakdown enables repeatable clipping thresholds with <10 ns response to fast transients. |
| Surge Protection in Sensor Interfaces | Constant Current Source Biasing |
Use Scenario: Protecting 12–24 V industrial sensor inputs against ESD and inductive kickback from solenoids or motors. IC Role / Device Role / Timing Role: Transient voltage suppressor placed across input terminals ahead of conditioning circuitry. Use Value: RD18UJ-T1-A absorbs 2.2 W surges (10 µs) without degradation, preserving downstream amplifier integrity in harsh environments. |
Use Scenario: Establishing stable bias current for photodiode transimpedance amplifiers and LED driver references. IC Role / Device Role / Timing Role: Current-setting element in series with a ballast resistor to define precise Iz-dependent current. Use Value: RD18UJ-T1-A's ≤200 Ω Zz ensures current stability within ±1.5% over 0.1–1 mA operating range, critical for low-drift sensing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C18LT1G | 18 V nominal, ±5% tolerance, 300 mW rating, SOT-23 package | Higher power handling but larger footprint; higher IR (≤100 µA at 14.4 V) | Preferred where board space allows and higher surge margin is needed; not drop-in due to 3-pin SOT-23 vs. 2-pin SOD-323 |
| MMSZ5246B-TP | 18 V nominal, ±5% tolerance, 500 mW rating, SOD-123 package | Larger thermal mass; higher Zz (≤35 Ω typical but only at 20 mA Iz) | Suitable for higher-current regulation; requires layout revision due to 2.7 × 1.4 mm body vs. RD18UJ-T1-A's 1.3 × 0.8 mm |
Compared with BZX84-C18LT1G and MMSZ5246B-TP, RD18UJ-T1-A offers tighter voltage tolerance (±3.1% vs. ±5%), lower profile (0.7 mm height), and optimized low-current performance (Zz specified at 0.5 mA), making it preferable for miniaturized, low-power, precision-clipping designs where thermal constraints limit larger packages.
Availability
RD18UJ-T1-A is available at Aetrix Electronics and suitable for audio equipment, instrumentation signal conditioning, industrial sensor protection, and low-power constant-current biasing requiring stable component supply and long-term obsolescence management.
Supply support for RD18UJ-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, with global design and manufacturing infrastructure.
RD18UJ-T1-A belongs to the RDxUJ series of low-noise zener diodes developed for high-fidelity audio and precision measurement applications where sharp breakdown and minimal noise are essential.
FAQ
What is the exact zener voltage range for RD18UJ-T1-A?
The RD18UJ-T1-A is offered in three tolerance classes: N1 (16.63–17.52 V), N2 (17.24–18.15 V), and N3 (17.87–18.81 V), all tested at Iz = 0.5 mA. The part marking does not indicate class; users must verify class via lot-specific test data or ordering code suffix. RD18UJ-T1-A corresponds to the N2/N3 variants per Renesas datasheet D13938EJ3V0DS00.
Is RD18UJ-T1-A RoHS compliant?
Yes, RD18UJ-T1-A complies with EU RoHS Directive 2011/65/EU. Renesas confirms lead-free termination and halogen-free molding compound in accordance with its environmental compliance documentation. No exemptions apply; full substance declarations are available upon request from Renesas sales offices.
Can RD18UJ-T1-A be used in series for higher voltage regulation?
No-RD18UJ-T1-A is not characterized or guaranteed for series connection. Zener voltage matching, thermal coupling, and current-sharing imbalance between devices introduce unpredictability. For >18.81 V regulation, select a single higher-voltage zener (e.g., RD20UJ) or use active regulation instead.
What is the maximum allowable reverse surge current for RD18UJ-T1-A?
RD18UJ-T1-A supports a peak reverse surge power of 2.2 W for 10 µs pulses (Fig. 5). At Vz ≈ 18 V, this corresponds to ~122 mA peak surge current. Exceeding this limit-even briefly-risks irreversible junction damage. Always verify pulse energy (I²t) against the transient thermal impedance curve (Fig. 4).
Does RD18UJ-T1-A require derating at elevated ambient temperatures?
Yes-RD18UJ-T1-A must be derated linearly above 25 °C ambient. Per Fig. 1, power dissipation drops to 0 mW at ~150 °C. At 70 °C ambient, maximum continuous power is ~105 mW. PCB copper area, material, and airflow directly affect actual junction temperature and must be validated in final layout.
RD18UJ-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
RD18UJ-T1-A FAQ
1.How can I place an order for RD18UJ-T1-A through Aetrix?
Please submit a Request for Quotation (RFQ) for RD18UJ-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 RD18UJ-T1-A reliable?
The price and inventory of RD18UJ-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 RD18UJ-T1-A is usually 5 days.
3.What payment methods are accepted for RD18UJ-T1-A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD18UJ-T1-A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD18UJ-T1-A?
RD18UJ-T1-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD18UJ-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 RD18UJ-T1-A?
For technical support, including RD18UJ-T1-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD18UJ-T1-A requirements.
6.How does Aetrix verify that RD18UJ-T1-A is sourced from the original manufacturer or authorized distributors?
All RD18UJ-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 RD18UJ-T1-A meets industry standards.
7.What is the process for return or replacement of RD18UJ-T1-A?
All RD18UJ-T1-A units undergo pre-shipment inspection (PSI). If there is an issue with RD18UJ-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 RD18UJ-T1-A part is unused and in its original packaging.
Return procedure for RD18UJ-T1-A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD18UJ-T1-A Tags
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