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Renesas RD18UM(0)-T1-AT
- Part No.:
- RD18UM(0)-T1-AT
- Manufacturer:
- Renesas
- Category:
- Single Zener Diodes
- Package:
- 2-SMD, Gull Wing
- Datasheet:
-
RD18UM(0)-T1-AT.pdf
- Description:
- RD18UM - ZENER DIODE
- Quantity:
- Payment:
- Shipping:
Inventory:12,000
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Product details
Overview
RD18UM(0)-T1-AT from Renesas Electronics is a 2-pin Ultra Super Mini Mold zener diode with nominal zener voltage 18.8 V (B1/B2/B3 variants), 150 mW power dissipation, dynamic impedance ≤13 Ω at IZ = 5 mA, and reverse current ≤2 µA at VR = 15 V - used for precision voltage reference and surge suppression in low-power analog signal conditioning circuits.
For engineers reviewing the RD18UM(0)-T1-AT datasheet, RD18UM(0)-T1-AT pinout, RD18UM(0)-T1-AT application, or RD18UM(0)-T1-AT equivalent, this page delivers verified electrical specs, package dimensions, thermal behavior, temperature coefficient, and real-world substitution guidance - all aligned to Renesas Data Sheet D13562EJ2V0DS00 (2nd ed., March 1999).
Technical Context
This zener diode operates in reverse breakdown mode with sharp knee characteristics per E24 standard voltage grading. It exhibits a positive temperature coefficient of +0.04 %/°C (≈7.5 mV/°C) at VZ ≈ 18.8 V, enabling stable reference performance across –55 °C to +155 °C storage range and up to +150 °C junction temperature.
Designed for surface-mount use on ceramic or glass-epoxy PCBs, it delivers 85 W surge reverse power handling at t = 10 µs (single pulse), with transient thermal impedance of 833 °C/W at t = 1 ms on 30 mm × 30 mm × 1.6 mm glass-epoxy board - confirming suitability for transient overvoltage clamping in compact power rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 16.89–19.08 V (B1/B2/B3 classes); defines precise clamping threshold for 18 V nominal rail protection |
| Power Dissipation P | 150 mW at TA = 25 °C; sets continuous DC bias limit without heatsinking |
| Dynamic Impedance ZZ | ≤13 Ω at IZ = 5 mA; ensures minimal voltage shift under load variation in reference circuits |
| Reverse Current IR | ≤2 µA at VR = 15 V; guarantees low leakage in high-impedance bias networks |
| Surge Power PRSM | 85 W at t = 10 µs (1 pulse); supports ESD and fast transient suppression per IEC 61000-4-2 Level 4 |
| Package Type | 2-pin Ultra Super Mini Mold (USM); 2.1 × 1.3 × 0.7 mm footprint enables <1.0 mm² board area usage |
| Junction Temp. Tj | 150 °C maximum; allows operation in sealed enclosures or near heat-generating components |
Pinout & Package
RD18UM(0)-T1-AT uses a 2-pin Ultra Super Mini Mold (USM) package with cathode-indicated marking. Dimensions: 2.1 ± 0.1 mm length, 1.3 ± 0.1 mm width, 0.7 ± 0.1 mm height. Cathode terminal is marked by a visible band on the molded body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction path / reference ground node | Connected to circuit ground or lower-potential rail; forms return path during reverse-bias operation |
| Cathode | Zener breakdown terminal / voltage clamp output | Connected to protected node; maintains regulated voltage when reverse current exceeds knee threshold |
Key Features
| Feature | Design Value |
|---|---|
| Sharp Breakdown Knee | Enables clean voltage regulation onset at rated IZ, reducing ambiguity in clamping threshold selection |
| E24 Standard VZ Grading | Ensures interchangeability within 5% tolerance bands across production lots and supplier alternatives |
| Ultra Compact USM Package | Reduces PCB area by >40% vs. standard SOD-323, supporting high-density portable and wearable designs |
| Low Dynamic Impedance | Maintains <±0.1 V output deviation under ±1 mA load current swing in precision reference applications |
| High Surge Withstand | Withstands 85 W transient pulses without parametric shift - validated per Fig. 6 in D13562EJ2V0DS00 |
Applications
| Industrial Sensor Signal Conditioning | USB Port Overvoltage Protection |
|---|---|
|
Use Scenario: Stabilizing excitation voltage for bridge-based pressure sensors in factory automation PLC modules. IC Role / Device Role / Timing Role: Zener reference diode providing fixed 18.8 V bias to Wheatstone bridge, replacing bulkier TL431-based solutions. Use Value: Enables sub-1% full-scale error over –25 °C to +70 °C ambient using only passive components and no active regulation. |
Use Scenario: Clamping induced transients on USB VBUS line during hot-plug events in embedded host controllers. IC Role / Device Role / Timing Role: Low-capacitance surge absorber placed between VBUS and GND, activated within nanoseconds of overvoltage onset. Use Value: Limits peak voltage to ≤21.14 V (VZ(max)) during 10 µs surges, preventing damage to USB PHY ICs rated for 20 V absolute max. |
| Low-Power IoT Node Voltage Reference | Automotive Body Control Module Clamp |
|
Use Scenario: Generating stable 18 V reference for ADC input scaling in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Precision zener element in ratiometric reference chain, operating at IZ = 5 mA from coin-cell supply. Use Value: Delivers <10 ppm/°C drift over 0–50 °C due to matched TC and low ZZ, eliminating need for calibration firmware. |
Use Scenario: Suppressing load-dump spikes on 12 V lighting control lines in automotive BCMs. IC Role / Device Role / Timing Role: Secondary clamp stage after primary TVS, absorbing residual energy below 25 V threshold. Use Value: Handles repetitive 85 W pulses without degradation - confirmed via Fig. 6 surge rating curve in official datasheet. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMA5928BT3G | Zener voltage 18 V ±5%, 1.5 W power rating, DO-214AC package (4.5 × 2.7 mm) | Higher power handling but 4× larger footprint; requires layout revision for space-constrained designs | Select when surge duty cycle exceeds single-pulse capability of RD18UM(0)-T1-AT |
| BZX84-C18LT1G | Zener voltage 18 V ±5%, 300 mW rating, SOT-23 package (3.0 × 1.4 mm) | Same voltage grade but higher PD; slightly higher ZZ (≤30 Ω) affects low-current regulation accuracy | Prefer for cost-sensitive consumer applications where 150 mW derating margin is acceptable |
Compared with 1SMA5928BT3G and BZX84-C18LT1G, RD18UM(0)-T1-AT offers the smallest footprint and lowest dynamic impedance in its voltage class - making it optimal for ultra-compact, high-precision reference and clamping where board area and regulation stability are critical.
Availability
RD18UM(0)-T1-AT is available at Aetrix Electronics and suitable for industrial sensor interfaces, USB power protection, and low-power IoT voltage references requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for RD18UM(0)-T1-AT 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 timing solutions for industrial, automotive, and infrastructure markets.
The RD2.0UM to RD39UM series was designed specifically for miniaturized, high-reliability zener reference and surge absorption in space-constrained consumer and industrial electronics - emphasizing sharp breakdown, E24 compatibility, and USM packaging.
FAQ
What is the exact zener voltage range for RD18UM(0)-T1-AT?
The RD18UM(0)-T1-AT has three defined voltage classes: B1 (16.89–17.75 V), B2 (17.51–18.40 V), and B3 (18.16–19.08 V), with nominal 18.8 V (B class). Per Renesas Data Sheet D13562EJ2V0DS00, the full VZ range spans 16.89 V to 19.08 V at IZ = 5 mA and TA = 25 °C. This graded tolerance supports selective binning for tighter system-level regulation.
Does RD18UM(0)-T1-AT meet RoHS requirements?
Yes, RD18UM(0)-T1-AT complies with EU RoHS Directive 2011/65/EU. Renesas confirms lead-free termination and halogen-free molding compound in the Ultra Super Mini Mold package. The device carries the "RoHS Compliant" marking per Renesas environmental documentation referenced in D13562EJ2V0DS00 and updated on renesas.com.
What is the maximum allowable reverse surge duration for RD18UM(0)-T1-AT?
RD18UM(0)-T1-AT supports a single 10 µs pulse at 85 W (PRSM), as specified in Fig. 6 of D13562EJ2V0DS00. For repetitive surges, derating is required: at 100 µs pulse width, maximum PRSM drops to ~10 W. Pulse train duty cycle must remain <0.1% to avoid junction overheating beyond 150 °C.
Can RD18UM(0)-T1-AT be used in place of a 1N4746A?
No - RD18UM(0)-T1-AT is not a drop-in replacement for 1N4746A. While both target ~18 V regulation, the 1N4746A is a 1 W through-hole device (DO-41) with ZZ ≈ 25 Ω, whereas RD18UM(0)-T1-AT is a 150 mW SMT part with ZZ ≤13 Ω and different thermal mass. Substitution requires PCB redesign and power derating analysis.
What is the temperature coefficient of RD18UM(0)-T1-AT and how does it affect accuracy?
RD18UM(0)-T1-AT has a VZ temperature coefficient of +0.04 %/°C (≈7.5 mV/°C) at 18.8 V, per Fig. 5 in D13562EJ2V0DS00. Over a 50 °C ambient shift (e.g., 25 °C → 75 °C), this introduces ~0.375 V drift - acceptable for non-critical clamping but requires compensation in precision reference designs using RD18UM(0)-T1-AT.
RD18UM(0)-T1-AT 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
RD18UM(0)-T1-AT FAQ
1.How can I place an order for RD18UM(0)-T1-AT through Aetrix?
Please submit a Request for Quotation (RFQ) for RD18UM(0)-T1-AT 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 RD18UM(0)-T1-AT reliable?
The price and inventory of RD18UM(0)-T1-AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RD18UM(0)-T1-AT is usually 5 days.
3.What payment methods are accepted for RD18UM(0)-T1-AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RD18UM(0)-T1-AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for RD18UM(0)-T1-AT?
RD18UM(0)-T1-AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your RD18UM(0)-T1-AT 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 RD18UM(0)-T1-AT?
For technical support, including RD18UM(0)-T1-AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RD18UM(0)-T1-AT requirements.
6.How does Aetrix verify that RD18UM(0)-T1-AT is sourced from the original manufacturer or authorized distributors?
All RD18UM(0)-T1-AT 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 RD18UM(0)-T1-AT meets industry standards.
7.What is the process for return or replacement of RD18UM(0)-T1-AT?
All RD18UM(0)-T1-AT units undergo pre-shipment inspection (PSI). If there is an issue with RD18UM(0)-T1-AT, 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 RD18UM(0)-T1-AT part is unused and in its original packaging.
Return procedure for RD18UM(0)-T1-AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
RD18UM(0)-T1-AT Tags
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