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Diodes Incorporated SR302-T
- Part No.:
- SR302-T
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Diodes
- Package:
- DO-201AD, Axial
- Datasheet:
-
SR302-T.pdf
- Description:
- DIODE SCHOTTKY 20V 3A DO201AD
- Quantity:
- Payment:
- Shipping:
Inventory:9,325
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Product details
Overview
SR302-T from Diodes Incorporated is a high-current Schottky barrier rectifier in DO-201AD axial package, rated for 20 V peak repetitive reverse voltage, 3.0 A average rectified output current at 95°C lead temperature, and 80 A non-repetitive surge current (8.3 ms half-sine). It delivers low forward voltage drop (0.55 V @ 3.0 A) and low thermal resistance (20 °C/W), enabling efficient DC power conversion in compact AC/DC adapters and switch-mode power supplies.
For engineers reviewing the SR302-T datasheet, SR302-T pinout, SR302-T application, or SR302-T equivalent, key selection criteria include its 20 V blocking rating, 0.55 V VF at rated current, 300 pF junction capacitance at 4 V, -65 to +150 °C operating range, and DO-201AD mechanical compatibility with legacy axial-mount PCB layouts.
Technical Context
This Schottky rectifier uses a guard-ringed silicon die structure to enhance transient voltage immunity while maintaining low forward conduction loss. Its low VF and high IFSM support high-efficiency, high-density secondary-side rectification in offline SMPS and DC-DC converters where thermal management is constrained.
The device operates with no minority-carrier storage delay, enabling fast switching with minimal reverse recovery loss. Its 300 pF junction capacitance at 4 V reverse bias and 20 °C/W junction-to-ambient thermal resistance are optimized for 50–100 kHz power stage frequencies in cost-sensitive consumer and industrial power supplies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 20 V - Maximum repetitive reverse voltage before breakdown; sets usable input voltage headroom in 12 V output designs. |
| IO (TL = 95°C) | 3.0 A - Continuous DC output current capability with vertical PCB mounting and 9.5 mm lead length; defines minimum heatsinking requirement. |
| VF @ 3.0 A | 0.55 V - Forward voltage drop at rated current; directly determines conduction loss (1.65 W) and thermal load in steady-state operation. |
| IFSM | 80 A - Peak non-repetitive surge current tolerance (8.3 ms half-sine); supports inrush current handling during cold start. |
| RJA | 20 °C/W - Junction-to-ambient thermal resistance under specified test conditions; enables thermal budget calculation for board-level layout. |
| CT @ 4 V | 300 pF - Typical junction capacitance at 4 V reverse bias; impacts high-frequency switching noise and EMI filter design. |
Pinout & Package
DO-201AD molded plastic axial-leaded package (UL 94V-0 rated), with cathode identified by a band on the body. Leads are solderable per MIL-STD-202, Method 208. Weight: ~1.2 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unbanded end) | Input current entry point | Connects to transformer secondary or switching node; must handle full load current and surge transients. |
| Cathode (banded end) | Output current exit point | Connects to output capacitor and load; polarity marking prevents reverse-bias damage during assembly. |
Key Features
| Feature | Design Value |
|---|---|
| Low forward voltage drop | 0.55 V @ 3.0 A reduces conduction loss by >30% vs. comparable PN rectifiers, lowering thermal stress in sealed enclosures. |
| Guard ring construction | Enhances ruggedness against voltage transients and improves long-term reliability in unregulated line-connected applications. |
| High surge current rating | 80 A IFSM withstands repeated cold-start surges without degradation, supporting robust design in universal-input AC/DC adapters. |
| DO-201AD mechanical standardization | Enables direct replacement in existing axial-mount footprints, minimizing PCB redesign effort during component refresh. |
Applications
| AC/DC Adapter Secondary Rectification | USB Power Delivery (PD) Output Stage |
|---|---|
Use Scenario: 12 V/2.5 A output stage in wall-mounted AC/DC adapter with universal input (90–264 VAC). IC Role / Device Role / Timing Role: Primary secondary-side rectifier converting transformer output to regulated DC; operates continuously at 3 A average load. Use Value: 0.55 V VF minimizes heat generation in confined space, allowing use of smaller heatsinks or no heatsink at ambient ≤40°C. | Use Scenario: 5 V/3 A output rectification in USB-C PD source module with synchronous buck topology. IC Role / Device Role / Timing Role: Freewheeling diode during low-side switch off-time; handles 3 A DC plus ripple current up to 1.5 A pk-pk. Use Value: 300 pF CT limits high-frequency ringing, reducing conducted EMI without requiring snubber networks. |
| Industrial DC-DC Converter Input Protection | LED Driver Constant-Current Stage |
Use Scenario: Reverse-polarity and surge protection at 24 V DC input of isolated 12 V/1 A industrial DC-DC converter. IC Role / Device Role / Timing Role: Series-blocking rectifier preventing backfeed and absorbing line transients; biased near zero volts during normal operation. Use Value: Guard ring structure sustains 80 A surge events without parametric shift, extending field life in factory automation environments. | Use Scenario: Output rectification in constant-current LED driver powering 10× 350 mA white LEDs in series (35 V total). IC Role / Device Role / Timing Role: Main output rectifier conducting continuous 350 mA with 20 V reverse bias across cathode-anode. Use Value: 20 V VRRM provides 2× safety margin over 35 V string voltage, ensuring reliable blocking during open-circuit fault conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Schottky rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SB320-T | Same DO-201AD package, 20 V VRRM, but lower VF (0.52 V @ 3 A) and higher IFSM (100 A); RoHS-compliant lead finish. | Preferred for new designs targeting improved efficiency and extended surge margin; requires same footprint. | Select SB320-T when upgrading legacy designs for better thermal performance and compliance. |
| SS32 | DO-204AL (SMA) surface-mount package; identical 20 V/3 A ratings but VF = 0.5 V @ 3 A and RJA = 45 °C/W. | Suitable only for SMT-based boards; requires rework of pad layout and thermal relief design. | Choose SS32 only if transitioning to surface-mount assembly and accepting higher thermal resistance. |
Compared with SR302-T, SB320-T offers lower conduction loss and higher surge tolerance in the same axial package, while SS32 enables miniaturization at the cost of reduced thermal performance and incompatible mounting.
Availability
SR302-T is available at Aetrix Electronics and suitable for AC/DC adapters, USB power delivery modules, and industrial DC-DC converters requiring stable component supply and proven axial-leaded reliability.
Supply support for SR302-T 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in power management, signal integrity, and protection devices for high-volume industrial and consumer applications.
The SR302-T belongs to the SR3xx family of high-current Schottky rectifiers designed specifically for cost-effective, thermally efficient secondary-side rectification in offline power supplies with legacy through-hole constraints.
FAQ
Is SR302-T suitable for new designs?
No - the datasheet explicitly states "NOT RECOMMENDED FOR NEW DESIGNS, USE SB3X0 SERIES". SR302-T remains viable for legacy repair, maintenance, and continuity builds where DO-201AD axial mounting is fixed, but SB320-T or SB330-T offer improved efficiency, surge rating, and RoHS compliance for new projects.
What is the maximum allowable case temperature during operation?
The SR302-T has a maximum junction temperature of +150°C and a storage temperature range of -65°C to +150°C. With RJA = 20°C/W and 3.0 A load, junction temperature rise is ~60°C above ambient; thus, maximum ambient must be limited to +90°C to stay within TJ limit under full load.
Can SR302-T replace a 1N5822 in an existing design?
Yes - both are DO-201AD axial Schottky rectifiers rated for 3 A average current. SR302-T (20 V VRRM) matches 1N5822's 20 V rating and offers lower VF (0.55 V vs. typical 0.65 V), improving efficiency. Polarity marking and lead dimensions are identical, enabling direct substitution without layout change.
Does SR302-T require derating for capacitive loads?
Yes - the datasheet specifies "For capacitive load, derate current by 20%". At full-rated 3.0 A average output, the safe continuous current drops to 2.4 A when feeding bulk capacitance directly, due to increased peak current stress and potential thermal runaway from high ripple current.
SR302-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-201AD, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Technology:
- Schottky
- Voltage - DC Reverse (Vr) (Max):
- 20 V
- Current - Average Rectified (Io):
- 3A
- Voltage - Forward (Vf) (Max) @ If:
- 550 mV @ 3 A
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- -
- Current - Reverse Leakage @ Vr:
- 1 mA @ 20 V
- Capacitance @ Vr, F:
- 300pF @ 4V, 1MHz
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-201AD
- Operating Temperature - Junction:
- -65°C ~ 150°C
SR302-T FAQ
1.How can I place an order for SR302-T through Aetrix?
Please submit a Request for Quotation (RFQ) for SR302-T 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 SR302-T reliable?
The price and inventory of SR302-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SR302-T is usually 5 days.
3.What payment methods are accepted for SR302-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SR302-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SR302-T?
SR302-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SR302-T 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 SR302-T?
For technical support, including SR302-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SR302-T requirements.
6.How does Aetrix verify that SR302-T is sourced from the original manufacturer or authorized distributors?
All SR302-T 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 SR302-T meets industry standards.
7.What is the process for return or replacement of SR302-T?
All SR302-T units undergo pre-shipment inspection (PSI). If there is an issue with SR302-T, 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 SR302-T part is unused and in its original packaging.
Return procedure for SR302-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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