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Nexperia USA Inc. BAS521,135
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- Part No.:
- BAS521,135
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BAS521,135.pdf
- Description:
- DIODE GEN PURP 300V 250MA SOD523
- Quantity:
- Payment:
- Shipping:
Inventory:25,549
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Product details
Overview
BAS521,135 from Nexperia is a high-voltage switching diode in SOD523 (SC-79) package, designed for fast transient response in flyback snubbers and voltage clamping circuits. It delivers 300 V repetitive peak reverse voltage, ≤50 ns reverse recovery time, 1 A repetitive peak forward current, and 0.95 V typical forward voltage at 100 mA - enabling reliable operation in offline AC/DC power supplies and LED driver flyback stages.
For engineers reviewing the BAS521,135 datasheet, BAS521,135 pinout, BAS521,135 application, or BAS521,135 equivalent, key selection criteria include verified trr ≤ 50 ns under IF = 30 mA / IR = 30 mA test conditions, VR = 300 V absolute maximum rating, thermal resistance Rth(j-sp) = 120 K/W to cathode solder point, and SOD523 footprint compatibility with space-constrained PCB layouts.
Technical Context
The BAS521,135 employs a planar epitaxial silicon junction structure optimized for high-voltage blocking and rapid carrier recombination. Its trr specification is validated using a standardized square-wave test circuit with 50 Ω source impedance, 100 Ω load, and 3 mA reverse current measurement threshold per IEC 60747-2.
Thermal performance is defined relative to the cathode tab solder point (Rth(j-sp) = 120 K/W), not ambient, reflecting its intended use in thermally anchored snubber placements. The 500 mW total power dissipation limit applies only under reflow-soldered conditions on FR4 with standard single-sided copper footprint.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 300 V - supports direct rectification of 230 VAC mains with ≥2× safety margin before breakdown |
| trr | 16–50 ns - enables >1 MHz switching in quasi-resonant converters without excessive switching loss |
| IFRM | 1 A - sustains pulsed snubber currents in 65–100 kHz flyback topologies with 25% duty cycle |
| VF | 0.95 V typ @ 100 mA - minimizes conduction loss in low-duty-cycle clamp paths |
| Cd | 0.4–5 pF @ 0 V - ensures negligible capacitive loading on high-impedance gate drive or feedback nodes |
| Rth(j-sp) | 120 K/W - defines thermal path efficiency when cathode tab is soldered to dedicated copper pour |
Pinout & Package
Package: SOD523 (SC-79), ultra-small surface-mount plastic package measuring 1.2 mm × 0.8 mm × 0.6 mm body height, with flat leads and cathode tab optimized for thermal transfer.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Main heat extraction path; must be soldered to thermal pad per reflow footprint Fig. 10 for rated Ptot |
| 2 | Anode (A) | Forward current entry point; electrically isolated from cathode tab; connects to switching node |
Key Features
| Feature | Design Value |
|---|---|
| High-speed switching | 16 ns typical trr enables clean turn-off in <100 ns dead-time control schemes |
| High-voltage blocking | 300 V VRRM supports 230 VAC input designs with full EN 62368-1 clearance margin |
| Ultra-compact footprint | SOD523 outline fits 1.2 mm × 0.8 mm PCB area - ideal for multi-rail DC/DC modules |
| Thermally anchored cathode | Cathode tab design achieves 120 K/W junction-to-solder-point resistance under reflow |
Applications
| Offline AC/DC Flyback Snubber | LED Driver Voltage Clamp |
|---|---|
Use Scenario: Absorbs leakage inductance energy during MOSFET turn-off in 230 VAC-input flyback converters. IC Role / Device Role / Timing Role: Fast-recovery clamping diode placed across primary winding and MOSFET drain. Use Value: 16 ns trr prevents voltage overshoot beyond 300 V rating while limiting snubber loss to <50 mW. |
Use Scenario: Clamps transient overvoltage spikes across LED strings during hot-swap or dimming transitions. IC Role / Device Role / Timing Role: High-voltage transient suppressor connected in parallel with LED load. Use Value: 300 V VRRM withstands 2× nominal bus voltage; 0.4 pF Cd avoids signal distortion in PWM dimming paths. |
| Industrial Sensor Signal Protection | Smart Meter Surge Suppression |
Use Scenario: Protects analog front-end inputs from ESD and inductive kickback in 4–20 mA loop transmitters. IC Role / Device Role / Timing Role: Bidirectional clamping diode pair (with complementary device) referenced to supply rails. Use Value: 30 nA max IR at 250 V ensures <1 µV offset error in precision current sensing paths. |
Use Scenario: Front-end protection stage in polyphase electricity meters exposed to 6 kV surge events per IEC 61000-4-5. IC Role / Device Role / Timing Role: First-stage voltage clamp in series with MOV and gas discharge tube. Use Value: 4.5 A IFSM handles 1 µs surge pulses; 150 °C Tj rating supports extended meter lifetime at elevated ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage switching diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ON Semiconductor MMBD7000LT1G | VRRM = 100 V, trr = 4 ns - lower voltage rating but faster recovery | Not suitable for 230 VAC snubbing; limited to ≤48 V systems with aggressive switching | Select only when VRRM margin < 150 V is acceptable and trr < 20 ns is mandatory |
| Vishay ES1J | VRRM = 600 V, trr = 35 ns, SMC package - higher voltage, slower, larger footprint | Supports 400 VDC bus clamping but requires 2.5× PCB area and lacks SOD523 thermal anchoring | Choose when VRRM > 400 V is required and board space allows SMC footprint |
Compared with MMBD7000LT1G and ES1J, the BAS521,135 uniquely balances 300 V blocking, sub-50 ns recovery, and SOD523 thermal efficiency - making it optimal for compact, thermally constrained 230 VAC-derived power stages where both voltage margin and speed matter.
Availability
BAS521,135 is available at Aetrix Electronics and suitable for offline AC/DC flyback snubbers, LED driver voltage clamps, industrial sensor signal protection, and smart meter surge suppression requiring stable component supply and consistent SOD523 packaging.
Supply support for BAS521,135 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
Nexperia is a global semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified and industrial-grade components.
The BAS521,135 belongs to Nexperia's high-voltage switching diode product line, engineered specifically for efficient energy clamping and fast transient suppression in space-limited power conversion and protection circuits.
FAQ
What is the maximum allowable soldering temperature profile for BAS521,135?
The BAS521,135 is qualified for reflow soldering only, with peak temperature not exceeding 260 °C for ≤10 seconds. Reflow profiles must follow JEDEC J-STD-020, and wave or hand soldering is not recommended due to thermal stress on the SOD523 package and cathode tab interface.
Can BAS521,135 replace BAS21 in existing designs?
No - BAS21 has VRRM = 250 V and trr = 50 ns, but uses SOT-23 package with different thermal path and 2.9 mm × 1.3 mm footprint. BAS521,135's SOD523 size and cathode-tab thermal design require PCB layout revision and thermal validation before substitution.
Is BAS521,135 suitable for automotive applications?
No - the BAS521,135 is not AEC-Q101 qualified and lacks automotive-specific testing (e.g., HTOL, temperature cycling). Nexperia explicitly states non-automotive qualification in Section 15 of the datasheet; use only in industrial, consumer, or commercial power systems.
What is the meaning of marking code 'L4' on BAS521,135 devices?
'L4' is the manufacturer-specific top-side marking for BAS521,135 per Table 4 of the datasheet. It identifies the device type and is laser-etched on the anode side of the SOD523 package - not a date code or lot identifier. No functional or parametric variation is associated with this marking.
BAS521,135 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- SC-79, SOD-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Standard
- Voltage - DC Reverse (Vr) (Max):
- 300 V
- Current - Average Rectified (Io):
- 250mA
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 100 mA
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- 50 ns
- Current - Reverse Leakage @ Vr:
- 150 nA @ 250 V
- Capacitance @ Vr, F:
- 5pF @ 0V, 1MHz
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-523
- Operating Temperature - Junction:
- 150°C (Max)
BAS521,135 FAQ
1.How can I place an order for BAS521,135 through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS521,135 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 BAS521,135 reliable?
The price and inventory of BAS521,135 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS521,135 is usually 5 days.
3.What payment methods are accepted for BAS521,135?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS521,135 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS521,135?
BAS521,135 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS521,135 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 BAS521,135?
For technical support, including BAS521,135 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS521,135 requirements.
6.How does Aetrix verify that BAS521,135 is sourced from the original manufacturer or authorized distributors?
All BAS521,135 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 BAS521,135 meets industry standards.
7.What is the process for return or replacement of BAS521,135?
All BAS521,135 units undergo pre-shipment inspection (PSI). If there is an issue with BAS521,135, 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 BAS521,135 part is unused and in its original packaging.
Return procedure for BAS521,135:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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