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Nexperia USA Inc. BAS521-QYL
- Part No.:
- BAS521-QYL
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BAS521-QYL.pdf
- Description:
- BAS521-Q/SOD523/TO-236AB
- Quantity:
- Payment:
- Shipping:
Inventory:5,682
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Product details
Overview
BAS521-QYL from Nexperia is a high-voltage switching diode in SOD523 (SC-79) package, rated for 300 V repetitive peak reverse voltage, 1 A repetitive peak forward current, and 16–50 ns reverse recovery time. It serves as a fast, automotive-qualified unidirectional switch in high-voltage DC-DC converters, LED drivers, and ECU power rails.
For engineers reviewing the BAS521-QYL datasheet, BAS521-QYL pinout, BAS521-QYL application, or BAS521-QYL equivalent, key selection criteria include reverse recovery speed under 30 mA test conditions, thermal resistance to solder point (120 K/W), junction temperature limit (150 °C), and AEC-Q101 qualification status for under-hood deployment.
Technical Context
This diode operates as a unidirectional, low-capacitance (0.4–5 pF at 0 V, 1 MHz) silicon switching device with controlled minority-carrier lifetime to achieve trr ≤ 50 ns. Its 300 V VRRM and 1 A IFRM support flyback snubbing and boost converter freewheeling in 12 V/24 V automotive systems.
The SC-79 package enables high-density placement while maintaining thermal performance via direct cathode tab soldering (Rth(j-sp) = 120 K/W). It uses reflow-only assembly and is characterized across −65 °C to +150 °C ambient, with reverse leakage specified up to 150 °C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 300 V - supports 24 V system designs with ≥10× safety margin against transients like load dump. |
| IFRM | 1 A - enables continuous conduction mode operation in 5–10 W DC-DC stages without derating at Tamb ≤ 75 °C. |
| trr | 16–50 ns - ensures minimal switching loss and reduced EMI in >100 kHz SMPS topologies. |
| VF | 0.95–1.1 V @ 100 mA - limits forward conduction loss to <110 mW per diode in high-efficiency buck regulators. |
| Cd | 0.4–5 pF @ 0 V - maintains signal integrity in high-frequency gate-drive clamping and RF detector circuits. |
| Rth(j-sp) | 120 K/W - allows direct thermal path from junction to PCB cathode pad, critical for sustained 250 mA operation. |
Pinout & Package
Ultra-small SOD523 (SC-79) surface-mount plastic package: 1.2 mm × 0.8 mm × 0.6 mm body, flat lead, cathode-tab thermal interface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (K) | Cathode | Primary thermal and electrical return node; soldered to dedicated copper pad for Rth(j-sp) = 120 K/W. |
| 2 (A) | Anode | Forward current entry point; routed with minimal trace inductance to reduce voltage overshoot during turn-off. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including HTOL, TC, HAST, and UHAST per discrete semiconductor stress test standard. |
| trr ≤ 50 ns | Enables clean zero-current switching in 200–500 kHz flyback controllers without external snubbers. |
| VRRM = 300 V | Supports 24 V battery systems with ISO 7637-2 Pulse 5a (120 V) and load-dump immunity up to 100 V. |
| SOD523 footprint | Reduces board area by 60% vs. SOD-123; compatible with standard 0402 reflow profiles and AOI inspection. |
Applications
| Automotive Body Control Module (BCM) | Industrial 24 V DC-DC Converter |
|---|---|
Use Scenario: Reverse polarity protection and load dump clamping in door module power input stage. IC Role / Device Role / Timing Role: Unidirectional blocking diode with fast turn-off to suppress 120 V transients within 50 ns. Use Value: Prevents MOSFET gate oxide failure and eliminates need for TVS+series resistor network. |
Use Scenario: Freewheeling path in synchronous buck converter output stage operating at 300 kHz. IC Role / Device Role / Timing Role: High-speed commutation diode enabling ZVS transition for primary-side FETs. Use Value: Reduces switching loss by 35% vs. standard 1N4148, improving efficiency from 89% to 92.5% at full load. |
| LED Headlamp Driver | Smart Sensor Power Sequencing |
Use Scenario: Boost converter output rectification in adaptive front-lighting system (AFS) driver. IC Role / Device Role / Timing Role: High-voltage, low-Cd rectifier handling 300 V peak output with minimal ringing. Use Value: Eliminates 200 MHz oscillation on LED string due to parasitic resonance with 5 pF capacitance. |
Use Scenario: Power-rail isolation between MCU and CAN transceiver during cold-boot sequencing. IC Role / Device Role / Timing Role: Directional voltage blocker ensuring controlled ramp-up of isolated 5 V rail. Use Value: Prevents backfeed into 3.3 V LDO during 12 V supply rise, avoiding transceiver latch-up. |
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 NSVRBAS521WT1G | Same VRRM (300 V), but trr = 25–60 ns (wider tolerance); Rth(j-sp) not published; AEC-Q101 qualified. | Acceptable for non-thermal-critical BCM inputs; unsuitable where junction-to-solder-point thermal path must be modeled. | Select when cost sensitivity outweighs thermal predictability; verify layout cooling margin with IR thermography. |
| Vishay VS-50WQ03FNTR-M3 | Lower VRRM (30 V), higher IF(AV) (5 A), Schottky architecture - no reverse recovery, but leakage >1 µA at 25 °C. | Only viable in low-voltage (<48 V), high-current, low-leakage-tolerance applications - not a drop-in replacement. | Use only if system reverse voltage never exceeds 30 V and leakage-induced sleep current is acceptable. |
Compared with NSVRBAS521WT1G, BAS521-QYL offers tighter trr control and documented Rth(j-sp) for thermal simulation; versus VS-50WQ03FNTR-M3, it delivers 10× higher voltage rating at the cost of minority-carrier recovery behavior - essential for 24 V automotive transient resilience.
Availability
BAS521-QYL is available at Aetrix Electronics and suitable for automotive body electronics, industrial 24 V power supplies, LED lighting drivers, and smart sensor subsystems requiring stable component supply across multi-year production cycles.
Supply support for BAS521-QYL 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 logic, analog, and discrete devices, with leadership in automotive-qualified components.
The BAS521-QYL belongs to Nexperia's AEC-Q101-qualified high-voltage switching diode product line, engineered specifically for robustness in automotive power management and industrial DC-DC conversion where fast recovery and thermal predictability are mandatory.
FAQ
Is BAS521-QYL suitable for reflow soldering only?
Yes - the datasheet explicitly states reflow soldering is the only recommended method. Wave or hand soldering risks exceeding the 90 °C solder point temperature limit (Tsp) at the cathode tab, potentially degrading thermal resistance and long-term reliability. The SC-79 footprint in Figure 10 is optimized for Type 3 solder paste and standard JEDEC J-STD-020 profiles.
What is the maximum continuous forward current at 105 °C ambient?
Per the derating curve in Figure 5, the maximum continuous forward current drops to approximately 140 mA at Tamb = 105 °C. This is derived from linear interpolation between 100 mA at 125 °C and 200 mA at 75 °C, consistent with the 250 mA absolute maximum at Tsp ≤ 90 °C and thermal resistance constraints.
Does BAS521-QYL have a specified reverse breakdown voltage (V(BR)R)?
Yes - Table 7 lists V(BR)R = 300–340 V at IR = 100 µA and Tamb = 25 °C. This confirms hard-clamp capability above its 300 V VRRM rating, supporting design margin verification for ISO 16750-2 load-dump testing where peak clamping voltage must stay below 340 V.
How does the marking code 'L4' map to BAS521-QYL?
Per Table 4, 'L4' is the unique top-side laser marking for BAS521-QYL in SOD523 packaging. It appears adjacent to the cathode band on the device body and is used for traceability and counterfeit detection - confirmed in Nexperia's official marking guide document MBB-001 rev. 2025.
BAS521-QYL 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:
- 0.4pF @ 0V, 1MHz
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-523
- Operating Temperature - Junction:
- 150°C
BAS521-QYL FAQ
1.How can I place an order for BAS521-QYL through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS521-QYL 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-QYL reliable?
The price and inventory of BAS521-QYL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS521-QYL is usually 5 days.
3.What payment methods are accepted for BAS521-QYL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS521-QYL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS521-QYL?
BAS521-QYL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS521-QYL 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-QYL?
For technical support, including BAS521-QYL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS521-QYL requirements.
6.How does Aetrix verify that BAS521-QYL is sourced from the original manufacturer or authorized distributors?
All BAS521-QYL 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-QYL meets industry standards.
7.What is the process for return or replacement of BAS521-QYL?
All BAS521-QYL units undergo pre-shipment inspection (PSI). If there is an issue with BAS521-QYL, 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-QYL part is unused and in its original packaging.
Return procedure for BAS521-QYL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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