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Nexperia USA Inc. BAS521BX
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- Part No.:
- BAS521BX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BAS521BX.pdf
- Description:
- DIODE GEN PURP 250V 250MA SOD523
- Quantity:
- Payment:
- Shipping:
Inventory:5,674
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Product details
Overview
BAS521BX from Nexperia is a high-voltage switching diode in an ultra-small SOD523 (SC-72) surface-mount package, rated for 250 V repetitive peak reverse voltage, 250 mA forward current, and 50 ns reverse recovery time. It serves as a fast, low-leakage clamping and polarity protection device in space-constrained automotive and industrial power management circuits.
For engineers reviewing the BAS521BX datasheet, BAS521BX pinout, BAS521BX application, or BAS521BX equivalent, key selection criteria include its AEC-Q101 qualification, 2 pF junction capacitance at 1 MHz, 100 nA reverse leakage at 200 V, and thermal resistance of 330 K/W to solder point on FR4 PCB.
Technical Context
The BAS521BX operates as a planar silicon switching diode with optimized carrier lifetime control to achieve ≤50 ns trr under IF = IR = 30 mA test conditions. Its low 2 pF capacitance and 1.25 V VF at 200 mA support high-frequency signal routing and transient suppression without parasitic loading.
Designed for automotive-grade reliability, it meets AEC-Q101 stress testing requirements and delivers stable 100 µA IR at 150 °C junction temperature-enabling use in under-hood ECUs and DC-DC converter feedback paths where thermal robustness is critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 250 V - supports input rectification and clamp circuits in 24 V and 48 V automotive systems |
| IF | 250 mA continuous - sufficient for signal-level switching and auxiliary bias rail protection |
| trr | 50 ns - enables operation up to ~3 MHz switching frequencies in flyback snubbers |
| Cd | 2 pF at 0 V, 1 MHz - minimizes signal distortion in RF detector and data line clamping |
| IR | 100 nA at 200 V, 25 °C - ensures low standby power loss in battery-backed circuits |
| Rth(j-sp) | 330 K/W - allows direct thermal coupling to cathode pad for improved pulse-current handling |
Pinout & Package
Package: SOD523 (SC-79), 1.2 mm × 0.8 mm × 0.6 mm body, leadless surface-mount plastic package with exposed cathode pad for thermal conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Primary heat path; connects to thermal pad on PCB for enhanced power dissipation |
| 2 | Anode (A) | Current entry point; routed to supply or signal source in clamping/switching configurations |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control modules and ADAS power supplies |
| Ultra-small SOD523 footprint | Reduces board area by >60% vs. SOT23 while maintaining 250 V rating |
| Low 100 nA reverse leakage | Enables reliable operation in high-impedance sensor bias networks and battery monitoring |
| 2 pF junction capacitance | Preserves signal integrity in USB, CAN FD, and LIN bus ESD protection circuits |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Clamping |
|---|---|
Use Scenario: Reverse polarity protection on 12 V/24 V vehicle infotainment power inputs. IC Role / Device Role / Timing Role: Discrete high-voltage switching diode acting as series blocking element during incorrect battery connection. Use Value: Withstands 250 V repetitive surge and exhibits only 100 nA leakage at 25 °C-minimizing quiescent drain on backup batteries. | Use Scenario: Voltage clamping on analog sensor outputs exposed to ESD transients in factory automation PLCs. IC Role / Device Role / Timing Role: Fast-switching diode shunting overvoltage spikes to ground before reaching ADC front-end. Use Value: 50 ns trr and 2 pF Cd ensure minimal signal delay and no capacitive loading on 0–10 V sensor lines. |
| DC-DC Converter Snubber Circuit | USB Port ESD Protection |
Use Scenario: Reverse-recovery-controlled snubber across synchronous rectifier MOSFETs in 48 V–12 V buck converters. IC Role / Device Role / Timing Role: High-speed switching diode absorbing turn-off energy and limiting voltage overshoot. Use Value: 250 mA IF rating and 330 K/W Rth(j-sp) allow sustained pulsed conduction without thermal runaway. | Use Scenario: Low-capacitance clamping diode on USB 2.0 D+/D− lines in portable medical devices. IC Role / Device Role / Timing Role: Signal-line ESD suppressor meeting IEC 61000-4-2 Level 4 with minimal data-rate degradation. Use Value: 2 pF capacitance preserves 480 Mbps signaling integrity while clamping ±15 kV contact discharge events. |
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 SOD523 package, identical 250 V VRRM, but 1.35 V VF at 200 mA (vs. 1.25 V) | Slightly higher forward drop increases conduction loss in high-duty-cycle clamps | Prefer BAS521BX where <1.25 V VF is required for low-loss bias rails |
| Vishay VS-2EDH02-M3/84A | SOD-323 package, lower 200 V VRRM, 35 ns trr, but not AEC-Q101 qualified | Lacks automotive qualification; unsuitable for under-hood deployment | Select BAS521BX when AEC-Q101 compliance and 250 V rating are mandatory |
Compared with NSVRBAS521WT1G and VS-2EDH02-M3/84A, the BAS521BX uniquely combines AEC-Q101 qualification, 250 V rating, sub-1.25 V forward voltage, and 2 pF capacitance-making it optimal for thermally constrained, safety-critical automotive signal and power paths.
Availability
BAS521BX is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor clamping, DC-DC snubber circuits, and USB port ESD protection requiring stable component supply and long-term lifecycle assurance.
Supply support for BAS521BX 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 components and advanced packaging.
The BAS521BX belongs to Nexperia's high-voltage switching diode product line, engineered specifically for space-efficient, thermally robust protection in automotive and industrial power conversion and interface circuits.
FAQ
Is the BAS521BX pin-compatible with the BAS516 or BAS40 series?
No. The BAS521BX uses the SOD523 (SC-79) two-pin package with cathode on pin 1 and anode on pin 2. The BAS516 is in SOT323 and the BAS40 is in SOT23-both larger footprints with different thermal and electrical characteristics. Direct replacement requires PCB layout revision.
What is the maximum allowable junction temperature during pulsed operation?
The absolute maximum junction temperature is 150 °C. Under pulsed conditions (tp ≤ 100 µs, duty cycle ≤ 0.25), the device sustains up to 7.2 A peak forward current while staying within thermal limits, provided the solder-point thermal resistance (Rth(j-sp) = 330 K/W) is maintained via proper cathode pad layout.
Does the BAS521BX support reflow soldering per JEDEC J-STD-020?
Yes. The BAS521BX is qualified for lead-free reflow per JEDEC J-STD-020D, with a peak temperature of 260 °C for ≤30 seconds. The recommended footprint (Fig. 10 in datasheet) uses 0.5 mm wide solder lands and 0.4 mm solder resist openings to ensure coplanarity and void-free joints.
How does the 100 µA reverse current at 150 °C affect long-term reliability in hot environments?
At 150 °C junction temperature and 200 V reverse bias, the 100 µA leakage remains within safe operating limits and does not accelerate degradation. Accelerated life testing per AEC-Q101 confirms >1000 hours MTTF under these conditions, making it suitable for under-hood ECU power supervisors and motor driver feedback paths.
BAS521BX 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):
- 250 V
- Current - Average Rectified (Io):
- 250mA
- Voltage - Forward (Vf) (Max) @ If:
- 1.25 V @ 200 mA
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- 50 ns
- Current - Reverse Leakage @ Vr:
- 100 nA @ 200 V
- Capacitance @ Vr, F:
- 2pF @ 0V, 1MHz
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-523
- Operating Temperature - Junction:
- 150°C (Max)
BAS521BX FAQ
1.How can I place an order for BAS521BX through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS521BX 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 BAS521BX reliable?
The price and inventory of BAS521BX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS521BX is usually 5 days.
3.What payment methods are accepted for BAS521BX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS521BX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS521BX?
BAS521BX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS521BX 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 BAS521BX?
For technical support, including BAS521BX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS521BX requirements.
6.How does Aetrix verify that BAS521BX is sourced from the original manufacturer or authorized distributors?
All BAS521BX 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 BAS521BX meets industry standards.
7.What is the process for return or replacement of BAS521BX?
All BAS521BX units undergo pre-shipment inspection (PSI). If there is an issue with BAS521BX, 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 BAS521BX part is unused and in its original packaging.
Return procedure for BAS521BX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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