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Nexperia USA Inc. BAS521B-QF
- Part No.:
- BAS521B-QF
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Diodes
- Package:
- SC-79, SOD-523
- Datasheet:
-
BAS521B-QF.pdf
- Description:
- BAS521B-Q/SOD523/SC-79
- Quantity:
- Payment:
- Shipping:
Inventory:3,203
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Product details
Overview
BAS521B-Q from Nexperia is a high-voltage switching diode in SOD523 (SC-79) package, rated for 200 V reverse voltage, 250 mA forward current, and 50 ns reverse recovery time. It delivers low leakage (≤100 nA), low capacitance (≤2 pF), and AEC-Q101 qualification for automotive-grade reliability in compact space-constrained designs.
For engineers reviewing the BAS521B-Q datasheet, BAS521B-Q pinout, BAS521B-Q application, or BAS521B-Q equivalent, this diode supports high-speed switching, reverse polarity protection, voltage clamping, and general-purpose SMD switching where ultra-small footprint and thermal robustness are critical.
Technical Context
This discrete silicon switching diode uses a planar epitaxial construction optimized for fast turn-off with controlled minority-carrier lifetime. Its 50 ns trr is measured under standardized conditions (IF = IR = 30 mA, RL = 100 Ω, IR(meas) = 3 mA), ensuring consistent performance in pulse-driven circuits.
The device operates across –55 °C to 150 °C ambient, with junction-to-ambient thermal resistance of 500 K/W on FR4 PCB and 95 K/W to solder point-enabling reliable operation in thermally demanding automotive modules without heatsinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 250 V repetitive peak reverse voltage - withstands transient surges up to 250 V without breakdown |
| VR | 200 V DC reverse voltage - stable blocking capability at full rated temperature (Tj = 25 °C) |
| IF | 250 mA continuous forward current - supports sustained switching loads on standard FR4 PCB |
| trr | 50 ns reverse recovery time - enables >10 MHz switching frequency in flyback and clamp topologies |
| Cd | 2 pF diode capacitance at 0 V - minimizes signal distortion and crosstalk in RF-adjacent routing |
| IR | 100 nA reverse leakage at 200 V - ensures low standby power loss in battery-backed systems |
| Ptot | 380 mW total power dissipation - defines maximum steady-state thermal load at Tamb ≤ 25 °C |
Pinout & Package
Package: SOD523 (SC-79), ultra-small surface-mount plastic package measuring 1.2 mm × 0.8 mm × 0.6 mm, leadless, with tin-plated copper pads for reflow compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | K (cathode) | Negative terminal; connects to higher-potential node during reverse bias; solder pad serves as primary thermal path |
| 2 | A (anode) | Positive terminal; carries forward current into cathode; minimal parasitic inductance due to short internal bond |
Key Features
| Feature | Design Value |
|---|---|
| High-speed switching | 50 ns trr enables clean edge transitions in PWM control and snubber-free flyback designs |
| Low-leakage blocking | 100 nA IR at 200 V preserves battery life in always-on automotive modules (e.g., CAN wake-up receivers) |
| Ultra-compact SMD form | SOD523 footprint occupies <0.96 mm² board area - ideal for multi-rail power management ICs and sensor nodes |
| AEC-Q101 qualified | Stress-tested per automotive discrete standard - validated for temperature cycling, HTRB, and ESD (HBM ≥ 8 kV) |
Applications
| Automotive Body Control Module (BCM) | USB-C Port Protection |
|---|---|
|
Use Scenario: Reverse polarity protection for 12 V supply rails feeding microcontrollers and LIN transceivers. IC Role / Device Role / Timing Role: Unidirectional blocking diode placed upstream of LDOs to prevent damage from incorrect battery connection. Use Value: Withstands 200 V transients and adds <0.15 V drop at 200 mA - avoids thermal derating seen with larger Schottky alternatives. |
Use Scenario: Voltage clamping and ESD suppression on VBUS lines in USB-C receptacles. IC Role / Device Role / Timing Role: Fast-switching clamp diode shunting overvoltage spikes to ground during hot-plug events. Use Value: 2 pF capacitance prevents signal integrity degradation on 10 Gbps SuperSpeed lanes while responding within 50 ns. |
| Industrial Sensor Signal Conditioning | Smart Meter Power Supply Clamp |
|
Use Scenario: High-speed switching in isolated ADC front-end sample-and-hold circuits. IC Role / Device Role / Timing Role: Precision timing diode in charge-transfer networks requiring sub-100 ns recovery and minimal charge injection. Use Value: 100 nA leakage ensures <1 µV offset drift over 10-year field life in precision analog paths. |
Use Scenario: Transient voltage suppression on AC/DC converter input stages exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Clamping diode in parallel with MOVs to handle fast-rising 1–10 µs transients beyond MOV response time. Use Value: 250 V VRRM rating provides margin above 230 VAC line peaks and meets IEC 61000-4-5 Level 4 immunity requirements. |
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 NSR0230P2T5G | 30 V VR, 200 mA IF, 4 ns trr, SOD-523 package | Lower voltage rating limits use to ≤30 V systems; faster recovery suits high-frequency SMPS but lacks automotive qualification | Select only for non-automotive, low-voltage (<30 V), ultra-high-frequency (>50 MHz) switching where speed outweighs voltage headroom |
| Vishay VS-2EDH02HM3/85A | 200 V VR, 2 A IF, 25 ns trr, SOD-123FL package (3.7 mm × 1.7 mm) | Larger footprint and higher thermal mass; suited for higher-current clamping but incompatible with ultra-dense layouts | Choose when board space permits and peak forward current exceeds 250 mA - not suitable for AEC-Q101-compliant automotive modules |
Compared with NSR0230P2T5G and VS-2EDH02HM3/85A, the BAS521B-Q uniquely balances 200 V blocking, AEC-Q101 compliance, and SOD523 miniaturization - making it the only option for space-constrained automotive switching where both voltage margin and qualification are mandatory.
Availability
BAS521B-Q is available at Aetrix Electronics and suitable for automotive body control modules, USB-C port protection circuits, industrial sensor signal conditioning, and smart meter power supply clamps requiring stable component supply and long-term lifecycle assurance.
Supply support for BAS521B-Q 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 essential efficiency technologies - delivering high-performance, high-reliability discrete and logic devices for automotive, industrial, and consumer markets.
The BAS521B-Q belongs to Nexperia's AEC-Q101-qualified high-voltage switching diode product line, engineered specifically for automotive power management, ESD protection, and signal integrity-critical switching in harsh environments.
FAQ
What is the maximum allowable junction temperature for BAS521B-Q?
The absolute maximum junction temperature is 150 °C, as defined in IEC 60134 limiting values. Operation at this temperature requires strict thermal design - including proper PCB copper area under the cathode pad - and must not exceed 380 mW total power dissipation at ambient ≤25 °C.
Is BAS521B-Q compatible with lead-free reflow soldering profiles?
Yes - the device is qualified for standard IPC/JEDEC J-STD-020D reflow profiles, including peak temperatures up to 260 °C. The SOD523 package uses matte tin plating and is designed for compatibility with Pb-free SAC305 solder paste and typical 240–260 °C peak reflow cycles.
How does the 50 ns reverse recovery time impact circuit layout?
A 50 ns trr demands minimized loop inductance in high-di/dt paths: keep anode-to-cathode traces short and direct, avoid vias near terminals, and place bypass capacitors within 2 mm of the diode. Layout errors can cause ringing that exceeds VRRM during turn-off.
Can BAS521B-Q replace BAS21 in existing designs?
No - BAS21 is a TO-92 packaged 250 V diode with 500 ns trr and 200 mA rating. While voltage ratings overlap, the BAS521B-Q's 10× faster recovery, SOD523 footprint, and AEC-Q101 qualification require PCB redesign and validation; it is not a drop-in replacement.
BAS521B-QF 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):
- 200 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
BAS521B-QF FAQ
1.How can I place an order for BAS521B-QF through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS521B-QF 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 BAS521B-QF reliable?
The price and inventory of BAS521B-QF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS521B-QF is usually 5 days.
3.What payment methods are accepted for BAS521B-QF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS521B-QF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS521B-QF?
BAS521B-QF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS521B-QF 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 BAS521B-QF?
For technical support, including BAS521B-QF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS521B-QF requirements.
6.How does Aetrix verify that BAS521B-QF is sourced from the original manufacturer or authorized distributors?
All BAS521B-QF 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 BAS521B-QF meets industry standards.
7.What is the process for return or replacement of BAS521B-QF?
All BAS521B-QF units undergo pre-shipment inspection (PSI). If there is an issue with BAS521B-QF, 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 BAS521B-QF part is unused and in its original packaging.
Return procedure for BAS521B-QF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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