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Nexperia USA Inc. BAS321-QX
- Part No.:
- BAS321-QX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Diodes
- Package:
- SC-76, SOD-323
- Datasheet:
-
BAS321-QX.pdf
- Description:
- DIODE GEN PURP 200V 250MA SOD323
- Quantity:
- Payment:
- Shipping:
Inventory:35,440
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Product details
Overview
BAS321-Q from Nexperia is a general-purpose silicon switching diode fabricated in planar technology and housed in an SOD323 (SC-76) surface-mount package. It delivers 250 mA continuous forward current, 200 V reverse voltage rating, 1.25 V forward voltage at 200 mA, 50 ns reverse recovery time, and AEC-Q101 qualification for automotive use - enabling reliable signal routing and polarity protection in compact DC/DC converter feedback paths.
For engineers reviewing the BAS321-Q datasheet, BAS321-Q pinout, BAS321-Q application, or BAS321-Q equivalent, key selection criteria include its 50 ns switching speed, 200 V VR rating, thermal resistance of 366 K/W (junction-to-ambient), SOD323 footprint compatibility, and AEC-Q101 qualification status for under-hood automotive modules.
Technical Context
The BAS321-Q operates as a unidirectional, low-capacitance (2 pF at 0 V, 1 MHz) PN junction diode optimized for fast switching in space-constrained PCB layouts. Its 50 ns trr and 1.25 V VF at 200 mA support efficient flyback snubbing and logic-level clamping without significant conduction loss.
Thermally, it sustains 150 °C maximum junction temperature with 300 mW total power dissipation at 25 °C ambient, and exhibits 130 K/W junction-to-solder-point resistance - critical for thermal management in densely populated automotive control units where solder-point cooling dominates heat removal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Forward Voltage (VF) | 1.25 V at IF = 200 mA, Tj = 25 °C - ensures low conduction loss in 3.3 V–5 V logic-level clamp circuits |
| Reverse Recovery Time (trr) | 50 ns - enables stable operation up to ~10 MHz switching frequencies in flyback and buck converter snubbers |
| Repetitive Peak Reverse Voltage (VRRM) | 250 V - supports transient suppression in 24 V automotive systems with ISO 7637-2 pulse 5a compliance margin |
| Continuous Forward Current (IF) | 250 mA - sufficient for biasing, level-shifting, and low-power signal steering in ECUs and body controllers |
| Diode Capacitance (Cd) | 2 pF at VR = 0 V, f = 1 MHz - minimizes high-frequency signal distortion in RF detector and clock line protection |
| Junction-to-Ambient Thermal Resistance (Rth(j-a)) | 366 K/W on FR4 PCB - defines derating curve: max IF drops to ~150 mA at Tamb = 85 °C per Fig. 1 |
Pinout & Package
Package: SOD323 (SC-76), 1.7 mm × 1.25 mm × 0.95 mm body, 1.3 mm lead pitch, tin-plated copper leads on FR4 PCB.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Cathode (K) | Negative terminal; connects to lower-potential node; solder point serves as primary thermal path (Rth(j-sp) = 130 K/W) |
| 2 | Anode (A) | Positive terminal; accepts forward-biased current flow; marked side of package aligns with cathode band |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control, lighting, and infotainment - no additional qualification required for Tier-1 designs |
| SOD323 footprint | Enables <1.8 mm² board area usage - compatible with standard reflow profiles and wave soldering footprints per Fig. 9–10 |
| 50 ns reverse recovery | Reduces switching loss and EMI generation in 1–10 MHz DC/DC converters versus slower general-purpose diodes (e.g., 1N4148: 4 ns) |
| 2 pF junction capacitance | Minimizes capacitive loading on high-speed digital lines and crystal oscillator inputs - avoids frequency pulling or startup delay |
Applications
| Automotive Body Control Module | USB Port Polarity Protection |
|---|---|
Use Scenario: Reverse-voltage protection for LIN bus transceivers and LED driver ICs in door modules. IC Role / Device Role / Timing Role: Unidirectional blocking diode placed between battery rail and IC VCC input. Use Value: Withstands 250 V VRRM and 150 °C Tj, ensuring survival during load-dump transients and under-hood thermal cycling. |
Use Scenario: Preventing damage from miswired USB cables in automotive infotainment head units. IC Role / Device Role / Timing Role: Series protection element on VBUS line before USB controller. Use Value: 250 mA IF rating handles full USB 2.0 charging current; 50 ns trr avoids data corruption during hot-plug events. |
| Industrial Sensor Signal Conditioning | Low-Power IoT Node Power Management |
Use Scenario: Clamping analog sensor outputs (e.g., thermistor bridges) to MCU ADC reference rails. IC Role / Device Role / Timing Role: Precision voltage limiter using forward conduction and leakage-controlled reverse blocking. Use Value: 100 nA IR at 200 V/25 °C ensures minimal offset error; 2 pF Cd prevents bandwidth degradation above 100 kHz. |
Use Scenario: Isolating backup coin-cell supply from main Li-ion battery in smart meter sleep-mode circuitry. IC Role / Device Role / Timing Role: Low-leakage OR-ing diode in dual-supply path. Use Value: 100 µA IR at 200 V/150 °C maintains >10-year shelf life; SOD323 size fits tight 2-layer PCB layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar general-purpose switching diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4148W-7-F | Slower trr (4 ns typical but 4–6 ns max), higher VF (1.25 V @ 10 mA), same SOD-123 package | Not AEC-Q101 qualified; limited to commercial-temp industrial use | Select when cost sensitivity outweighs automotive qualification and higher-speed switching is unnecessary |
| BAS16H,115 | Higher IF (215 mA continuous), same SOD-123, trr = 4 ns, VF = 1.25 V @ 50 mA | Lower power handling; not rated for 200 V VR - max VR = 80 V | Choose only for sub-48 V systems where ultra-fast switching is prioritized over voltage margin |
Compared with BAS321-Q, the 1N4148W lacks automotive qualification and has inferior thermal performance (Rth(j-a) ≈ 500 K/W), while BAS16H sacrifices reverse voltage capability for faster switching - making BAS321-Q the sole option balancing AEC-Q101, 200 V rating, and SOD323 miniaturization.
Availability
BAS321-Q is available at Aetrix Electronics and suitable for automotive body electronics, USB interface protection, industrial sensor front-ends, and low-power IoT power-path isolation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for BAS321-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 high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and advanced packaging.
The BAS321-Q belongs to Nexperia's AEC-Q101-qualified general-purpose diode family, engineered specifically for space-constrained automotive subsystems requiring robust transient immunity and thermal stability.
FAQ
Is BAS321-Q suitable for reverse polarity protection in 24 V automotive systems?
Yes. With 250 V VRRM and AEC-Q101 qualification, BAS321-Q withstands ISO 7637-2 load-dump pulses (up to 120 V for 400 ms) and operates reliably from −40 °C to +150 °C. Its 250 mA IF rating supports most 24 V control module loads, and the SOD323 package allows placement near protected ICs for minimal loop inductance.
What is the maximum ambient temperature for continuous 250 mA operation?
Per Figure 1 in the datasheet, the maximum ambient temperature for 250 mA continuous forward current is 25 °C on a standard FR4 PCB. At 85 °C ambient, derated IF drops to approximately 150 mA due to Rth(j-a) = 366 K/W and Ptot = 300 mW limit - thermal design must account for local board heating and airflow.
How does BAS321-Q compare to BAS21 in terms of switching speed and package?
BAS321-Q has 50 ns trr and uses SOD323 (1.7 mm × 1.25 mm); BAS21 has 50 ns trr but uses larger SOT-23 (3.0 mm × 1.4 mm). Both share 200 V VR and 250 mA IF ratings, but BAS321-Q offers 40% smaller footprint and is AEC-Q101 qualified, whereas BAS21 is commercial-grade only.
Can BAS321-Q be used in high-frequency RF detector circuits?
Yes. Its 2 pF junction capacitance at 0 V and 1.25 V VF enable clean rectification of signals up to 100 MHz. Measured Cd remains below 3 pF up to 10 V reverse bias (Fig. 5), minimizing detuning of LC tank circuits - confirmed by Nexperia's characterization in Section 10.
BAS321-QX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- SC-76, SOD-323
- 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-323
- Operating Temperature - Junction:
- 150°C
BAS321-QX FAQ
1.How can I place an order for BAS321-QX through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS321-QX 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 BAS321-QX reliable?
The price and inventory of BAS321-QX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS321-QX is usually 5 days.
3.What payment methods are accepted for BAS321-QX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS321-QX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS321-QX?
BAS321-QX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS321-QX 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 BAS321-QX?
For technical support, including BAS321-QX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS321-QX requirements.
6.How does Aetrix verify that BAS321-QX is sourced from the original manufacturer or authorized distributors?
All BAS321-QX 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 BAS321-QX meets industry standards.
7.What is the process for return or replacement of BAS321-QX?
All BAS321-QX units undergo pre-shipment inspection (PSI). If there is an issue with BAS321-QX, 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 BAS321-QX part is unused and in its original packaging.
Return procedure for BAS321-QX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BAS321-QX Tags
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BAV21W-7-F
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