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Diodes Incorporated BAS21T-7
- Part No.:
- BAS21T-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Diodes
- Package:
- SOT-523
- Datasheet:
-
BAS21T-7.pdf
- Description:
- DIODE GEN PURP 200V 200MA SOT523
- Quantity:
- Payment:
- Shipping:
Inventory:4,700
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Product details
Overview
BAS21T-7 from Diodes Incorporated is a surface-mount fast-switching general-purpose diode in SOT-523 package, rated for 250 V repetitive peak reverse voltage, 400 mA forward continuous current, and 50 ns reverse recovery time. It delivers high conductance and low capacitance (5.0 pF) for signal routing and clamping in compact DC-DC converter feedback paths and logic-level interface protection circuits.
For engineers reviewing the BAS21T-7 datasheet, BAS21T-7 pinout, BAS21T-7 application, or BAS21T-7 equivalent, key selection criteria include its ultra-small SOT-523 footprint, 200 mA average rectified output current capability, 1.25 V max forward voltage at 200 mA, and suitability for high-speed switching in space-constrained industrial control I/O modules and automotive body electronics.
Technical Context
The BAS21T-7 is a silicon planar epitaxial fast-switching diode optimized for general-purpose signal and power switching where low forward voltage, fast recovery, and minimal junction capacitance are critical. Its 50 ns trr and 5.0 pF CT at 0 V enable clean edge transitions in 1–10 MHz digital signal conditioning and transient suppression.
Designed for operation across –65 °C to +150 °C ambient, it maintains stable reverse leakage (≤100 nA at 25 °C, ≤15 A at 100 °C) and forward conduction under thermal stress, supporting reliable performance in unregulated power rails and sensor interface front-ends without active cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 250 V - supports isolation of 24 V and 48 V DC systems with 5× safety margin against transients |
| IFM | 400 mA - handles peak currents in low-power logic-level signal steering and LED biasing |
| trr | 50 ns - enables clean switching in 10 MHz clock distribution and pulse shaping networks |
| CT | 5.0 pF @ 0 V - minimizes capacitive loading on high-impedance analog inputs and RF detector nodes |
| VF | 1.25 V max @ 200 mA - ensures low conduction loss in 3.3 V and 5 V supply rail clamping |
| RJA | 833 °C/W - requires no heatsink on FR-4 PCBs with standard pad layout per AP02001 |
Pinout & Package
SOT-523 is a 3-terminal ultra-small plastic surface-mount package (1.60 mm × 0.80 mm × 0.50 mm), with anode and cathode leads formed from a single leadframe; polarity is marked by a bar on the cathode end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry point | Connected to higher-potential node during conduction; must route with low-inductance trace in fast-switching paths |
| Cathode | Forward current exit / reverse blocking terminal | Marked with bar; ties to ground or lower-potential rail in clamp and freewheeling configurations |
| Case | Non-electrical mechanical body | No internal connection; serves only as thermal and mechanical anchor; not electrically isolated |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SOT-523 footprint | Enables placement in <1.0 mm² board area-critical for multi-rail PMIC monitoring and wearable sensor modules |
| Fast 50 ns reverse recovery | Reduces switching losses and ringing in 1–5 MHz boost converter catch diodes and level translators |
| Low 5.0 pF junction capacitance | Maintains signal integrity in 100 Mbps digital isolator input stages and ESD protection networks |
| High 250 V VRRM rating | Permits use in 24 V industrial fieldbus receivers and 48 V telecom backup power interfaces |
Applications
| Industrial Sensor Signal Conditioning | Automotive Body Control Module I/O Protection |
|---|---|
Use Scenario: Protecting 3.3 V microcontroller ADC inputs from 12 V sensor line transients in factory automation encoders. IC Role / Device Role / Timing Role: Fast clamping diode shunting overvoltage spikes to VCC or GND before they reach sensitive analog front-end circuitry. Use Value: 50 ns trr prevents latch-up during 100 ns surge events; 1.25 V VF limits clamp voltage to safe levels without loading reference rails. | Use Scenario: Isolating LIN bus data lines from battery reverse-connection and load-dump surges in door module ECUs. IC Role / Device Role / Timing Role: Bidirectional transient suppressor placed between LIN transceiver and connector, operating in forward and reverse breakdown modes. Use Value: 250 V VRRM withstands ISO 7637-2 Pulse 5a (75 V/350 ms); 100 nA IR at 25 °C avoids signal leakage in sleep-mode communication. |
| DC-DC Converter Feedback Path | Logic-Level Translation Interface |
Use Scenario: Biasing optocoupler LED in isolated flyback feedback loop for 5 V/3 A AC-DC adapter. IC Role / Device Role / Timing Role: High-conductance forward path ensuring stable current drive into opto-LED despite wide input voltage variation (90–264 VAC). Use Value: 400 mA IFM and low VF support >5 mA LED current across full line range; SOT-523 fits tight spacing near transformer primary. | Use Scenario: Level-shifting 1.8 V GPIO signals to 3.3 V peripherals in portable medical diagnostic devices. IC Role / Device Role / Timing Role: Passive bidirectional translator using forward conduction and reverse blocking to shift logic thresholds without active circuitry. Use Value: 5.0 pF CT avoids timing skew on 20 MHz clock/data pairs; 1.25 V VF ensures clean 1.8 V → 3.3 V high-level translation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fast-switching diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BAS16W-7-F | Same SOT-523 package; 100 V VRRM, 4 ns trr, 1.25 V VF @ 100 mA | Better for sub-24 V logic switching; insufficient for 48 V rail clamping | Select when speed > voltage rating; verify trr-driven EMI compliance in 10+ MHz designs |
| 1N4148W-7-F | SOD-123 package; 100 V VRRM, 4 ns trr, 1.25 V VF @ 100 mA | Larger footprint (2.7 × 1.6 mm); higher RJA (500 °C/W) | Choose if board space allows larger package and thermal derating is acceptable |
Compared with BAS21T-7, BAS16W-7-F trades 150 V reverse rating for 45 ns faster recovery, while 1N4148W-7-F sacrifices miniaturization and thermal efficiency for legacy compatibility and wider availability in high-volume production.
Availability
BAS21T-7 is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body electronics, and compact DC-DC converter feedback loops requiring stable component supply and guaranteed long-term sourcing.
Supply support for BAS21T-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.
The BAS series targets high-reliability, space-constrained signal routing and protection applications-designed specifically for fast-switching, low-capacitance performance in industrial, computing, and automotive subsystems.
FAQ
What is the maximum junction temperature for BAS21T-7?
The BAS21T-7 has a specified operating junction temperature range of –65 °C to +150 °C. Its thermal resistance is 833 °C/W (junction-to-ambient, mounted on FR-4 per AP02001 layout), meaning at 150 mW dissipation, junction temperature rises ~125 °C above ambient-so operation up to +25 °C ambient ensures Tj stays within limit.
Is BAS21T-7 suitable for reverse polarity protection?
Yes, BAS21T-7 can be used for low-current reverse polarity protection in 24 V systems due to its 250 V VRRM and 400 mA IFM rating. However, its 1.25 V forward drop causes ~500 mW loss at 400 mA, making it appropriate only for sub-200 mA loads unless thermally managed via copper pour or forced air.
Does BAS21T-7 have a built-in ESD protection structure?
No, BAS21T-7 is not rated or characterized for ESD immunity beyond standard human-body model (HBM) handling per JESD22-A114. It lacks integrated ESD clamps; external TVS diodes or RC filters are required for IEC 61000-4-2 compliant system-level ESD protection on signal lines.
Can BAS21T-7 replace 1N4148 in SOT-523 footprint designs?
Yes, BAS21T-7 is a direct SOT-523 drop-in replacement for 1N4148-based designs requiring higher voltage rating (250 V vs. 100 V) and same package size. Its 50 ns trr is slower than 1N4148's typical 4 ns, so verify timing margins in >1 MHz switching paths before substitution.
BAS21T-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOT-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Technology:
- Standard
- Voltage - DC Reverse (Vr) (Max):
- 200 V
- Current - Average Rectified (Io):
- 200mA
- Voltage - Forward (Vf) (Max) @ If:
- 1.25 V @ 200 mA
- Speed:
- Small Signal =< 200mA (Io), Any Speed
- Reverse Recovery Time (trr):
- 50 ns
- Current - Reverse Leakage @ Vr:
- 100 nA @ 200 V
- Capacitance @ Vr, F:
- 5pF @ 0V, 1MHz
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-523
- Operating Temperature - Junction:
- -65°C ~ 150°C
BAS21T-7 FAQ
1.How can I place an order for BAS21T-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for BAS21T-7 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 BAS21T-7 reliable?
The price and inventory of BAS21T-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BAS21T-7 is usually 5 days.
3.What payment methods are accepted for BAS21T-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BAS21T-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BAS21T-7?
BAS21T-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BAS21T-7 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 BAS21T-7?
For technical support, including BAS21T-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BAS21T-7 requirements.
6.How does Aetrix verify that BAS21T-7 is sourced from the original manufacturer or authorized distributors?
All BAS21T-7 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 BAS21T-7 meets industry standards.
7.What is the process for return or replacement of BAS21T-7?
All BAS21T-7 units undergo pre-shipment inspection (PSI). If there is an issue with BAS21T-7, 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 BAS21T-7 part is unused and in its original packaging.
Return procedure for BAS21T-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BAS21T-7 Tags
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BAV21W-7-F
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