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Alpha & Omega Semiconductor Inc. AO3421
- Part No.:
- AO3421
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- FETs, MOSFETs
- Package:
- 3-SMD, SOT-23-3 Variant
- Datasheet:
-
AO3421.pdf
- Description:
- MOSFET P-CH 30V 2.6A SOT23-3L
- Quantity:
- Payment:
- Shipping:
Inventory:4,688
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Product details
Overview
AO3421 from Alpha & Omega Semiconductor is a P-channel enhancement-mode MOSFET in SOT-23 package, rated for -30 V VDS, -2.6 A continuous drain current, and 130 mΩ RDS(on) at VGS = −10 V, commonly used in load switching and battery protection circuits.
For engineers reviewing the AO3421 datasheet, pinout, applications, or equivalent options, key selection criteria include gate threshold voltage (−1.5 V typ), low RDS(on) at logic-level drive, SOT-23 thermal performance, and halogen-free compliance per AOS Green Policy.
Technical Context
The AO3421 operates as a single P-channel power switch with enhancement-mode gate control. Its gate threshold voltage range of −0.5 V to −2.5 V enables direct interfacing with 3.3 V and 5 V microcontrollers without level shifting.
Designed for low-voltage DC-DC power path management, it supports bidirectional blocking up to −30 V and features 100% EAS-tested ruggedness for reliable operation under inductive load switching conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDS | −30 V: Maximum reverse drain-source voltage before breakdown; defines safe operating range in high-side switch configurations. |
| ID (continuous) | −2.6 A @ TA = 25°C: Continuous current handling capability under natural convection; derates to −1.9 A at 70°C ambient. |
| RDS(on) | 130 mΩ @ VGS = −10 V: On-resistance determines conduction loss and junction temperature rise in load-switch applications. |
| VGS(th) | −1.5 V (typ): Gate threshold voltage enabling turn-on with standard logic-level outputs; ensures compatibility with 3.3 V GPIOs. |
| Qg | 5.6 nC @ VGS = −10 V: Total gate charge affecting switching speed and driver sizing in PWM-controlled power paths. |
| PD | 1.4 W @ TA = 25°C: Maximum power dissipation in SOT-23 package; limits usable current in non-heatsinked PCB layouts. |
Pinout & Package
SOT-23 package: surface-mount, 3-pin plastic case with gull-wing leads; JEDEC TO-236AB compliant; footprint compatible with industry-standard SOT-23 land pattern.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Source) | Current return path for P-channel device | Connected to higher potential rail (e.g., battery +); sets reference for gate drive and body diode orientation. |
| 2 (Gate) | Control terminal for channel conduction | Receives negative gate drive relative to source; logic-level compatible with 3.3 V/5 V MCU outputs. |
| 3 (Drain) | Current output terminal | Connected to load; body diode anode faces drain, enabling reverse-current blocking in high-side configuration. |
Key Features
| Feature | Design Value |
|---|---|
| Logic-level gate drive | Turns on fully with −3.3 V or −5 V gate-source voltage, eliminating need for external level shifters in MCU-driven switches. |
| Low RDS(on) | 130 mΩ at −10 V reduces I²R losses below 9 mW at 250 mA load, critical for portable battery life extension. |
| Halogen-free construction | Complies with AOS Green Policy (Br/Cl < 900 ppm each, total ≤ 1500 ppm), meeting IPC-4101D and JEDEC J-STD-609A requirements. |
| 100% EAS tested | Guarantees avalanche energy handling of 30 mJ minimum, supporting robust operation during inductive load turn-off transients. |
Applications
| Battery Protection Circuit | USB Power Switch |
|---|---|
Use Scenario: Reverse-polarity and overcurrent protection in single-cell Li-ion battery packs. IC Role / Device Role / Timing Role: High-side P-channel MOSFET controlling battery connection to system load. Use Value: Low RDS(on) minimizes voltage drop across protection FET, preserving battery runtime and enabling accurate voltage monitoring. | Use Scenario: Controlled 5 V power delivery to USB peripherals in embedded hosts. IC Role / Device Role / Timing Role: Load switch isolating VBUS from downstream devices during suspend or fault conditions. Use Value: Logic-level gate drive allows direct control by USB controller GPIO, reducing BOM count and PCB area. |
| Power Bank Output Stage | Industrial Sensor Node Supply Control |
Use Scenario: Output power path management in portable power banks with dual-input charging. IC Role / Device Role / Timing Role: P-channel switch enabling/disabling regulated 5 V output to connected devices. Use Value: 1.4 W power rating supports sustained 2 A output with minimal heatsinking, simplifying mechanical design. | Use Scenario: Remote sensor nodes requiring periodic wake-up and low-quiescent-power sleep mode. IC Role / Device Role / Timing Role: Power gating element disconnecting sensor subsystems during deep-sleep intervals. Use Value: −1.5 V VGS(th) ensures reliable turn-off with leakage-limited gate drive, preventing phantom current draw. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar P-channel load switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Si2301DS | RDS(on) = 115 mΩ @ −4.5 V; slightly lower threshold (−1.0 V typ); same SOT-23 package. | Better suited for ultra-low-voltage gate drive; marginally improved conduction loss at 3.3 V logic. | Select Si2301DS when driving from 3.3 V GPIO with minimal headroom; AO3421 remains preferred for −5 V gate bias stability. |
| DMG2301U | RDS(on) = 145 mΩ @ −4.5 V; higher gate charge (7.5 nC); identical pinout and package. | Higher switching losses in PWM applications; acceptable for static on/off control. | Choose DMG2301U only if AO3421 is unavailable; verify thermal margin due to higher RDS(on) and Qg. |
Compared with Si2301DS and DMG2301U, the AO3421 offers balanced trade-offs: tighter VGS(th) distribution for consistent turn-on behavior, proven EAS ruggedness for industrial environments, and halogen-free compliance verified under AOS Green Policy-making it optimal for battery-powered and safety-critical load switching.
Availability
AO3421 is available at Aetrix Electronics and suitable for battery protection circuits, USB power switches, and industrial sensor node supply control requiring stable component supply and long-term lifecycle support.
Supply support for AO3421 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
Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, IGBTs, and power modules for power conversion and management.
The AO3421 belongs to AOS's logic-level P-channel MOSFET product line, engineered for compact, low-voltage load switching in space-constrained portable and battery-operated systems.
FAQ
What is the maximum continuous drain current rating for AO3421?
The AO3421 is rated for −2.6 A continuous drain current at TA = 25°C with no heatsink. This value decreases to −1.9 A at 70°C ambient due to thermal derating. The actual usable current depends on PCB copper area, airflow, and duty cycle in pulsed applications. Always verify junction temperature using RθJA = 200°C/W and power dissipation calculations for AO3421 in your layout.
Does AO3421 require a gate resistor for typical switching applications?
The AO3421 does not require a gate resistor for basic on/off control, but a 10–100 Ω series gate resistor is recommended to dampen ringing and limit peak gate current during fast transitions. This improves EMI performance and prevents overshoot when driven by low-impedance MCU GPIOs. For PWM frequencies above 100 kHz, gate resistance selection must balance switching loss and rise/fall time for AO3421.
Is AO3421 halogen-free and RoHS compliant?
Yes, AO3421 is halogen-free per AOS Green Policy (Br/Cl < 900 ppm each, total ≤ 1500 ppm) and fully RoHS compliant. It uses halogen-free molding compound and meets IPC-4101D and JEDEC J-STD-609A standards. No "L" suffix is required for AO3421, as all SOT-23 packaged AOS parts produced after 2010-including AO3421-are green by default.
Can AO3421 be used in high-side switch configurations?
Yes, AO3421 is specifically designed for high-side switching with its P-channel structure. When placed between the positive supply rail and load, it enables simple logic-level control: pulling the gate low relative to source turns the device on. Its −30 V VDS rating and body diode orientation make AO3421 suitable for reverse-polarity protection and active OR-ing in dual-supply systems.
What is the gate threshold voltage range for AO3421?
The AO3421 has a gate threshold voltage (VGS(th)) range of −0.5 V to −2.5 V, with a typical value of −1.5 V. This wide range ensures reliable turn-on with 3.3 V and 5 V logic signals while maintaining adequate noise margin. Designers should use −1.5 V typ for initial calculations and verify worst-case behavior at −0.5 V (early turn-on) and −2.5 V (delayed turn-on) in AO3421-based circuits.
AO3421 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Series:
- -
- Package/Case:
- 3-SMD, SOT-23-3 Variant
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Last Time Buy
- FET Type:
- P-Channel
- Technology:
- MOSFET (Metal Oxide)
- Drain to Source Voltage (Vdss):
- 30 V
- Current - Continuous Drain (Id) @ 25°C:
- 2.6A (Ta)
- Drive Voltage (Max Rds On, Min Rds On):
- 4.5V, 10V
- Rds On (Max) @ Id, Vgs:
- 110mOhm @ 2.6A, 10V
- Vgs(th) (Max) @ Id:
- 2.4V @ 250µA
- Gate Charge (Qg) (Max) @ Vgs:
- 5.2 nC @ 10 V
- Vgs (Max):
- ±20V
- Input Capacitance (Ciss) (Max) @ Vds:
- 240 pF @ 15 V
- FET Feature:
- -
- Power Dissipation (Max):
- 1.4W (Ta)
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
AO3421 FAQ
1.How can I place an order for AO3421 through Aetrix?
Please submit a Request for Quotation (RFQ) for AO3421 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 AO3421 reliable?
The price and inventory of AO3421 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AO3421 is usually 5 days.
3.What payment methods are accepted for AO3421?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AO3421 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AO3421?
AO3421 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AO3421 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 AO3421?
For technical support, including AO3421 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AO3421 requirements.
6.How does Aetrix verify that AO3421 is sourced from the original manufacturer or authorized distributors?
All AO3421 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 AO3421 meets industry standards.
7.What is the process for return or replacement of AO3421?
All AO3421 units undergo pre-shipment inspection (PSI). If there is an issue with AO3421, 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 AO3421 part is unused and in its original packaging.
Return procedure for AO3421:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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