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Alpha & Omega Semiconductor Inc. AO3438
- Part No.:
- AO3438
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- FETs, MOSFETs
- Package:
- 3-SMD, SOT-23-3 Variant
- Datasheet:
-
AO3438.pdf
- Description:
- MOSFET N-CH 20V 3A SOT23-3L
- Quantity:
- Payment:
- Shipping:
Inventory:9,959
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Product details
Overview
AO3438 from Alpha & Omega Semiconductor is a 30V, 5.8A N-channel enhancement-mode MOSFET in SOT-23 package, featuring 42mΩ RDS(on) at VGS = 10V and 55mΩ at VGS = 4.5V, designed for DC-DC converters and load switching in portable electronics.
For engineers reviewing the AO3438 datasheet, pinout, applications, or equivalent options, key selection criteria include its low gate charge (7.5nC), fast switching speed (trise = 12ns, tfall = 9ns), and halogen-free green packaging compliant with AOS's 2010 environmental policy.
Technical Context
The AO3438 uses trench-gate process technology to achieve low on-resistance and high power efficiency in compact SOT-23 footprint. Its threshold voltage range of 1.0–2.5V enables reliable turn-on with 3.3V and 5V logic-level gate drive.
Thermal resistance RθJA is 125°C/W (standard PCB layout), supporting continuous drain current up to 5.8A at TA = 25°C. The device is rated for 100% UIS (Unclamped Inductive Switching) tested and RoHS-compliant per AOS Green Policy effective July 2005.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDS | 30V - maximum drain-source blocking voltage for 5V/3.3V system rail switching |
| RDS(on) @ VGS = 10V | 42mΩ - enables <100mW conduction loss at 5A load in DC-DC high-side switch |
| RDS(on) @ VGS = 4.5V | 55mΩ - ensures full enhancement under typical battery-powered logic drive |
| Qg | 7.5nC - reduces gate driver power requirement and switching transition time |
| trise/tfall | 12ns/9ns - supports >1MHz PWM operation in synchronous buck converters |
| Package | SOT-23 - surface-mount, 3-pin, 2.9mm × 1.3mm footprint for space-constrained PCBs |
Pinout & Package
SOT-23 package with gull-wing leads; standard pin assignment: Pin 1 = Gate, Pin 2 = Drain, Pin 3 = Source.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (G) | Gate terminal | Controls channel conduction; requires ≤2.5V VGS(th) for turn-on with 3.3V logic |
| Pin 2 (D) | Drain terminal | High-side connection point; rated for 30V repetitive blocking and 100% UIS stress |
| Pin 3 (S) | Source terminal | Reference node for gate drive; tied to ground or low-side return path in common-source topology |
Key Features
| Feature | Design Value |
|---|---|
| Halogen-free green packaging | Complies with AOS Green Policy: Br/Cl <900ppm each, total Br+Cl <1500ppm (2010+ production) |
| Low RDS(on) at 4.5V | 55mΩ enables efficient operation directly driven by 3.3V microcontrollers without level-shifting |
| Fast switching performance | 12ns rise / 9ns fall time minimizes overlap loss in high-frequency synchronous rectification |
| 100% UIS tested | Guarantees ruggedness against inductive kickback in motor drive and solenoid control applications |
Applications
| USB Power Delivery Switch | Portable SSD Power Rail Control |
|---|---|
Use Scenario: Enables/disables 5V VBUS power path in USB-C PD sink devices with overcurrent protection. IC Role / Device Role / Timing Role: Low-side load switch controlling power delivery to downstream peripherals. Use Value: 55mΩ RDS(on) at 4.5V ensures <150mW loss at 5A, minimizing thermal impact in slim form factors. | Use Scenario: Isolates NVMe controller power domain during sleep/wake transitions in portable SSDs. IC Role / Device Role / Timing Role: High-efficiency power gating switch between PMIC output and storage controller rail. Use Value: 7.5nC gate charge allows fast, low-power enable/disable cycling synchronized with PCIe link state changes. |
| Bluetooth Headset Battery Protection | Smartwatch Display Backlight Dimming |
Use Scenario: Blocks reverse current and isolates battery during charging fault detection in Class 1 Bluetooth headsets. IC Role / Device Role / Timing Role: Reverse-battery protection switch placed between Li-ion cell and charging IC. Use Value: 30V VDS rating provides margin above 4.4V max cell voltage, ensuring long-term reliability. | Use Scenario: PWM-controlled current sink for white LED backlight in always-on smartwatch displays. IC Role / Device Role / Timing Role: Low-RDS(on) constant-current switch modulating LED brightness via gate duty cycle. Use Value: 12ns/9ns switching supports >5kHz dimming frequency without visible flicker or audible noise. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar N-channel MOSFET switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DMN3026LSD-13 | RDS(on) = 32mΩ @ 10V, but 75mΩ @ 4.5V; higher Qg = 10.5nC | Less suitable for 3.3V logic drive; better for 5V-only systems | Prefer AO3438 where 4.5V RDS(on) and low Qg are critical |
| SI2302DS-T1-E3 | RDS(on) = 60mΩ @ 4.5V; lower VDS = 20V; no UIS rating specified | Limited to 20V systems; not recommended for inductive loads | AO3438 preferred for 30V-rated, inductive-switching, or green-compliance requirements |
Compared with DMN3026LSD-13 and SI2302DS-T1-E3, the AO3438 delivers superior 4.5V drive capability, lower switching losses, and verified UIS ruggedness-making it optimal for battery-powered, space-constrained, and environmentally regulated designs.
Availability
AO3438 is available at Aetrix Electronics and suitable for USB-C PD implementations, portable SSD power management, Bluetooth headset battery protection, and smartwatch display backlight control requiring stable component supply and halogen-free compliance.
Supply support for AO3438 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-performance MOSFETs, IGBTs, and power modules for computing, consumer, and industrial markets.
The AO3438 belongs to AOS's logic-level N-channel MOSFET product line, engineered for energy-efficient, low-voltage switching in portable and battery-operated electronics.
FAQ
What is the maximum continuous drain current for AO3438 at 25°C ambient temperature?
The AO3438 supports a continuous drain current of 5.8A at TA = 25°C with standard PCB layout (1in² copper, 2oz). Derating applies above 25°C per its RθJA = 125°C/W specification. This rating assumes proper thermal design and is validated under AOS's test conditions defined in the official datasheet.
Does AO3438 meet halogen-free requirements per AOS Green Policy?
Yes, AO3438 is manufactured per AOS Green Policy with halogen-free molding compound: bromine and chlorine each <900ppm, total Br+Cl <1500ppm. All SOT-23 packaged AO3438 units produced after 2010 comply, regardless of "L" suffix usage, as confirmed in AOS's September 2020 policy update.
Can AO3438 be driven directly by a 3.3V GPIO without a level shifter?
Yes, AO3438 has a guaranteed VGS(th) range of 1.0–2.5V and delivers 55mΩ RDS(on) at VGS = 4.5V. When driven by a robust 3.3V source, it achieves sufficient enhancement for most load-switching applications, though RDS(on) will be slightly higher than at 4.5V.
Is AO3438 rated for unclamped inductive switching (UIS)?
Yes, AO3438 is 100% UIS tested per AOS qualification standards. It withstands single-pulse inductive energy up to EAS = 35mJ at TJ = 25°C, making it suitable for driving relays, solenoids, and other inductive loads without external snubbers in many cases.
What is the gate charge (Qg) of AO3438 and why does it matter in high-frequency operation?
The AO3438 has a total gate charge Qg of 7.5nC at VGS = 10V. This low value reduces gate driver power consumption and shortens switching transitions-critical for minimizing overlap loss and improving efficiency in >1MHz DC-DC converters where the AO3438 is commonly deployed.
AO3438 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:
- Obsolete
- FET Type:
- N-Channel
- Technology:
- MOSFET (Metal Oxide)
- Drain to Source Voltage (Vdss):
- 20 V
- Current - Continuous Drain (Id) @ 25°C:
- 3A (Ta)
- Drive Voltage (Max Rds On, Min Rds On):
- 1.8V, 4.5V
- Rds On (Max) @ Id, Vgs:
- 62mOhm @ 3A, 4.5V
- Vgs(th) (Max) @ Id:
- 1V @ 250µA
- Gate Charge (Qg) (Max) @ Vgs:
- 3.8 nC @ 4.5 V
- Vgs (Max):
- ±8V
- Input Capacitance (Ciss) (Max) @ Vds:
- 320 pF @ 10 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
AO3438 FAQ
1.How can I place an order for AO3438 through Aetrix?
Please submit a Request for Quotation (RFQ) for AO3438 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 AO3438 reliable?
The price and inventory of AO3438 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AO3438 is usually 5 days.
3.What payment methods are accepted for AO3438?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AO3438 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AO3438?
AO3438 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AO3438 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 AO3438?
For technical support, including AO3438 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AO3438 requirements.
6.How does Aetrix verify that AO3438 is sourced from the original manufacturer or authorized distributors?
All AO3438 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 AO3438 meets industry standards.
7.What is the process for return or replacement of AO3438?
All AO3438 units undergo pre-shipment inspection (PSI). If there is an issue with AO3438, 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 AO3438 part is unused and in its original packaging.
Return procedure for AO3438:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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