AO3400 is an N-channel field effect transistor commonly used for switching and amplification functions in low-voltage, low-power circuits. It consists of a P-type channel on an N-type substrate and two N-type doped regions. There is an insulating oxide layer above the channel, often called the gate oxide. When a voltage is applied to the gate, the electric field between the gate and the channel controls the number of carriers in the channel, thereby controlling the conduction state of the transistor.

Due to its low resistance, low leakage, fast switching and other characteristics, the AO3400 device has broad application prospects in the fields of power management, battery management, charge and discharge control, and DC-DC converters.

Ⅰ.Specification parameters of AO3400

•Number of pins:3
•Recovery time:5ns
•FET type:N channel
•Packaging:Tape and Reel (TR)
•Installation type:surface mount type
•Vgs (maximum value):±12V
•Drain-source voltage (Vdss):30 V
•Technology:MOSFET (Metal Oxide)
•Power dissipation (maximum):1.4W (Ta)
•Current at 25°C-Continuous Drain (Id):5.8A (Ta)
•Unmatched gate charge:Qg=75 nC (typ)
•Vgs(th) (maximum value) at different Id:1.45V @ 250µA
•Gate charge (Qg) (max) at different Vgs:7 nC @ 4.5 V
•Drive voltage (maximum Rds On,minimum Rds On):2.5V, 10V
•Input capacitance (Ciss) (max) at different Vds:630 pF@15 V
•On-resistance (maximum value) at different Id,Vgs:28 milliohms@5.8A,10V

Ⅱ.Basic working principle of AO3400

In AO3400, the main structure consists of P-type substrate and N-type channel. When a positive voltage is applied to the gate, an electric field is formed between the gate and the channel, causing the carriers in the channel to drift and form a conductive channel. When this conductive channel is formed, current can flow between the drain and source. On the contrary, when a negative voltage is applied to the gate, the N-type material in the channel will form a depletion layer, the conductive channel is cut off, and current cannot flow.

1.Gate control: The main control of AO3400 is completed through the gate. When a positive voltage is applied to the gate, an electric field is formed between the gate and the substrate. This electric field controls the movement of carriers (electrons) in the channel. When the voltage applied to the gate is high enough, the electric field attracts enough electrons into the channel to turn it on. In other words, when a positive voltage is applied between the gate and source, electrons in the channel are attracted to the vicinity of the gate, forming a conductive channel that allows current to flow through the transistor.

2.Structure: The AO3400 transistor consists of a P-type channel on an N-type substrate and two N-type doped regions. The channel is located between the substrate and the source/drain.

3.Source-drain control: Once the channel is formed, current will flow from source to drain. The greater the voltage difference between source and drain, the greater the current through the transistor.

4.Off state: When no voltage is applied to the gate or a negative voltage is applied, the electrons in the channel are repelled by the gate electric field, the channel is blocked, and the transistor is in an off state, with almost no current passing through.

 

Ⅲ.Circuit application of AO3400

1.Motor driver: AO3400 can be used in motor control circuits, such as to control the speed and direction of DC motors or stepper motors.

2.LED driver: In the LED lighting system, AO3400 can be used as a switch tube in the LED driver to control the brightness and current of the LED.

3.Battery management: In the charging and discharging control circuit, AO3400 can be used as a protection circuit and switch to ensure the safe charging and discharging of the battery.

4.Pulse modulation circuit: In the pulse modulation circuit, AO3400 can respond quickly and accurately control the on and off of the current to meet the needs of pulse modulation.

5.Power switch: In various power switch applications, AO3400 can be used to control the switching state of the circuit and realize the startup and shutdown of the circuit.

6.Power switching circuit: The high performance characteristics of AO3400 make it an ideal choice for power switching circuits, which can effectively control the switching state of current.

7.DC-DC converter: AO3400 can be used in switching tubes in DC-DC converters, such as buck and boost converters, to adjust circuit input and output voltages.

8.Battery protection circuit: AO3400 can be used in battery protection circuits to protect the battery from overcurrent, overcharge or overdischarge by controlling the on and off of current.

9.Power management circuit: AO3400 can be used as a control switching element for low-power voltage regulators, switch-mode power supplies and linear power supplies. It helps manage and regulate power output, providing stable voltage and current.

Ⅳ.The role of AO3400 in battery protection circuit

1.Over-discharge protection: When the battery is discharged to the lower safe voltage limit, the battery protection circuit needs to cut off the load circuit to prevent the battery from being damaged by over-discharge. AO3400 can be used as a switch of the discharge circuit. When the battery voltage drops to the set safe lower limit, it turns off the load circuit and stops the discharge process.

2.Overcharge protection: When the battery is charged to the upper limit of the safe voltage, the battery protection circuit needs to cut off the charging current to prevent the battery from being damaged due to overcharging. AO3400 can be used as a switch for the charging circuit. When the set safety voltage limit is reached, the charging circuit is turned off to prevent the battery from continuing to be charged.

3.Short circuit protection: When the battery output is short-circuited, the protection circuit needs to quickly cut off the connection between the battery and the load to prevent the battery from over-discharge and damage. The AO3400 can be used as a switch in a short circuit protection circuit. When a short circuit is detected, it closes the connection between the battery and the load, preventing current from flowing.

Ⅴ.Absolute Maximum Ratings of AO3400

 

Ⅵ.Electrical Characteristics of AO3400(Tj=25℃ unless otherwise noted)

 

Ⅶ.Characteristics of AO3400

1.Power handling capability: The power handling capability of AO3400 refers to the maximum power it can handle under normal working conditions. This is usually related to its on-resistance and maximum withstand voltage.

2.Excellent electrical characteristics: AO3400 also has excellent thermal performance and can withstand high temperature environments. It also has a high switching rate and is suitable for use in high-frequency circuits.

3.Turn-on voltage (VGS(th)): Turn-on voltage refers to the voltage at which the transistor begins to conduct after the voltage between the gate and source reaches a certain level. The turn-on voltage of the AO3400 is usually specified in the data sheet.

4.Leakage current (IDSS): Leakage current refers to the tiny current leaked by the transistor in the off state. The leakage current of the AO3400 should be as small as possible to ensure reduced power consumption in the shutdown state.

5.Gate voltage (VGS): Gate voltage refers to the voltage applied between the gate and source under normal operating conditions. The AO3400 usually requires a certain gate voltage to achieve a sufficient conduction state.

6.Excellent switching characteristics: It uses N-channel MOSFET technology, has excellent switching performance, can operate stably at high frequencies, and is suitable for use in circuits that require fast switching.

7.Package type: AO3400 is available in different package types, such as SOT23, SOT23-3, SOT-23-5, etc. Each package type has specific size and pin layout to meet the needs of different applications.

8.Maximum withstand voltage (VDS): The maximum withstand voltage refers to the maximum drain-source voltage that the transistor can withstand. Exceeding this voltage may cause damage to the transistor. The maximum withstand voltage of the AO3400 is usually an important specification parameter.

9.On-resistance (RDS(on)): The on-resistance of AO3400 is one of its important characteristics. It determines the resistance of the transistor when it is in the on-state. The AO3400 typically has lower on-resistance, helping to reduce power consumption and improve efficiency.

10.Operating temperature range: The operating temperature range of AO3400 refers to the temperature range in which it can work safely and reliably under normal operating conditions. Generally, the AO3400 is capable of operating over a wide temperature range, but may be limited in extreme temperature conditions.

Ⅷ.Replacement model of AO3400

•AO3402
•AO3401
•AO3404
•2N7002
•AO3406

Frequently Asked Questions

1.How is the application of AO3400 in battery management implemented?
The general applications of AO3400 in battery management include: overcharge protection, charge control, over-discharge protection and discharge control.

2.What is the failure mode of AO3400?
Increased gate leakage current, increased leakage current, thermal failure, increased on-resistance, breakdown and damage.

3.How does AO3400 contribute to power management circuits?
AO3400 can be used as a switch in power management circuits to control the flow of current, enabling efficient regulation of voltage and current levels.

4.What are some key specifications of AO3400?
Key specifications of AO3400 include its drain-source on-resistance (RDS(on)), gate-source voltage (VGS), drain-source voltage (VDS), maximum drain current (ID), and threshold voltage (VGS(th) ).