Part Number: AOZ1073AIL

Manufacturer: Alpha and Omega Semiconductor


Shipped from: Shenzhen/HK Warehouse

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The AOZ1073 is a synchronous 3A buck regulator that boasts good efficiency and ease of use. The input voltage range for the AOZ1073 is 4.5V to 16V, and it can deliver up to 3A of continuous output current at an output voltage that can be adjusted down to 0.8V. The SO-8 package AOZ1073 operates between -40 and +85 degrees Celsius. Stay with me here, and I’ll tell you everything you need to know about this device.

AOZ1073AIL Features

It includes the following features: output over-voltage protection, a 4.5V to 16V operational input voltage range, synchronized rectification with an internal high-side switch of 85m, an internal low-side switch of 30m, and high efficiency of up to 95%.

Other features include

  • Cycle-by-cycle current limit
  • Internal soft start
  • Thermal shutdown
  • Small dimension SO-8 package
  • Short-circuit safety
  • Output voltage adjusted to 0.8V
  • 3A continuous output current
  • Fixed 500kHz PWM operation

AOZ1073AIL Applications

  • It is utilized in DC/DC conversion at the point of load.
  • It is incorporated into Set-Top-Boxes, PCIe graphics cards, DVD drives, and HDD.
  • Used in LCD panels, Cable modems, and Telecom/networking/datacom equipment

AOZ1073AIL Operation Features

Enable and Soft Start

To reduce inrush current and guarantee that the output voltage ramps up gradually to regulation voltage, the AOZ1073 incorporates an inherent soft start feature. A soft start process starts when the input voltage reaches 4.1V and the EN pin voltage reaches HIGH. The output voltage typically ramps to regulatory voltage during the soft start process in 4ms. Internally, a 4ms soft start time is predetermined.

The AOZ1073’s EN pin is active HIGH. If the enable function isn’t being used, connect the EN pin to VIN. The AOZ1073 can be stopped by pulling EN to the ground. Never leave it unlocked. To activate the AOZ1073, the EN pin’s voltage must be greater than 2V. The AOZ1073 is turned off when the voltage on the EN pin drops below 0.6V. If your application circuit requires the AOZ1073 to be disabled, you can do it by connecting the EN pin to an open drain or open collector circuit.

Steady-State Operation

The converter maintains a constant frequency and Continuous-Conduction Mode operation at a steady state (CCM). The AOZ1073 has a P-MOSFET built in for use as the high-side switch. The drain-to-source voltage drop of the high-side power MOSFET is amplified and used to measure the current in the inductor. A voltage divider connected externally to the FB pin lowers the output voltage. The inbuilt transconductance error amplifier boosts the difference between the FB pin voltage and the reference.

At the PWM comparator input, the error voltage displayed on the COMP pin is compared to the current signal, which is the addition of the inductor current signal and the ramp compensation signal. The internal high-side switch is activated if the current signal is less than the error voltage.

The inductor’s input is where the current begins, and its output is where it ends. The high-side type of switch is disabled whenever the current signal exceeds the error voltage. The current from the inductor is unrestricted as it flows through the low-side N-MOSFET switch on the circuit’s logic level. The integrated adaptive FET driver ensures that the high-side and low-side switches never turn on simultaneously.

Protection Features

The AOZ1073’s many protection mechanisms prevent circuit damage in the event of an abnormality.

Over Current Protection (OCP)

Furthermore, over-current protection takes advantage of the signal from the measured inductor current. Given that the AOZ1073 operates in peak current mode control, the COMP pin voltage is proportional to the peak inductor current. Internally, the voltage at the COMP pin cannot exceed 2.5V. An automatic cycle-by-cycle cap on the maximum current can flow through the inductor.

Under fault conditions, when the output is shorted to ground, VO = 0V, and the inductor current decays relatively slowly throughout a switching cycle. In the AOZ1073, an additional current restriction has been implemented to prevent catastrophic failure. The current limitation is determined by comparing the measured inductor current to a fixed voltage, typically between 3.5A and 5.0A. The high side switch will shut off if the output current is higher than the current limit. After the over-current condition has been corrected, the converter will begin a soft start.

Output over Voltage Protection (OVP)

The AOZ1073 keeps an eye on the feedback voltage, and if it rises beyond 960mV, it instantly shuts off the PMOS to prevent the output voltage from going into an unsafe overshoot during a fault state. If the feedback voltage is lower than 940mV, the PMOS will be activated in the next cycle.

Power-On Reset (POR)

A power-on reset circuit continuously monitors the input voltage. The converter turns on when the input voltage is higher than 4.1V. The converter turns off if the input voltage is lower than 3.7V.

Thermal Protection

An internal temperature sensor is constantly tracking the junction temperature. If the junction temperature rises above 150 degrees Celsius, the internal control circuit and high-side PMOS are disabled. The soft-start circuit automatically restarts the regulator when the junction temperature drops below 100 degrees Celsius.

The AOZ1073 is an improved alternative to regulators that use freewheeling Schottky diodes by employing freewheeling NMOSFET to achieve synchronous rectification. Doing so considerably increases the converter’s efficiency and decreases power loss at the low-side switch. A P-Channel MOSFET serves as the high-side switch in the AOZ1073. It eliminates the need for the bootstrap capacitor typically present in an NMOS switch circuit.

When in linear regulation mode, the high-side switch can be turned on. Multiplying the load current by the MOSFET’s DC resistance and the buck inductor’s DC resistance yields a minimal voltage drop from VIN to VO. Maximum output voltage, input voltage (4.5V to 16V), output current (0A to 3A), and resistance of internal MOSFET (97m to 200m, depending on input voltage and junction temperature) are inputs into the following equation:


The AOZ1073 is a 3A buck regulator that is synchronous, efficient, and easy to operate. The AOZ1073 accepts input voltages between 4.5V and 16V, has a maximum output voltage of 0.8V, and can supply a continuous output current of up to 3A. The AOZ1073 can operate between -40 and +85 degrees Celsius and is available in SO-8 packaging.

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