AOZ1284PI-1 Datasheet Summary

General Description

The AOZ1284PI is a high voltage, high efficiency, simple to use, 4A buck regulator optimized for a variety of applications. It works from a 3.0V to 36V input voltage range and provides up to 4A of continuous output current. The output voltage is adjustable from 30V down to 0.8V. It integrates an N-channel high-side power MOSFET and offers adjustable switching frequency from 200kHz to 2MHz with an external resistor.

Features

• 3.0V to 36V operating input voltage range
• 50mΩ internal NMOS
• Up to 95% efficiency
• Adjustable soft-start
• Output voltage adjustable from 0.8V to 30V
• 4A continuous output current
• Adjustable switching frequency from 200kHz to 2MHz
• Cycle-by-cycle current limit
• Short-circuit protection
• Over-voltage protection
• Over-temperature protection
• EPAD SO-8 package

Applications

• Point-of-load DC/DC conversion
• Set top boxes and cable modems
• Automotive applications
• DVD drives and HDDs
• LCD Monitors & TVs
• Telecom/Networking/Datacom equipment

Ordering Information

AOS products are offered in packages with Pb-free plating and compliant to RoHS standards. For more information, visit AOS Green Policy.

Pin Configuration

TableCopy

Absolute Maximum Ratings

• Supply Voltage (VIN): 40V
• LX to GND: -0.7V to VIN+0.3V
• EN, SS, FB and COMP to GND: -0.3V to +6V
• BST to GND: -0.3V to VLX + 6V
• Junction Temperature (TJ): +150°C
• Storage Temperature (TS): -65°C to +150°C
• ESD Rating: 2kV

Recommended Operating Conditions

• Supply Voltage (VIN): 3.0V to 36V
• Output Voltage (VOUT): 0.8V to VIN*0.85V
• Ambient Temperature (TA): -40°C to +85°C
• Package Thermal Resistance (EPAD SO-8): 50°C/W

Electrical Characteristics (TA = 25 °C, VIN = 12V, VEN = 3V, VOUT = 3.3V)

• Input Under-Voltage Lockout Threshold (VIN rising/falling): 2.3V/2.9V
• Supply Current (Quiescent): 1mA to 1.5mA
• Shutdown Supply Current: 10µA
• Feedback Voltage (VFB): 788mV to 812mV
• Feedback Voltage Input Current (VFB = 800mV): 0.5µA to 1µA
• EN Input Threshold (Off/On): 1.2V/0.4V
• EN Input Hysteresis: 200mV
• Peak Current Limit: 5A to 6A
• Soft Start Source Current: 2µA to 3µA
• Frequency (RF = 270kΩ/RF = 46.6kΩ): 160kHz to 240kHz
• Maximum Duty Cycle (fO = 1MHz): 87%
• Minimum On Time: 150ns
• Error Amplifier Voltage Gain: 500V/V
• Error Amplifier Transconductance: 170µA/V
• Current Sense Circuit Transconductance: 4.5A/V

Thermal Protection

• Thermal Shutdown Threshold: 145°C
• Thermal Shutdown Hysteresis: 45°C

Detailed Description

The AOZ1284PI is a current-mode step down regulator with an integrated high side NMOS switch. It operates from a 3V to 36V input voltage range and supplies up to 4A of load current. It includes enable control, Power-On Reset, input under voltage lockout, external soft-start, and thermal shutdown.

Protection Features

• Over Current Protection (OCP): Limits peak inductor current cycle by cycle.
• Short Circuit Protection: Triggers when FB pin voltage is below 0.2V.
• Power-On Reset (POR): Monitors input voltage and starts/stops operation accordingly.
• Thermal Protection: Shuts down the control circuit and NMOS if junction temperature exceeds 145°C.

Application Information

• Input Capacitor: Must handle input ripple current and maintain steady input voltage.
• Inductor: Selected based on inductance, switching frequency, and peak current handling capability.
• Output Capacitor: Selected based on DC output voltage rating, output ripple voltage specification, and ripple current rating.
• Schottky Diode: Recommended for low forward voltage drop and recovery.

Thermal Management and Layout Considerations

• Minimize loop areas for input and output currents to reduce noise and improve efficiency.
• Use a ground plane and pour copper on unused board areas for better thermal dissipation.
• Keep sensitive signal traces away from high current paths.

Package Dimensions

• Package Type: SO-8 EP1
• Dimensions: Refer to the datasheet for detailed dimensions and land pattern recommendations.

Legal Disclaimer

• AOZ1284PI is not authorized for use as critical components in life support devices or systems.
• AOS reserves the right to make changes to product specifications without notice.
• Customers are responsible for evaluating the suitability of the product for their intended application and complying with applicable legal requirements.