1. Overview

️· What it is: A constant frequency peak current mode PWM converter designed for step-down voltage conversion.
️· Function: Converts input voltage (2.7V - 5.5V) to an output voltage ranging from 0.6V up to the input voltage (adjustable).
️· Current Capability: 400mA load capability.
️· Efficiency: Up to 96% efficiency (typical). Light load efficiency is > 80% at 500µA.
️· Part Numbers: AAT2510 (fixed and adjustable versions)

2. Features

️· Independent Channels: Each channel has separate input, enable, feedback, and ground pins.
️· Switching Frequency: 1MHz.
️· Soft Start: Prevents output voltage overshoot and inrush current.
️· Enable Input: Low state forces converter into a low-power, non-switching state (<1µA bias current).
️· Low Dropout Operation: Operates even when input voltage is close to the output voltage. Duty cycle increases to 100% when input drops below output voltage.
️· Under-Voltage Lockout (UVLO): Ensures proper operation of internal circuitry.
️· Overload Protection: Peak inductor current is limited.
️· Thermal Protection: Disables switching when temperature is excessive (junction temperature threshold: 140°C with 15°C hysteresis).

3. Operation

️· Peak Current Mode Control: Uses peak current mode control with slope compensation to maintain stability.
️· Duty Cycle: From 50% up to 100%.
️· Slope Compensation: Important for stability (see Applications section).
️· Feedback: Includes an internal resistor divider (≥ 1.2V versions). For lower voltage versions, the feedback pin is tied directly to the error amplifier input.
️· 100% Duty Cycle: When input voltage drops below output voltage, converter enters 100% duty cycle.

4. Applications

️· Typical Applications: Portable devices, battery-powered systems, general power management.
️· Inductor Selection:
- Slope compensation requirement: For adjustable versions with 0.6V output, inductor is 4.7µH (internal slope compensation: 0.24A/µsec). For 2.5V output, inductor must be 10µH.
- Consider DCR (DC Resistance) losses when choosing an inductor.
️· Input Capacitor Selection:
- 4.7µF to 10µF ceramic capacitors (X7R or X5R) are recommended.
- The formula for input capacitor size depends on input voltage and required ripple level.
️· Table 1 Summary:

Configuration	Output Voltage	Inductor	Slope Compensation
0.6V Adjustable With External Resistive Divider	0.6V to 2.0V	4.7µH	0.24A/µsec
0.6V Adjustable With External Resistive Divider	2.5V	10µH	0.24A/µsec
Fixed Output	0.6V to 2.0V	4.7µH	0.24A/µsec
Fixed Output	2.5V to 3.3V	4.7µH	0.48A/µsec

5. Key Parameters

️· Input Voltage Range: 2.7V - 5.5V
️· Output Voltage Range: 0.6V - Input Voltage (adjustable)
️· Switching Frequency: 1MHz
️· Output Current: 400mA
️· Bias Current (Enable Low): <1µA
️· Junction Temperature Threshold (Thermal Protection): 140°C
️· Internal Slope Compensation: 0.24A/µsec (0.6V version, and low voltage fixed versions). 0.48A/µsec (2.5V - 3.3V fixed versions).