AW3605

The AW3605 achieves excellent efficiency across a wide load range due to its synchronous rectification architecture: At light loads (10-50mA), efficiency is typically 85-90%, which is important for extending battery life in standby modes. At medium loads (100-500mA), efficiency peaks at >95%, making it ideal for typical operating conditions. At heavy loads (1-2A), efficiency remains above 90%, minimizing heat generation during peak operation. The efficiency varies with input-output voltage differential - the converter is most efficient when the input voltage is close to the output voltage. The 100% duty cycle capability allows the converter to maintain high efficiency even as the battery voltage drops near the output voltage. For a typical smartphone application with 3.3V output from a 3.7V lithium battery, the AW3605 maintains >93% efficiency across most operating conditions.

Excellent efficiency across load range. Ideal for battery-powered applications.

Selecting the right inductor for the AW3605 is important for optimal performance: Inductance value - 2.2uH is recommended for the 1.5MHz switching frequency. This value provides a good balance of ripple current and transient response. Current rating - select an inductor with saturation current rating at least 1.5x the maximum output current (3A for 2A output). DC resistance - lower DCR improves efficiency, especially at high currents. Look for inductors with DCR <100mohm. Shielding - shielded inductors are recommended to minimize EMI radiation. Size - chip inductors (2.0mm x 1.6mm or 2.0mm x 1.2mm) are suitable for compact designs. Core material - ferrite core inductors are preferred for their low loss at switching frequencies. Awinic provides a list of recommended inductors from various manufacturers. The inductor should be placed close to the IC with short, wide traces to minimize parasitic resistance.

Use 2.2uH inductor with 3A+ saturation current. Contact our FAE team for recommended parts.

The AW3605 output voltage ripple depends on operating conditions and external components: Typical ripple is 10-30mV peak-to-peak at 1A load with standard 10uF output capacitor. The ripple increases with higher load current and decreases with larger output capacitance. The 1.5MHz switching frequency helps keep ripple low while using small capacitors. For applications requiring ultra-low ripple (such as RF or analog circuits), additional output filtering can be added: A small LC filter (1uH inductor + 10uF capacitor) can reduce ripple to <5mV. A ferrite bead in series with the output provides high-frequency filtering. Increasing output capacitance to 22uF or 47uF reduces ripple proportionally. The AW3605 uses voltage mode control with internal compensation, providing stable operation with various output capacitor types including ceramic and tantalum. For most digital loads, the standard 10uF ceramic output capacitor provides adequate ripple performance.

Standard configuration provides 10-30mV ripple. Add filtering for noise-sensitive applications.

The AW3605 includes an internal soft-start circuit that limits inrush current during startup. When the converter is enabled, the output voltage ramps up gradually rather than immediately reaching the regulated value. This soft-start process takes approximately 1ms from enable to full output voltage. The benefits of soft-start include: Reduced inrush current - prevents excessive current draw from the input source during startup, which could cause voltage droop and system reset. Controlled startup - minimizes stress on input capacitors and power switches. Sequential startup - multiple converters can be sequenced by enabling them at different times. The soft-start is automatic and requires no external components. If a fault occurs during startup (such as a short circuit), the converter will detect the fault and shut down before reaching full operation. The soft-start feature is particularly important for battery-powered systems where input current must be carefully managed.

Soft-start is automatic. No external components needed for startup control.

Yes, the AW3605 can operate at 100% duty cycle, which means the high-side switch remains continuously on and the converter operates in dropout mode. This is important for battery-powered applications because: As the battery discharges, its voltage approaches the regulated output voltage. Without 100% duty cycle capability, the converter would lose regulation when input voltage drops below the required headroom. With 100% duty cycle, the converter passes the input voltage directly to the output (minus small resistive drops), maintaining regulation even with minimal voltage differential. This extends battery life by allowing the battery to discharge to lower voltages while still powering the system. The dropout voltage is determined by the high-side switch resistance (typically 100-150mohm) multiplied by the load current. At 2A load, dropout voltage is approximately 200-300mV. The converter automatically transitions to 100% duty cycle when needed, with no external control required.

100% duty cycle extends battery life. Automatic operation, No configuration is needed.

The AW3605 requires minimal thermal management due to its high efficiency and compact thermal design. At typical operating conditions (1A output, 3.3V output from 3.7V input), the device dissipates less than 50mW of power. The SOT-23-5 package has thermal resistance of approximately 200°C/W junction-to-ambient. With 50mW dissipation, temperature rise is only 10°C above ambient. For maximum load (2A) and worst-case conditions, dissipation may reach 200-300mW, resulting in 40-60°C temperature rise. The device includes over-temperature protection that shuts down if the junction temperature exceeds safe limits. For most applications, no special thermal management is required beyond standard PCB design practices: Use adequate copper area for the ground connection. Connect the GND pin to a solid ground plane with multiple vias. Keep other heat-generating components away from the converter. For high ambient temperature applications (>85°C), additional copper area or airflow may be beneficial.

Minimal thermal management needed. Follow standard PCB practices.