A7545
DC-DC CONVERTER/BOOST (STEP-UP)
AiT Semiconductor Inc.
www.ait-ic.com
LOW-NOISE 4.5A STEP-UP CURRENT MODE PWM CONVERTER
Application Information
Inductor Selection
Inductance value is decided based on different condition. 3.3uH to 4.7μH inductor value is recommended for
general application circuit. There are three important inductor specifications, DC resistance, saturation current
and core loss. Low DC resistance has better power efficiency.
Capacitor Selection
The output capacitor is required to maintain the DC voltage. Low ESR capacitors are preferred to reduce the
output voltage ripple. Ceramic capacitor of X5R and X7R are recommended, which have low equivalent
series resistance (ESR) and wider operation temperature range.
Diode Selection
Schottky diodes with fast recovery times and low forward voltages are recommended. Ensure the diode
average and peak current rating exceed the average output current and peak inductor current. In addition, the
diode’s reverse breakdown voltage must exceed the output voltage.
Output Voltage Programming
The output voltage is set by a resistive voltage divider from the output voltage to FB. The output voltage is:
Layout Consideration
For best performance of the A7545, the following guidelines must be strictly followed.
Input and Output capacitors should be placed close to the IC and connected to ground plane to reduce
noise coupling.
The GND should be connected to a strong ground plane for heat sinking and noise protection.
Keep the main current traces as possible as short and wide.
SW node of DC-DC converter is with high frequency voltage swing. It should be kept at a small area.
Place the feedback components as close as possible to the IC and keep away from the noisy device.
REV1.0
- JUN 2014 RELEASED -
- 6 -
AITSEMI [ AiT Semiconductor ]
