Diodes Incorporated AP63356Q/AP63357Q Buck Converters
Automotive-grade offering excellent noise reduction capability
Diodes Incorporated has launched two highly integrated synchronous buck converters which simplify circuit design in automotive power systems.
The 3.5A AP63356Q and AP63357Q converters, which implement peak current-mode control, integrate high- and low-side power MOSFETs on-chip, enabling designers to reduce bill-of-materials costs and board size.
The converters operate over an input-voltage range of 3.8V to 32V, and provide an output ranging between 0.8V and the input voltage. Both devices provide a Power Good indicator with an internal 5MΩ pull-up resistor, a feature useful for power sequencing. To aid sequencing, the converters’ Enable pin has accurate voltage thresholds, which allows adjustment of the input-voltage device power-on, and of under-voltage lock-out values. In addition, the high-voltage capability of the Enable pin permits direct connection to the VIN pin to simplify auto-start operation.
The AP63356Q and AP63357Q feature a proprietary gate-driver scheme which ensures that switching transitions are clean while preventing switch-node ringing, to minimize high-frequency radiated noise. A frequency spread-spectrum scheme also helps reduce noise by dispersing switching-noise energy.
The AP63356Q operates continuously in PWM mode at the nominal 450kHz switching frequency for all loads. The AP63357Q changes to pulse-frequency modulation mode at light loads, keeping efficiency as high as 86% at a 5mA load, and drawing a quiescent current of just 22µA under no load.
Both devices feature low-dropout operation, which maintains their output-voltage regulation as the input falls to a level near the output voltage.
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