Date: 26/11/2020
Auto-grade sync buck converters with noise reduction and power good indicator
Diodes Inc has launched two synchronous buck converter ICs for automotive power systems design featuring power good output and EMI noise mitigation.
AP63356Q and AP63357Q with current capability of 3.5A can operate with input voltage in the range of 3.8V to 32V. By having the function of peak current mode control and on-chip high-side and low-side power MOSFETs, sales the board from external components reduce BOM cost.
Power-Good indicator output is provided with an internal 5MO pull-up resistor useful for power sequencing. To further aid sequencing, their enable pin has accurate voltage thresholds, which allows adjustment of the input voltage device power-on and undervoltage lockout (UVLO). The high-voltage capability of the EN pin allows direct connection to VIN to simplify the auto-start of the device. When disabled, the converter draws only 0.6ľA shutdown current typical.
By using a proprietary gate driver method for clean switching transitions prevents switch-node ringing to minimize high-frequency radiated noise. Frequency spread spectrum (FSS) technique is used to disperse switching-noise energy.
The AP63356Q operates continuously in PWM mode at the nominal 450kHz switching frequency for all loads. The AP63357Q changes to PFM mode at light loads, keeping efficiency as high as 86% at 5mA load and drawing quiescent current of just 22ľA under no load.
Both devices feature low-dropout (LDO) operation, which maintains their output-voltage regulation as the input reduces to a level near the output voltage. Built-in protection features include output undervoltage protection (UVP), cycle-by-cycle peak current limit, and thermal shutdown. The protection features, along with 40V (for 400ms) input voltage surge withstand capability, enable the devices to provide a robust Automotive POL solution.
The AP63356Q and AP63357Q are qualified to AEC-Q100 Grade 1, support PPAP documentation, and are manufactured in IATF 16949 certified facilities. The devices are each available in a 3mm × 2mm V-DFN3020-13 (SWP) package with wettable flanks to aid in automated optical inspection. The unit price is $0.46 in 3000 piece quantities.