Two synchronous buck converters from Diodes feature noise reduction

Two automotive-compliant synchronous buck converters from Diodes feature noise reduction and a ‘power good’ indicator.

The two integrated synchronous buck converters simplify circuit design in automotive power systems, says Diodes and have a ‘power good’ output and EMI mitigation for noise-sensitive applications.

The AP63356Q and AP63357Q are 3.5A converters with an input voltage range of 3.8V to 32V. Leveraging peak current mode control as well as high side and low side power MOSFETs on-chip, the converters minimise external components for a reduced bill of materials (BoM) costs and board size, says Diodes.

Both devices have a ‘power good’ indicator with an internal 5MOhm pull-up resistor which supports power sequencing. The enable pin’s voltage thresholds allow adjustment of the input voltage device power-on and under-voltage 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 0.6 microA shutdown current typical.

The synchronous buck converters have a proprietary gate driver scheme which ensures clean switching transitions while preventing switch node ringing to minimise high frequency radiated noise. Frequency spread spectrum (FSS) contributes further to quiet performance by dispersing switching noise energy, adds Diodes.

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 per cent at 5mA load and drawing quiescent current of just 22 microA 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 under-voltage 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 available in a 3.0 x 2.0mm V-DFN3020-13 (SWP) package with wettable flanks for automated optical inspection (AOI).

Diodes delivers semiconductor products to customers in the consumer electronics, computing, communications, industrial, and automotive markets. Its product portfolio comprises discrete, analogue and mixed-signal products and packaging technology.

The company has worldwide operations of 28 sites, including engineering, testing, manufacturing, and customer service.

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