Diodes Incorporated has announced new additions to its synchronous buck converter portfolio. With continuous output current ratings of 5 A and 8 A respectively, the AP62500 and AP62800 offer the flexibility engineers need to develop point-of-load (POL) solutions that are optimized for either efficiency or size. Enabling compact implementations with a minimal component count, these devices are targeted at use in mass-market consumer products, such as 5 V and 12 V distributed power bus supplies, television sets and monitors, white goods and small home appliances, FPGA, DSP, and ASIC supplies, home audio, network systems, gaming consoles, consumer electronics, and general purpose point of loads.
Both buck converters have wide input voltage ranges—with the AP62500 covering 4.5 V to 18 V, and the AP62800 covering 4.5 V to 17 V. Their output voltages can be adjusted down to 0.6 V. Three different switching frequencies may be selected (400 kHz, 800 kHz, and 1.2 MHz), allowing engineers to prioritize elevated conversion efficiency or focus on having a compact form factor. In addition, the devices have three selectable operating modes; pulse frequency modulation (PFM) for improved light-load efficiency, pulse width modulation (PWM) for reduced output voltage ripple, and ultrasonic (USM) for avoiding audible frequency range while ensuring the switching frequency stays above 20 kHz.
On-resistance (RDS(ON)) figures are kept low in relation to both the high-side MOSFET (47 mΩ for AP62500; 22 mΩ for AP62800) and low-side MOSFET (18 mΩ for AP62500; 10 mΩ for AP62800). This helps to improve step-down conversion efficiency levels. An ultra-low quiescent current (IQ) is also achieved while in PFM mode (195 μA typical), further enhancing light-load efficiencies.
The design of these buck converters minimizes electromagnetic interference (EMI) issues. A proprietary gate-driver design mitigates switching-node ringing without having to extend MOSFET turn-on/turn-off times, which would otherwise impact high-frequency switching capabilities. Constant on-time (COT) control results in fast transient response and low-output voltage ripple, as well as facilitate better loop stabilization. Soft-start time adjustability is another important feature to protect against the risk of damage from inrush currents.
In 1,000-piece quantities, the AP62500 is available at $0.325 and the AP62800 is available at $0.570. They are both supplied in 12-pin V-QFN2030 packages.
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