High-PSRR LDO enables lower noise and ripple in noise-sensitive applications

Diodes Incorporated has announced the AP7372 low-noise LDO regulator for powering precision components such as ADCs, DACs, VCOs, and PLLs.

With up to 90dB PSRR across a wide frequency range, and extremely low output noise at only 8μVrms, the device helps designers mitigate the effects of input source noise and fulfil stringent output ripple and noise targets. This is most crucial within test and measurement, communication, industrial automation, and medical equipment.

The LDO delivers up to 200mA output current, with a dropout voltage (VDO) of 120mV. Five variants provide fixed output voltages of 1.8V, 2.5V, 3.3V, and 5V, and an adjustable voltage down to 1.2V. A dedicated pin for a resistor-divider permits fine adjustments of the fixed outputs. With an input voltage range from 2.7V to 20V, the device can be powered from common bus standards such as 12V and 5V or battery voltage (VBAT) down to a single Li-Ion cell.

The regulator also supplies adjustable soft-start time, easily set utilising an external capacitor, that allows designers to optimise the power-rail ramp up to mitigate inrush currents and produce a consistent and stable supply. A current limiter protects against short-circuit and overcurrent, and thermal protection is built in. A small 2.2μF ceramic output capacitor ensures stability, and the circuit is complete with just the input capacitor and soft-start capacitor. The low BoM and the AP7372’s 1.2mm x 1mm U-WLB1012-6 (Type A1) ball-grid array package allow a compact circuit footprint for high power density.

Also, the LDO supplies an enable pin that can be used for system-level control, such as power-up sequencing, and to save energy by shutting down the regulator when unused. The shutdown current is approximately 3µA with a quiescent current of 66μA, ensuring the AP7372 has minimal impact on the overall system power budget.