Power Electronics

LDOs Combine High PSRR with Low IQ

Intersil’s new family of high-performance dual LDOs (low dropout regulators) provide a high PSRR (power supply rejection ratio), low quiescent current (IQ), and excellent noise performance for RF and noise-sensitive applications. Output voltage options range from 1.2 V to 3.6 V, and the input voltage capability is 2.3 V to 6.5 V. Intersil’s ISL9000 offers a 90-dB PSRR at 1 kHz, and the quiescent current is typically only 21 µA per LDO regulator when active. The output voltage accuracy over temperature is 1.8% with a dropout of typically 200 mV at 300 mA. The ISL9011 and ISL9012 offer a PSRR of 70 dB at 1 kHz, and quiescent current is typically only 45 µA with both LDO regulators enabled and active. For all three devices, current consumption in shutdown mode is typically less than 0.1 µA.

The ISL9000 integrates output voltage sequencing and individual power-on-reset (POR) functions for each output. The POR delay for voltage output VO1 is internally fixed at approximately 2 ms to ensure voltage stability after start-up; the POR delay for VO2 can be externally programmed through an externally connected timing capacitor. Intersil’s ISL9011 and ISL9012 are high-performance dual LDO regulators capable of sourcing 150 mA of current from channel 1 and 300 mA from channel 2. All three devices feature a reference bypass pin for connecting a noise filtering capacitor to improve the noise and PSRR performance. Output noise for the LDO regulators is typically 30 µVrms at 100 uA for a 1.5-V output.

The ISL9000, ISL9011 and ISL9012 are priced in 1000-unit quantities at $1.30, $1.10 and $1.15, respectively. Each device is available in a 10-pin, lead-free DFN package.

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