LDO family offers high PSRR for low-power, noise-sensitive apps - Embedded.com

LDO family offers high PSRR for low-power, noise-sensitive apps

Intersil's family of high-performance dual low dropout regulators (LDOs) provide high power-supply rejection ratio (PSRR), low quiescent current, and excellent noise performance for RF/noise-sensitive applications such as imaging sensors for digital still cameras or cellular phone camera modules, MP3 players, and portable medical and instrumentation devices.

Intersil's ISL9000 offers 90 dB PSRR at 1 kHz, and the quiescent current is typically only 21 ΜA/LDO when active. The output voltage accuracy over temperature is 1.8% with a drop-out of typically 200 mV at 300 mA. Separate enable pins control each individual LDO output. When both enable pins are low, the device is in shutdown, typically drawing less than 0.1 ΜA.

The ISL9000 integrates output voltage sequencing and individual power-on-reset (POR) functions for each output to remove the requirement for separate voltage monitoring/reset circuits. The POR delay for voltage output can be externally programmed by connecting a timing capacitor to the POR pin. The POR delay for VO1 is internally fixed at about 2 ms to ensure voltage stability after start-up. A reference bypass pin is provided for connecting a noise filtering capacitor to increase the noise and PSRR performance.

Intersil’s ISL9011 and ISL9012 are high-performance dual LDOs capable of sourcing 150 mA current from channel 1 and 300 mA from channel 2. These devices have low standby current and are stable with output capacitance of 1 to 10 ΜF with ESR of up to 200 mê. A reference bypass pin allows an external capacitor for adjusting a noise filter for low-noise and high-PSRR applications.

The ISL9011 and ISL9012 offer PSRR of 70 dB at 1 kHz and quiescent current is typically only 45 ΜA with both LDOs enabled and active. Separate enable pins control each individual LDO output. When both enable pins are low, these devices are in shutdown mode, typically drawing less than 0.1 ΜA. Several combinations of voltage outputs are standard on the ISL9000/11/12, ranging from 1.2 to 3.6 V.

The ISL9000 is in a 10-pin, lead-free DFN package and priced at $1.30; the ISL9011 is in a 10-pin, lead-free DFN package and is priced at $1.10; and the ISL9012 is in a 10-pin, lead-free DFN package and is priced at $1.15. More information on the ISL9000 is available at www.intersil.com/power. To view application block diagrams, visit Intersil’s Application Design Center at www.intersil.com/apps.

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