LDO cites best PSRR-noise performance for cell phones

Milpitas, Calif.&#8212Intersil's ISL9003A low-dropout regulator, touting superior power supply rejection ratio, delivers 150 mA continuous for GSM portable wireless applications.

“The ISL9003A provides outstanding low noise and low quiescent current and ripple rejection, critical for handheld and cell phone applications,” said Andrew Rhind, general manager of the Consumer Power Products group. “All of these features are housed in a very tiny package solution of 1.6-by-1.6 mm µTDFN. High performance is achieved through a circuit that delivers fast transient response to varying load conditions, and in a quiescent condition the ISL9003A adjusts its biasing to achieve the lowest possible standby current consumption.”

The ISL9003A, working from a 2.3 to 6.5-volt source, boasts very low output noise, just 20 microvolts RMS. The switching RF power amplifier in GSM cell phones operates at 217 Hz. During the off-state, the phone conserves power, during which time the cell phone battery can drop as much as 0.5 volt from its nominal voltage. The ISL9003A, with a PSRR of 90 dB at 1 kHz, is immune to these voltage drops; load regulation is less than 0.1 percent over the LDO's full current range.

Features include a dropout of just 200 mV maximum at 150 mA, a no-load quiescent current of 30 microamps (typical), and shutdown current of 0.5 microamp. The LDO is stable with 1 microfarad multilayer ceramic capacitors having an equivalent series resistance (ESR) of up to 200 milliohms.

The LDO, which includes current-limit and thermal protection, comes in several fixed voltage options with ±1.8 percent voltage accuracy over temperature, line and load. Other output voltage options are available on request.

Click here for additional information. The ISL9003A, rated for operation over -40 to +85&degC, is available now in a 5-lead Pb-free SC-70 package and is priced at $1.27 in 1,000-unit quantities.

Intersil , 1-888-INTERSIL,

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