Intersil’s LDO Provides Stable Power for GSM-Based Cell Phone Applications

Intersil's LDO Provides Stable Power for GSM-Based Cell Phone Applications

Intersil has introduced the ISL9003A LDO (low dropout) regulator which combines PSRR (power supply rejection ratio) for stability and low noise for integration, suited for GSM (global system for mobile) portable wireless applications.

Intersil's ISL9003A Delivers PSRR of 90dB at 1kHz and Output Noise of 20μVRMS in a Tiny 1.6×1.6 μTDFN Package

Intersil has introduced the ISL9003A LDO (low dropout) regulator which combines PSRR (power supply rejection ratio) for stability and low noise for integration, suited for GSM (global system for mobile) portable wireless applications.

In GSM cell phones, the RF PA switches on and off at a rate of 217Hz. During the on state, the RF PA sends data to the base station and the off state allows the phone to conserve battery power. During this on/off state the cell phone battery can drop as low as 500mV from its nominal voltage. The ISL9003A with a PSRR of 90dB is immune to these wide voltage drops, providing a very stable output voltage rail and continuous 150mA of load current.

The ISL9003A, with an output noise of just 20μVRMS, also provides a discrete solution that enables integration of several modules or functions into a cell phone. This low noise, along with the PSRR, allows this device to be interfaced with an RX transceiver module or a camera module in a cell phone, as applications like this require a high level of performance that is not often achieved in integrated PMIC solutions.

“The ISL9003A provides outstanding low noise and low quiescent current and ripple rejection, critical for handheld and cell phone applications. All of these features are housed in a very tiny package solution of 1.6×1.6mm μTDFN,” said Andrew Rhind, vice president and general manager of Intersil’s Consumer Power products group. “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. This is an incredibly high-performing part that gives customers the extra level of performance required for handheld and cell phone applications.”

High Performance and Low Power Consumption
The ISL9003A has a no-load quiescent current of 30μA (typical) and 0.5μA shutdown current and is stable with 1μF of MLCC output capacitance with an ESR of up to 200mΩ. It comes in many fixed voltage options with ±1.8% output voltage accuracy over temperature, line and load. Other output voltage options are available on request.