High performance, tiny LDO regulator provides stable power for GSM-based cell phone 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 the 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 1.6x1.6mm 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 device is an incredibly high-performing part that gives customers the extra level of performance required for handheld and cell phone applications.
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 200mohms. 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.
With an excellent load regulation of <0.1% voltage change across full range of load current, the ISL9003A features a wide input voltage capability of 2.3V - 6.5V, and a low dropout voltage of typically 200mV @ 150mA.
Other key features are a shutdown pin that turns off LDO with 1μA (max) standby current, a soft-start limits input current surge during enable, and current limit and overheat protection
Target applications for the ISL9003A include PDAs, cell phones and smart phones, portable instruments, MP3 players, and handheld devices including medical handhelds.
With a -40 to +85 degrees C operating temperature range, the ISL9003A is available now in 5 Ld SC-70, and tiny 1.6x1.6mm µTDFN package solutions. Pb-free plus anneal is also available (RoHS compliant).