Intersil Announces New LDO to Provide Stable Power for GSM-Based Cell Phone Applications
Intersil Corp. introduced the ISL900 3ALDO (low dropout) regulator. This device combines impressive PSRR (power supply rejection ratio) for stability and low noise for integration, making it well-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 20uVRMS, 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 1.6x1.6mm uTDFN," 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."
The ISL9003A has a no-load quiescent current of 30uA (typical) and 0.5µA shutdown current and is stable with 1uF of MLCC output capacitance with an ESR of up to 200Ω. 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.
The ISL9003A is available now in a 5-lead SC-70 package and is priced at $1.27 in 1,000-unit quantities.
