Home > Products > MAX8896: Dual buck converter powers the WCDMA PA and RF transceiver to extend battery life in 3G handsets

Power

MAX8896: Dual buck converter powers the WCDMA PA and RF transceiver to extend battery life in 3G handsets

18th February 2010

Maxim Integrated

ES Admin

0 0

Datasheet

Maxim introduced the MAX8896, a dual step-down converter designed for powering WCDMA/NCDMA PA (power amplifier) modules and RF transceivers. This 4mm2 device integrates a high-efficiency, PA step-down converter that is optimized for medium- and low-power transmission, and includes a bypass FET for powering the PA directly from the battery during high-power transmission. By using the MAX8896 between the battery and RF-transceiver/PA, designers can reduce current consumption by up to 50% under typical operating conditions, thus extending battery life.

The MAX8896 also includes an RF step-down converter that supplies a high-PSRR, low-noise LDO (low-dropout linear voltage regulator) to provide a high-efficiency voltage supply for the RF transceiver. The MAX8896 is well suited for multiband WCDMA/NCDMA applications such as cellular handsets, netbooks, and smartphones. The MAX8896 is available in the Infineon(R) SMARTi(TM) UE HSPA RF transceiver and the XMM(TM) 6160 mobile phone platform, providing users with best-in-class battery life.

Supporting 1.9A of peak current, the integrated low-impedance 140milliohm (typ) bypass FET provides maximum power with minimum dropout, even under low-battery conditions. During high-power transmission, the bypass FET automatically turns on if the required output voltage is within 99% of the input voltage, and the PA step-down converter is forced into a 100% duty cycle.

The RF step-down converter has 94% peak efficiency with a 2MHz fixed switching frequency. It supports a 100% duty cycle, and provides a fixed 3.1V output voltage with ±2% output-voltage accuracy. The high-PSRR (65dB), low-noise (16microVrms), 2.8V LDO delivers a guaranteed 200mA output current. The low-noise output makes this LDO ideal for RF transceiver biasing or applications that require an exceptionally clean power source.