High-Efficiency WCDMA Buck Converters Provides 1.5A of Peak Current from Only 4mm2
SUNNYVALE, CA—April 25, 2007—Maxim Integrated (NASDAQ: MXIM) introduces the MAX8805Y/MAX8805Z 600mA, PWM step-down converters in 2mm x 2mm wafer-level packages (WLPs) for WCDMA/NCDMA power amplifiers (PAs). These devices optimize battery efficiency by integrating a high-efficiency step-down converter for medium- and low-power transmission, as well as a 60mΩ bypass FET that provides 1.5A of peak current. High efficiency and tiny packaging make the MAX8805Y/MAX8805Z ideal for multiband WCDMA/NCDMA applications, such as cellular handsets, wireless PDAs, and smartphones.
Supporting 1.5A of peak current, the integrated 60mΩ bypass FET provides maximum power with minimum dropout under even low-battery conditions. Each device automatically enters bypass mode if the required output voltage is within 92% of the input voltage; or, the user can force the IC into bypass mode using a simple logic input. The output voltage is dynamically controlled using an external analog input signal, which has a gain of 2V/V. Additionally, the extremely fast 7.5µs (typ) slew rate of the output voltage ensures plenty of margin to the CDMA-required maximum time of 50µs.
The MAX8805Y/MAX8805Z also integrate two low-noise (35µVRMS), high-PSRR (70dB at 1kHz, typ) low-dropout regulators (LDOs), making them ideal for PA biasing or applications that require an exceptionally clean power source. Each LDO features a separate ON/OFF control, provides 3% (max) output accuracy, and requires only 10nF of output capacitance for loads of 10mA or less. Output voltage options include combinations of 1.80, 2.5, 2.7, 2.8, 2.85, and 3.0V.
Other MAX8805Y/MAX8805Z features include overcurrent protection for the buck regulator and LDOs, overtemperature protection, and operation over the extended temperature range (-40°C to +85°C). Available with either a 2MHz (MAX8805Y) or 4MHz (MAX8805Z) switching frequency, these devices provide the flexibility to optimize for size, cost, or efficiency. Both devices are available in lead-free, 16-bump, 2mm x 2mm x 0.7mm WLPs. Prices start at $1.75 (2500-up, FOB USA).