The MAX250_ series of complete transmitters are designed for low-cost cellular applications. The miniature 7mm x 7mm transmitter includes a quadrature modulator, upconverters, drivers, power amplifiers (PAs), a peak detector, a monolithic voltage-controlled oscillator (VCO), and a PLL. Each transmitter is tailored for specific frequency bands according to the Selector Guide. The MAX2500/MAX2502/MAX2503/MAX2504/MAX2504A/MAX2506/MAX2507 are compatible with voltage-mode baseband interfaces.
The devices are based on quasi-direct I/Q modulation. The devices accept differential I/Q baseband inputs, which are upconverted to IF. The IF signal is then upconverted to the RF frequency. Each signal is then fed into separate on-chip PAs through external RF filters. PA matching is integrated onto the chip to further reduce external component count. These chips feature an on-chip VCO and synthesizer to generate LO signals for both the IF and RF sections.
The MAX250_ devices are programmed with an SPI™/MICROWIRE™-compatible 3-wire serial bus. These devices feature multiple modes of operation, including shutdown, idle, high power, and low power, for flexible power management. To further reduce the current consumption, the PA supply voltage can be reduced to as low as 0.5V at lower output powers. The devices operate from single 2.7V to 3.3V regulated supplies and are packaged in a small 7mm x 7mm, 48-lead LGA package.
