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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.
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