handset transceiver diagram is presented showing MAX2361 as the
transmit IC, the MAX2291 as the power amplifier (PA), and the MAX2388
and MAX2309 form the receiver. A VCO buffer amplifier is used to provide
isolation and maintains a clean LO signal.
China. In November 1999, the TD-SCDMA standard was adopted by the ITU as one of the
options in the 3GPP mobile communication standard.
synchronization, a software radio, and a smart antenna, to increase channel capacity and
improve bandwidth efficiency.
high dynamic range, and high linearity in both the transmitter and receiver sections. Maxim's
chipset delivers the highest performance, the smallest implementation size, and the least
expensive radio solution available in the TD-SCDMA handset market. The following block
diagram shows a typical application.
gain IF and RF amplifiers, an image-rejecting upconverting mixer, a dual RF and IF synthesizer,
and a dual-band power amplifier (PA) driver amplifier. It is the ideal transmitter for TD-SCDMA
because of these features:
output power with 30% power-added efficiency (PAE) and 37dBc ACLR1.
buffer amplifier. Requiring ultra-low current consumption (9.9mA), the device is ideal for TD-
SCDMA application. The LNA delivers fixed gains of 15dB and -3dB, and it has a 1.7dB noise
figure (NF) and +4.2dBm IIP3 at high-gain mode. The mixer is also optimized for high linearity
and low noise with two gain steps. Even with 3dB filter insertion loss, the total cascade NF can
be as low as 2.3dB. The LO buffer provides excellent isolation and adequate amplification. This
feature enables the system to have single RF-LO to drive both the transmitter and the receiver.
The device is available in an ultra-small (3mm x 3mm) 12-pin QFN package.
cellular phone system. The input frequency range is optimized from 70MHz to 300MHz. A
variable-gain amplifier (VGA) and an I/Q demodulator make up the signal path. The device
features guaranteed +2.7V operation, a dynamic range of more than 110dB, and high input IP3 (-
33dBm at 35dBm gain, +1.7dBm at -35dBm). In addition to demodulation, the MAX2309
includes an oscillator, a synthesizer, and an LO buffer to form a self-contained IF subsystem.
The device will be able to provide the IF-LO to drive the transmitter's modulator. The MAX2309
is available in a small, 28-pin, QFN package measuring only 5mm by 5mm.
frequency range from 500MHz to 2500MHz. The high isolation (49dB) minimizes the transmitting
modulation signal to pull VCO frequency. The MAX2472 also includes a shutdown pin, making it
ideal for a TDD system such as TD-SCDMA.