Motorola T720 - RF Section; Ifr3300

19 © 2002 Motorola, Inc.
T720
Circuit Description &
Theory of Operation
Semtech SC801 Charger Controller:
Charging algorithm is controlled by this IC,
it is more of a hardware control than soft-
ware control. It also provides an overvoltage
input (>6.5V), reverse current, and output
short circuit protection.
T720 does not support no battery/dead battery
operation with fast charger since current is
limited to 1A by hardware.
Harness Asic: To take care of the multiplex-
ing of CE bus lines.
Have the following features: 1. Parallel to
Serial conversion 2. 16 additional dedicated
GPIO and 8 optional GPIO 3. EPIT
(Enhanced Programmable Interrupt Timer)
CE bus multiplexing, to allow Qualcomm
based radio to look like a CE bus compliant
radio. One wire bus serial interface for bat-
tery EPROM.
• USB transceiver chip does the interface
function of USB to CE bus
• 32 Mbit (4Mbyte -4Mx8 bits) Intel Sawtooth-
Main software code
• 32 Mbit (4 Mbyte) Intel Sawtooth C3-Main
software code & NVM, voice tags, phone book
• 16 Mbit(2 Mbyte) SRAM
RF SECTION
The RF side consists of 3 Qualcomm RF
chipset solution: RFR3300, IFR3300/
and RFT3100.
• Dual band VCO/PLL module and Cellular and
PCS PA’s
• RFR3300 is a tri-band/quad mode
• RF to IF analog receive IC, it contains the
programmable cellular LNA gain control for
all three bands and four modes and the Mixer
(down converter)
• RF to IF for all three bands and four modes.
• The IF frequency for all bands and mode is
183.6Mhz.
• Programmable 1xLO and ½ xLO frequency
settings, Independent CDMA, AMPS FM, and
GPS IF outputs.
IFR3300 is a IF to digital baseband con-
verter. It features the following:
• Quad mode operatin:PCS-CDMA,
Cellular-CDMA, AMPS FM, and
GPS position location
• Quadrature down conversion from IF
to analog baseband Low pass base-
band I and Q filtering with mode spe-
cific performance characteristics
• 4 bit I and Q analog to digital con-
verters with parallel outputs for
CDMA and GPS
• 8 bit I and Q analog to digital con-
verters with serial outputs for FM
• Rx slotted operation for very low
power consumption in FM mode
• Clock generators for all operating
modes
• VCO for generating the receivers IF
to base band LO
• Operational modes compatible with
MSM devices
• Three line serial bus interface for ini-
tialization and control
•