Service manual

is then multiplied up in the reference oscillator step up loop to an output
frequency of 13MHz. The reference oscillator will be within 150ppm of 26MHz
within 100msec of the REG_REF input rising to 2.775V.
The 13MHz reference will be provided externally for the logic sections as a
CMOS output at 1Vp-p at CLK_OUT. At power up, the crystal oscillator
divided by 2 will be routed to the CLK_OUT pin by pulling CLK_SEL low. An
SPI bit is then used to activate the digital AFC. Finally CLK_OUT is pulled
high to route the output of the multiplied 200kHz reference to the CLK_OUT
pin.
RX 2nd Local Oscillator
The 2nd LO VCO will be 800 MHz for both GSM and DCS-1800 in the Taichi
radio with the MAGIC IC. The VCO frequency will be divided by 2 internal to the
IC. Note that in the programming the factor of two is ignored so that if an IF
frequency of 400MHz is desired, the programming is calculated as if the LO
was at 400MHz even though it is actually at 800MHz.
Power Supplies
The IC will contain 2 tracking regulators (external PNP or PMOS pass
transistors) which will generate the supplies for the entire IC as well as the
front end and the main VCO. A voltage of 2.775v must be provided to the
REG_REF input. This pin has a maximum current draw of 200µA in mode.
The reference voltage will be filtered and buffered for use on the IC. The
buffered voltage should track the reference within ± 50mV. A raw supply
voltage will be provided to the IC tracking regulators which will be at least
100mV above the reference (50mA output) and could be as high as 6.5Vdc. A
superfilter will be needed for the external VCO power supply. This superfilter,
cascaded with the normal regulator and any filtering in front of the IC, will
need to provide 80dB of rejection to a 0.1V step (risetime = 20µS) in the raw
supply (battery). The superfilter will use an internal pass transistor that will be
capable of driving a 45mA load with a voltage drop of less than 300mV
relative to V2_OUT from the SF_OUT pin. An external .01µF cap will be
required on SF_OUT.
All supplies within the IC must be within 5% of their final values after 10msec.
The power on reset circuit contained within the crystal reference oscillator
may be used to aid this functionality.
Magic / Whitecap MQSPI Interace
The following is the interconnection between MAGIC and WHITECAP in Taichi:
Board Signal
Name
MAGIC ball
MAGIC Pin
Name
WHITECAP
ball
WHITECAP
Signal Name
DX1
Ball J3,
input
SPI DATA
Ball M7,
output
DX1
MQSPI CLK1 Ball H4, SPI CLK_SC Ball M8, MQSPI CLK1