LC72121MA
(7) Front end connection example
Since this product is designed with the relatively high resistance of 200kΩ for the pulldown (on) resistors built in to
the FMIN and AMIN pins, a common AM/FM local oscillator buffer can be used as shown in the following circuit.
FM OSC
AM OSC
OSC buffer out
FMIN
On resistance: 200kΩ
AMIN
On resistance: 200kΩ
FE
PLL
(8) PD pin
Note that the charge pump output voltage is reduced when this IC, which is a 3-V system, is used to replace the
LC72131K/KMA, which is a 5-V system. This means that since the loop gain is reduced, the loop filter constants,
the lock time (SD wait time), and other related parameters must be reevaluated in the end product design.
Pin States after a Power on Reset
Open
Open
Open
Open
Open
Input port
XIN
VSSX
CE
DI
CL
DO
BO1
BO2
BO3
BO4
IO1
NC
XOUT
NC
VSSa
AOUT
AIN
PD
VDD
FMIN
AMIN
VSSd
IO2
IFIN
Input port
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