LG -P970 Service Manual page 34

The BCM4751 supports additional satellite constellations including the Satellite Based Augmentation System
(SBAS) and the Quasi-Zenith Satellite System (QZSS) for Japanese applications, making as many as twelve
additional satellites available for use in navigation.
The BCM4751 GPS receiver offers 65nm CMOS design featuring a highly-integrated RF and baseband processor
with extremely low power consumption. It also claims smallest complete PCB footprint at 30mm2 including
band-pass filter, TCXO and passives.
BCM4751 GPS receiver includes software that meets international standards bodies such as 3GPP, GERAN and
OMA, which promote the delivery of GPS assistance data over cellular networks. Figure shows block diagram of
BCM4751.
The GPS signal is received by the antenna and amplified by an internal LNA. The differential signal coming out of
the LNA is sent to an I/Q mixer, which uses a local Oscillator to directly down-convert the signal to an IF Near
6MHz.
C802
47p
L803 9.1n
C808
1.8p
LGE Internal Use Only
Fig3.7. Block diagram of BCM4751
GPS_2.8V GPS_2.8V
R801 10
R802
4.7K
C803
L801
0.1u
1.8n
5 2
VDD RF_IN
4 3
FIL_OUT GND
U802
Fig3.8. The Schematic of GPS RF path circuit of P970
C804
330p
FL801
1575.42 MHz
L802 6.8n
4
OUT
G3
L804
C807
100n
0.5p
- 34 - Copyright © 011 LG Electronics. Inc. All right reserved.
3. TECHNICAL BRIEF
CN801
1
L812
1
IN
2.2n
G2 G1
C816
C806
5 3 2
DNI
DNI
Only for training and service purposes
CN802
1