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UC6580 Hardware Reference Design
UC-06-C21 EN R1.0 Reference Design 1
1 Reference Design

If you do not need the RTC and backup function, connect V_BCKP to VDD_IO.
RTC and backup function are the prerequisites of GNSS hot start. Refer to
UC6580
Datasheet
for more details.
1.1 LDO Mode
Under the LDO mode:

DCDC_IN and VDD_IO use the same power supply;

Use the internal LDO_EX to power the system;
 Power the external TCXO by LDO_X;
 Connect RTC Crystal externally;

Connect LNA and SAW externally;

Use the UART interfaces to communicate;
 Lower cost but higher power consumption.
RF Short 50ohm Line
TCXO
VBCKP ： 1.7V~3 .6V
VMAIN
：
2.7V~3 .6V
V_DET
：
2.7V~3 .6V
LDO_RE T LDO_X
LDO_X
VMAIN
DCDC_OUT
VDD_ANT
LDO_C
LDO_EX
VMAIN
VMAIN
V_DE T
V_BCKP
Figure 1-1 Reference design of LDO mode

If the antenna feed supply and the chip’s main supply use the same power rail, the
ESD, surge and overvoltage from the antenna will have an effect on the main supply,
which may cause damage to the chip. Therefore, it is recommended to design an
independent power rail for the antenna feed supply to reduce the possibility of chip
damage.