unicore UM621N, Справочный проект, Страница: 5 / 7

UM621N V1R0 Hardware Reference Design
2
2 Reference Circuit Using a Passive Antenna
 When using a passive antenna, a low noise amplifier should be added between
the antenna and the RF_IN of the module in order to ensure the performance of
the system.
 For the RF routing (antenna  LNA  RF_IN), note the 50 Ω impedance matching
 The supply voltage for VBCKP is 1.7 V ~ 3.6 V
 Requirement for the odometer speed pulse: width ≥ 100 us, frequency ≤ 5 KHz
Active Low
VCC 2. 7 V~3.6V
VBCK P 1.7 V~3.6V
RF Short 50ohm Line
Figure 2-1 Reference Circuit Using a Passive Antenna