unicore UM621 Series, Справочник по аппаратуре

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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 μs, frequency ≤ 5 KHz
Active Low
VCC: 2.7 V ~ 3.6 V
VBCKP: 1.7 V ~ 3.6 V
RF, Short 50ohm Line
Figure 2-1 Reference Circuit Using a Passive Antenna