¡ Semiconductor
FEDL7584D-02
MSM7584D
(RSSI-ADC)
RSSI, RSGAIN
RSSI input and level adjustment.
RSSI is connected to the inverting input pin of the internal amplifier. RSGAIN is connected to
the output pin of the amplifier.
Adjust the gain and DC so that the signal amplitude is between 0.7 V and 2.1 V on the RSGAIN
pin. See Fig. 7 for connection.
Gain: A = R2/R1 = 1.4/ (Vmax - Vmin)
if R1 + R2 ≥ 20 kW
DC adjustment value : Vadj = A/(1+A) ¥ ((Vmax + Vmin) /2– 1.4)
Set the register CR20 to the DC adjustment value nearest to Vadj.
See the control register map (CR20) for setup values.
SGRS
Internal reference voltage output for the RSSI - ADC.
The output voltage is 2.0 V. Insert an approx. 0.1 mF bypass capacitor between this pin and the
AGM pin.
RSSI signal
R2
R1
Gain = R2/R1
RSGAIN
RSSI
–
+
Control
ADC
register
CR19:B7 to B0
DC
ADJUST
CR20:B7 to B3
Reference
voltage
generator
Figure 7 RSSI-ADC Interface
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