MSM7715 View Datasheet(PDF) - Oki Electric Industry
Part Name
Description
MFG CO.
'MSM7715' PDF : 21 Pages View PDF
¡ Semiconductor
External adjustment of the carrier detection level
MSM7715
11 VR1
VREF
R4
r1
VR2
12
R5
SG
r2
6
COMP
R4 + R5 ≥ 20 kW
r1 : 300 kW, r2 : 600 kW
Figure 11 External Adjustment of the Carrier Detection Level
The carrier detection level is determined by the resistance ratio between the MSM7715's internal
resistors r1 and r2, unless external resistors R4 and R5 are connected.
By connecting external resistors R4 and R5, the detection level can be adjusted. However, the
width of hysteresis cannot be changed.
Caution:
Ra = R4 ¥ r1/(R4 + r1), Parallel-connected resistance of R4 and r1
Rb = R5 ¥ r2/(R5 + r2), Parallel-connected resistance of R5 and r2
VON = 20 ¥ log (Rb/(Ra + Rb)) –40.5 (dBm)
VOFF = 20 ¥ log (Rb/(Ra + Rb)) –42.5 (dBm)
r1 and r2 may vary in similar proportions over a 0.5 to 2.0 ¥ range, due to the lot
variation and temperature variation.
18/21
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