msm7715 Oki Semiconductor, msm7715 Datasheet - Page 18

• Manufacturer Part Number: msm7715
• Description: Multi-function Telecommunication Lsi
• Manufacturer: Oki Semiconductor

¡ Semiconductor
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:
R4
R5
Ra = R4 ¥ r
Rb = R5 ¥ r
V
V
r
variation and temperature variation.
1
Figure 11 External Adjustment of the Carrier Detection Level
ON
OFF
and r
= 20 ¥ log (Rb/(Ra + Rb)) –40.5 (dBm)
= 20 ¥ log (Rb/(Ra + Rb)) –42.5 (dBm)
2
11
12
6
may vary in similar proportions over a 0.5 to 2.0 ¥ range, due to the lot
1
2
VR1
VR2
SG
/(R4 + r
/(R5 + r
r
1
1
2
), Parallel-connected resistance of R4 and r
), Parallel-connected resistance of R5 and r
r
r
2
1
: 300 kW, r
VREF
2
: 600 kW
COMP
R4 + R5 ≥ 20 kW
1
2
MSM7715
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