Datasheet

detected signal with a reference voltage determined by
V
SET
. The integrator, acting like a comparator, increas-
es or decreases the voltage at OUT, according to how
closely the detected signal level matches the V
SET
ref-
erence. The MAX2015 adjusts the power of the PA to a
level determined by the voltage applied to SET. With R1 =
0Ω, the controller mode slope is approximately
19mV/dB (RF = 100MHz).
Layout Considerations
As with any RF circuit, the layout of the MAX2015 circuit
affects the device’s performance. Use an abundant num-
ber of ground vias to minimize RF coupling. Place the
input capacitors (C1, C2) and the bypass capacitors
(C3–C6) as close to the IC as possible. Connect the
bypass capacitors to the ground plane with multiple vias.
MAX2015
0.1GHz to 3GHz, 75dB Logarithmic
Detector/Controller
_______________________________________________________________________________________ 9
MAX2015
C6
R4
C1
C5
1
2
OUT
SET
V
S
C4 C3
4
V
CC
V
CC
INLO
V
OUT
V
SET
20kΩ
20kΩ
INHI
7
8
RFIN
C2
3
DETECTORS
GND
6
PWDN
5
Figure 2. Controller-Mode Typical Application Circuit
MAX2015
OUT
SET
20kΩ
20kΩ
IN
COUPLER
LOGARITHMIC
DETECTOR
TRANSMITTER
POWER AMPLIFIER
GAIN-CONTROL INPUT
SET-POINT
DAC
Figure 3. System Diagram for Automatic Gain-Control Loop