Datasheet

REV. A
AD8306
–14–
Table III. Evaluation Board Setup Options
Component Function Default Condition
SW1 Device Enable. When in Position A, the ENBL pin is connected to +V
S
and the SW1 = A
AD8306 is in normal operating mode. In Position B, the ENBL pin is connected
to an SMA connector labeled Ext Enable. A signal can be applied to this connector
to enable/disable the AD8306.
R1 This pad is used to ac-couple INLO to ground for single-ended input drive. To drive R1 = 0 Ω
the AD8306 differentially, R1 should be removed.
R/L, C1, C2 Input Interface. The 52.3 Ω resistor in position R10, along with C1 and C2, create R10 = 52.3 Ω
a high-pass input filter whose corner frequency (640 kHz) is equal to 1/(2πRC), C1 = C2 = 0.01 µF
where C = (C1)/2 and R is the parallel combination of 52.3 Ω and the AD8306’s
input impedance of 1000 Ω. Alternatively, the 52.3 Ω resistor can be replaced by
an inductor to form an input matching network. See Input Matching Network
section for more details.
R3/R4 Slope Adjust. A simple slope adjustment can be implemented by adding a resistive R3 = 0 Ω
divider at the VLOG output. R3 and R4, whose sum should be about 1 kΩ, and R4 = ⬁
never less than 40 Ω (see specs), set the slope according to the equation:
Slope = 20 mV/dB × R4/(R3 + R4).
L1, C5, C6 Limiter Output Coupling. C5 and C6 ac-couple the limiter’s differential outputs. L1 = Open
By adjusting these values and installing an inductor in L1, an output matching C5 = 0.01 µF
network can be implemented. To convert the limiter’s differential output to single- C6 = 0.01 µF
ended, R11 and R12 (nominally 0 Ω) can be replaced with a surface mount balun R9 = Open
such as the ETC1-1-13 (Macom). The balun can be grounded by soldering a 0 Ω R10 = R11 = 0 Ω
into Position R9 (nominally open).
R8, LK1 Limiter Output Current. With LK1 installed, R8 enables and sets the limiter LK1 Installed. R8 = 402 Ω
output current. The limiter’s output current is set according to the equation R6, R7 (Limited Load
(I
OUT
= 400 mV/R8). The limiter current can be as high as 10 mA (R8 = 40 Ω). Resistors) = 50 Ω
To disable the limiter (recommended if the limiter is not being used), LK1 should
be removed.
C7 RSSI Bandwidth Adjust. The addition of C7 (farads) will lower the RSSI bandwidth of C7 = Open
the VLOG output according to the equation: f
CORNER
(Hz) = 12.7 × 10
–6
/(C7 + 3.5 × 10
–12
).
1
2
3
4
5
6
7
8
VLOG
VPS2
PADL
LMHI
LMLO
PADL
FLTR
LMDR
COM2
VPS1
PADL
INHI
INLO
PADL
COM1
ENBL
AD8306
9
10
11
14
15
16
12
13
C3
0.1mF
R10
52.3V
C1
0.01mF
C2
0.01mF
R2
10V
R1
0V
+V
S
EXT
ENABLE
C7 (OPEN)
R6
50V
C4
0.1mF
R7
50V
R3
0V
R5
10V
R4
(OPEN)
V
RSSI
+V
S
L1
(OPEN)
C5
0.01mF
C6
0.01mF
LK1
R8
402V
SIG
INHI
SIG
INLO
A
BSW1
R12
0V
R11
0V
R9
(OPEN)
Figure 33. Evaluation Board Schematic