Datasheet
removing the shunt on jumper JU1 and connecting an
external controller to the SHDN pad. See Table 1 for
jumper JU1 shutdown configurations.
Gain Control
The MAX9814 maximum signal gain can be configured
to 40dB, 50dB, or 60dB. Jumper JU2 selects the overall
gain for the MAX9814 EV kit. See Table 2 for jumper
JU2 gain control configurations.
Attack/Release Ratio Setting
Jumper JU3 sets the ratio of the attack time to the release
time of the MAX9814 AGC circuit to ratios of 1:500,
1:2000, and 1:4000. See Table 3 for configuring the
desired attack/release ratio using jumper JU3 position.
Jumpers JU4, JU5, and JU6 configure the attack time.
Capacitor C4 sets the attack time to 53µs. To increase
the attack time, configure the shunts on JU4, JU5,
and/or JU6, which change the total capacitance con-
nected at the MAX9814 CT pin. See Table 4 for
jumpers JU4, JU5, and JU6 configurations. Table 5 lists
the attack/release times. The attack time can be esti-
mated using the following equation:
t
Attack
≈ 2400 * C
CT
where C
CT
is in farads and the total connected capaci-
tance.
Evaluates: MAX9814
MAX9814 Evaluation Kit
______________________________________________________________________________________________________________________________________________________________________________
3
SHUNT POSITION SHDN PIN EV KIT FUNCTION
1-2 Connected to VCC MAX9814 enabled
2-3 Connected to GND MAX9814 disabled
— Not connected
SHDN driven by
external controller
Table 1. Shutdown Configuration (JU1)
SHUNT
POSITION
GAIN PIN
MAXIMUM GAIN
(dB)
1-2 Connected to VCC 40
2-3 Connected to GND 50
— Not connected 60
Table 2. Gain Control Configuration (JU2)
SHUNT
POSITION
ATTACK/RELEASE
PIN
ATTACK/RELEASE
RATIO
2-3 Connected to GND 1:500
1-2 Connected to VCC 1:2000
— Not connected 1:4000
Table 3. Attack/Release Ratio
Configuration (JU3)
RELEASE TIMES (ms)
ATTACK TIME
(µs)
1:500 1:2000 1:4000
53 26.4 105.6 211.2
166 83 332 664
406 203 812 1624
937 468 1874 3748
Table 5. Attack/Release Times
JU4 SHUNT POSITION JU5 SHUNT POSITION JU6 SHUNT POSITION
CT PIN CAPACITANCE
(µF)
ATTACK TIME
(µs)
Not installed Not installed Not installed 0.022 53
Installed Not installed Not installed 0.069 166
Installed Installed Not installed 0.169 406
Installed Installed Installed 0.389 937
Table 4. Attack Time Configuration (JU4, JU5, and JU6)