Datasheet
3Maxim Integrated
Evaluates: MAX9632
MAX9632 Evaluation Kit
Op-Amp Configuration
Transimpedance Application
To configure the EV kit as a transimpedance amplifier
(TIA), replace R2 with a 0I resistor, install a shunt on
jumper JU2, and capacitor C5 remains open. The output
voltage of the TIA is the input current multiplied by the
feedback resistor:
( )
−= × ×±
OUT IN BIAS OS
V I I R4 V
where R4 is installed as a 100I resistor, I
IN
is defined as
IN current, I
BIAS
is the input bias current, and V
OS
is the
input offset voltage of the op amp. Use capacitor C6 to
stabilize the op amp by rolling off high-frequency gain
due to a large cable capacitance.
Inverting Configuration
To configure the EV kit as an inverting amplifier, replace
R2 and R4 with the desired 1% gain-setting resistors,
install a shunt on jumper JU2, and feed a voltage VIN
between the IN- and IN+ pads. Install a shunt on JU2
to ground the IN+ input in this configuration. The output
voltage is given by the following equation:
OUT IN OS
R4
V (V V )
R2
=−+
The offset voltage V
OS
can be either positive or negative.
Noninverting Configuration
To configure the device as a noninverting amplifier,
replace R2 and R4 with the desired 1% gain-setting
resistors, and feed a voltage VIN between the IN+ and
IN- pads. Install a shunt on JU1 to ground the IN- input
in this configuration. The output voltage is given by the
following equation:
=+±
OUT IN OS
R4
V (1 )(V V )
R2
Differential Amplifier
To configure the EV kit as a differential amplifier, replace
R1–R4 with appropriate resistors. Make sure R1 = R4
and R2 = R3. The CMRR of the differential amplifier is
determined by the matching of the resistor ratios R4/R2
and R1/R3:
OUT
R4 R1
V Gain(INP INN), where Gain
R2 R3
=−==
Capacitive Loads
Some applications require driving large capacitive loads.
To improve the stability of the amplifier in such cases,
replace R5 with a suitable resistor value to improve
amplifier phase margin. The R5/C7 filter can also be
used as an anti-alias filter or to limit amplifier output noise
by reducing its output bandwidth.