Data Sheet

11
LMV321A/LMV358A/ LMV324A
80μA, 1.0MHz, Micro-Power Rail-to-Rail I/O Op Amps
www.3peakic.com.cn Rev. A.02
and types of components, where possible to match the number and type of thermocouple junctions. For example,
dummy components such as zero value resistors can be used to match real resistors in the opposite input path.
Matching components should be located in close proximity and should be oriented in the same manner. Ensure leads
are of equal length so that thermal conduction is in equilibrium. Keep heat sources on the PCB as far away from
amplifier input circuitry as is practical.
The use of a ground plane is highly recommended. A ground plane reduces EMI noise and also helps to maintain a
constant temperature across the circuit board.
Instrumentation Amplifier
The LMV321A/358A/324A OPA is well suited for conditioning sensor signals in battery-powered applications. Figure 4
shows a two op-amp instrumentation amplifier, using the LMV321A/358A/324A OPA.
The circuit works well for applications requiring rejection of Common Mode noise at higher gains. The reference
voltage (V
REF
) is supplied by a low-impedance source. In single voltage supply applications, V
REF
is typically V
DD
/2.
VREF VOUT
RG
R2
R2
R1
R1
V2
V1
11
12
2
2
=( )(1 )
OUT REF
G
RR
V V V V
RR
   
Figure 4
Gain-of-100 Amplifier Circuit
Figure 5 shows a Gain-of-100 amplifier circuit using two LMV321A/358A/324A OPAs. It draws 74uA total current
from supply rail, and has a -3dB frequency at 100kHz. Figure 6 shows the small signal frequency response of the
circuit.
VOUT
VIN
90.9k 90.9k
10k 10k
-0.9V
+0.9V
Figure 5: 100kHz, 74μA Gain-of-100 Amplifier