CS3011
CS3012
3. CS3011/CS3012 OVERVIEW
The CS3011/CS3012 amplifiers are designed for
precision measurement of signals from DC to
1 kHz when operating from a supply voltage of
+2.7 V to +6.7 V (± 1.35 to
±
3.35 V). The amplifi-
ers are designed with a patented architecture that
utilizes multiple amplifier stages to yield very high
open loop gain at frequencies of 1 kHz and below.
The amplifiers yield low noise and low offset drift
while consuming relatively low supply current. An
increase in noise floor above 1 kHz is the result of
intermediate stages of the amplifier being operated
at very low currents. The amplifiers are intended
for amplifying small signals with large gains in ap-
plications where the output of the amplifier can be
band-limited to frequencies below 1 kHz.
3.1
Open Loop Gain and Phase Response
illustrates the open loop gain and phase
response of the CS3011/CS3012. The gain slope
of the amplifier is about –100 dB/decade between
500 Hz and 30 kHz and transitions to –20 dB/de-
cade between 30 kHz and its unity gain crossover
frequency at about 2.4 MHz. Phase margin at unity
gain is about 70 degrees; gain margin is about
20 dB.
80
60
Gain (dB)
Phase (degrees)
40
20
0
0
-45
-90
-135
-180
-225
-270
-315
-360
10000
10 K
100000
100 K
1000000
1M
10000000
10 M
Figure 9. CS3011/CS3012 Open Loop Gain and Phase Response
7
CIRRUS [ CIRRUS LOGIC ]
