Cirrus Logic CS3002 - Manual (Page 8)

CS3002
8 DS490F10
3. OVERVIEW
The CS3002 amplifiers are designed for precision
measurement of signals from DC to 2kHz when
operating from a supply voltage of +2.7V to +6.7V
(
1.35V to 3.35V). The amplifiers are designed with
a patented architecture that utilizes multiple amplifier
stages to yield very high open-loop gain at frequencies
of 10 kHz and below.
The amplifiers yield low noise and low offset drift while
consuming relatively low supply current. An increase in
noise floor above 2kHz 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 applications where the
output of the amplifier can be band-limited to
frequencies below 2kHz.
3.1 Open-loop Gain and Phase Response
Figure 13 illustrates the open-loop gain and phase
response of the CS3002. The gain slope of the amplifier
is approximately -100dB/decade between 500Hz and
60kHz and transitions to -20dB/decade between 60kHz
and its unity gain crossover frequency at approximately
4.8MHz. Phase margin at unity gain is about 70

and
the gain margin is approximately 20dB.
-360
-315
-270
-225
-180
-135
-90
-45
10K 100K 1M 10M
Gain (dB)
Phase (Degrees)
0
20
40
60
80
100
-100 dB/ dec
-20 dB/ dec
Figure 13. Open-loop Gain and Phase Response