CS3011_09 Datasheet, PDF (11/18 Pages) Cirrus Logic – Precision Low-voltage Amplifier; DC to 1 kHz

CS3011
CS3012
Vin
Cin
50 pF
Vo
50 pF
Cin
R2
R1
Choose C2 so that R2 • C2 ≥ R? 1 • C_in
C2
Figure 16. Non-Inverting Gain Configuration with Compensation
The feedback capacitor C2 is required for closed- duces a pole and a zero in th e loop gain transfer
loop gains greater than 50 V/V. The capacitor intro- function.
T
=
-–---^--1-----+------z--s---^{1---}-


1
+
-p-s--_{1}
A_o
l
P₁
=
2----π^----(^--R----₁^----1|^-|^---R----₂^---)^--C----₂^-
≅
------------1------------
2π(R₁C₂)
for
R₂ » R₁
Z₁
=
-----------------1------------------
2π(A × R₁)C₂
where
A = -R----²
R₁
Z₁
=
------------1------------
2π(R₂)C₂
This indicates that the sep aration of the pole and
the zero is governed by the clo sed loop gain. It is
required that th e ze ro falls o n the steep slo pe
(–100 dB/decade) of the loop ga in plot so that
there is some gain higher than 0 dB (typically 20
dB) at the ha nd-over frequency (the frequ ency at
which the slope changes from – 100 dB/decade to
–20 dB/decade).
DS597F6
11