Datasheet

ADA4430-1
Rev. C | Page 14 of 20
USABLE INPUT VOLTAGE RANGE
The output voltage range of the ADA4430-1 limits its usable
input voltage range. The lower end of the input range is
typically 0 V. The upper end of the usable input voltage
range is calculated as
V
IN
(max) = (V
OM
V
OO
)/2
where:
V
IN
(max) is the upper end of the usable input voltage range.
V
OM
is the maximum output swing.
V
OO
is the output-referred offset voltage.
SAG CORRECTION FREQUENCY RESPONSE
When using the SAG corrected circuit, the gain from the input
to the immediate output of the ADA4430-1 is ×2.5 (8 dB) at
extremely low frequencies where the outer feedback loop
formed by the 22 µF capacitor effectively opens (see Figure 29)
and exhibits a second-order peak of approximately 11 dB at
about 5 Hz. This gain is approximately 7.5 dB at 30 Hz. The
extra gain must be accounted for when considering low
frequency input and output signal swings to keep them within
their specified limits. The gain from the ADA4430-1 input to
the load side of the 47 µF capacitor does not exhibit this
behavior; rather, it appears more like a single-pole high-
pass response. Figure 32 illustrates the SAG frequency response
immediately at the ADA4430-1 output and at the load side of the
47 µF capacitor.
12
10
8
6
4
2
0
–2
–4
–6
–8
–10
1 10 100 1000 10000010000
05885-040
GAIN (dB)
FREQUENCY (Hz)
AT ADA4430-1 OUTPUT
AT LOAD SIDE OF 47µF CAPACITOR
Figure 32. SAG Corrected Frequency Response at ADA4430-1 Output and
at the Load Side of the 47 μF Capacitor