Datasheet

C
1
0.1 Fm
R
100W
1
(1)
+5V
V
IN
ADS8327
LowPower
16-Bit
500kSPS
C
3
(1)
1.2nF
C4
100nF
+5V
REFIN
-IN
+IN
REF5040
4.096V
+5V
OPA377
C
1
1nF
C
150pF
2
R
3
5.49kW
R
1
5.49kW
R
2
12.4kW
V+
V
OUT
V
IN
OPA377
(V+)/2
OPA377
OPA2377
OPA4377
www.ti.com SBOS504B –FEBRUARY 2010–REVISED JANUARY 2011
ACTIVE FILTERING DRIVING AN ANALOG-TO-DIGITAL
CONVERTER
The OPA377 series is well-suited for filter
applications requiring a wide bandwidth, fast slew The low noise and wide gain bandwidth of the
rate, low-noise, single-supply operational amplifier. OPA377 family make it an ideal driver for ADCs.
Figure 25 shows a 50kHz, 2nd-order, low-pass filter. Figure 26 illustrates the OPA377 driving an
The components have been selected to provide a ADS8327, 16-bit, 250kSPS converter. The amplifier is
maximally-flat Butterworth response. Beyond the connected as a unity-gain, noninverting buffer.
cutoff frequency, roll-off is –40dB/dec. The
Butterworth response is ideal for applications
requiring predictable gain characteristics such as the
anti-aliasing filter used ahead of an analog-to-digital
converter (ADC).
(1) Suggested value; may require adjustment based on specific
application.
(2) Initial calibration recommended.
Figure 26. Driving an ADS8327
(2)
Figure 25. Second-Order Butterworth 50kHz
Low-Pass Filter
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Product Folder Link(s): OPA377 OPA2377 OPA4377