OPA365-Q1_16 Datasheet, PDF (16/22 Pages) Texas Instruments – Single-Supply Operational Amplifiers

OPA365-Q1, OPA2365-Q1
SBOS512D – MARCH 2010 – REVISED DECEMBER 2015
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Application Information (continued)
MFB and Sallen-Key, low-pass and high-pass filter synthesis is quickly accomplished using TI's FilterPro
program. This software is available as a free download at www.ti.com.
C₃
220pF
V_IN = 1V_RMS
R₁
1.8kΩ
R₂
19.5kΩ
C₁
3.3nF
R₃
150kΩ
C₂
47pF
OPA365
V_OUT
Figure 27. Configured as a 3-Pole, 20 kHz, Sallen-Key Filter
9.1.4 Driving an ADS7822-Q1 Analog-to-Digital Converter
The OPAx365-Q1 operational amplifiers are optimized for driving medium to high speed sampling A/D
converters. The OPAx365-Q1 op amps buffer the A/D’s input capacitance and resulting charge injection while
providing signal gain. Figure 28 shows the OPAx365-Q1 in a basic noninverting configuration driving the
ADS7822-Q1. The ADS7822-Q1 is a 12-bit, micro-power sampling converter in the MSOP-8 package. When
used with the low-power, miniature packages of the OPAx365-Q1, the combination is ideal for space-limited, low
power applications. In this configuration, an RC network at the A/D’s input can be used to filter charge injection.
5V
–
OPA365
+
0.1µF
V_IN
0 to 4.096 V
100 W
0.1nF
V+
V_ref
IN+
ADS7822-Q₁
IN–
1 nF
GND
0.1µF
Figure 28. Driving the ADS7822-Q1
9.1.5 Driving ADS1115-Q1 Analog-to-Digital Converter
Some applications such as mutli-channels mid range radar need selection between channels. OPA2365-Q1
combined with ADS1115-Q1 fit very well for 2 channels radar selection. The circuit in Figure 29 shows the same
band pass filter but the components can be modified for different desired band pass.
The DAS1115-Q1 inputs are set as differential. the inputs accept up the ±2 V. The OPA2365-Q1 flat gain is 100
so the input signal peak is 20 mV.
16
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