OPA2631 Datasheet, PDF (12/17 Pages) Burr-Brown (TI) – Dual, Low Power, Single-Supply OPERATIONAL AMPLIFIER

V_OUT
2.2nF
60.4Ω 7.32kΩ
1% Resistors
5% Capacitors
V_IN
681Ω
1/2
OPA2631
1.2nF
1.2nF
200Ω
59Ω
3.9nF
86.6Ω
1.8nF
1.2nF
130Ω
1/2
330pF
OPA2631
200Ω
133Ω
73.2Ω
20Ω 27pF
3.9nF
46.4Ω
FIGURE 3. Bandpass Filter.
10
0
–10
–20
–30
–40
–50
–60
10K
100K
1M
10M
Frequency (Hz)
100M
R₁
V_IN
+V_S
R₂
1/2
OPA2631
V_OUT
R₃
R₄
FIGURE 4. Nominal Filter Response.
FIGURE 5. DC Level Shifting Circuit.
at the center of its range, the following equations give the
resistor values that produce the best DC offset.
where:
NG = G + ∆V_OUT/V_S
R₁ = R₄/G
R₂ = R₄/(NG – G)
R₃ = R₄/(NG –1)
NG = 1 + R₄/R₃ (Noise Gain)
V_OUT = (G)V_IN + (NG – G)V_S
Make sure that V_IN and V_OUT stay within the specified input
and output voltage ranges.
The front page circuit is a good example of this type of
application. It was designed to take V_IN between 0V and
0.5V, and produce V_OUT between 1V and 2V, when using a
+3V supply. This means G = 2.00, and ∆V_OUT = 1.50V – G
• 0.25V = 1.00V. Plugging into the above equations gives:
NG = 2.33, R₁ = 375Ω, R₂ = 2.25kΩ, and R₃ = 563Ω. The
resistors were adjusted to the nearest standard values.
®
OPA2631
12