Datasheet

OPA227, 2227, 4227
OPA228, 2228, 4228
16
SBOS110A
www.ti.com
FIGURE 15. Long-Wavelength Infrared Detector Amplifier.
FIGURE 16. High Performance Synchronous Demodulator.
V
OUT
V
IN
OPA227
68nF
10nF
33nF
330pF
2.2nF
OPA227
1.43kΩ
1.91kΩ
2.21kΩ
1.43kΩ
1.1kΩ
1.65kΩ1.1kΩ
f
N
= 13.86kHz
Q = 1.186
f
N
= 20.33kHz f = 7.2kHz
Q = 4.519
dc Gain = 1
Output
NOTE: Use metal film resistors
and plastic film capacitor. Circuit
must be well shielded to achieve
low noise.
Responsivity ≈ 2.5 x 10
4
V/W
Output Noise ≈ 30µVrms, 0.1Hz to 10Hz
Dexter 1M
Thermopile
Detector
100Ω 100kΩ
OPA227
2
3
6
0.1µF
Output
4.99kΩ
D2
D1
DG188
TTL
In
S1
S2
9.76kΩ
500Ω
Balance
Trim
OPA227
2
3
1
8
6
20pF
10kΩ
1kΩ
4.75kΩ
Offset
Trim
4.75kΩ
+V
CC
Input
TTL INPUT
“1”
“0”
GAIN
+1
–1
FIGURE 14. Three-Pole, 20kHz Low Pass, 0.5dB Chebyshev Filter.