AD704AQ AD [Analog Devices], AD704AQ Datasheet - Page 8

• Manufacturer Part Number: AD704AQ
• Description: Quad Picoampere Input Current Bipolar Op Amp
• Manufacturer: AD [Analog Devices]

AD704
The 1 Hz, 4-pole active filter offers dc precision with a mini-
mum of components and cost. The low current noise, I
I
1 V/ C drift of the AD704. This means lower capacitor values
may be used, reducing cost and space. Furthermore, since the
AD704’s I
ture range, most applications do not require the use of the
normal balancing resistor (with its stability capacitor). Adding the
optional balancing resistor enhances performance at high
temperatures, as shown in Figure 26. Table II gives capacitor
values for several common low pass responses.
Desired Low
Pass Response
Bessel
Butterworth
0.1 dB Chebychev
0.2 dB Chebychev
0.5 dB Chebychev
1.0 dB Chebychev
Specified Values are for a –3 dB point of 1.0 Hz. For other frequencies simply scale capacitors C1 through C4 directly; i.e., for 3 Hz Bessel response, C1 = 0.0387 F,
C2 = 0.0357 F, C3 = 0.0533 F, C4 = 0.0205 F.
B
allow the use of 1 M resistors without sacrificing the
B
is as low as its I
16-Pin Plastic SO (R) Package
14-Pin Cerdip (Q) Package
Section 1
Frequency
(Hz)
1.43
1.00
0.648
0.603
0.540
0.492
OS
Table II. 1 Hz, 4-Pole Low-Pass Filter Recommended Component Values
, over most of the MIL tempera-
Q
0.522
0.541
0.619
0.646
0.705
0.785
Dimensions shown in inches and (mm).
OUTLINE DIMENSIONS
OS
, and
Section 2
Frequency
(Hz)
1.60
1.00
0.948
0.941
0.932
0.925
–8–
Figure 26. V
Filter Circuit
Q
0.806
1.31
2.18
2.44
2.94
3.56
0.100 (2.54)
0.064 (1.63)
–180
–120
180
120
–60
OS
60
0
20-Terminal LCCC (E) Package
14-Pin Plastic DIP (N) Package
vs. Temperature Performance of the 1 Hz
C1
( F)
0.116
0.172
0.304
0.341
0.416
0.508
–40
(1.27)
0.050
BSC
WITHOUT OPTIONAL
BALANCE RESISTOR, R3
0
TEMPERATURE – C
WITH OPTIONAL
BALANCE RESISTOR, R3
C2
( F)
0.107
0.147
0.198
0.204
0.209
0.206
0.358 (9.09)
0.342 (8.69)
NO. 1 PIN
+40
INDEX
o
+80
C3
( F)
0.160
0.416
0.733
0.823
1.00
1.23
0.040 (1.02)
0.020 (0.51)
x 45 REF
x 45 REF
+120
3 PLCS
0.028 (0.71)
0.022 (0.56)
C4
( F)
0.0616
0.0609
0.0385
0.0347
0.0290
0.0242
REV. A