AD704JNZ View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD704JNZ Datasheet PDF : 8 Pages
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2V
100
90
50µs
100
90
5µS
100
90
AD704
5µS
10
10
10
0%
0%
0%
20mV
20mV
Figure 23b. Unity Gain Inverter
Large Signal Pulse Response,
CL = 1,000 pF
Figure 23c. Unity Gain Inverter
Small Signal Pulse Response,
CL = 100 pF
Figure 23d. Unity Gain Inverter Small
Signal Pulse Response, CL = 1,000 pF
OPTIONAL
AC CMRR TRIM
2.4k 47.5k
R5
R4
Ct
DC
CMRR
TRIM
(5k POT)
–V IN
GAIN TRIM
(500k POT)
6.34k RG
R3
6.34k
R1
+VS 0.1 µF
1/4
AD704
49.9k
R2
C1
Q1= 4C2
ω = _____1____
R6 C1C2
R6 = R7
1/4
AD704
1MΩ
R6
0.1 µF
1MΩ
R7
C2
C1
1/4
AD704
C3
Q 2 = 4C4
ω = _____1____
R8 C3C4
R8 = R9
1MΩ 1MΩ
R8
R9
C4
C3
1/4
AD704
OUTPUT
+VIN
–VS
INSTRUMENTATION
AMPLIFIER
GAIN
=
1
+
RR__21 +
2_R__2
RG
(FOR R1 = R3, R2 = R4 + R5)
ALL RESISTORS METAL FILM, 1%
R10
2MΩ
C5 0.01µF
OPTIONAL BALANCE RESISTOR
NETWORKS CAN BE REPLACED
WITH A SHORT
R11
2MΩ
C6 0.01µF
CAPACITORS C2 AND C4 ARE
SOUTHERN ELECTRONICS MPCC,
POLYCARBONATE, ±5%, 50 VOLT
Figure 24. Gain of 10 Instrumentation Amplifier with Post Filtering
The instrumentation amplifier with post filtering (Figure 24)
combines two applications which benefit greatly from the
AD704. This circuit achieves low power and dc precision over
temperature with a minimum of components.
The instrumentation amplifier circuit offers many performance
benefits including BiFET level input bias currents, low input
offset voltage drift and only 1.2 mA quiescent current. It will
operate for gains G ≥ 2, and at lower gains it will benefit from
the fact that there is no output amplifier offset and noise
contribution as encountered in a 3 op amp design. Good low
frequency CMRR is achieved even without the optional AC
CMRR trim (Figure 25). Table I provides resistance values for
3 common circuit gains. For other gains, use the following
equations:
R2 = R4 + R5 = 49.9 kΩ
R1 =
R3
=
49.9 kΩ
0.9 G − 1
Max Value
of
RG
=
99.8 k
0.06 G
Ct
≈
2
1
π (R3) 5 × 105
Table I. Resistance Values for Various Gains
Circuit Gain
RG (Max Value
Bandwidth
(G)
R1 & R3 of Trim Potentiometer) (–3 dB), Hz
10
6.34 kΩ 166 kΩ
50k
100
526 Ω 16.6 kΩ
5k
1,000
56.2 Ω 1.66 kΩ
0.5k
160
GAIN = 10, 0.2V p-p COMMON-MODE INPUT
140
CIRCUIT TRIMMED
120
USING CAPACITOR Ct
100
80
TYPICAL MONOLITHIC IN AMP
60
40
WITHOUT CAPACITOR C t
20
0
1
10
100
1k
10k
FREQUENCY – Hz
Figure 25. Common-Mode Rejection vs. Frequency with
and without Capacitor Ct
REV. A
–7–
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