AD713AQ 데이터 시트보기 (PDF) - Analog Devices
부품명
상세내역
제조사
AD713AQ Datasheet PDF : 21 Pages
| |||
AD713
A HIGH SPEED INSTRUMENTATION AMPLIFIER
CIRCUIT
A HIGH SPEED 4-OP-AMP CASCADED AMPLIFIER
CIRCUIT
The instrumentation amplifier circuit shown in Figure 33 can
provide a range of gains from unity up to 1000 and higher using
only a single AD713. The circuit bandwidth is 1.2 MHz at a gain
of 1 and 250 kHz at a gain of 10; settling time for the entire
circuit is less than 5 μs to within 0.01% for a 10 V step, (G = 10).
Other uses for Amplifier A4 include an active data guard and an
active sense input.
20,000
CIRCUIT GAIN =
1/4
RG
+1
AD713
–IN
3
*1.5pF TO 20pF
A1 1
(TRIM FOR BEST SETTLING TIME)
2
10kΩ
10kΩ**
RG
+IN
+VS
COM
–VS
7.5pF
7.5pF
10kΩ
10kΩ**
10kΩ**
5pF
9
A3 8
10
1/4
AD713
10kΩ**
SENSE
6
A2 7
5
1/4
AD713
0.1µF +1µF
0.1µF +1µF
13
14 A4
12
1/4
AD713
TO BUFFERED
VOLTAGE
REFERENCE
OR REMOTE
GROUND SENSE
AD713
PIN 4
*VOLTRONICS SP20 TRIMMER CAPACITOR
OR EQUIVALENT
**RATIO MATCHED 1% METAL FILM
AD713 RESISTORS
PIN 11
Figure 33. High Speed Instrumentation Amplifier Circuit
Figure 35 shows how the four amplifiers of the AD713 can be
connected in cascade to form a high gain, high bandwidth
amplifier. This gain of 100 amplifier has a −3 dB bandwidth
greater than 600 kHz.
+VS
1µF
0.1µF
INPUT
3
4
1
2
1/4
AD713
2.15kΩ
1kΩ
1kΩ
22MΩ
–VS
+VS
100kΩ
OPTIONAL VOS
ADJUSTMENT
5
7
6
1/4
AD713
2.15kΩ
10
8
9
1/4
AD713
1/4
AD713
12
14
13 11
OUTPUT
2.15kΩ
2.15kΩ
1kΩ
1kΩ
1µF 0.1µF
+
–VS
4-OP-AMP CASCADED AMPLIFIER
GAIN = 100
BANDWIDTH (–3dB) = 632kHz
Figure 35. High Speed 4-Op-Amp Cascaded Amplifier Circuit
TO SPECTRUM ANALYZER
ERROR SIGNAL
OUTPUT
NULL
(ERROR/11)
1kΩ
ADJUST 10kΩ
100kΩ 10kΩ
+VS
1kΩ
LOW DISTORTION
SINEWAVE INPUT
4
1/4
AD713
11
+
1µF 0.1µF
100pF
Table 4 provides a performance summary for this circuit. Figure 34
shows the pulse response of this circuit for a gain of 10.
Table 4. Performance Summary for the High Speed
Instrumentation Amplifier Circuit
Gain RG
Bandwidth Settling Time (0.01%)
1
NC1
1.2 MHz
2 μs
2
20 kΩ 1.0 MHz
2 μs
10
4.04 kΩ 0.25 MHz
2 μs
1 NC = no connect.
5V
100 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
90
1µF
–VS +
0.1µF
Figure 36. THD Test Circuit
HIGH SPEED OP AMP APPLICATIONS AND
TECHNIQUES
DAC Buffers (I-to-V Converters)
The wide input dynamic range of JFET amplifiers makes them
ideal for use in both waveform reconstruction and digital audio
DAC applications. The AD713, in conjunction with a 16-bit
DAC, can achieve 0.0016% THD without requiring the use of a
deglitcher in digital audio applications.
Driving the Analog Input of an Analog-to-Digital
Converter
An op amp driving the analog input of an analog-to-digital
converter (ADC), such as that shown in Figure 37, must be
capable of maintaining a constant output voltage under dynami-
cally changing load conditions. In successive approximation
10
0% • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •
converters, the input current is compared to a series of switched
trial currents. The comparison point is diode clamped but may
2µs
vary by several hundred millivolts, resulting in high frequency
modulation of the analog-to-digital input current. The output
Figure 34. Pulse Response of High Speed Instrumentation Amplifier,
Gain = 10
impedance of a feedback amplifier is made artificially low by its
Rev. F | Page 12 of 20
Share Link: 