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High Common-Mode Voltage,
Programmable Gain Difference Amplifier
AD628
Rev. G
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
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FEATURES
High common-mode input voltage range
±120 V at V
S
= ±15 V
Gain range 0.1 to 100
Operating temperature range: −40°C to +85°C
Supply voltage range
Dual supply: ±2.25 V to ±18 V
Single supply: 4.5 V to 36 V
Excellent ac and dc performance
Offset temperature stability RTI: 10 μV/°C maximum
Offset: ±1.5 V mV maximum
CMRR RTI: 75 dB minimum, dc to 500 Hz, G = +1
APPLICATIONS
High voltage current shunt sensing
Programmable logic controllers
Analog input front end signal conditioning
+5 V, +10 V, ±5 V, ±10 V, and 4 to 20 mA
Isolation
Sensor signal conditioning
Power supply monitoring
Electrohydraulic controls
Motor controls
GENERAL DESCRIPTION
The AD628 is a precision difference amplifier that combines
excellent dc performance with high common-mode rejection
over a wide range of frequencies. When used to scale high
voltages, it allows simple conversion of standard control
voltages or currents for use with single-supply ADCs. A
wideband feedback loop minimizes distortion effects due to
capacitor charging of Σ- ADCs.
A reference pin (V
REF
) provides a dc offset for converting bipolar
to single-sided signals. The AD628 converts +5 V, +10 V, ±5 V,
±10 V, and 4 to 20 mA input signals to a single-ended output
within the input range of single-supply ADCs.
The AD628 has an input common mode and differential mode
operating range of ±120 V. The high common mode, input
impedance makes the device well suited for high voltage
measurements across a shunt resistor. The inverting input of
the buffer amplifier is available for making a remote Kelvin
connection.
FUNCTIONAL BLOCK DIAGRAM
+IN
–IN
+IN
–IN
–V
S
V
REF
R
EXT1
R
G
+V
S
R
EXT2
C
FILT
A2
A1
+IN
–IN
100k
100k
10k
10k
10k
AD628
OUT
G = +0.1
8
1
2 3 4
5
67
0
2992-001
Figure 1.
30
40
50
60
70
80
90
100
110
120
130
CMRR (dB)
FREQUENCY (Hz)
10010 1k 10k 100k
02992-002
V
S
= ±2.5V
V
S
= ±15V
Figure 2. CMRR vs. Frequency of the AD628
A precision 10 kΩ resistor connected to an external pin is
provided for either a low-pass filter or to attenuate large
differential input signals. A single capacitor implements a low-
pass filter. The AD628 operates from single and dual supplies
and is available in an 8-lead SOIC_N or an 8-lead MSOP. It
operates over the standard industrial temperature range of
−40°C to +85°C.
Verzeichnis
- ・ Konfiguration des Pinbelegungsdiagramms on Seite 9
- ・ Abmessungen des Paketumrisses on Seite 21
- ・ Teilenummerierungssystem on Seite 21
- ・ Blockdiagramm on Seite 1 Seite 16
- ・ Beschreibung der Funktionen on Seite 1 Seite 9
- ・ Technische Daten on Seite 1 Seite 4 Seite 8
- ・ Anwendungsbereich on Seite 1 Seite 17 Seite 18
- ・ Elektrische Spezifikation on Seite 10
