AD830JRZ-REEL7 Analog Devices Inc, AD830JRZ-REEL7 Datasheet - Page 12

• Manufacturer Part Number: AD830JRZ-REEL7
• Manufacturer: Analog Devices Inc

Specifications of AD830JRZ-REEL7

• Single Supply Voltage (typ): Not RequiredV
• Single Supply Voltage (min): Not RequiredV
• Single Supply Voltage (max): Not RequiredV
• Mounting: Surface Mount
• Pin Count: 8
• Lead Free Status / RoHS Status: Compliant

AD830
Differential Line Receiver
The AD830 was specifically designed to perform as a differential
line receiver. The circuit in Figure 19 shows how simple it is to
configure the AD830 for this function. The signal from System A
is received differentially relative to A’s common and that voltage
is exactly reproduced relative to the common in System B. The
common-mode rejection versus frequency, shown in TPC 1, is
excellent, typically 100 dB at low frequencies. The high input
impedance permits the AD830 to operate as a bridging amplifier
across low impedance terminations with negligible loading. The
differential gain and phase specifications are very good, as
shown in TPC 7 for 500 Ω and TPC 10 for 150 Ω. The input
and output common should be separated to achieve the full
CMR performance of the AD830 as a differential amplifier.
However, a common return path is necessary between Sys-
tems A and B.
Wide Range Level Shifter
The wide common-mode range and accuracy of the AD830
allows easy level shifting of differential signals referred to an
input common-mode voltage to any new voltage defined at the
output. The inputs may be referenced to levels as high as 10 V
at the inputs with a ± 2 V swing around 10 V. In the circuit in
Figure 20, the output voltage, V
equation shown below. The excellent linearity and low distortion
are preserved over the full input and output common-mode
V
Figure 18. Output Swing Limit for Single Supply
CM
28
24
20
16
12
Z
8
4
0
CM
10
COMMON IN
Figure 19. Differential Line Receiver
SYSTEM A
SIGNAL
V
INPUT
V
1
2
V
OUT
14
1
2
3
4
= V
1
– V
SUPPLY VOLTAGE – V
G
G
2
TO V
18
M
M
TO GND
P
OUT
, is defined by the simple
C
22
AD830
A = 1
COMMON IN
SYSTEM B
26
8
7
6
5
V
V
P
0.1 F
N
0.1 F
V
30
OUT
–12–
range. The voltage sources need not be of low impedance, since
the high input resistance and modest input bias current of the
AD830 V-to-I converters permit the use of resistive voltage
dividers as reference voltages.
Difference Amplifier with Gain > 1
The AD830 can provide instrumentation amplifier style differential
amplification at gains greater than 1. The input signal is connected
differentially and the gain is set via feedback resistors, as shown in
Figure 21. The gain, G = (R
either inverting or noninverting differential amplification. The
polarity of the gain is established by the polarity of the connection
at the input. Feedback resistor R
maintain closed-loop stability and also keep bias current induced
offsets low. Highest CMRR and lowest dc offsets are preserved by
including a compensating resistor in series with Pin 3. The gain
may be as high as 100.
Offsetting the Output with Gain
Some applications, such as A/D drivers, require that the signal
be amplified and also offset, typically to accommodate the input
range of the device. The AD830 can offset the output signal
very simply through Pin 3 even with gain > 1. The voltage
applied to Pin 3 must be attenuated by an appropriate factor
so that V
from a voltage reference is used to produce the attenuated
offset voltage.
Figure 20. Differential Amplification with Level Shifting
V
Figure 21. Gain of G Differential Amplifier, G > 1
CM
Z
3
CM
INPUT
SIGNAL
INPUT
COMMON
× G = desired offset. In Figure 22, a resistive divider
V
V
SIGNAL
1
2
V
INPUT
V
1
2
V
V
R
OUT
OUT
1
R
= (V
2
1
2
3
4
= V
1
2
3
4
1
1
– V
– V
G
G
2
2
)(1 + R
M
M
+ V
2
G
G
M
M
+ R
3
2
1
/R
1
should generally be R
)/R
2
)
C
AD830
2
A = 1
. The AD830 can provide
C
AD830
A = 1
COMMON
8
7
6
5
OUTPUT
8
7
6
5
V
V
0.1 F
P
N
V
0.1 F
V
0.1 F
P
N
0.1 F
2
V
OUT
≤ 1 kΩ to
V
V
3
REV. B
OUT
R
R
1
2