AD830AN Analog Devices Inc, AD830AN Datasheet - Page 12

• Manufacturer Part Number: AD830AN
• Description: IC VIDEO DIFF AMP HS 8-DIP
• Manufacturer: Analog Devices Inc

Specifications of AD830AN

• Rohs Status: RoHS non-compliant
• Applications: Differential
• Number Of Circuits: 1
• -3db Bandwidth: 85MHz
• Slew Rate: 360 V/µs
• Current - Supply: 14.5mA
• Current - Output / Channel: 50mA
• Voltage - Supply, Single/dual (±): 8 V ~ 33 V, ±4 V ~ 16.5 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Single Supply Voltage (typ): Not RequiredV
• Single Supply Voltage (min): Not RequiredV
• Single Supply Voltage (max): Not RequiredV
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 8
• Lead Free Status / RoHS Status: Not Compliant

AD830
Precise amplification is accomplished through closed-loop
operation of this topology. Voltage feedback is implemented via
the Y G
for negative feedback, as shown in Figure 27. An input signal is
applied across the X G
ended referred to common. It produces a current signal that is
summed at the high impedance node with the output current
from the Y G
error current necessary to develop the output voltage at the high
impedance node. The error current is usually negligible, so the
null condition essentially forces the Y G
to equal the exact X G
transconductances are identical, the differential voltage across
the Y inputs equals the negative of the differential voltage across
the X input; V
This simple relation provides the basis to easily analyze any
function possible to synthesize with the AD830, including any
feedback situation.
The bandwidth of the circuit is defined by the G
capacitor, C
single-pole response, excluding the output amplifier and
loading effects. It is important to note that the bandwidth and
general dynamic behavior is symmetrical (identical) for the
noninverting and the inverting connections of the AD830. In
addition, the input impedance and CMRR are the same for
either connection. This is very advantageous and unlike in a
voltage or current feedback amplifier where there is a distinct
difference in performance between the inverting and
noninverting gain. The practical importance of this cannot be
overemphasized and is a key feature offered by the AD830
amplifier topology.
M
stage where the output is connected to the −Y input
V
V
V
V
X2
Y1
Y2
X1
C
. The highly linear G
V
V
V
M
V
Y
X2
Y1
Y2
X1
stage. Negative feedback nulls this sum to a small
= −V
G
G
V
FOR V
V
X1
OUT
M
M
Figure 27. Closed-Loop Connection
G
G
– V
Figure 26. Topology Diagram
I
I
X
Y
= (V
M
M
X
Y2
X2
M
M
or, more precisely, V
= V
I
I
X1
X
Y
= V
output current. Because the two
stage, either fully differential or single-
OUT
– V
Y2
C
C
X2
I
– V
Z
+ V
Y1
R
Y1
C
A = 1
P
M
C
)
stages give the amplifier a
1 + S(C
I
I
I
X
Y
Z
A
A = 1
OLS
= I
= (V
= (V
X
1
M
=
X1
Y1
C
+ I
/G
output stage current
1 + S (C
Y
– V
– V
Y2
V
M
OUT
G
)
− V
X2
Y2
V
M
OUT
R
) G
) G
P
C
M
R
Y1
M
M
and the
P
)
= V
X1
− V
Rev. C | Page 12 of 20
X2
.
INTERFACING THE INPUT
Common-Mode Voltage Range
The common-mode range of the AD830 is defined by the
amplitude of the differential input signal and the supply voltage.
The general definition of common-mode voltage, V
usually applied to a symmetrical differential signal centered
around a particular voltage, as illustrated in Figure 28. This is
the meaning implied here for common-mode voltage. The
internal circuitry establishes the maximum allowable voltage on
the input or feedback pins for a given supply voltage. This
constraint and the differential input voltage sets the common-
mode voltage limit. Figure 29 shows a curve of the common-
mode voltage range versus the differential voltage for three
supply voltage settings.
Differential Voltage Range
The maximum applied differential voltage is limited by the
clipping range of the input stages. This is nominally set at a
2.4 V magnitude and depicted in the cross plot (X-Y) in Figure 30.
The useful linear range of the input stages is set at 2 V but is
actually a function of the distortion required for a particular
application. The distortion increases for larger differential input
voltages. A plot of relative distortion versus the input differential
voltage is shown in Figure 13 and Figure 16. The distortion
characteristics impose a secondary limit to the differential input
voltage for high accuracy applications.
Figure 29. Input Common-Mode Voltage Range vs. Differential Input Voltage
15
12
9
0
6
3
0
–V
CM
Figure 28. Common-Mode Definition
0.4
DIFFERENTIAL INPUT VOLTAGE (V
–V
CM
–V
CM
V
PEAK
0.8
+V
+V
CM
CM
+V
1.2
CM
PEAK
1.6
)
±15V = V
±10V = V
±5V = V
CM
V
V
S
, is
MAX
CM
S
S
2.0