AD827 Analog Devices, AD827 Datasheet - Page 7

• Manufacturer Part Number: AD827
• Description: High Speed, Low Power Dual Op Amp
• Manufacturer: Analog Devices

Specifications of AD827

• -3db Bandwidth: 50MHz
• Slew Rate: 300V/µs
• Vos: 500µV
• Ib: 3.3µA
• # Opamps Per Pkg: 2
• Input Noise (nv/rthz): 15nV/rtHz
• Vcc-vee: 9V to 36V
• Isy Per Amplifier: 6.75mA
• Packages: DIP,LCC,SOIC

REV. C
VIDEO LINE DRIVER
The AD827 functions very well as a low cost, high speed line
driver for either terminated or unterminated cables. Figure 23
shows the AD827 driving a doubly terminated cable in a
follower configuration.
The termination resistor, R
characteristic impedance) minimizes reflections from the far end
of the cable. While operating from ± 5 V supplies, the AD827
maintains a typical slew rate of 200 V/µs, which means it can
drive a ± 1 V, 30 MHz signal into a terminated cable.
V
0 dB or ± 500 mV Step ± 15
0 dB or ± 500 mV Step ± 15
0 dB or ± 500 mV Step ± 15
0 dB or ± 500 mV Step ± 5
0 dB or ± 500 mV Step ± 5
0 dB or ± 500 mV Step ± 5
*–3 dB bandwidth numbers are for the 0 dBm signal input. Overshoot numbers
A back-termination resistor (R
impedance of the cable) may be placed between the AD827
output and the cable input, in order to damp any reflected
signals caused by a mismatch between R
characteristic impedance. This will result in a flatter frequency
response, although this requires that the op amp supply ± 2 V to
the output in order to achieve a ± 1 V swing at resistor R
are the percent overshoot of the 1 V step input.
IN
*
Table I. Video Line Driver Performance Summary
V
IN
Figure 23. A Video Line Driver
50Ω
AD827
V
1/2
–V
+V
SUPPLY
T
S
S
, (when equal to the cable’s
BT
C
C
0.1 µF
, also equal to the characteristic
0.1 µF
C
20 pF
15 pF
0 pF
20 pF
15 pF
0 pF
C
500Ω
500Ω
R
T
50Ω
BT
and the cable’s
–3 dB B
23 MHz
21 MHz
13 MHz
18 MHz
16 MHz
11 MHz
50Ω
R
T
W
V
T
OUT
.
Over-
shoot
4%
0%
0%
2%
0%
0%
–7–
A HIGH SPEED THREE OP AMP INSTRUMENTATION
AMPLIFIER CIRCUIT
The instrumentation amplifier circuit shown in Figure 24 can
provide a range of gains. Table II details performance.
+V
Figure 24. A High Bandwidth Three Op Amp
Instrumentation Amplifier
IN
–V
IN
Table II. Performance Specifications for the
Three Op Amp Instrumentation Amplifier
Gain
1
2
10
100
R
G
3
2
6
5
BANDWIDTH
+
+
AD827
–
AD827
–
TRIM FOR
OPTIMUM
7 – 15 pF
1/2
1/2
+V
1kΩ
1kΩ
S
4
–V
8
0.1µF
0.1µF
S
1
7
R
Open
2 k
226 Ω
20 Ω
G
NOTE: PINOUT SHOWN IS FOR MINIDIP PACKAGE
2kΩ
2kΩ
3pF
Small Signal
Bandwidth
@ 1 V p-p Output
16.1 MHz
14.7 MHz
4.9 MHz
660 kHz
CIRCUIT GAIN =
2kΩ
2
3
TRIM FOR BEST
SETTLING TIME
+V
+
–
AD847
–V
S
7
2 – 8pF
S
4
2kΩ
0.1µF
0.1µF
6
2000
R
AD827
G
+ 1
2kΩ
R
L
V
OUT