AD829 Analog Devices, AD829 Datasheet - Page 15

• Manufacturer Part Number: AD829
• Description: High Speed, Low Noise Video Op Amp
• Manufacturer: Analog Devices

Specifications of AD829

• -3db Bandwidth: 120MHz
• Slew Rate: 230V/µs
• Vos: 200µV
• Ib: 3.3µA
• # Opamps Per Pkg: 1
• Input Noise (nv/rthz): 1.7nV/rtHz
• Vcc-vee: 9V to 36V
• Isy Per Amplifier: 6.5mA
• Packages: DIP,LCC,SOIC

Data Sheet
Figure 44 and Figure 45 show the closed-loop frequency
response of the AD829 for different closed-loop gains and
different supply voltages.
When a noninverting amplifier configuration using a current
feedback compensation is needed, the circuit shown in Figure 46 is
recommended. This circuit provides a slew rate twice that of the
shunt compensated noninverting amplifier of Figure 47 at the
expense of gain flatness. Nonetheless, this circuit delivers 95 MHz
bandwidth with 1 dB flatness into a back-terminated cable,
with a differential gain error of only 0.01% and a differential
phase error of only 0.015 at 4.43 MHz.
Figure 44. Closed-Loop Frequency Response for the Inverting Amplifier Using
Figure 45. Closed-Loop Frequency Response vs. Supply for the Inverting
–12
–15
–17
–20
–23
–26
–29
–32
–35
–38
–41
–44
–47
15
12
–3
–6
–9
9
6
3
0
1
1
Amplifier Using Current Feedback Compensation
V
R
R
V
V
R
R
GAIN = –1
C
GAIN = –4
C
GAIN = –2
C
GAIN = –1
C
S
IN
L
F
IN
L
F
COMP
COMP
COMP
COMP
= ±15V
= 1kΩ
= 1kΩ
= 1kΩ
= 1kΩ
= –30dBm
= –20dBm
= 4pF
= 2pF
= 3pF
= 4pF
Current Feedback Compensation
FREQUENCY (MHz)
FREQUENCY (MHz)
10
10
±5V
±15V
100
100
Rev. I | Page 15 of 20
LOW ERROR VIDEO LINE DRIVER
The buffer circuit shown in Figure 47 drives a back-terminated
75 Ω video line to standard video levels (1 V p-p), with 0.1 dB
gain flatness to 30 MHz and with only 0.04° and 0.02% differential
phase and gain at the 4.43 MHz PAL color subcarrier frequency.
This level of performance, which meets the requirements for
high definition video displays and test equipment, is achieved
using only 5 mA quiescent current.
Figure 47. Video Line Driver with a Flatness over Frequency Adjustment
Figure 46. Noninverting Amplifier Connection Using Current Feedback
V
V
IN
IN
CABLE
COAX
50Ω
75Ω
0.1µF
50Ω
0.1µF
C
COMP
30pF
3
2
AD829
+
–
+15V
–15V
0.1µF
3
2
7
5
AD829
+
–
+15V
–15V
4
Compensation
7
4
5
0.1µF
6
3pF
C
COMP
6
300Ω
300Ω
2kΩ
2kΩ
75Ω
50Ω
CABLE
CABLE
COAX
COAX
50Ω
50Ω
OPTIONAL
2pF TO 7pF
FLATNESS
TRIM
75Ω
50kΩ
AD829
V
V
OUT
OUT