AD811ANZ Analog Devices Inc, AD811ANZ Datasheet - Page 15

• Manufacturer Part Number: AD811ANZ
• Description: IC OPAMP VIDEO HP 8-DIP
• Manufacturer: Analog Devices Inc

Specifications of AD811ANZ

• Slew Rate: 2500 V/µs
• Applications: Current Feedback
• Number Of Circuits: 1
• -3db Bandwidth: 140MHz
• Current - Supply: 16.5mA
• Current - Output / Channel: 100mA
• Voltage - Supply, Single/dual (±): ±4.5 V ~ 18 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Gain Bandwidth: 140MHz
• Supply Voltage Range: ± 4.5V To ± 18V
• No. Of Amplifiers: 1
• Output Current: 100mA
• Amplifier Output: Single Ended
• Amplifier Type: Video
• Bandwidth: 140 MHz
• Common Mode Rejection Ratio: 60
• Current, Input Bias: 2 μA
• Current, Output: 100 mA
• Harmonic Distortion: -74 dBc
• Impedance, Thermal: 90 °C/W
• Package Type: PDIP-8
• Resistance, Input: 1.5 Megohms (+Input), 14 Ohms (-Input)
• Temperature, Operating, Range: -40 to +85 °C
• Voltage, Input: ±3 V (Common-Mode)
• Voltage, Noise: 1.9 nV/sqrt Hz
• Voltage, Offset: 0.5 mV
• Voltage, Output, High: +12 V
• Voltage, Output, Low: -12 V
• Voltage, Supply: ±15 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

AN 80 MHZ VOLTAGE-CONTROLLED AMPLIFIER
CIRCUIT
The voltage-controlled amplifier (VCA) circuit of Figure 48
shows the AD811 being used with the AD834, a 500 MHz,
4-quadrant multiplier. The AD834 multiplies the signal
input by the dc control voltage, V
the form of differential currents from a pair of open collectors,
ensuring that the full bandwidth of the multiplier (which
exceeds 500 MHz) is available for certain applications. Here, the
AD811 op amp provides a buffered, single-ended, ground-
referenced output. Using feedback resistors R8 and R9 of 511 Ω,
the overall gain ranges from −70 dB for V
(a numerical gain of +4) when V
function of the VCA is V
reduces to V
shown in Figure 47. The circuit’s −3 dB bandwidth of 80 MHz is
maintained essentially constant—that is, independent of gain.
The response can be maintained flat to within ±0.1 dB from dc
to 40 MHz at full gain with the addition of an optional capacitor
of about 0.3 pF across the feedback resistor R8. The circuit
produces a full-scale output of ±4 V for a ±1 V input and can
drive a reverse-terminated load of 50 Ω or 75 Ω to ±2 V.
V
V
IN
G
+
–
OUT
= 4 V
R1 100Ω
R2 100Ω
G
V
IN
OUT
using the labeling conventions
= 4 (X1 − X2)(Y1 − Y2), which
X2
Y1
G
8
1
G
. The AD834 outputs are in
= 1 V. The overall transfer
Y2
249Ω
7
X1 +V
AD834
2
U1
R3
–V
G
6
3
*R8 = R9 = 511Ω FOR ×4 GAIN
S
R8 = R9 = 1.27kΩ FOR ×10 GAIN
S
= 0 dB to +12 dB
W1
W2
5
4
Figure 47. An 80 MHz Voltage-Controlled Amplifier
182Ω
182Ω
R4
R5
Rev. E | Page 15 of 20
294Ω
294Ω
R6
R7
The gain can be increased to 20 dB (×10) by raising R8 and R9
to 1.27 kΩ, with a corresponding decrease in −3 dB bandwidth
to approximately 25 MHz. The maximum output voltage under
these conditions is increased to ±9 V using ±12 V supplies.
The gain-control input voltage, V
ground-referenced voltage, or fully differential, depending on
the choice of connections at Pins 7 and 8. A positive value of V
results in an overall noninverting response. Reversing the sign
of V
fact, although this circuit has been classified as a voltage-
controlled amplifier, it is also quite useful as a general-purpose,
four-quadrant multiplier, with good load driving capabilities
and fully symmetrical responses from the X and Y inputs.
The AD811 and AD834 can both be operated from power
supply voltages of ±5 V. While it is not necessary to power them
from the same supplies, the common-mode voltage at W1 and
W2 must be biased within the common-mode range of the
AD811’s input stage. To achieve the lowest differential gain and
phase errors, it is recommended that the AD811 be operated
from power supply voltages of ±10 V or greater. This VCA
circuit operates from a ±12 V dual power supply.
G
simply causes the sign of the overall response to invert. In
R9*
R8*
2
3
–
+
AD811
U3
7
4
0.1µF
0.1µF
C1
C2
G
6
, may be a positive or negative
FB
FB
R
L
V
+12V
–12V
OUT
AD811
G