VCA822 Datasheet, PDF (1/35 Pages) Texas Instruments – Wideband, > 40dB Gain Adjust Range, Linear in V/V VARIABLE GAIN AMPLIFIER

BurrĆBrown Products
from Texas Instruments
VCA822
VCA822
VCA822
SBOS343A – SEPTEMBER 2007 – REVISED OCTOBER 2007
Wideband, > 40dB Gain Adjust Range, Linear in V/V
VARIABLE GAIN AMPLIFIER
FEATURES
1
•23 150MHz SMALL-SIGNAL BANDWIDTH
(G = +10V/V)
• 137MHz, 5V_PP BANDWIDTH (G = +10V/V)
• 0.1dB GAIN FLATNESS to 28MHz
• 1700V/µs SLEW RATE
• > 40dB GAIN ADJUST RANGE
• HIGH GAIN ACCURACY: 20dB ±0.3dB
• HIGH OUTPUT CURRENT: ±160mA
APPLICATIONS
• DIFFERENTIAL LINE RECEIVERS
• DIFFERENTIAL EQUALIZERS
• PULSE AMPLITUDE COMPENSATION
• VARIABLE ATTENUATORS
• VOLTAGE-TUNABLE ACTIVE FILTERS
• DROP-IN UPGRADE TO LMH6503
V_IN1
V_IN2
+V_IN
R_F
R_S
R_G+
R₁
R_G
FB
VCA822
C₁
R_G-
-V_IN
20W
R_S
R_L
V_OUT
C_L
Figure 1. Differential Equalizer
9
Equalized Frequency
6
Response
3
0
-3
-6
-9
Initial Frequency Response
of VCA822 with RC Load
-12
-15
-18
R_L = 75W
-21 _{CF = 100pF}
-24
1M
10M
100M
1G
Frequency (Hz)
Figure 2. Differential Equalization of an RC Load
DESCRIPTION
The VCA822 is a dc-coupled, wideband, linear in V/V,
continuously variable, voltage-controlled gain
amplifier. It provides a differential input to
single-ended conversion with a high-impedance gain
control input used to vary the gain down 40dB from
the nominal maximum gain set by the gain resistor
(R_G) and feedback resistor (R_F).
The VCA822 internal architecture consists of two
input buffers and an output current feedback amplifier
stage integrated with a multiplier core to provide a
complete variable gain amplifier (VGA) system that
does not require external buffering. The maximum
gain is set externally with two resistors, providing
flexibility in designs. The maximum gain is intended
to be set between +2V/V and +100V/V. Operating
from ±5V supplies, the gain control voltage for the
VCA822 adjusts the gain linearly in V/V as the control
voltage varies from +1V to –1V. For example, set for
a maximum gain of +10V/V, the VCA822 provides
10V/V, at +1V input, to 0.1V/V at –1V input of gain
control range. The VCA822 offers excellent gain
linearity. For a 20dB maximum gain, and a
gain-control input voltage varying between 0V and
1V, the gain does not deviate by more than ±0.3dB
(maximum at +25°C).
Table 1. VCA822 RELATED PRODUCTS
SINGLES
VCA810
—
—
—
—
VCA820
VCA821
VCA822
VCA824
DUALS
—
VCA2612
VCA2613
VCA2615
VCA2617
—
—
—
—
GAIN
ADJUST
RANGE
(dB)
80
45
45
52
48
40
40
40
40
INPUT
NOISE
(nV/√Hz)
2.4
1.25
1
0.8
4.1
8.2
7.0
8.2
7.0
SIGNAL
BANDWIDTH
(MHz)
35
80
80
50
50
150
420
150
420
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
X2Y is a trademark of X2Y Corporation.
2
All other trademarks are the property of their respective owners.
3
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007, Texas Instruments Incorporated