VCA824_08 Datasheet, PDF (1/36 Pages) Texas Instruments – Ultra-Wideband, > 40dB Gain Adjust Range, Linear in V/V VARIABLE GAIN AMPLIFIER

VCA824
VCA824
VCA824
www.ti.com....................................................................................................................................... SBOS394C – NOVEMBER 2007 – REVISED DECEMBER 2008
Ultra-Wideband, > 40dB Gain Adjust Range, Linear in V/V
VARIABLE GAIN AMPLIFIER
FEATURES
1
•23 710MHz SMALL-SIGNAL BANDWIDTH
(G = +2V/V)
• 320MHz, 4V_PP BANDWIDTH (G = +10V/V)
• 0.1dB GAIN FLATNESS to 135MHz
• 2500V/µs SLEW RATE
• > 40dB GAIN ADJUST RANGE
• HIGH GAIN ACCURACY: 20dB ±0.3dB
• HIGH OUTPUT CURRENT: ±90mA
APPLICATIONS
• DIFFERENTIAL LINE RECEIVERS
• DIFFERENTIAL EQUALIZERS
• PULSE AMPLITUDE COMPENSATION
• VARIABLE ATTENUATORS
• VOLTAGE-TUNABLE ACTIVE FILTERS
V_IN1
V_IN2
+V_IN
R_F
R_S
R_G+
R₁
R_G
FB
VCA824
C₁
R_G-
-V_IN
20W
R_S
R_L
V_OUT
C_L
Differential Equalizer
9
Equalized Frequency Response
6
3
0
Initial Frequency Response
-3 _{of the VCA824 with RC Load}
-6
-9
-12
-15
-18
-21
-24
1M
10M
100M
1G
Frequency (Hz)
Differential Equalization of an RC Load
DESCRIPTION
The VCA824 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 VCA824 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 +40V/V. Operating from
±5V supplies, the gain control voltage for the VCA824
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 VCA824 provides
10V/V, at +1V input, to 0.1V/V at –1V input of gain
control range. The VCA824 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).
VCA824 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
6.0
8.2
6.0
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 registered trademark of X2Y Attenuators LLC.
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 © 2007–2008, Texas Instruments Incorporated