VCA820IDGSR Datasheet, PDF (1/37 Pages) Texas Instruments – Wideband, 40dB Adjust Range, Linear in dB VARIABLE GAIN AMPLIFIER

VCA820
VCA820
VCA820
www.ti.com............................................................................................................................................ SBOS395C – OCTOBER 2007 – REVISED OCTOBER 2009
Wideband, > 40dB Adjust Range, Linear in dB
VARIABLE GAIN AMPLIFIER
Check for Samples: VCA820
FEATURES
1
•23 150MHz SMALL-SIGNAL BANDWIDTH
• 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 ±0.4dB
• HIGH OUTPUT CURRENT: 160mA
APPLICATIONS
• AGC RECEIVERS with RSSI
• DIFFERENTIAL LINE RECEIVERS
• PULSE AMPLITUDE COMPENSATION
• VARIABLE ATTENUATORS
• DROP-IN UPGRADE TO LMH6502
V_IN+
V_IN-
R_S
R_G
R_S
R_F
+V_IN
R_G+
FB
VCA820
R_G-
-V_IN
20W
Figure 1. Differential Equalizer
95
90
85
80
75
70
65
60
55
50
45
Input-Referred
40
100k
1M
10M
Frequency (Hz)
100M
Figure 2. Common-Mode Rejection Ratio
DESCRIPTION
The VCA820 is a dc-coupled, wideband, linear in dB,
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 VCA820 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
VCA820 adjusts the gain linearly in dB as the control
voltage varies from 0V to +2V. For example, set for a
maximum gain of +10V/V, the VCA820 provides
20dB, at +2V input, to –20dB at 0V input of gain
control range. The VCA820 offers excellent gain
linearity. For a 20dB maximum gain, and a
gain-control input voltage varying between 1V and
2V, the gain does not deviate by more than ±0.4dB
(maximum at +25°C).
VCA820 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
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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 © 2007–2009, Texas Instruments Incorporated