Image VCA821
型号: VCA821
厂商: Texas Instruments Texas Instruments
标准:
分类: 半导体
描述: wideband, > 40db gain adjust range, linear in V/V variable gain amplifier
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VCA821的详细信息

Feature: Wideband, >
40dB Adjust Range, Linear in dB Variable Gain Amplifier:
VCA821  
www.ti.com ....................................................................................................................................... SBOS407BDECEMBER 2007REVISED DECEMBER 2008  
Ultra-Wideband, > 40dB Gain Adjust Range, Linear in dB  
VARIABLE GAIN AMPLIFIER  
1
FEATURES  
DESCRIPTION  
23  
710MHz SMALL-SIGNAL BANDWIDTH  
(G = +2V/V)  
The VCA821 is a dc-coupled, wideband, linear in dB,  
continuously variable, voltage-controlled gain  
amplifier. It provides 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  
(RG) and feedback resistor (RF).  
320MHz, 4VPP BANDWIDTH (G = +10V/V)  
0.1dB GAIN FLATNESS to 135MHz  
2500V/µs SLEW RATE  
a
> 40dB GAIN ADJUST RANGE  
HIGH GAIN ACCURACY: 20dB ±0.3dB  
HIGH OUTPUT CURRENT: ±90mA  
The VCA821 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 6dB and 32dB. Operating from ±5V  
supplies, the gain control voltage for the VCA821  
adjusts the gain linearly in dB as the control voltage  
varies from 0V to +2V. For example, set at a  
maximum gain of 20dB, the VCA821 provides 20dB,  
at VG = +2V, to less than –20dB at VG = 0V. The  
VCA821 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 ±0.3dB (maximum at +25°C).  
APPLICATIONS  
AGC RECEIVERS with RSSI  
DIFFERENTIAL LINE RECEIVERS  
PULSE AMPLITUDE COMPENSATION  
VARIABLE ATTENUATORS  
VOLTAGE-TUNABLE ACTIVE FILTERS  
RF  
VIN1  
+VIN  
RG+  
RS  
RL  
FB  
VCA821  
R1  
C1  
RG  
VOUT  
CL  
RG-  
VIN2  
-VIN  
20W  
RS  
VCA821 RELATED PRODUCTS  
GAIN  
ADJUST  
RANGE  
(dB)  
INPUT  
NOISE  
(nV/Hz)  
SIGNAL  
BANDWIDTH  
(MHz)  
Differential Equalizer  
SINGLES  
VCA810  
DUALS  
80  
45  
45  
52  
48  
40  
40  
40  
40  
2.4  
1.25  
1
35  
80  
9
6
EqualizedFrequencyResponse  
VCA2612  
VCA2613  
VCA2615  
VCA2617  
3
80  
0
0.8  
4.1  
8.2  
6.0  
8.2  
6.0  
50  
InitialFrequencyResponse  
oftheVCA821withRCLoad  
-3  
-6  
-9  
50  
VCA820  
VCA821  
VCA822  
VCA824  
150  
420  
150  
420  
-12  
-15  
-18  
-21  
-24  
1M  
10M  
100M  
1G  
Frequency(Hz)  
Differential Equalization of an RC Load  
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.  
2
3
X2Y is a trademark of X2Y Attenuators LLC.  
All other trademarks are the property of their respective owners.  
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