V
IN+
V
IN-
95
90
40
Frequency (Hz)
C
o
m
m
o
n
-
M
o
d
e
R
e
j
e
c
t
i
o
n
R
a
t
i
o
(
d
B
)
100k100M
85
45
75
80
10M
1M
50
55
60
65
70
VCA820
https://www.doczj.com/doc/f6119672.html,............................................................................................................................................SBOS395C–OCTOBER2007–REVISED OCTOBER2009 Wideband,>40dB Adjust Range,Linear in dB
VARIABLE GAIN AMPLIFIER
Check for Samples:VCA820
FEATURES
DESCRIPTION
?150MHz SMALL-SIGNAL BANDWIDTH
The VCA820is a dc-coupled,wideband,linear in dB,?137MHz,5V PP BANDWIDTH(G=+10V/V)
continuously variable,voltage-controlled gain ?0.1dB GAIN FLATNESS to28MHz amplifier.It provides a differential input to
?1700V/μs SLEW RATE single-ended conversion with a high-impedance gain
control input used to vary the gain down40dB from ?>40dB GAIN ADJUST RANGE
the nominal maximum gain set by the gain resistor ?HIGH GAIN ACCURACY:20dB±0.4dB
(R G)and feedback resistor(R F).
?HIGH OUTPUT CURRENT:160mA
The VCA820internal architecture consists of two
input buffers and an output current feedback amplifier APPLICATIONS
stage integrated with a multiplier core to provide a ?AGC RECEIVERS with RSSI complete variable gain amplifier(VGA)system that ?DIFFERENTIAL LINE RECEIVERS does not require external buffering.The maximum
gain is set externally with two resistors,providing ?PULSE AMPLITUDE COMPENSATION
flexibility in designs.The maximum gain is intended ?VARIABLE ATTENUATORS
to be set between+2V/V and+100V/V.Operating ?DROP-IN UPGRADE TO LMH6502from±5V supplies,the gain control voltage for the
VCA820adjusts the gain linearly in dB as the control
voltage varies from0V to+2V.For example,set for a
maximum gain of+10V/V,the VCA820provides
20dB,at+2V input,to–20dB at0V input of gain
control range.The VCA820offers excellent gain
linearity.For a20dB maximum gain,and a
gain-control input voltage varying between1V and
2V,the gain does not deviate by more than±0.4dB
(maximum at+25°C).
Figure1.Differential Equalizer
VCA820RELATED PRODUCTS
GAIN
ADJUST INPUT SIGNAL
RANGE NOISE BANDWIDTH
SINGLES DUALS(dB)(nV/√Hz)(MHz)
VCA810—80 2.435
—VCA261245 1.2580
—VCA261345180
—VCA2615520.850
—VCA261748 4.150
VCA820—408.2150
VCA821—407.0420
VCA822—408.2150
VCA824—407.0420 https://www.doczj.com/doc/f6119672.html,mon-Mode Rejection Ratio
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.
a trademark of X2Y Corporation.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.Copyright?2007–2009,Texas Instruments Incorporated Products conform to specifications per the terms of the Texas
Instruments standard warranty.Production processing does not
necessarily include testing of all parameters.
12345
109876
GND V OUT -V CC -V IN -R G
I -+V CC V G +V IN +R G
1234567
141312111098
V+NC I -GND V OUT V REF V -
V+V G +V IN +R G -R G -V IN V -VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
This integrated circuit can be damaged by ESD.Texas Instruments recommends that all integrated circuits be handled with appropriate precautions.Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure.Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ORDERING INFORMATION (1)
SPECIFIED PACKAGE TEMPERATURE
PACKAGE ORDERING TRANSPORT PRODUCT PACKAGE-LEAD
DESIGNATOR
RANGE MARKING NUMBER MEDIA,QUANTITY
VCA820ID Rail,50VCA820SO-14D –40°C to +85°C VCA820ID VCA820IDR Tape and Reel,2500VCA820IDGST Tape and Reel,250VCA820MSOP-10
DGS
–40°C to +85°C
BOQ
VCA820IDGSR
Tape and Reel,2500
(1)
For the most current package and ordering information see the Package Option Addendum at the end of this document,or see the TI web site at https://www.doczj.com/doc/f6119672.html, .
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range,unless otherwise noted.
VCA820
UNIT Power supply
±6.3
V
Internal power dissipation See Thermal Characteristics Input voltage range ±V S V Storage temperature range –65to +125
°C Junction temperature (T J )
+150°C Junction temperature (T J ),maximum continuous operation
+140°C Human body model (HBM)
2000V ESD rating:
Charge device model (CDM)500V Machine model
200
V (1)
Stresses above these ratings may cause permanent damage.Exposure to absolute maximum conditions for extended periods may degrade device reliability.These are stress ratings only,and functional operation of the device at these or any other conditions beyond those specified is not implied.
PIN CONFIGURATIONS
SO-14MSOP-10(Top View)
(Top View)
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Product Folder Link(s):VCA820
VCA820
https://www.doczj.com/doc/f6119672.html,............................................................................................................................................SBOS395C–OCTOBER2007–REVISED OCTOBER2009
ELECTRICAL CHARACTERISTICS:V S=±5V
At A VMAX=20dB,R F=1k?,R G=200?,and R L=100?,unless otherwise noted.
VCA820
MIN/MAX OVER
TYP TEMPERATURE
0°C to–40°C to MIN/TEST PARAMETER CONDITIONS+25°C+25°C(2)+70°C(3)+85°C(3)UNITS MAX LEVEL(1) AC PERFORMANCE
Small-signal bandwidth(SO-14package)A VMAX=6dB,V O=1V PP,V G=+2V168MHz typ C
A VMAX=20dB,V O=1V PP,V G=+2V150MHz typ C
A VMAX=40dB,V O=1V PP,V G=+2V118MHz typ C Large-signal bandwidth A VMAX=20dB,V O=5V PP,V G=+2V137MHz typ C
Gain control bandwidth V G=1V DC+10mV PP200170170165MHz min B Bandwidth for0.1dB flatness A VMAX=20dB,V O=1V PP,V G=+2V28MHz typ C Slew rate A VMAX=20dB,V O=5V step,V G=+2V1700150015001450V/μs min B
Rise-and-fall time A VMAX=20dB,V O=5V step,V G=+2V 2.5 3.1 3.2 3.2ns max B Settling time to0.01%A VMAX=20dB,V O=5V step,V G=+2V11ns typ C Harmonic distortion
2nd-harmonic V O=2V PP,f=20MHz–62–60–60–60dBc min B 3rd-harmonic V O=2V PP,f=20MHz–68–66–66–66dBc min B Input voltage noise f>100kHz8.2nV/√Hz typ C Input current noise f>100kHz 2.6pA/√Hz typ C GAIN CONTROL
Absolute gain error A VMAX=20dB,V G=2V±0.1±0.4±0.5±0.6dB max A
V CTRL00.85V typ C
V SLOPE0.09V typ C Absolute gain error A VMAX=20dB,V G=1V,(G=18.06dB)±0.3±0.4±0.5±0.6dB max A
Gain at V G=0.2V Relative to maximum gain–26–24–24–23dB max A
Gain control bias current101616.616.7μA max A Average gain control bias current drift±12±12nA/°C max B
Gain control input impedance70||1k?||pF typ C
DC PERFORMANCE
Input offset voltage A VMAX=20dB,V CM=0V,V G=1V±4±17±17.8±19mV max A Average input offset voltage drift A VMAX=20dB,V CM=0V,V G=1V3030μV/°C max B Input bias current A VMAX=20dB,V CM=0V,V G=1V19252931μA max A Average input bias current drift A VMAX=20dB,V CM=0V,V G=1V9090nA/°C max B Input offset current A VMAX=20dB,V CM=0V,V G=1V±0.5±2.5±3.2±3.5μA max A Average input offset current drift A VMAX=20dB,V CM=0V,V G=1V±16±16nA/°C max B Maximum current through gain resistance±2.6±2.55±2.55±2.5mA max B INPUT
Most positive common-mode input voltage R L=100?+1.6+1.6+1.6+1.6V min A
Most negative common-mode input voltage R L=100?–2.1–2.1–2.1–2.1V max A Common-mode rejection ratio V CM=±0.5V80656060dB min A Input impedance
Differential0.5||1M?||pF typ C Common-mode0.5||2M?||pF typ C (1)Test levels:(A)100%tested at+25°C.Over temperature limits set by characterization and simulation.(B)Limits set by characterization
and simulation.(C)Typical value only for information.
(2)Junction temperature=ambient for+25°C tested specifications.
(3)Junction temperature=ambient at low temperature limit;junction temperature=ambient+23°C at high temperature limit for over
temperature specifications.
Copyright?2007–2009,Texas Instruments Incorporated Submit Documentation Feedback3
Product Folder Link(s):VCA820
VCA820
SBOS395C–OCTOBER2007–REVISED https://www.doczj.com/doc/f6119672.html,
ELECTRICAL CHARACTERISTICS:V S=±5V(continued)
At A VMAX=20dB,R F=1k?,R G=200?,and R L=100?,unless otherwise noted.
VCA820
MIN/MAX OVER
TYP TEMPERATURE
0°C to–40°C to MIN/TEST PARAMETER CONDITIONS+25°C+25°C(2)+70°C(3)+85°C(3)UNITS MAX LEVEL(1) OUTPUT
Output voltage swing R L=1k?±4.0±3.8±3.75±3.7V min A
R L=100?±3.9±3.7±3.6±3.5V min A Output current V O=0V,R L=5?±160±140±130±130mA min A Output impedance A VMAX=20dB,f>100kHz,V G=+2V0.01?typ C POWER SUPPLY
Specified operating voltage±5V typ C Minimum operating voltage±3.5V typ C Maximum operating voltage±6±6±6V max A Maximum quiescent current V G=1V343535.536mA max A Minimum quiescent current V G=1V3432.53231.5mA max A Power-supply rejection ratio(–PSRR)–68–61–59–58dB min A THERMAL CHARACTERISTICS
Specified operating range,D package–40to+85°C typ C Thermal resistanceθJA Junction-to-ambient
DGS MSOP-10130°C/W typ C
D SO-1480°C/W typ C
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Product Folder Link(s):VCA820
10
1
0.1
Gain Resistor ()
W D i f f e r e n t i a l I n p u t V o l t a g e (V )
P P 10100
1k
40
35302520151050
Feedback Resistor ()
W M a x i m u m G a i n A d j u s t R a n g e (d B )
1001k
10k
60
50403020100Output Voltage (V )
PP M a x i m u m G a i n A d j u s t R a n g e (d B )
0.1
1
10
Control Voltage (V)
G a i n (V /V )
12108
64
2
0Control Voltage (V)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
G a i
n (V /V )
40200
-20-40-60
-80-100
15001400
1300120011001000900800700
A (V/V)
VMAX F e e d b a c k R e s i s t o r ()
W 1
10100
VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,DC Parameters
At T A =+25°C,R L =100?,V G =+1V,and V IN =single-ended input on +V IN with –V IN at ground,unless otherwise noted.
MAXIMUM DIFFERENTIAL INPUT VOLTAGE
MAXIMUM GAIN ADJUST RANGE
vs GAIN RESISTOR
vs FEEDBACK RESISTOR
Figure 3.
Figure 4.
MAXIMUM GAIN ADJUST RANGE GAIN ERROR BAND
vs PEAK-TO-PEAK OUTPUT VOLTAGE
vs GAIN CONTROL VOLTAGE
Figure 5.
Figure 6.
NOMINAL GAIN RECOMMENDED R F and R G
vs CALCULATED GAIN
vs A VMAX
Figure 7.Figure 8.
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5
Product Folder Link(s):VCA820
36
3534
33323129
Gain Control Voltage (V)
Q u i e s c e n t C u r r e n t (m A /d i v )
2.0
310.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
36
353433323129
Gain Control Voltage (V)
Q u i e s c e n t C u r r e n t (m A /d i v )
2.0
310.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
T emperature (C)
°-50-250255075100
125
I n p u t O f f s e t V V )
o l t a g e (m Input Bias and Offset Current (A)m 0
-0.5-1.0-1.5
-2.0-
2.5
-3.0
25
201510
50-536
353433323129
Gain Control Voltage (V)
Q u i e s c e n t C u r r e n t (m A /d i v )
2.0
310.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,DC and Power-Supply Parameters
At T A =+25°C,R L =100?,V G =+1V,and V IN =single-ended input on +V IN with –V IN at ground,unless otherwise noted.
SUPPLY CURRENT vs CONTROL VOLTAGE
SUPPLY CURRENT vs CONTROL VOLTAGE
(A VMAX =6dB)
(A VMAX =20dB)
Figure 9.
Figure 10.SUPPLY CURRENT vs CONTROL VOLTAGE
TYPICAL DC DRIFT (A VMAX =40dB)
vs TEMPERATURE
Figure 11.Figure 12.
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Product Folder Link(s):VCA820
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
30
-3-6-9-12-15-18
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
30
-3-6
-9
-12-15-18
Time (10ns/div)
V (m V )
O U T
---Time (10ns/div)
V (V )
O U T
---
0-0.05
-0.10-0.15-0.20-0.25-0.30
Video Loads
D i f f e r e n t i a l G a i n (%)
1
4
2
3
0-0.02
-0.04-0.06-0.08-0.10-0.12
Differential Phase ()
°0-0.05-0.10-0.15-0.20-0.25-0.30-0.35-0.40-0.45-0.50
Frequency (MHz)
M a g n i t u d e (d B )
0-0.05-0.10-0.15-0.20-0.25-0.30-0.35-0.40-0.45
-0.50
Deviation from Linear Phase ()
°0
10
20
30
40
50VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =6dB
At T A =+25°C,R L =100?,R F =1.33k ?,R G =1.33k ?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and
SO-14package,unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
LARGE-SIGNAL FREQUENCY RESPONSE
Figure 13.
Figure 14.
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
Figure 15.
Figure 16.
VIDEO DIFFERENTIAL GAIN/DIFFERENTIAL PHASE
Figure 17.Figure 18.
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Product Folder Link(s):VCA820
-45-50-55-60-65-70-75-80-85-90-95
Frequency (MHz)
H a r m o n i c D i s t o r t i o n (d B c )
0.1
1
10
100
-60
-65-70-75-80
-85
Resistance ()W H a r m o n i c D i s t o r t i o n (d B c )
100
1k
-50-55-60-65
-70-75-80
Output Voltage Swing (V )
PP H a r m o n i c D i s t o r t i o n (d B c )
0.1
1
10
-40-45-50-55-60
-65-70
Gain Control Voltage (V)
H a r m o n i c D i s t o r t i o n (d B c )
0.8
2.0
1.0
1.2
1.4
1.6
1.8
45
4035
30
25
20
Frequency (V)
I n t e r c e p t P o i n t (+d B m )
10
20
30
40
50
60
70
Gain Control Voltage (V)
0.8
1.0
1.2
1.4
1.6
1.8
2.0
I n t e r c e p t P o i n t (+d B m )
4038
36343230
20
28262422VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =6dB (continued)
At T A =+25°C,R L =100?,R F =1.33k ?,R G =1.33k ?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
HARMONIC DISTORTION vs FREQUENCY
HARMONIC DISTORTION vs LOAD RESISTANCE
Figure 19.
Figure 20.
HARMONIC DISTORTION vs OUTPUT VOLTAGE
20MHz HARMONIC DISTORTION vs GAIN CONTROL VOLTAGE
Figure 21.Figure 22.
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT
vs GAIN CONTROL VOLTAGE
Figure 23.Figure 24.
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Product Folder Link(s):VCA820
Gain Control Voltage (V)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
G a i n (V /V )
2.22.01.81.61.4
1.21.00.80.60.40.20-
0.2
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
3
-3-6-9-12
Time (10ns/div)
V (V )
I N V (V)
OUT 2.52.0
1.51.00.50-0.5
2.52.01.51.00.50
-
0.5
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
100-10
-20-30-40-50-60-70-80-90-100
12
10
8
640Gain Control Voltage (V)
G r o u p D e l a y (n s )
0.4
0.6
0.2
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2
2.5
2.01.5
1.0
0.5
0Frequency (MHz)
G r o u p D e l a y (n s )
20
40
60
80
100
VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =6dB (continued)
At T A =+25°C,R L =100?,R F =1.33k ?,R G =1.33k ?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
GAIN vs GAIN CONTROL VOLTAGE
GAIN CONTROL FREQUENCY
Figure 25.
Figure 26.
GAIN CONTROL PULSE RESPONSE
FULLY-ATTENUATED RESPONSE
Figure 27.
Figure 28.
GROUP DELAY vs GAIN CONTROL VOLTAGE
GROUP DELAY vs FREQUENCY
Figure 29.Figure 30.
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Product Folder Link(s):VCA820
100
10
0Capacitive Load (pF)
R ()
W S 1
10
1k
100
9
6-12
Frequency (Hz)
N o r m a l i z e d G a i n t o C a p a c i t i v e L o a d (d B )
1M 10M 1G
100M
3
-9-6-3
1000
100
10Frequency (Hz)
O u t p u t V o l t a g e N o i s e D e n s i t y (n V /)
H z 100
1k
10k
10M
100k
1M
10
1
Frequency (Hz)
I n p u t V o l t a g e N o i s e D
e n s i t y (p A /)
?H z 100
1k 10k 10M
100k 1M VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =6dB (continued)
At T A =+25°C,R L =100?,R F =1.33k ?,R G =1.33k ?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
RECOMMENDED R S vs CAPACITIVE LOAD
FREQUENCY RESPONSE vs CAPACITIVE LOAD
Figure 31.
Figure 32.
OUTPUT VOLTAGE NOISE DENSITY
INPUT CURRENT NOISE DENSITY
Figure 33.Figure 34.
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30
-3-6-9-12-15
-18
Frequency (MHz)
N o r m a l i z e d G a i n (d B )
050100150200250300350400
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
30
-3-6-9-12-15-18
Time (10ns/div)
V (m V )
O U T
---Time (10ns/div)
V (V )
O U T ---
0.050-0.05
-0.10-0.15-0.20-0.25-0.30-0.35
Frequency (MHz)
M a g n i t u d e (d B )
0.08
0.060.040.020-0.2-0.4
-0.6-0.8
Deviation From Linear Phase ()
°0
10
20
30
40
501000
100
10Frequency (Hz)
O u t p u t V o l t a g e N o i s e D e n s i t y (n V /)
?H z 100
1k
10k
10M
100k
1M
VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =20dB
At T A =+25°C,R L =100?,R F =1k ?,R G =200?,V G =+2V,and V IN =single-ended input on +V IN with –V IN at ground,unless
otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
LARGE-SIGNAL FREQUENCY RESPONSE
Figure 35.
Figure 36.
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
Figure 37.
Figure 38.
GAIN FLATNESS,DEVIATION FROM LINEAR PHASE
OUTPUT VOLTAGE NOISE DENSITY
Figure 39.Figure 40.
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Product Folder Link(s):VCA820
-45-50-55
-60-65-70-75-80-85
Frequency (MHz)
G a i n (d B )
0.1
1
10
100
-60
-65-70
-75-80-85-90
Resistance ()
W H a r m o n i c D i s t o r t i o n (d B c )
100
1k
-55-60
-65-70-75-80
Output Voltage Swing (V )
PP H a r m o n i c D i s t o r t i o n (d B c )
0.1
1
10
-40-45-50-55-60
-65-70
Gain Control Voltage (V)
H a r m o n i c D i s t o r t i o n (d B c )
0.8
2.0
1.0
1.2
1.4
1.6
1.8
45
4035
30
25
20
Frequency (MHz)
I n t e r c e p t P o i n t (+d B m )
5
152010
2530354045
5055
6065
70
Gain Control Voltage (V)
0.8
1.0
1.2
1.4
1.6
1.8
2.0
I n t e r c e p t P o i n t (+d B
m )
4038
3634323020
28262422VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =20dB (continued)
At T A =+25°C,R L =100?,R F =1k ?,R G =200?,V G =+2V,and V IN =single-ended input on +V IN with –V IN at ground,unless otherwise noted.
HARMONIC DISTORTION vs FREQUENCY
HARMONIC DISTORTION vs LOAD RESISTANCE
Figure 41.Figure 42.
20MHz HARMONIC DISTORTION HARMONIC DISTORTION vs OUTPUT VOLTAGE
vs GAIN CONTROL VOLTAGE
Figure 43.
Figure 44.
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT (G MAX =
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT
+10V/V)
vs GAIN CONTROL VOLTAGE (f IN =20MHz)
Figure 45.Figure 46.
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Product Folder Link(s):VCA820
Gain Control Voltage (V)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
G a i n (V /V )
1110
987
6543210-
1
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
----Time (10ns/div)
V (V )
I N V (V)
OUT 2.52.0
1.51.00.50-0.5
2.52.01.51.00.50
-
0.5
543
210-1-2-3-4
-5Output Current (mA)
O u t p u t V o l t a g e (V )
-300
-200-1000100200300
----Time (40ns/div)
V (m V )
I N 48
V (V)
OUT
2
63020
100-10-20-70
Frequency (Hz)
N o r m a l i z e d G a i n (d B )
1M
1G
10M 100M
-30-40-50-60VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =20dB (continued)
At T A =+25°C,R L =100?,R F =1k ?,R G =200?,V G =+2V,and V IN =single-ended input on +V IN with –V IN at ground,unless otherwise noted.
GAIN vs GAIN CONTROL VOLTAGE
GAIN CONTROL FREQUENCY
Figure 47.
Figure 48.
GAIN CONTROL PULSE RESPONSE
OUTPUT VOLTAGE AND CURRENT LIMITATIONS
Figure 49.
Figure 50.
FULLY-ATTENUATED RESPONSE
I RG LIMITED OVERDRIVE RECOVERY
Figure 51.Figure 52.
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13
Product Folder Link(s):VCA820
----Time (40ns/div)
I n p u t V o l t a g e (m V )
2468
V (V)
OUT
12
10
8
640Gain Control Voltage (V)
G r o u p D e l a y (n s )
0.4
0.6
0.2
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2
3.02.01.51.00.50Frequency (MHz)
G r o u p D e l a y (n s )
20
40
60
80
100
2.5
VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =20dB (continued)
At T A =+25°C,R L =100?,R F =1k ?,R G =200?,V G =+2V,and V IN =single-ended input on +V IN with –V IN at ground,unless otherwise noted.
OUTPUT LIMITED OVERDRIVE RECOVERY
GROUP DELAY vs GAIN CONTROL VOLTAGE
Figure 53.
Figure 54.
GROUP DELAY vs FREQUENCY
Figure 55.
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Product Folder Link(s):VCA820
Frequency (Hz)
1M
10M
100M
500M
N o r m a l i z e d G a i n (d B )
30
-3-6-9-12-15-18
Frequency (MHz)0
50
100
150
200
250
300
G a i n (d B )
30-3
-6
-9-12-15-18
Time (10ns/div)
V (m V )
O U T
---Time (10ns/div)
V (V )
O U T
---
0.100.050
-0.05-0.10-0.15-0.20-0.25-0.30
Frequency (MHz)
M a g n i t u d e (d B )
0.10-0.1-0.2-0.3-0.4-0.5-0.6-0.7
Deviation from Linear Phase ()
°0
10
20
30
40
50
1000
100
10Frequency (Hz)
O u t p u t V o l t a g e N o i s e D e n s i t y (n V /)
?H z 100
1k
10k
10M
100k
1M
VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =40dB
At T A =+25°C,R L =100?,R F =845?,R G =16.9?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and
SO-14package,unless otherwise noted.
SMALL-SIGNAL FREQUENCY RESPONSE
LARGE-SIGNAL FREQUENCY RESPONSE
Figure 56.
Figure 57.
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
Figure 58.Figure 59.
GAIN FLATNESS
OUTPUT VOLTAGE NOISE DENSITY
Figure 60.Figure 61.
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Product Folder Link(s):VCA820
-35-40
-45-50-55-60-65-70-75-80
Frequency (MHz)
H a r m o n i c D i s t o r t i o n (d B c )
0.11
10100
-40-45-50-55-60-65-70-75-80-85-90
Resistance ()
W H a r m o n i c D i s t o r t i o n (d B c )
100
1k
-40
-45-50
-55-60-65
Output Voltage Swing (V )
PP H a r m o n i c D i s t o r t i o n (d B c )
0.1
1
10
-35
-40-45-50
-55-60-65
Gain Control Voltage (V)
H a r m o n i c D i s t o r t i o n (d B c )
0.8
2.0
1.0
1.2
1.4
1.6
1.8
3331
2927252321191715
Frequency (MHz)
I n t e r c e p t P o i n t (+d B m )
5
10152025303540
455055606570
Gain Control Voltage (V)
0.8
1.0
1.2
1.4
1.6 1.8
2.0
I n t e r c e p t P o i n t
(+d B m )
3530
2520
15100
5VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =40dB (continued)
At T A =+25°C,R L =100?,R F =845?,R G =16.9?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
HARMONIC DISTORTION vs FREQUENCY
HARMONIC DISTORTION vs LOAD RESISTANCE
Figure 62.
Figure 63.
HARMONIC DISTORTION vs OUTPUT VOLTAGE
20MHz HARMONIC DISTORTION vs GAIN CONTROL VOLTAGE
Figure 64.Figure 65.
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT
2-TONE,3RD-ORDER INTERMODULATION INTERCEPT
vs GAIN CONTROL VOLTAGE (f IN =20MHz)
Figure 66.Figure 67.
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Product Folder Link(s):VCA820
Gain Control Voltage (V)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
G a i n (V /V )
110100
908070
6050403020100-
10
Frequency (Hz)
1M
10M
100M
1G
N o r m a l i z e d G a i n (d B )
3
-3-6-9-12
Time (10ns/div)
V (V )
I N V (V)
OUT 2.52.0
1.51.00.50-0.5
2.52.01.51.00.50
-
0.5
5040
3020100-50
Frequency (Hz)
N o r m a l i z e d G a i n (d B )
1M 1G
10M 100M
-10-20-30-
40----Time (40ns/div)
I n p u t V o l t a g e (m V )
8642
Output Voltage (V)
-Time (40ns/div)
I n p u t V o l t a g e (V )
--6
4
20-6
Output Voltage (V)
-2-4VCA820
https://www.doczj.com/doc/f6119672.html, ............................................................................................................................................SBOS395C –OCTOBER 2007–REVISED OCTOBER 2009
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =40dB (continued)
At T A =+25°C,R L =100?,R F =845?,R G =16.9?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
GAIN vs GAIN CONTROL VOLTAGE
GAIN CONTROL FREQUENCY
Figure 68.
Figure 69.
GAIN CONTROL PULSE RESPONSE
FULLY-ATTENUATED RESPONSE
Figure 70.
Figure 71.
INPUT LIMITED OVERDRIVE RECOVERY
OUTPUT LIMITED OVERDRIVE RECOVERY
Figure 72.Figure 73.
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Product Folder Link(s):VCA820
14108
640Gain Control Voltage (V)
G r o u p D e l a y (n s )
0.2
0.4
0.6
0.8
1.0
212
4.02.01.51.0
0.50Frequency (MHz)
G r o u p D e l a y (n s )
20
40
60
80
100
2.5
3.0
3.5
VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
TYPICAL CHARACTERISTICS:V S =±5V,A VMAX =40dB (continued)
At T A =+25°C,R L =100?,R F =845?,R G =16.9?,V G =+2V,V IN =single-ended input on +V IN with –V IN at ground,and SO-14package,unless otherwise noted.
GROUP DELAY vs GAIN CONTROL VOLTAGE
GROUP DELAY vs FREQUENCY
Figure 74.Figure 75.
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Product Folder Link(s):VCA820
VCA820
https://www.doczj.com/doc/f6119672.html,............................................................................................................................................SBOS395C–OCTOBER2007–REVISED OCTOBER2009
APPLICATION INFORMATION
For test purposes,the input impedance is set to50?
with a resistor to ground and the output impedance is WIDEBAND VARIABLE GAIN AMPLIFIER
set to50?with a series output resistor.Voltage OPERATION
swings reported in the Electrical Characteristics table The VCA820provides an exceptional combination of are taken directly at the input and output pins,while high output power capability with a wideband,greater output power(dBm)is at the matched50?load.For than40dB gain adjust range,linear in dB variable the circuit in Figure76,the total effective load is gain amplifier.The VCA820input stage places the100?1k?.Note that for the SO-14package,there
transconductance element between two input buffers,is a voltage reference pin,V
REF (pin9).For the
using the output currents as the forward signal.As SO-14package,this pin must be connected to the differential input voltage rises,a signal current is ground through a20?resistor in order to avoid generated through the gain element.This current is possible oscillations of the output stage.In the then mirrored and gained by a factor of two before MSOP-10package,this pin is internally connected reaching the multiplier.The other input of the and does not require such precaution.An X2Y?multiplier is the voltage gain control pin,V G.capacitor has been used for power-supply bypassing. Depending on the voltage present on V G,up to two The combination of low inductance,high resonance times the gain current is provided to the frequency,and integration of three capacitors in one transimpedance output stage.The transimpedance package(two capacitors to ground and one across output stage is a current-feedback amplifier providing the supplies)of this capacitor enables to achieve the high output current capability and high slew rate,low second-harmonic distortion reported in the 1700V/μs.This exceptional full-power performance Electrical Characteristics table.More information on comes at the price of a relatively high quiescent how the VCA820operates can be found in the current(34mA),but a low input voltage noise for this Operating Suggestions section.
type of architecture(8.2nV/√
Figure76shows the dc-coupled,gain of20dB,dual
power-supply circuit used as the basis of the±5V
Electrical Characteristics and Typical Characteristics.
Figure76.DC-Coupled,A VMAX=20dB,Bipolar Supply Specification and Test Circuit
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Product Folder Link(s):VCA820
G = 2′′R F R G 1 + sR C G 1
1 + sR C 11
VCA820
SBOS395C –OCTOBER 2007–REVISED OCTOBER https://www.doczj.com/doc/f6119672.html,
DIFFERENCE AMPLIFIER
DIFFERENTIAL EQUALIZER
Because both inputs of the VCA820are If the application requires frequency shaping (the high-impedance,a difference amplifier can be transition from one gain to another),the VCA820can implemented without any major problem.This be used advantageously because its architecture implementation is shown in Figure 77.This circuit allows the application to isolate the input from the provides excellent common-mode rejection ratio gain setting elements.Figure 79shows an (CMRR)as long as the input is within the CMRR implementation of such a configuration.The transfer range of –2.1V to +1.6V.Note that this circuit does function is shown in Equation 1.
not make use of the gain control pin,V G .Also,it is recommended to choose R S such that the pole formed by R S and the parasitic input capacitance (1)
does not limit the bandwidth of the circuit.The common-mode rejection ratio for this circuit implemented in a gain of 20dB for V G =+2V is shown in Figure 78.Note that because the gain control voltage is fixed and is normally set to +2V,the feedback element can be reduced in order to increase the bandwidth.When reducing the feedback element make sure that the VCA820is not limited by common-mode input voltage,the current flowing through R G ,or any other limitation described in this data sheet.
Figure 79.Differential Equalizer
This transfer function has one pole,P 1(located at R G C 1),and one zero,Z 1(located at R 1C 1).When equalizing an RC load,R L and C L ,compensate the pole added by the load located at R L C L with the zero Z 1.Knowing R L ,C L ,and R G allows the user to select C 1as a first step and then calculate R https://www.doczj.com/doc/f6119672.html,ing Figure 77.Difference Amplifier
R L =75?,C L =100pF and wanting the VCA820to operate at a gain of +2V/V,which gives R F =R G =1.33k ?,allows the user to select C 1=5pF to ensure a positive value for the resistor R 1.With all these values known,R 1can be calculated to be 170?.The frequency response for both the initial,unequalized frequency response and the resulting equalized frequency response are illustrated in Figure 80.
Figure https://www.doczj.com/doc/f6119672.html,mon-Mode Rejection Ratio
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Product Folder Link(s):VCA820