VCA
261
4
VCA2614
SBOS185D – JANUARY 2001 – REVISED MARCH 2003
Dual, VARIABLE GAIN AMPLIFIER
with Input Buffer
FEATURES
q
GAIN RANGE: 40dB
q
40MHz BANDWIDTH
q
LOW CROSSTALK: 70dB at Max Gain, 5MHz
q
HIGH-SPEED VARIABLE GAIN ADJUST
q
POWER SHUTDOWN MODE
q
HIGH IMPEDANCE INPUT BUFFER
DESCRIPTION
The VCA2614 is a highly integrated, dual receive channel,
Variable Gain Amplifier (VGA) with analog gain control.
The VCA2614’s VGA section consists of two parts: the Volt-
age Controlled Attenuator (VCA) and the Programmable Gain
Amplifier (PGA). The gain and gain range of the PGA can be
digitally programmed. The combination of these two program-
mable elements results in a variable gain ranging from 0dB up
to a maximum gain as defined by the user through external
connections. The single-ended unity gain input buffer provides
predictable high input impedance. The output of the VGA can
be used in either a single-ended or differential mode to drive
high-performance Analog-to-Digital Converters (ADCs). A sepa-
rate power-down pin reduces power consumption.
The VCA2614 also features low crosstalk and outstanding
distortion performance. The combination of low noise and gain
range programmability makes the VCA2614 a versatile build-
ing block in a number of applications where noise perfor-
mance is critical. The VCA2614 is available in a TQFP-32
package.
APPLICATIONS
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ULTRASOUND SYSTEMS
q
GAMMA CAMERAS
q
WIRELESS RECEIVERS
q
TEST EQUIPMENT
C
P2A
C
P1A
VCA2614
(1 of 2 Channels)
N
OUTA
Voltage
Control
Attenuator
Programmable
Gain Amplifier
IN
A
Buffer
P
OUTA
MGS
1
VCA
CNTL
Analog
Control
Maximum Gain
Select
MGS
2
MGS
3
Maximum
Gain Select
N
OUTB
Voltage
Control
Attenuator
Programmable
Gain Amplifier
IN
B
Buffer
P
OUTB
C
P2B
C
P1B
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.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright © 2001-2003, Texas Instruments Incorporated
www.ti.com
ABSOLUTE MAXIMUM RATINGS
(1)
Power Supply (+V
S
) ............................................................................. +6V
Analog Input ............................................................. –0.3V to (+V
S
+ 0.3V)
Logic Input ............................................................... –0.3V to (+V
S
+ 0.3V)
Case Temperature ......................................................................... +100°C
Junction Temperature .................................................................... +150°C
Storage Temperature ...................................................... –40°C to +150°C
NOTE: (1) Stresses above those listed under “Absolute Maximum Ratings”
may cause permanent damage to the device. Exposure to absolute maximum
conditions for extended periods may affect device reliability.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas Instru-
ments 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 degrada-
tion 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.
PACKAGE/ORDERING INFORMATION
PACKAGE
DESIGNATOR
(1)
PBS
SPECIFIED
TEMPERATURE
RANGE
–40°C to +85°C
PACKAGE
MARKING
VCA2614Y
ORDERING
NUMBER
VCA2614Y/250
VCA2614Y/2K
TRANSPORT
MEDIA, QUANTITY
Tape and Reel, 250
Tape and Reel, 2000
PRODUCT
VCA2614Y
PACKAGE-LEAD
TQFP-32 Surface-Mount
"
"
"
"
"
NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com.
ELECTRICAL CHARACTERISTICS
At T
A
= +25°C, V
DD
= 5V, load resistance = 500Ω on each output to ground differential output (2Vp-p), MGS = 011, and f
IN
= 5MHz, unless otherwise noted.
VCA2614Y
PARAMETER
BUFFER
Input Resistance
Input Capacitance
Input Bias Current
Maximum Input Voltage
Input Voltage Noise
Input Current Noise
Noise Figure
Bandwidth
CONDITIONS
MIN
TYP
600
5
1
1
4.8
350
13
100
1
40
300
2.5
±1
1
±40
–60
–50
–40 to –45
5
–59
70
13
10.5
±2
(1)
±50
0.2 to 3.0
1
0.2
4.75
Operating, Each Channel
5.0
120
9.2
5.25
150
MAX
UNITS
kΩ
pF
nA
Vp-p
nV/
√Hz
fA/
√Hz
dB
MHz
Vp-p
MHz
V/µs
V
Ω
mA
dBc
dBc
dB
ns
dBc
dB
ns
dB/V
dB
mV
V
MΩ
µs
V
mW
mW
MGS = 111, PGA Gain = 44.2dB, R
S
= 50Ω
Independent of Gain
R
F
= 550Ω, PGA Gain = 44.2dB, R
S
= 75Ω
PROGRAMMABLE VARIABLE GAIN AMPLIFIER
Peak Input Voltage
–3dB Bandwidth
Slew Rate
Output Signal Range
R
L
≥
500Ω Each Side to Ground
Output Impedance
f = 5MHz
Output Short-Circuit Current
3rd-Harmonic Distortion
f = 5MHz, V
OUT
= 2Vp-p, VCA
CNTL
= 3.0V
2nd-Harmonic Distortion
f = 5MHz, V
OUT
= 2Vp-p, VCA
CNTL
= 3.0V
Overload Performance (2nd-Harmonic
Input Signal = 1Vp-p, MGS = 111, VCA
CNTL
= 2V
Distortion)
Time Delay
IMD, 2-Tone
V
OUT
= 2Vp-p, f = 9.95MHz
Crosstalk
Group Delay Variation
1MHz < f < 10MHz, Full Gain Range
ACCURACY
Gain Slope
Gain Error
Output Offset Voltage
GAIN CONTROL INTERFACE
Input Voltage (VCA
CNTL
) Range
Input Resistance
Response Time
POWER SUPPLY
Specified Operating Range
Power Dissipation
Power-Down
NOTE: (1) Referenced to best fit dB-linear curve.
–45
–45
40dB Gain Change, MGS = 111
2
VCA2614
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SBOS185D
PIN CONFIGURATION
Top View
N
OUTA
GND
A
P
OUTA
TQFP
32
31
30
29
28
V
DDA
DNC
C
P2A
C
P1A
NC
27
26
+IN
A
NC
V
DDR
V
BIAS
V
CM
GND
R
NC
+IN
B
1
2
3
4
5
6
7
8
25
24
23
22
VCA
CNTL
MGS
3
MGS
2
MGS
1
PD
NC
NC
DNC
VCA2614
21
20
19
18
17
10
11
12
13
14
15
P
OUTB
PIN DESCRIPTIONS
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
DESIGNATOR
+IN
A
NC
V
DDR
V
BIAS
V
CM
GND
R
NC
+IN
B
NC
DNC
C
P2B
C
P1B
V
DDB
GND
B
P
OUTB
N
OUTB
DESCRIPTION
Input Channel A
No Internal Connection
Internal Reference Supply
Bias Voltage
Common-Mode Voltage
Internal Reference Ground
No Internal Connection
Input Channel B
No Internal Connection
Do Not Connect
Coupling Capacitor Channel B
Coupling Capacitor Channel B
+5V Supply Channel B
Ground Channel B
Positive Output Channel B
Negative Output Channel B
PIN
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
DESIGNATOR
DNC
NC
NC
PD
MGS
1
MGS
2
MGS
3
VCA
CNTL
N
OUTA
P
OUTA
GND
A
V
DDA
C
P1A
C
P2A
DNC
NC
DESCRIPTION
Do Not Connect
No Internal Connection
No Internal Connection
Power Down (Active LOW)
Maximum Gain Select 1 (MSB)
Maximum Gain Select 2
Maximum Gain Select 3 (LSB)
VCA Analog Control
Negative VCA Output Channel A
Positive VCA Output Channel A
Ground Channel A
+5V Supply Channel A
Coupling Capacitor Channel A
Coupling Capacitor Channel A
Do Not Connect
No Internal Connection
VCA2614
SBOS185D
N
OUTB
V
DDB
C
P2B
DNC
C
P1B
NC
GND
B
16
9
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3
TYPICAL CHARACTERISTICS
At T
A
= +25°C, V
DD
= 5V, load resistance = 500Ω on each output to ground, differential output (2Vp-p) MGS = 011, and f
IN
= 5MHz, unless otherwise noted.
GAIN vs VCA
CNTL
50
45
40
35
Gain (dB)
GAIN ERROR vs TEMPERATURE
MGS = 111
2.0
–40°C
1.5
1.0
Gain Error (dB)
MGS = 110
MGS = 101
+25°C
30
25
20
15
10
5
0
MGS = 011
MGS = 100
MGS = 001
MGS = 010
0.5
0
–0.5
+85°C
–1.0
–1.5
–2.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
GAIN ERROR vs VCA
CNTL
2.0
1.5
5MHz
1.0
Gain Error (dB)
1.0
2.0
1.5
GAIN ERROR vs VCA
CNTL
MGS = 001
0.5
0
1MHz
–0.5
–1.0
–1.5
–2.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
Gain Error (dB)
10MHz
MGS = 000
0.5
0
–0.5
–1.0
–1.5
–2.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
MGS = 111
GAIN MATCH: CHA to CHB, VCA
CNTL
= 0.2V
120
100
80
80
70
60
50
GAIN MATCH: CHA to CHB, VCA
CNTL
= 3.0V
Units
60
40
20
0
Units
–0.88
–0.81
–0.74
–0.68
–0.61
–0.55
–0.48
–0.42
–0.35
–0.29
–0.22
–0.16
–0.09
–0.03
0.04
0.10
0.17
0.23
0.30
0.36
0.43
0.49
40
30
20
10
0
Delta Gain (dB)
4
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–0.07
–0.06
–0.05
–0.04
–0.02
–0.01
0.00
0.01
0.02
0.04
0.05
0.06
0.07
0.08
0.10
0.11
0.12
0.13
0.14
0.16
0.17
0.18
Delta Gain (dB)
VCA2614
SBOS185D
TYPICAL CHARACTERISTICS
(Cont.)
At T
A
= +25°C, V
DD
= 5V, load resistance = 500Ω on each output to ground, differential output (2Vp-p) MGS = 011, and f
IN
= 5MHz, unless otherwise noted.
GAIN vs FREQUENCY
(VCA
CNTL
= 3.0V)
50
45
40
35
MGS = 011
MGS = 111
GAIN vs FREQUENCY
35
30
25
20
Gain (dB)
15
10
5
0
MGS = 001
VCA
CNTL
= 3.0V
Gain (dB)
30
25
20
15
10
5
0
100k
1M
Frequency (Hz)
10M
100M
VCA
CNTL
= 1.6V
–5
–10
–15
100k
1M
VCA
CNTL
= 0.2V
10M
Frequency (Hz)
100M
OUTPUT REFERRED NOISE vs VCA
CNTL
450
400
350
Noise (nV/√Hz)
220
INPUT REFERRED NOISE vs VCA
CNTL
200
R
S
= 50Ω
R
S
= 50Ω
MGS = 111
180
160
300
250
200
150
100
50
0
0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
MGS = 011
Noise (nV/√Hz)
140
120
100
80
60
40
20
0
0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0
VCA
CNTL
(V)
MGS = 011
MGS = 111
100
INPUT REFERRED NOISE vs R
S
NOISE FIGURE vs R
S
24
22
20
Noise Figure (dB)
18
16
14
12
10
8
6
4
Noise (nV√Hz)
10
1
1
10
R
S
(Ω)
100
1k
2
10
100
R
S
(Ω)
1k
VCA2614
SBOS185D
www.ti.com
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