OPA4
684
OPA4
684
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.
OPA4684
www.ti.com
Copyright 2002, Texas Instruments Incorporated
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.
SBOS240B JUNE 2002 REVISED AUGUST 2002
Quad, Low-Power, Current-Feedback
OPERATIONAL AMPLIFIER
FEATURES
q
MINIMAL BANDWIDTH CHANGE VERSUS GAIN
q
170MHz BANDWIDTH AT G = +2
q
> 120MHz BANDWIDTH TO GAIN > +10
q
LOW DISTORTION: < 78dBc at 5MHz
q
HIGH OUTPUT CURRENT: 120mA
q
SINGLE +5V TO +12V SUPPLY OPERATION
q
DUAL
2.5 TO
6.0V SUPPLY OPERATION
q
LOW SUPPLY CURRENT: 6.8mA Total
DESCRIPTION
The OPA4684 provides a new level of performance in low-
power, wideband, current-feedback (CFB) amplifiers. This
CFB
PLUS
amplifier is among the first to use an internally
closed-loop input buffer stage that enhances performance
significantly over earlier low-power CFB amplifiers. While
retaining the benefits of very low power operation, this new
architecture provides many of the benefits of a more ideal
CFB amplifier. The closed-loop input stage buffer gives a
very low and linearized impedance path at the inverting input
to sense the feedback error current. This improved inverting
input impedance retains exceptional bandwidth to much
higher gains and improves harmonic distortion over earlier
solutions limited by inverting input linearity. Beyond simple
high-gain applications, the OPA4684 CFB
PLUS
amplifier per-
mits the gain setting element to be set with considerable
APPLICATIONS
q
LOW-POWER BROADCAST VIDEO DRIVERS
q
EQUALIZING FILTERS
q
SAW FILTER HIGH-GAIN POST AMPLIFIERS
q
MULTICHANNEL SUMMING AMPLIFIERS
q
WIDEBAND DIFFERENTIAL CHANNELS
q
ANALOG-TO-DIGITAL CONVERTERS (ADC)
INPUT DRIVERS
q
MULTIPLE POLE ACTIVE FILTERS
q
OPA4658 LOW-POWER UPGRADE
freedom from amplifier bandwidth interaction. This allows
frequency response peaking elements to be added, multiple
input inverting summing circuits to have greater bandwidth,
and low-power line drivers to meet the demanding require-
ments of studio cameras and broadcast video.
The output capability of the OPA4684 also sets a new mark
in performance for low-power current-feedback amplifiers.
Delivering a full
4Vp-p swing on
5V supplies, the OPA4684
also has the output current to support >
3V swing into 50
.
This minimal output headroom requirement is complemented
by a similar 1.2V input stage headroom giving exceptional
capability for single +5V operation.
The OPA4684's low 6.8mA supply current is precisely trimmed
at 25
C. This trim, along with low shift over temperature and
supply voltage, gives a very robust design over a wide range
of operating conditions.
Patent Pending
V+
V
O
V
I
ERR
R
G
R
F
Z
(S)
I
ERR
+
Low-Power
Amplifier
1 of 4 Channels
6
3
0
3
6
9
12
15
18
21
24
Normalized Gain (3dB/div)
R
F
= 800
G = 100
G = 50
G = 20
G = 10
G = 2
G = 1
10
100
200
BW (MHz) vs GAIN
G = 5
MHz
OPA4684
2
SBOS240B
www.ti.com
ABSOLUTE MAXIMUM RATINGS
(1)
Power Supply ...............................................................................
6.5V
DC
Internal Power Dissipation ................................. See Thermal Information
Differential Input Voltage ..................................................................
1.2V
Input Voltage Range ............................................................................
V
S
Storage Temperature Range: ID, IDBV ......................... 40
C to +125
C
Lead Temperature (soldering, 10s) .............................................. +300
C
Junction Temperature (T
J
) ........................................................... +175
C
ESD Rating: HBM ........................................................................... 2000V
CDM ........................................................................... 1500V
NOTE: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability.
SPECIFIED
PACKAGE
TEMPERATURE
PACKAGE
ORDERING
TRANSPORT
PRODUCT
PACKAGE-LEAD
DESIGNATOR
(1)
RANGE
MARKING
NUMBER
MEDIA, QUANTITY
OPA4684
SO-14
D
40
C to +85
C
OPA4684
OPA4684ID
Rails, 58
"
"
"
"
"
OPA4684IDR
Tape and Reel, 2500
OPA4684
TSSOP-14
PW
40
C to +85
C
OPA4684
OPA4684IPWT
Tape and Reel, 250
"
"
"
"
"
OPA4684IPWR
Tape and Reel, 2500
PACKAGE/ORDERING INFORMATION
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas
Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper han-
dling 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.
PIN CONFIGURATION
OPA4684 RELATED PRODUCTS
SINGLES
DUALS
TRIPLES
FEATURES
OPA683
OPA2683
--
Very Low-Power CFB
PLUS
OPA684
OPA2684
OPA3684
Low-Power CFB
PLUS
OPA691
OPA2691
OPA3691
High Slew Rate CFB
OPA685
--
--
> 500MHz CFB
Top View
SO, TSSOP
NOTE: (1) For the most current specifications, and package information, refer to our web site at www.ti.com.
1
2
3
4
5
6
7
+V
+Input B
Input B
Output B
+Input A
Input A
Output A
+Input B
Input B
Output B
+Input A
Input A
Output A
V
14
13
12
11
10
9
8
OPA4684
D
A
B
C
OPA4684
3
SBOS240B
www.ti.com
AC PERFORMANCE (See Figure 1)
Small-Signal Bandwidth (V
O
= 0.5Vp-p)
G = +1, R
F
= 800
250
MHz
typ
C
G = +2, R
F
= 800
170
120
118
117
MHz
min
B
G = +5, R
F
= 800
138
MHz
typ
C
G = +10, R
F
= 800
120
MHz
typ
C
G = +20, R
F
= 800
95
MHz
typ
C
Bandwidth for 0.1dB Gain Flatness
G = +2, V
O
= 0.5Vp-p, R
F
= 800
19
16
14
14
MHz
min
B
Peaking at a Gain of +1
R
F
= 800
, V
O
= 0.5Vp-p
1.4
4.8
5.9
6.3
dB
max
B
Large-Signal Bandwidth
G = +2, V
O
= 4Vp-p
90
MHz
typ
C
Slew Rate
G = 1, V
O
= 4V Step
780
675
650
575
V/
s
min
B
G = +2, V
O
= 4V Step
750
680
660
650
V/
s
min
B
Rise-and-Fall Time
G = +2, V
O
= 0.5V Step
3
ns
typ
C
G = +2, V
O
= 4VStep
6.8
ns
typ
C
Harmonic Distortion
G = +2, f = 5MHz, V
O
= 2Vp-p
2nd-Harmonic
R
L
= 100
67
59
59
58
dBc
max
B
R
L
1k
82
66
65
65
dBc
max
B
3rd-Harmonic
R
L
= 100
70
66
65
65
dBc
max
B
R
L
1k
84
82
81
81
dBc
max
B
Input Voltage Noise
f > 1MHz
3.7
4.1
4.2
4.4
nV/
Hz
max
B
Noninverting Input Current Noise
f > 1MHz
9.4
11
12
12.5
pA/
Hz
max
B
Inverting Input Current Noise
f > 1MHz
17
18
18.5
19
pA/
Hz
max
B
Differential Gain
G = +2, NTSC, V
O
= 1.4Vp, R
L
= 150
0.04
%
typ
C
Differential Phase
G = +2, NTSC, V
O
= 1.4Vp, R
L
= 150
0.02
deg
typ
C
All Hostile Crosstalk, Input Referred
3 Channels Driven at 5MHz, 1Vp-p
52
dB
typ
C
4th Channel Measured
DC PERFORMANCE
(4)
Open-Loop Transimpedance Gain (Z
OL
)
V
O
= 0V, R
L
= 1k
355
160
155
153
k
min
A
Input Offset Voltage
V
CM
= 0V
1.5
4.0
4.6
4.8
mV
max
A
Average Offset Voltage Drift
V
CM
= 0V
12
12
V/
C
max
B
Noninverting Input Bias Current
V
CM
= 0V
5.0
13
14.5
15
A
max
A
Average Noninverting Input Bias Current Drift
V
CM
= 0V
25
30
nA/
C
max
B
Inverting Input Bias Current
V
CM
= 0V
5.0
17
18.5
19.5
A
max
A
Average Inverting Input Bias Current Drift
V
CM
= 0V
35
40
nA
/C
max
B
INPUT
Common-Mode Input Range
(5)
(CMIR)
3.75
3.65
3.65
3.6
V
min
A
Common-Mode Rejection Ratio (CMRR)
V
CM
= 0V
60
53
52
52
dB
min
A
Noninverting Input Impedance
50 || 2
k
|| pF
typ
C
Inverting Input Resistance (R
I
)
Open-Loop, DC
4.0
typ
C
OUTPUT
Voltage Output Swing
1k
Load
4.1
3.9
3.9
3.8
V
min
A
Current Output, Sourcing
V
O
= 0
160
120
115
110
mA
min
A
Current Output, Sinking
V
O
= 0
120
100
95
90
mA
min
A
Closed-Loop Output Impedance
G = +2, f = 100kHz
0.006
typ
C
POWER SUPPLY
Specified Operating Voltage
5
V
typ
C
Maximum Operating Voltage Range
6
6
6
V
max
A
Max Quiescent Current
V
S
=
5V
6.8
7.2
7.6
7.8
mA
max
A
Min Quiescent Current
V
S
=
5V
6.8
6.4
6.2
5.8
mA
min
A
Power-Supply Rejection Ratio (PSRR)
Input Referred
60
54
53
53
dB
typ
A
TEMPERATURE RANGE
Specification: ID, IPW
40 to +85
C
typ
C
Thermal Resistance,
JA
Junction-to-Ambient
D
SO-14
100
C/W
typ
C
PW
TSSOP-14
110
C/W
typ
C
NOTES: (1) Junction temperature = ambient for 25
C tested specifications. (2) Junction temperature = ambient at low temperature limit, junction temperature = ambient
+7
C at high temperature limit for over temperature tested specifications. (3) Test levels: (A) 100% tested at 25
C. Over temperature limits by characterization and
simulation. (B) Limits set by characterization and simulation. (C) Typical value only for information. (4) Current is considered positive out-of-node. V
CM
is the input
common-mode voltage. (5) Tested < 3dB below minimum specified CMR at
CMIR limits.
OPA4684ID, IPW
0
C to
40
C to
MIN/
TEST
PARAMETER
CONDITIONS
+25
C
+25
C
(1)
70
C
(2)
+85
C
(2)
UNITS
MAX
LEVEL
(3)
TYP
MIN/MAX OVER TEMPERATURE
ELECTRICAL CHARACTERISTICS: V
S
=
5V
Boldface limits are tested at +25
C.
R
F
= 800
, R
L
= 100
, and G = +2
,
(see Figure 1 for AC performance only), unless otherwise noted.
OPA4684
4
SBOS240B
www.ti.com
AC PERFORMANCE (See Figure 3)
Small-Signal Bandwidth (V
O
= 0.5Vp-p)
G = +1, R
F
= 1.3k
140
MHz
typ
C
G = +2, R
F
= 1.3k
110
86
85
82
MHz
min
B
G = +5, R
F
= 1.3k
100
MHz
min
C
G = +10, R
F
= 1.3k
90
MHz
typ
C
G = +20, R
F
= 1.3k
75
MHz
typ
C
Bandwidth for 0.1dB Gain Flatness
G = +2, V
O
< 0.5Vp-p, R
F
= 1.3k
21
12
11
10
MHz
min
B
Peaking at a Gain of +1
R
F
= 1.3k
, V
O
< 0.5Vp-p
0.5
2.6
3.4
3.7
dB
max
B
Large-Signal Bandwidth
G = 2, V
O
= 2Vp-p
86
MHz
typ
C
Slew Rate
G = 2, V
O
= 2V Step
300
300
290
280
V/
s
min
B
G = 2, V
O
= 0.5V Step
4.3
ns
typ
C
Rise-and-Fall Time
G = 2, V
O
= 2VStep
5.3
ns
typ
C
Harmonic Distortion
G = 2, f = 5MHz, V
O
= 2Vp-p
2nd-Harmonic
R
L
= 100
to V
S
/2
65
60
59
59
dBc
max
B
R
L
1k
to V
S
/2
84
62
61
61
dBc
max
B
3rd-Harmonic
R
L
= 100
to V
S
/2
65
64
63
63
dBc
max
B
R
L
1k
to V
S
/2
74
70
70
69
dBc
max
B
Input Voltage Noise
f > 1MHz
3.7
4.1
4.2
4.4
nV/
Hz
max
B
Noninverting Input Current Noise
f > 1MHz
9.4
11
12
12.5
pA/
Hz
max
B
Inverting Input Current Noise
f > 1MHz
17
18
18.5
19
pA/
Hz
max
B
Differential Gain
G = +2, NTSC, V
O
= 1.4Vp, R
L
= 150
0.04
%
typ
C
Differential Phase
G = +2, NTSC, V
O
= 1.4Vp, R
L
= 150
0.07
deg
typ
C
All Hostile X-Talk, Input Referred
3-Channels Driven at 5MHz, 1Vp-p
52
dB
typ
C
4th Channel Measured
DC PERFORMANCE
(4)
Open-Loop Transimpedance Gain (Z
OL
)
V
O
= V
S
/2, R
L
= 1k
to V
S
/2
355
160
155
153
k
min
A
Input Offset Voltage
V
CM
= V
S
/2
1.0
3.5
4.1
4.3
mV
max
A
Average Offset Voltage Drift
V
CM
= V
S
/2
12
12
V/
C
max
B
Noninverting Input Bias Current
V
CM
= V
S
/2
5
13
14.5
15
A
max
A
Average Noninverting Input Bias Current Drift
V
CM
= V
S
/2
25
30
nA/
C
max
B
Inverting Input Bias Current
V
CM
= V
S
/2
5
13
14.5
16
A
max
A
Average Inverting Input Bias Current Drift
V
CM
= V
S
/2
25
30
nA
/C
max
B
INPUT
Least Positive Input Voltage
(5)
1.25
1.32
1.35
1.38
V
max
A
Most Positive Input Voltage
(5)
3.75
3.68
3.65
3.62
V
min
A
Common-Mode Refection Ratio (CMRR)
V
CM
= V
S
/2
58
51
50
50
dB
min
A
Noninverting Input Impedance
50 || 1
k
|| pF
typ
C
Inverting Input Resistance (R
I
)
Open-Loop
5
typ
C
OUTPUT
Most Positive Output Voltage
R
L
= 1k
to V
S
/2
4.10
3.9
3.9
3.8
V
min
A
Least Positive Output Voltage
R
L
= 1k
to V
S
/2
0.9
1.1
1.1
1.2
V
max
A
Current Output, Sourcing
V
O
= V
S
/2
80
65
60
55
mA
min
A
Current Output, Sinking
V
O
= V
S
/2
70
55
50
45
mA
min
A
Closed-Loop Output Impedance
G = +2, f = 100kHz
0.006
typ
C
POWER SUPPLY
Specified Single-Supply Operating Voltage
5
V
typ
C
Max Single-Supply Operating Voltage Range
12
12
12
V
max
A
Max Quiescent Current
V
S
= +5V
5.8
6.2
6.2
6.2
mA
max
A
Min Quiescent Current
V
S
= +5V
5.8
5.2
4.8
4.6
mA
min
A
Power-Supply Rejection Ratio (+PSRR)
Input Referred
58
dB
typ
C
TEMPERATURE RANGE
Specification: ID, IPW
40 to +85
C
typ
C
Thermal Resistance,
JA
Junction-to-Ambient
D
SO-14
100
C/W
typ
C
PW
TSSOP-14
110
C/W
typ
C
NOTES: (1) Junction temperature = ambient for 25
C tested specifications. (2) Junction temperature = ambient at low temperature limit, junction temperature = ambient
+3
C at high temperature limit for over temperature tested specifications. (3) Test levels: (A) 100% tested at 25
C. Over temperature limits by characterization and
simulation. (B) Limits set by characterization and simulation. (C) Typical value only for information. (4) Current is considered positive out-of-node. V
CM
is the input
common-mode voltage. (5) Tested < 3dB below minimum specified CMR at
CMIR limits.
OPA4684ID, IPW
0
C to
40
C to
MIN/
TEST
PARAMETER
CONDITIONS
+25
C
+25
C
(1)
70
C
(2)
+85
C
(2)
UNITS
MAX
LEVEL
(3)
TYP
MIN/MAX OVER TEMPERATURE
ELECTRICAL CHARACTERISTICS: V
S
= +5V
Boldface limits are tested at +25
C.
R
F
= 1k
, R
L
= 100
, and G = +2
,
(see Figure 3 for AC performance only), unless otherwise noted.
OPA4684
5
SBOS240B
www.ti.com
ELECTRICAL CHARACTERISTICS: V
S
=
5V
At T
A
= +25
C, G = +2, R
F
= 800
, and R
L
= 100
, unless otherwise noted.
NONINVERTING PULSE RESPONSE
Time (10ns/div)
Output V
oltage (200mV/div)
Output V
oltage (400mV/div)
0.8
0.6
0.4
0.2
0
0.2
0.4
0.6
0.8
1.6
1.2
0.8
0.4
0
0.4
0.8
1.2
1.6
Large-Signal Right Scale
Small-Signal Left Scale
See Figure 1
G = +2
INVERTING PULSE RESPONSE
Time (10ns/div)
Output V
oltage (200mV/div)
Output V
oltage (400mV/div)
0.8
0.6
0.4
0.2
0
0.2
0.4
0.6
0.8
1.6
1.2
0.8
0.4
0
0.4
0.8
1.2
1.6
Large-Signal Right Scale
Small-Signal Left Scale
See Figure 2
G = 1
3
0
3
6
9
12
Frequency (MHz)
1
200
10
100
INVERTING SMALL-SIGNAL FREQUENCY RESPONSE
Normalized Gain (3dB/div)
V
O
= 0.5Vp-p
R
F
= 800
See Figure 2
G = 1
G = 10
G = 16
G = 5
G = 2
9
6
3
0
3
Frequency (MHz)
1
200
10
100
NONINVERTING LARGE-SIGNAL
FREQUENCY RESPONSE
Gain (dB)
G = +2
R
L
= 100
See Figure 1
V
O
= 1Vp-p
V
O
= 0.5Vp-p
V
O
= 5Vp-p
V
O
= 2Vp-p
3
0
3
6
9
12
Frequency (MHz)
1
200
10
100
INVERTING LARGE-SIGNAL FREQUENCY RESPONSE
Gain (dB)
G = 1
R
L
= 100
V
O
= 0.5Vp-p
See Figure 2
2Vp-p
1Vp-p
5Vp-p
6
3
0
3
6
9
12
15
18
Frequency (MHz)
1
200
10
100
NONINVERTING SMALL-SIGNAL
FREQUENCY RESPONSE
Normalized Gain (3dB/div)
V
O
= 0.5Vp-p
R
F
= 800
See Figure 1
G = 1
G = 2
G = 50
G = 20
G = 10
G = 5
G = 100
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