Document Outline
- FEATURES
- APPLICATIONS
- DESCRIPTION
- PACKAGE/ORDERING INFORMATION
- ABSOLUTE MAXIMUM RATINGS
- PIN ASSIGNMENTS
- ELECTRICAL CHARACTERISTICS: VS = 2.7V to 5.5V
- TYPICAL CHARACTERISTICS
- APPLICATIONS INFORMATION
- THEORY OF OPERATION
- OPERATING VOLTAGE
- PCB LAYOUT
- INPUT AND ESD PROTECTION
- ENABLE FUNCTION
- DRIVING CAPACITIVE LOADS
- DRIVING A 16-BIT ADC
FEATURES
D
High Bandwidth: 150MHz
D
16-Bit Settling in 150ns
D
Low Noise: 3nV/
Hz
D
Low Distortion: 0.003%
D
Low Power: 9.5mA (typ) on 5.5V
D
Shutdown to 5
A
D
Unity Gain Stable
D
Excellent Output Swing:
(V+) - 100mV to (V-) + 100mV
D
Single Supply: +2.7V to +5.5V
D
Tiny Packages: SO-8 and SOT23
APPLICATIONS
D
16-Bit ADC Input Drivers
D
Low-Noise Preamplifiers
D
IF/RF Amplifiers
D
Active Filtering
DESCRIPTION
The OPA300 and OPA301 high-speed, voltage-feed-
back, CMOS operational amplifiers are designed for
16-bit resolution systems. The OPA300 and OPA301
are unity-gain stable and feature excellent settling and
harmonic distortion specifications. Low power applica-
tions benefit from low quiescent current. The OPA300
features digital shutdown (Enable) function to provide
additional power savings during idle periods. Optimized
for single-supply operation, the OPA300 and OPA301
offer superior output swing and excellent common-
mode range.
The OPA300 and OPA301 have 150MHz of unity-gain
bandwidth, low 3nV/
Hz voltage noise, and 0.1%
settling within 30ns. Single-supply operation from 2.7V
(
1.35V) to 5.5V (
2.75V) and an available shutdown
function that reduces supply current to 5
A are useful
for portable low-power applications. The OPA300 and
OPA301 are available in SO-8 and SOT-23 packages,
and are specified over the industrial temperature range
of -40
C to +125
C.
1
2
3
4
8
7
6
5
Enable
V+
V
O U T
NC
NC
-
In
+In
V
-
OPA300
SO-8
NC = Not Connected
1
2
3
4
8
7
6
5
NC
V+
V
O UT
NC
NC
-
In
+In
V
-
OPA301
SO-8
NC = Not Connected
1
2
3
6
5
4
V+
Enable
-
In
Out
V
-
+In
OPA300
SOT23-6
1
2
3
5
4
V+
-
In
Out
V
-
+In
OPA301
SOT23-5
Typical Application of the OPA300
OPA300
16-Bit
ADC
VIN
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
Low-Noise, High-Speed, 16-Bit Accurate, CMOS
OPERATIONAL AMPLIFIER
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.
www.ti.com
Copyright
2003, 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.
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
2
PACKAGE/ORDERING INFORMATION
PRODUCT
PACKAGE-LEAD
PACKAGE
DESIGNATOR(1)
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT
MEDIA, QUANTITY
OPA300D
SO-8
D
-40
C to +125
C
300A
OPA300AID
Tube, 100
OPA300D
SO-8
D
-40
C to +125
C
300A
OPA300AIDR
Tape and Reel, 2500
OPA300DBV
SOT23-6
DBV
-40
C to +125
C
A52
OPA300AIDBVT
Tape and Reel, 250
OPA300DBV
SOT23-6
DBV
-40
C to +125
C
A52
OPA300AIDBVR
Tape and Reel, 2500
OPA301D
SO-8
D
-40
C to +125
C
301A
OPA301AID
Tube, 100
OPA301D
SO-8
D
-40
C to +125
C
301A
OPA301AIDR
Tape and Reel, 2500
OPA301DBV
SOT23-5
DBV
-40
C to +125
C
AUP
OPA301AIDBVT
Tape and Reel, 250
OPA301DBV
SOT23-5
DBV
-40
C to +125
C
AUP
OPA301AIDBVR
Tape and Reel, 2500
(1) For the most current specification and package information, refer to our web site at www.ti.com.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
Power Supply V+
5.5V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Input Terminals(2), Voltage
0.5V to (V+) + 0.5V
. . . . . . . . . . .
Current
10mA
. . . . . . . . . . . . . . . . . . . . .
Open Short-Circuit Current(3)
Continuous
. . . . . . . . . . . . . . . . . . . .
Operating Temperature Range
-55
C to +125
C
. . . . . . . . . . . . . . .
Storage Temperature Range
-60
C to +150
C
. . . . . . . . . . . . . . . . .
Junction Temperature
+150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (soldering, 10s)
+300
C
. . . . . . . . . . . . . . . . . . . . .
(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.
(2) Input terminals are diode clamped to the power-supply rails. Input
signals that can swing more than 0.5V beyond the supply rails
should be current limited to 10mA or less.
(3) Short-circuit to ground; one amplifier per package.
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 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.
PIN ASSIGNMENTS
SO
Top View
SOT23
Top View
1
2
3
4
8
7
6
5
Enable
V+
V
O UT
NC
NC
-
In
+In
V
-
OPA300
SO-8
NC = Not Connected
1
2
3
4
8
7
6
5
NC
V+
V
O UT
NC
NC
-
In
+In
V
-
OPA301
SO-8
NC = Not Connected
1
2
3
5
4
V+
-
In
Out
V
-
+In
OPA301
SOT23-5
1
2
3
6
5
4
V+
Enable
-
In
Out
V
-
+In
OPA300
SOT23-6
(1)
A52
(1)SOT23-6 pin 1 oriented as shown with reference to package marking.
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
3
ELECTRICAL CHARACTERISTICS: V
S
= 2.7V to 5.5V
Boldface limits apply over the temperature range, T
A
= -40
C to +125
C.
All specifications at TA = +25
C, RL = 2k
connected to VS/2, VOUT = VS/2, and VCM = VS/2, unless otherwise noted.
OPA300, OPA301
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
OFFSET VOLTAGE
Input Offset Voltage
VOS
VS = 5V
1
5
mV
Over Temperature
7
mV
Drift
dV
OS
/dT
2.5
V/
C
vs. Power Supply
PSRR
VS = 2.7V to 5.5V, VCM < (V+) 0.9V
50
200
V/V
INPUT VOLTAGE RANGE
Common-Mode Voltage Range
VCM
(V-) - 0.2
(V+) - 0.9
V
Common-Mode Rejection Ratio
CMRR
(V-) - 0.2V < VCM < (V+) 0.9V
66
80
dB
INPUT BIAS CURRENT
Input Bias Current
IB
0.1
5
pA
Input Offset Current
IOS
0.5
5
pA
INPUT IMPEDANCE
Differential
1013 || 3
|| pF
Common-Mode
1013 || 6
|| pF
NOISE
Input Voltage Noise, f = 0.1Hz to 1MHz
40
Vpp
Input Voltage Noise Density, f > 1MHz
en
3
nV/
Hz
Input Current Noise Density, f < 1kHz
in
1.5
fA/
Hz
Differential Gain Error
NTSC, RL = 150
0.01
%
Differential Phase Error
NTSC, RL = 150
0.1
OPEN-LOOP GAIN
Open-Loop Voltage Gain
AOL
VS = 5V, RL = 2k
, 0.1V < VO < 4.9V
95
106
dB
Over Temperature
VS = 5V, RL = 2k
, 0.1V < VO < 4.9V
90
dB
VS = 5V, RL = 100
, 0.5V < VO < 4.5V
95
106
dB
Over Temperature
VS = 5V, RL = 100
, 0.5V < VO < 4.5V
90
dB
OUTPUT
Voltage Output Swing from Rail
RL = 2k
, AOL > 95dB
75
100
mV
RL = 100
, AOL > 95dB
300
500
mV
Short-Circuit Current
ISC
70
mA
Capacitive Load Drive
CLOAD
See Typical Characteristics
FREQUENCY RESPONSE
Gain-Bandwidth Product
GBW
150
MHz
Slew Rate
SR
G = +1
80
V/
s
Settling Time, 0.01%
tS
VS = 5V, 2V Step, G = +1
90
ns
0.1%
30
ns
Overload Recovery Time
Gain = -1
30
ns
Total Harmonic Distortion + Noise
THD+N
VS = 5V, VO = 3Vpp, G = +1, f = 1kHz
0.003
%
POWER SUPPLY
Specified Voltage Range
VS
2.7
5.5
V
Operating Voltage Range
2.7 to 5.5
V
Quiescent Current (per amplifier)
IQ
IO = 0
9.5
12
mA
Over Temperature
13
mA
SHUTDOWN
tOFF
40
ns
tON
5
s
VL (shutdown)
(V-) - 0.2
(V-) + 0.8
V
VH (amplifier is active)
(V-) + 2.5
(V+) + 0.2
V
IQSD
3
10
A
TEMPERATURE RANGE
Specified Range
-40
125
C
Operating Range
-55
150
C
Storage Range
-65
150
C
Thermal Resistance
JA
C/W
SO-8
200
C/W
SOT23-5
200
C/W
SOT23-6
200
C/W
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
4
TYPICAL CHARACTERISTICS
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
NONINVERTING GAIN
SMALL-SIGNAL FREQUENCY RESPONSE
Frequency (Hz)
1M
10M
100M
1G
3
-
3
-
9
-
15
N
o
r
m
a
liz
e
d
G
a
i
n
(
d
B
)
G = 2
G = 1
G = 5
G = 10
V
O
= 0.1V
PP
R
F
= 310
for G > 1
LARGE-SIGNAL STEP RESPONSE
Time (50ns/div)
O
u
tput
V
o
l
t
age
(
5
0
0
mV
/di
v
)
LARGE-SIGNAL ENABLE/DISABLE RESPONSE
Time (100
s/div)
O
u
t
p
u
t
V
o
l
t
ag
e
(
500mV
/
d
i
v
)
Enable Pin
Amplifier
Output
INVERTING GAIN
SMALL-SIGNAL FREQUENCY RESPONSE
Frequency (Hz)
1M
10M
100M
1G
3
0
-
3
-
6
-
9
-
12
-
15
N
o
rm
a
l
i
z
e
d
Ga
i
n
(d
B
)
G =
-
2
G =
-
1
G =
-
5
G =
-
10
V
O
= 0.1V
PP
V
R
F
= 310
for G > 1
O
u
t
p
ut
V
o
l
t
ag
e
(
1
0
m
V
/
d
i
v
)
Time (5ns/div)
SMALL-SIGNAL STEP RESPONSE
V
OUT
0.1dB GAIN FLATNESS FOR VARIOUS R
F
Frequency (MHz)
1M
10M
100M
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-
0.1
-
0.2
-
0.3
N
o
r
m
a
liz
e
d
G
a
in
(
d
B)
R
F
= 825
Gain = 2
V
O
= 0.1V
PP
R
F
= 450
R
F
= 205
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
5
TYPICAL CHARACTERISTICS (continued)
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
HARMONIC DISTORTION vs OUTPUT VOLTAGE
Output Voltage (V
PP
)
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
-
50
-
60
-
70
-
80
-
90
-
100
Ha
r
m
o
n
i
c
Di
s
t
o
r
t
i
o
n
(
d
B
c
)
THD
2nd-Harmonic
3rd-Harmonic
R
L
= 200
f = 1MHz
R
F
= 310
G = 2
HARMONIC DISTORTION vs INVERTING GAIN
Gain (V/V)
1
10
-
50
-
60
-
70
-
80
-
90
-
100
-
110
H
a
rm
o
n
i
c
D
i
s
t
o
rt
i
o
n
(
d
B
c
)
THD
2nd-Harmonic
3rd-Harmonic
V
O
= 2V
PP
R
L
= 200
f = 1MHz
R
F
= 310
HARMONIC DISTORTION vs LOAD RESISTANCE
Load Resistance (
)
100
1k
-
60
-
65
-
70
-
75
-
80
-
85
-
90
-
95
-
100
Ha
r
m
o
n
i
c
Di
s
t
o
r
ti
o
n
(
d
B
c
)
THD
2nd-Harmonic
3rd-Harmonic
V
O
= 2V
PP
f = 1MHz
Gain = 2
R
F
= 310
HARMONIC DISTORTION vs NONINVERTING GAIN
Gain (V/V)
1
10
-
50
-
60
-
70
-
80
-
90
-
100
-
110
H
a
rm
o
n
i
c
D
i
s
t
o
rt
i
o
n
(
d
B
c)
THD
2nd-Harmonic
3rd-Harmonic
V
O
= 2V
PP
R
L
= 200
f = 1MHz
R
F
= 310
HARMONIC DISTORTION vs FREQUENCY
Frequency (Hz)
100k
1M
10M
-
50
-
60
-
70
-
80
-
90
-
100
-
110
-
120
Ha
r
m
o
n
i
c
Di
s
t
o
r
ti
o
n
(
d
B
c
)
THD
2nd-Harmonic
3rd-Harmonic
V
O
= 2V
PP
R
L
= 200
Gain = 2
R
F
= 310
INPUT VOLTAGE AND CURRENT NOISE
SPECTRAL DENSITY vs FREQUENCY
Frequency (Hz)
10
100
1k
10k
100k
1M
10M
10k
1k
100
10
1
Vo
l
t
a
g
e
N
o
i
s
e
(
n
V
/
Hz
)
Cu
r
r
e
n
t
No
i
s
e
(
fA
/
Hz
)
Voltage Noise
Current Noise
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
6
TYPICAL CHARACTERISTICS (continued)
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
FREQUENCY RESPONSE FOR VARIOUS R
L
Frequency (Hz)
10M
100M
1G
9
3
-
3
-
9
-
15
-
21
Ga
i
n
(d
B
)
R
LOAD
= 1k
R
LOAD
= 150
R
LOAD
= 50
Gain = 1
V
O
= 0.1V
PP
FREQUENCY RESPONSE vs CAPACITIVE LOAD
Frequency (Hz)
10M
100M
1G
3
-
3
-
9
-
15
-
21
-
27
N
o
r
m
a
liz
e
d
G
a
i
n
(
d
B
)
C
LOAD
= 100pF
R
S
= 20
C
LOAD
= 47pF
R
S
= 30
C
LOAD
= 1pF
R
S
= 75
C
LOAD
= 5pF
R
S
= 55
C
LOAD
= 10pF
R
S
= 40
R
S
C
L
OPEN-LOOP GAIN AND PHASE vs FREQUENCY
Frequency (Hz)
10k
1k
100
100k
1M
10M
100M
1G
110
100
90
80
70
60
50
40
30
20
10
0
-
10
0
-
30
-
60
-
90
-
120
-
150
-
180
Ga
i
n
(d
B
)
P
has
e
(
_
)
Phase
Gain
FREQUENCY RESPONSE FOR VARIOUS C
L
Frequency (Hz)
10M
100M
1G
15
9
3
-
3
-
9
-
15
-
21
Ga
i
n
(d
B
)
C
LOAD
= 100pF
C
LOAD
= 47pF
C
LOAD
= 4.7pF
Gain = 1
C
L
COMMON-MODE REJECTION RATIO AND
POWER-SUPPLY REJECTION RATIO vs FREQUENCY
Frequency (Hz)
10k
100k
1M
10M
100M
1G
100
90
80
70
60
50
40
30
20
10
0
PS
R
R
(
d
B
)
CM
RR
(
d
B
)
CMRR
PSRR V
-
PSRR V+
COMPOSITE VIDEO
DIFFERENTIAL GAIN AND PHASE
Number of 150
Loads
1
2
3
4
1.0
0.8
0.6
0.4
0.2
0
dP
(
_
)
dG
(
%
)
dP
dG
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
7
TYPICAL CHARACTERISTICS (continued)
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
Output Current (mA)
0
10
20
30
40
50
60
70
80
5.0
4.0
3.0
2.0
1.0
0
O
u
t
p
u
t
Vo
lt
a
g
e
(
V)
V
S
= 5V
150
_
C 125
_
C 85
_
C
25
_
C
25
_
C
-
40
_
C
-
55
_
C
INPUT BIAS CURRENT vs TEMPERATURE
Temperature (
_
C)
-
40
-
20
0
20
40
60
80
100
140
120
1
0.1
0.01
Inp
u
t
B
i
a
s
C
ur
r
e
nt
(
p
A
)
INPUT BIAS CURRENT vs COMMON-MODE VOLTAGE
Common-Mode Voltage (V)
-
3
-
2
-
1
0
1
2
3
2
1
0
-
1
-
2
Inpu
t
B
i
a
s
C
ur
r
e
n
t
(
p
A
)
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
Output Current (mA)
0
10
20
30
40
50
60
70
80
2.7
2.4
2.1
1.8
1.5
1.2
0.9
0.6
0.3
0
O
u
tput
V
o
l
t
age
(
V
)
V
S
= 2.7V
150
_
C 125
_
C 85
_
C 25
_
C
-
40
_
C
-
55
_
C
QUIESCENT CURRENT vs TEMPERATURE
Temperature (
_
C)
-
40
-
20
0
20
40
60
80
100
140
120
12
11
10
9
8
7
6
Q
u
i
e
s
c
en
t
C
u
r
r
e
nt
(
m
A
)
POWER-SUPPLY REJECTION RATIO AND
COMMON-MODE REJECTION RATIO vs TEMPERATURE
Temperature (
_
C)
-
40
-
20
0
20
40
60
80
100
120
140
100
95
90
85
80
75
70
65
60
PSR
R
(
d
B
)
CM
RR
(
d
B
)
PSRR
CMRR
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
8
TYPICAL CHARACTERISTICS (continued)
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
SHORT-CIRCUIT CURRENT vs TEMPERATURE
Temperature (
_
C)
-
40
-
20
0
20
40
60
80
100
120
80
60
40
20
0
-
20
-
40
-
60
-
80
Sh
o
r
t
-
C
i
rc
u
i
t
C
u
r
r
e
n
t
(m
A
)
V
S
= 3.5V
V
S
= 5V
V
S
= 5.5V
V
S
= 5.5V
V
S
= 2.7V
OUTPUT IMPEDANCE vs FREQUENCY
Frequency (Hz)
10k
100k
1M
10M
100M
1000
100
10
1
0.1
0.01
O
u
tpu
t
Impe
danc
e,
Z
O
(
)
G = 2
G = 1
OPEN-LOOP GAIN vs TEMPERATURE
Temperature (
_
C)
-
40
-
20
0
20
40
60
80
100
120
140
120
110
100
90
80
70
60
O
p
e
n
-
Loo
p
G
a
i
n
(
dB
)
R
LOAD
= 2k
R
LOAD
= 100
QUIESCENT CURRENT vs SUPPLY VOLTAGE
Supply Voltage (V)
0
1
2
3
4
5
6
9
8
7
6
5
4
3
2
1
0
Q
u
i
e
s
c
ent
C
u
r
r
e
n
t
(
m
A
)
MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
Frequency (MHz)
1
10
100
5
4
3
2
1
0
Ou
t
p
u
t
V
o
l
t
a
g
e
(
V
PP
)
V
S
= 5V
V
S
= 2.7V
R
LOAD
= 2k
OUTPUT SETTLING TIME TO 0.1%
Time (ns)
0
20
40
60
80
100
0.2
0.1
0
-
0.1
-
0.2
-
0.3
-
0.4
-
0.5
-
0.6
-
0.7
-
0.8
-
0.9
-
1.0
Ou
t
p
u
t
E
rro
r
(
%
)
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
9
TYPICAL CHARACTERISTICS (continued)
All specifications at TA = 25
C, V+ = 5V, and RL = 150
connected to VS/2 unless otherwise noted.
OFFSET VOLTAGE
PRODUCTION DISTRIBUTION
Offset Voltage (mV)
-
5
-
4
-
3
-
2
-
1
0
1
3
4
2
5
20
18
16
14
12
10
8
6
4
2
0
Pe
r
c
e
n
t
o
f
Am
p
l
if
i
e
r
s
OFFSET VOLTAGE DRIFT
PRODUCTION DISTRIBUTION
Offset Voltage Drift (
V/
_
C)
-
10
-
8
-
6
-
4
-
2
0
2
6
8
4
10
20
15
10
5
0
Pe
r
c
e
n
t
o
f
Am
p
l
if
i
e
r
s
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
10
APPLICATIONS INFORMATION
Built on HPA07, the latest TI high-precision analog
process, the OPA300 single-supply CMOS op amp is
designed to interface with high-speed 16-bit
analog-to-digital converters (ADCs). Featuring wide
150MHz bandwidth, fast 150nS settling time to 16 bits,
and high open loop gain, the OPA300 series offer
excellent performance in a small SO-8 and tiny SOT23
packages.
THEORY OF OPERATION
The OPA30x uses a classic two-stage topology, shown
in Figure 1. The differential input pair is biased to
maximize slew rate without compromising stability or
bandwidth. The folded cascode adds the signal from the
input pair and presents a differential signal to the class
AB output stage. The class AB output stage allows rail
to rail output swing, with high-impedance loads
(> 2k
), typically 100mV from the supply rails. With 10
loads, a useful output swing can be achieved and still
maintain high open-loop gain. See the typical
characteristic Output Voltage Swing vs Output Current.
+V
S
V
BIAS
+
V
IN
-
V
OUT
Figure 1. OPA30x Classic Two-Stage Topology
OPERATING VOLTAGE
OPA30x op amp parameters are fully specified from
+2.7V to +5.5V. Supply voltages higher than 5.5V
(absolute maximum) can cause permanent damage to
the amplifier. Many specifications apply from 40
C to
+125
C. Parameters that vary significantly with
operating voltages or temperature are shown in the
Typical Characteristics.
PCB LAYOUT
As with most high-speed operational amplifiers, board
layout requires special attention to maximize AC and
DC performance. Extensive use of ground planes, short
lead lengths, and high-quality bypass capacitors will
minimize leakage that can compromise signal quality.
Guard rings applied with potential as near to the input
pins as possible help minimize board leakage.
INPUT AND ESD PROTECTION
All OPA30x pins are static protected with internal ESD
protection diodes tied to the supplies, as shown in
Figure 2. These diodes will provide overdrive protection
if the current is externally limited to 10mA, as stated in
the Absolute Maximum Ratings. Any input current
beyond the Absolute Maximum Ratings, or long-term
operation at maximum ratings, will shorten the lifespan
of the amplifier.
External
Pin
+V
-
V
Internal
Circuitry
Figure 2. ESD Protection Diodes
ENABLE FUNCTION
The shutdown function of the OPA300 is referenced to
the negative supply voltage of the operational amplifier.
A logic level HIGH enables the op amp. A valid logic
HIGH is defined as 2.5V above the negative supply
applied to the enable pin. A valid logic LOW is defined
as < 0.8V above the negative supply pin. If dual or split
power supplies are used, care should be taken to
ensure logic input signals are properly referred to the
negative supply voltage. If this pin is not connected to
a valid high to low voltage, the internal circuitry will pull
the node high and enable the part to function.
The logic input is a high-impedance CMOS input. For
battery-operated applications, this feature may be used
to greatly reduce the average current and extend
battery life. The enable time is 10
s; disable time is 1
s.
When disabled, the output assumes a high-impedance
state. This allows the OPA300 to be operated as a gated
amplifier, or to have its output multiplexed onto a
common analog output bus.
OPA300
OPA301
SBOS271A - MAY 2003 - REVISED DECEMBER 2003
www.ti.com
11
DRIVING CAPACITIVE LOADS
When using high-speed operational amplifiers, it is
extremely important to consider the effects of
capacitive loading on amplifier stability. Capacitive
loading will interact with the output impedance of the
operational amplifier, and depending on the capacitor
value, may significantly decrease the gain bandwidth,
as well as introduce peaking. To reduce the effects of
capacitive loading and allow for additional capacitive
load drive, place a series resistor between the output
and the load. This will reduce available bandwidth, but
permit stable operation with capacitive loading.
Figure
3 illustrates the recommended relationship
between the resistor and capacitor values.
Capacitive Load (pF)
1
10
100
100
75
50
25
0
S
e
r
i
e
s
R
e
s
i
s
t
anc
e
(
)
Figure 3. Recommended R
S
and C
L
Combinations
Amplifiers configured in unity gain are most susceptible
to stability issues. The typical characteristic, Frequency
Response vs Capacitive Load, describes the relation-
ship between capacitive load and stability for the
OPA30x. In unity gain, the OPA300 is capable of driving
a few picofarads of capacitive load without compromis-
ing stability. Board level parasitic capacitance can often
fall into the range of a picofarad or more, and should be
minimized through good circuit-board layout practices
to avoid compromising the stability of the OPA30x. For
more information on detecting parasitics during testing,
see the Application Note Measuring Board Parasitics in
High-Speed Analog Design (SBOA094), available at
the TI web site www.ti.com.
DRIVING A 16-BIT ADC
The OPA30x features excellent THD+noise, even at
frequencies greater than 1MHz, with a 16-bit settling
time of 150ns. Figure 4 shows a total single supply
solution for high-speed data acquisition. The OPA30x
directly drives the ADS8401, a 1.25 mega sample per
second (MSPS) 16-bit data converter. The OPA30x is
configured in an inverting gain of 1, with a 5V single
supply. Results of the OPA30x performance are
summarized in Table 1.
ADS8401
10
V
IN
1.5nF
130pF
(mica)
OPA30x
1820
f
S
= 1.25MSPS
f = 10kHz
5V
130pF
(mica)
1820
Figure 4. The OPA30x Drives the 16-Bit ADS8401
PARAMETER
RESULTS (f = 10kHz)
THD
-99.3dB
SFDR
101.2dB
THD+N
84.2dB
SNR
84.3dB
Table
1. OPA30x Performance Results Driving a
1.25MSPS ADS8401
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