OPA227UA [BB]
High Precision, Low Noise OPERATIONAL AMPLIFIERS; 高精度，低噪声运算放大器
| 型号： | OPA227UA |
| 厂家： | 
BURR-BROWN CORPORATION |
| 描述： | High Precision, Low Noise OPERATIONAL AMPLIFIERS |
| 文件： | 总17页 (文件大小：368K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
®
OPA4227
OPA227
OPA2227
OPA4227
OPA227
OPA2227
O
P
A4227
O
P
A
2
O
P
A
2
2
7
2
2
7
OPA228
OPA2228
OPA4228
For most current data sheet and other product
information, visit www.burr-brown.com
High Precision, Low Noise
OPERATIONAL AMPLIFIERS
FEATURES
DESCRIPTION
● LOW NOISE: 3nV/√Hz
The OPA227 and OPA228 series op amps combine
low noise and wide bandwidth with high precision to
make them the ideal choice for applications requiring
both ac and precision dc performance.
● WIDE BANDWIDTH:
OPA227: 8MHz, 2.3V/µs
OPA228: 33MHz, 10V/µs
● SETTLING TIME: 5µs
The OPA227 is unity gain stable and features high
slew rate (2.3V/µs) and wide bandwidth (8MHz). The
OPA228 is optimized for closed-loop gains of 5 or
greater, and offers higher speed with a slew rate of
10V/µs and a bandwidth of 33MHz.
(significant improvement over OP-27)
● HIGH CMRR: 138dB
● HIGH OPEN-LOOP GAIN: 160dB
● LOW INPUT BIAS CURRENT: 10nA max
● LOW OFFSET VOLTAGE: 75µV max
● WIDE SUPPLY RANGE: ±2.5V to ±18V
● OPA227 REPLACES OP-27, LT1007, MAX427
● OPA228 REPLACES OP-37, LT1037, MAX437
● SINGLE, DUAL, AND QUAD VERSIONS
The OPA227 and OPA228 series op amps are ideal
for professional audio equipment. In addition, low
quiescent current and low cost make them ideal for
portable applications requiring high precision.
The OPA227 and OPA228 series op amps are pin-
for-pin replacements for the industry standard OP-27
and OP-37 with substantial improvements across the
board. The dual and quad versions are available for
space savings and per-channel cost reduction.
APPLICATIONS
● DATA ACQUISITION
● TELECOM EQUIPMENT
● GEOPHYSICAL ANALYSIS
● VIBRATION ANALYSIS
● SPECTRAL ANALYSIS
● PROFESSIONAL AUDIO EQUIPMENT
● ACTIVE FILTERS
The OPA227, OPA228, OPA2227, and OPA2228
are available in DIP-8 and SO-8 packages. The
OPA4227 and OPA4228 are available in DIP-14
and SO-14 packages with standard pin configura-
tions. Operation is specified from –40°C to +85°C.
OPA4227, OPA4228
● POWER SUPPLY CONTROL
Out A
–In A
+In A
V+
1
2
3
4
5
6
7
14 Out D
13 –In D
12 +In D
11 V–
SPICE Model available for OPA227 at www.burr-brown.com
OPA227, OPA228
A
D
C
Trim
–In
+In
V–
1
2
3
4
8
7
6
5
Trim
V+
OPA2227, OPA2228
+In B
–In B
Out B
10 +In C
Out A
–In A
+In A
V–
1
2
3
4
8
7
6
5
V+
B
Output
NC
9
8
–In C
Out C
A
Out B
–In B
+In B
B
DIP-8, SO-8
DIP-14, SO-14
DIP-8, SO-8
International Airport Industrial Park
•
Mailing Address: PO Box 11400, Tucson, AZ 85734
•
Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706
• Tel: (520) 746-1111
Twx: 910-952-1111 Internet: http://www.burr-brown.com/
•
•
Cable: BBRCORP Telex: 066-6491
•
•
FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
•
© 1998 Burr-Brown Corporation
PDS-1494B
Printed in U.S.A. May, 1999
SPECIFICATIONS: VS = ±5V to ±15V
OPA227 Series
At TA = +25°C, and RL = 10kΩ, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = –40°C to +85°C.
OPA227PA, UA
OPA2227PA, UA
OPA4227PA, UA
OPA227P, U
OPA2227P, U
PARAMETER
CONDITION
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OFFSET VOLTAGE
Input Offset Voltage
OTA = –40°C to +85°Cver Temperature
vs Temperature
vs Power Supply
VOS
±5
±75
±100
±0.6
±2
±10
±200
±200
±2
✻
✻
µV
µV
dVOS/dT
PSRR
±0.1
±0.5
±0.3
✻
µV/°C
µV/V
µV/V
µV/mo
µV/V
dB
VS = ±2.5V to ±18V
T
A = –40°C to +85°C
±2
vs Time
0.2
0.2
110
✻
✻
✻
Channel Separation (dual, quad)
dc
f = 1kHz, RL = 5kΩ
INPUT BIAS CURRENT
Input Bias Current
IB
±2.5
±2.5
±10
±10
±10
±10
✻
✻
✻
✻
✻
✻
nA
nA
nA
nA
T
A = –40°C to +85°C
Input Offset Current
A = –40°C to +85°C
IOS
T
NOISE
Input Voltage Noise, f = 0.1Hz to 10Hz
90
15
3.5
3
3
0.4
✻
✻
✻
✻
✻
✻
nVp-p
nVrms
nV/√Hz
nV/√Hz
nV/√Hz
pA/√Hz
Input Voltage Noise Density, f = 10Hz en
f = 100Hz
f = 1kHz
Current Noise Density, f = 1kHz
in
INPUT VOLTAGE RANGE
Common-Mode Voltage Range
Common-Mode Rejection
VCM
CMRR
(V–)+2
120
120
(V+)–2
✻
✻
✻
✻
V
dB
dB
VCM = (V–)+2V to (V+)–2V
VCM = (V–)+2V to (V+)–2V
138
✻
T
A = –40°C to +85°C
INPUT IMPEDANCE
Differential
Common-Mode
107 || 12
109 || 3
✻
✻
Ω || pF
Ω || pF
OPEN-LOOP GAIN
Open-Loop Voltage Gain
AOL
VO = (V–)+2V to (V+)–2V, RL = 10kΩ
VO = (V–)+3.5V to (V+)–3.5V, RL = 600Ω
132
132
132
132
160
160
✻
✻
✻
✻
✻
✻
dB
dB
dB
dB
T
A = –40°C to +85°C
T
A = –40°C to +85°C
FREQUENCY RESPONSE
Gain Bandwidth Product
Slew Rate
Settling Time: 0.1%
0.01%
GBW
SR
8
2.3
5
5.6
1.3
✻
✻
✻
✻
✻
✻
MHz
V/µs
µs
µs
µs
G = 1, 10V Step, CL = 100pF
G = 1, 10V Step, CL = 100pF
VIN • G = VS
Overload Recovery Time
Total Harmonic Distortion + Noise THD+N
f = 1kHz, G = 1, VO = 3.5Vrms
0.00005
%
OUTPUT
Voltage Output
RL = 10kΩ
RL = 10kΩ
RL = 600Ω
RL = 600Ω
(V–)+2
(V–)+2
(V–)+3.5
(V–)+3.5
(V+)–2
(V+)–2
(V+)–3.5
(V+)–3.5
✻
✻
✻
✻
✻
✻
✻
✻
V
V
V
V
mA
T
A = –40°C to +85°C
T
A = –40°C to +85°C
Short-Circuit Current
Capacitive Load Drive
ISC
CLOAD
±45
See Typical Curve
✻
✻
POWER SUPPLY
Specified Voltage Range
Operating Voltage Range
Quiescent Current (per amplifier)
TA = –40°C to +85°C
VS
IQ
±5
±2.5
±15
±18
±3.8
±4.2
✻
✻
✻
✻
✻
✻
V
V
mA
mA
IO = 0
IO = 0
±3.7
✻
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
SO-8 Surface Mount
DIP-8
–40
–55
–65
+85
+125
+150
✻
✻
✻
✻
✻
✻
°C
°C
°C
θJA
150
100
80
✻
✻
✻
✻
°C/W
°C/W
°C/W
°C/W
DIP-14
SO-14 Surface Mount
100
✻ Specifications same as OPA227P, U.
®
OPA227, 2227, 4227
OPA228, 2228, 4228
2
SPECIFICATIONS: VS = ±5V to ±15V
OPA228 Series
At TA = +25°C, and RL = 10kΩ, unless otherwise noted.
Boldface limits apply over the specified temperature range, TA = –40°C to +85°C.
OPA228PA, UA
OPA2228PA, UA
OPA4228PA, UA
OPA228P, U
OPA2228P, U
PARAMETER
CONDITION
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OFFSET VOLTAGE
Input Offset Voltage
OTA = –40°C to +85°Cver Temperature
vs Temperature
vs Power Supply
VOS
±5
±75
±100
±0.6
±2
±10
±200
±200
±2
✻
✻
µV
µV
dVOS/dT
PSRR
±0.1
±0.5
±0.3
✻
µV/°C
µV/V
µV/V
µV/mo
µV/V
dB
VS = ±2.5V to ±18V
T
A = –40°C to +85°C
±2
vs Time
0.2
0.2
110
✻
✻
✻
Channel Separation (dual, quad)
dc
f = 1kHz, RL = 5kΩ
INPUT BIAS CURRENT
Input Bias Current
IB
±2.5
±2.5
±10
±10
±10
±10
✻
✻
✻
✻
✻
✻
nA
nA
nA
nA
T
A = –40°C to +85°C
Input Offset Current
A = –40°C to +85°C
IOS
T
NOISE
Input Voltage Noise, f = 0.1Hz to 10Hz
90
15
3.5
3
3
0.4
✻
✻
✻
✻
✻
✻
nVp-p
nVrms
nV/√Hz
nV/√Hz
nV/√Hz
pA/√Hz
Input Voltage Noise Density, f = 10Hz en
f = 100Hz
f = 1kHz
Current Noise Density, f = 1kHz
in
INPUT VOLTAGE RANGE
Common-Mode Voltage Range
Common-Mode Rejection
VCM
CMRR
(V–)+2
120
120
(V+)–2
✻
✻
✻
✻
V
dB
dB
VCM = (V–)+2V to (V+)–2V
VCM = (V–)+2V to (V+)–2V
138
✻
T
A = –40°C to +85°C
INPUT IMPEDANCE
Differential
Common-Mode
107 || 12
109 || 3
✻
✻
Ω || pF
Ω || pF
OPEN-LOOP GAIN
Open-Loop Voltage Gain
AOL
VO = (V–)+2V to (V+)–2V, RL = 10kΩ
VO = (V–)+3.5V to (V+)–3.5V, RL = 600Ω
132
132
132
132
160
160
✻
✻
✻
✻
✻
✻
dB
dB
dB
dB
T
A = –40°C to +85°C
T
A = –40°C to +85°C
FREQUENCY RESPONSE
Minimum Closed-Loop Gain
Gain Bandwidth Product
Slew Rate
Settling Time: 0.1%
0.01%
5
33
11
1.5
2
✻
✻
✻
✻
✻
✻
✻
V/V
MHz
V/µs
µs
µs
µs
GBW
SR
G = 5, 10V Step, CL = 100pF, CF =12pF
G = 5, 10V Step, CL = 100pF, CF =12pF
VIN • G = VS
Overload Recovery Time
Total Harmonic Distortion + Noise THD+N
0.6
0.00005
f = 1kHz, G = 5, VO = 3.5Vrms
%
OUTPUT
Voltage Output
RL = 10kΩ
RL = 10kΩ
RL = 600Ω
RL = 600Ω
(V–)+2
(V–)+2
(V–)+3.5
(V–)+3.5
(V+)–2
(V+)–2
(V+)–3.5
(V+)–3.5
✻
✻
✻
✻
✻
✻
✻
✻
V
V
V
V
mA
T
A = –40°C to +85°C
TA = –40°C to +85°C
Short-Circuit Current
Capacitive Load Drive
ISC
CLOAD
±45
See Typical Curve
✻
✻
POWER SUPPLY
Specified Voltage Range
Operating Voltage Range
Quiescent Current (per amplifier)
VS
IQ
±5
±2.5
±15
±18
±3.8
±4.2
✻
✻
✻
✻
✻
✻
V
V
mA
mA
IO = 0
IO = 0
±3.7
✻
T
A = –40°C to +85°C
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
SO-8 Surface Mount
DIP-8
–40
–55
–65
+85
+125
+150
✻
✻
✻
✻
✻
✻
°C
°C
°C
θJA
150
100
80
✻
✻
✻
✻
°C/W
°C/W
°C/W
°C/W
DIP-14
SO-14 Surface Mount
100
✻ Specifications same as OPA228P, U.
®
OPA227, 2227, 4227
OPA228, 2228, 4228
3
ABSOLUTE MAXIMUM RATINGS(1)
Supply Voltage .................................................................................. ±18V
Signal Input Terminals, Voltage ........................(V–) –0.7V to (V+) +0.7V
Current ....................................................... 20mA
ELECTROSTATIC
DISCHARGE SENSITIVITY
Output Short-Circuit(2) .............................................................. Continuous
Operating Temperature ..................................................–55°C to +125°C
Storage Temperature .....................................................–65°C to +150°C
Junction Temperature ...................................................................... 150°C
Lead Temperature (soldering, 10s) ................................................. 300°C
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
NOTE: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability. (2) Short-circuit to ground, one amplifier per package.
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
OFFSET
VOLTAGE
max, µV
OFFSET
VOLTAGE DRIFT
max, µV/°C
PACKAGE
DRAWING
NUMBER(1)
TEMPERATURE
RANGE
ORDERING
NUMBER(2)
TRANSPORT
MEDIA
PRODUCT
PACKAGE
OPA227 Series
Single
OPA227PA
OPA227P
OPA227UA
"
±200
±75
±200
"
±75
"
±2
±0.6
±2
"
±0.6
"
DIP-8
DIP-8
SO-8 Surface Mount
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
OPA227PA
OPA227P
OPA227UA
OPA227UA/2K5
OPA227U
Rails
Rails
Rails
"
"
Tape and Reel
Rails
Tape and Reel
OPA227U
"
SO-8 Surface Mount
"
–40°C to +85°C
"
OPA227U/2K5
Dual
OPA2227PA
OPA2227P
OPA2227UA
"
OPA2227U
"
±200
±75
±200
"
±75
"
±2
±0.6
±2
"
±0.6
"
DIP-8
DIP-8
SO-8 Surface Mount
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
OPA2227PA
OPA2227P
OPA2227UA
OPA2227UA/2K5
OPA2227U
Rails
Rails
Rails
"
"
Tape and Reel
Rails
Tape and Reel
SO-8 Surface Mount
"
–40°C to +85°C
"
OPA2227U/2K5
Quad
OPA4227PA
OPA4227UA
"
±200
±200
"
±2
±2
"
DIP-14
SO-14 Surface Mount
"
010
235
"
–40°C to +85°C
–40°C to +85°C
OPA4227PA
OPA4227UA
OPA4227UA/2K5
Rails
Rails
Tape and Reel
"
OPA228 Series
Single
OPA228PA
OPA228P
OPA228UA
"
±200
±75
±200
"
±75
"
±2
±0.6
±2
"
±0.6
"
DIP-8
DIP-8
SO-8 Surface Mount
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
OPA228PA
OPA228P
OPA228UA
OPA228UA/2K5
OPA228U
Rails
Rails
Rails
"
"
Tape and Reel
Rails
Tape and Reel
OPA228U
"
SO-8 Surface Mount
"
–40°C to +85°C
"
OPA228U/2K5
Dual
OPA2228PA
OPA2228P
OPA2228UA
"
OPA2228U
"
±200
±75
±200
"
±75
"
±2
±0.6
±2
"
±0.6
"
DIP-8
DIP-8
SO-8 Surface Mount
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
OPA2228PA
OPA2228P
OPA2228UA
OPA2228UA/2K5
OPA2228U
Rails
Rails
Rails
"
"
Tape and Reel
Rails
Tape and Reel
SO-8 Surface Mount
"
–40°C to +85°C
"
OPA2228U/2K5
Quad
OPA4228PA
OPA4228UA
"
±200
±200
"
±2
±2
"
DIP-14
SO-14 Surface Mount
"
010
235
"
–40°C to +85°C
–40°C to +85°C
OPA4228PA
OPA4228UA
OPA4228UA/2K5
Rails
Rails
Tape and Reel
"
NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Products followed by a slash
(/) are only available in Tape and Reel in the quantities indicated (e.g. /2K5 indicates 2500 devices per reel). Ordering 2500 pieces of “OPA227UA/2K5” will get
a single 2500 piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
®
OPA227, 2227, 4227
4
OPA228, 2228, 4228
TYPICAL PERFORMANCE CURVES
At TA = +25°C, RL = 10kΩ, and VS = ±15V, unless otherwise noted.
OPEN-LOOP GAIN/PHASE vs FREQUENCY
OPA228
OPEN-LOOP GAIN/PHASE vs FREQUENCY
180
160
140
120
100
80
180
160
140
120
100
0
0
–20
–40
–60
–80
OPA227
–20
–40
G
G
–60
–80
φ
80
φ
–100
–120
–140
–160
–180
–200
–100
60
60
–120
40
40
–140
20
20
–160
0
0
–180
–20
–20
–200
0.01 0.10
1
10 100 1k 10k 100k 1M 10M 100M
0.01 0.10
1
10 100 1k 10k 100k 1M 10M 100M
Frequency (Hz)
Frequency (Hz)
POWER SUPPLY AND COMMON-MODE
REJECTION RATIO vs FREQUENCY
INPUT VOLTAGE AND CURRENT NOISE
SPECTRAL DENSITY vs FREQUENCY
140
120
100
80
100k
10k
1k
+CMRR
Current Noise
+PSRR
–PSRR
60
100
10
40
Voltage Noise
-20
–0
1
0.1
1
10
100
1k
10k
100k
1M
0.1
1
10
100
1k
10k
Frequency (Hz)
Frequency (Hz)
TOTAL HARMONIC DISTORTION + NOISE
vs FREQUENCY
TOTAL HARMONIC DISTORTION + NOISE
vs FREQUENCY
0.01
0.001
0.01
0.001
VOUT = 3.5Vrms
OPA227
VOUT = 3.5Vrms
OPA228
0.0001
0.00001
0.0001
0.00001
G = 1, RL = 10kΩ
G = 1, RL = 10kΩ
20
100
1k
10k 20k
20
100
1k
10k 50k
Frequency (Hz)
Frequency (Hz)
®
OPA227, 2227, 4227
OPA228, 2228, 4228
5
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, RL =10kΩ, and VS = ±15V, unless otherwise noted.
INPUT NOISE VOLTAGE vs TIME
CHANNEL SEPARATION vs FREQUENCY
140
120
100
80
Dual and quad devices. G = 1, all channels.
Quad measured Channel A to D, or B to C;
other combinations yield similiar or improved
rejection.
60
40
10
100
1k
10k
100k
1M
1s/div
Frequency (Hz)
VOLTAGE NOISE DISTRIBUTION (10Hz)
OFFSET VOLTAGE PRODUCTION DISTRIBUTION
24
16
8
17.5
15.0
12.5
10.0
5.5
Typical distribution
of packaged units.
5.0
2.5
0
0
0
3.16 3.25 3.34 3.43 3.51 3.60 3.69 3.78
Noise (nV/√Hz)
Offset Voltage (µV)
OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION
WARM-UP OFFSET VOLTAGE DRIFT
12
8
10
8
Typical distribution
of packaged units.
6
4
2
0
–2
–4
–6
–8
–10
4
0
0
50
100
150
200
250
300
0
0.5
1.0
1.5
Time from Power Supply Turn-On (s)
Offset Voltage Drift (µV)/°C
®
OPA227, 2227, 4227
OPA228, 2228, 4228
6
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, RL = 10kΩ, and VS = ±15V, unless otherwise noted.
AOL, CMRR, PSRR vs TEMPERATURE
AOL
AOL, CMRR, PSRR vs TEMPERATURE
160
150
140
130
120
110
100
90
160
150
140
130
120
110
100
90
AOL
CMRR
CMRR
PSRR
PSRR
80
80
OPA227
OPA228
70
70
60
60
–75
–75
0
–50
–25
0
25
50
75
100
125
125
20
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
Temperature (°C)
SHORT-CIRCUIT CURRENT vs TEMPERATURE
INPUT BIAS CURRENT vs TEMPERATURE
60
50
40
30
20
10
0
2.0
1.5
1.0
–ISC
0.5
+ISC
0
–0.5
–1.0
–1.5
–2.0
–50
–25
0
25
50
75
100
–60 –40 –20
0
20
40
60
80 100 120 140
Temperature (°C)
Temperature (°C)
QUIESCENT CURRENT vs SUPPLY VOLTAGE
QUIESCENT CURRENT vs TEMPERATURE
3.8
3.6
3.4
3.2
3.0
2.8
5.0
4.5
4.0
3.5
3.0
2.5
±18V
±15V
±12V
±10V
±5V
±2.5V
2
4
6
8
10
12
14
16
18
–60 –40 –20
0
20
40 60
80 100 120 140
Supply Voltage (±V)
Temperature (°C)
®
OPA227, 2227, 4227
OPA228, 2228, 4228
7
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, RL = 10kΩ, and VS = ±15V, unless otherwise noted.
SLEW RATE vs TEMPERATURE
SLEW RATE vs TEMPERATURE
3.0
2.5
2.0
1.5
1.0
0.5
0
12
10
8
OPA227
OPA228
Positive Slew Rate
Negative Slew Rate
6
4
RLOAD = 2kΩ
RLOAD = 2kΩ
LOAD = 100pF
2
CLOAD = 100pF
C
0
–75
–50
–25
0
25
50
75
100
125
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
Temperature (°C)
CHANGE IN INPUT BIAS CURRENT
vs COMMON-MODE VOLTAGE
CHANGE IN INPUT BIAS CURRENT
vs POWER SUPPLY VOLTAGE
1.5
1.0
2.0
1.5
Curve shows normalized change in bias current
with respect to VCM = 0V. Typical IB may range
from –2nA to +2nA at VCM = 0V.
Curve shows normalized change in bias current
with respect to VS = ±10V. Typical IB may range
from –2nA to +2nA at VS = ±10V.
1.0
0.5
0.5
0
0
VS = ±15V
–0.5
–1.0
–1.5
–2.0
–0.5
–1.0
–1.5
VS = ±5V
–15
–10
–5
0
5
10
15
0
5
10
15
20
25
30
35
40
Common-Mode Voltage (V)
Supply Voltage (V)
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
SETTLING TIME vs CLOSED-LOOP GAIN
15
14
13
12
11
10
V+
100
10
1
VS = ±15V, 10V Step
CL = 1500pF
RL = 2kΩ
(V+) –1V
(V+) –2V
(V+) –3V
–40°C
125°C
85°C
25°C
–55°C
OPA227
0.01%
0.1%
–10
–11
–12
–13
–14
–15
–55°C
OPA228
85°C
0.01%
0.1%
125°C
(V–) +3V
(V–) +2V
(V–) +1V
V–
–40°C
25°C
0
10
20
30
40
50
60
±1
±10
±100
Output Current (mA)
Gain (V/V)
®
OPA227, 2227, 4227
OPA228, 2228, 4228
8
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, RL = 10kΩ, and VS = ±15V, unless otherwise noted.
SMALL-SIGNAL OVERSHOOT
vs LOAD CAPACITANCE
MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
30
25
20
15
10
5
70
60
50
40
30
20
10
0
OPA227
OPA227
VS = ±15V
Gain = +10
VS = ±5V
Gain = –10
Gain = –1
100
Gain = +1
0
1k
10k
100k
1M
10M
1
10
1k
10k
100k
Frequency (Hz)
Load Capacitance (pF)
SMALL-SIGNAL STEP RESPONSE
G = +1, CL = 1000pF
LARGE-SIGNAL STEP RESPONSE
G = –1, CL = 1500pF
OPA227
OPA227
400ns/div
5µs/div
SMALL-SIGNAL STEP RESPONSE
G = +1, CL = 5pF
OPA227
400ns/div
®
OPA227, 2227, 4227
OPA228, 2228, 4228
9
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, RL = 10kΩ, and VS = ±15V, unless otherwise noted.
SMALL-SIGNAL OVERSHOOT
vs LOAD CAPACITANCE
MAXIMUM OUTPUT VOLTAGE vs FREQUENCY
30
25
20
15
10
5
70
60
50
40
30
20
10
0
VS = ±15V
OPA228
OPA228
G = –100
VS = ±5V
G = +100
G = ±10
0
1
10
100
1k
10k
100k
1k
10k
100k
Frequency (Hz)
1M
10M
Load Capacitance (pF)
LARGE-SIGNAL STEP RESPONSE
G = –10, CL = 100pF
SMALL-SIGNAL STEP RESPONSE
G = +10, CL = 1000pF, RL = 1.8kΩ
OPA228
OPA228
2µs/div
500ns/div
SMALL-SIGNAL STEP RESPONSE
G = +10, CL = 5pF, RL = 1.8kΩ
OPA228
500ns/div
®
OPA227, 2227, 4227
OPA228, 2228, 4228
10
APPLICATIONS INFORMATION
Trim range exceeds
offset voltage specification
V+
The OPA227 and OPA228 series are precision op amps with
very low noise. The OPA227 series is unity-gain stable with
a slew rate of 2.3V/µs and 8MHz bandwidth. The OPA228
series is optimized for higher-speed applications with gains
of 5 or greater, featuring a slew rate of 10V/µs and 33MHz
bandwidth. Applications with noisy or high impedance
power supplies may require decoupling capacitors close to
the device pins. In most cases, 0.1µF capacitors are ad-
equate.
0.1µF
20kΩ
7
1
2
3
8
OPA227
6
OPA227 and OPA228 single op amps only.
Use offset adjust pins only to
null offset voltage of op amp.
See text.
4
0.1µF
V–
OFFSET VOLTAGE AND DRIFT
The OPA227 and OPA228 series have very low offset
voltage and drift. To achieve highest dc precision, circuit
layout and mechanical conditions should be optimized.
Connections of dissimilar metals can generate thermal po-
tentials at the op amp inputs which can degrade the offset
voltage and drift. These thermocouple effects can exceed
the inherent drift of the amplifier and ultimately degrade its
performance. The thermal potentials can be made to cancel
by assuring that they are equal at both input terminals. In
addition:
FIGURE 1. OPA227 Offset Voltage Trim Circuit.
amp. This adjustment should not be used to compensate for
offsets created elsewhere in the system since this can
introduce additional temperature drift.
INPUT PROTECTION
Back-to-back diodes (see Figure 2) are used for input protec-
tion on the OPA227 and OPA228. Exceeding the turn-on
threshold of these diodes, as in a pulse condition, can cause
current to flow through the input protection diodes due to the
amplifier’s finite slew rate. Without external current-limiting
resistors, the input devices can be destroyed. Sources of high
input current can cause subtle damage to the amplifier.
Although the unit may still be functional, important param-
eters such as input offset voltage, drift, and noise may shift.
• Keep thermal mass of the connections made to the two
input terminals similar.
• Locate heat sources as far as possible from the critical
input circuitry.
• Shield op amp and input circuitry from air currents such
as those created by cooling fans.
RF
500Ω
OPERATING VOLTAGE
OPA227 and OPA228 series op amps operate from ±2.5V to
±18V supplies with excellent performance. Unlike most op
amps which are specified at only one supply voltage, the
OPA227 series is specified for real-world applications; a
single set of specifications applies over the ±5V to ±15V
supply range. Specifications are guaranteed for applications
between ±5V and ±15V power supplies. Some applications
do not require equal positive and negative output voltage
swing. Power supply voltages do not need to be equal. The
OPA227 and OPA228 series can operate with as little as 5V
between the supplies and with up to 36V between the
supplies. For example, the positive supply could be set to
25V with the negative supply at –5V or vice-versa. In
addition, key parameters are guaranteed over the specified
temperature range, –40°C to +85°C. Parameters which vary
significantly with operating voltage or temperature are shown
in the Typical Performance Curves.
–
OPA227
Output
+
Input
FIGURE 2. Pulsed Operation.
When using the OPA227 as a unity-gain buffer (follower), the
input current should be limited to 20mA. This can be accom-
plished by inserting a feedback resistor or a resistor in series
with the source. Sufficient resistor size can be calculated:
RX = VS/20mA – RSOURCE
where RX is either in series with the source or inserted in
the feedback path. For example, for a 10V pulse (VS =
10V), total loop resistance must be 500Ω. If the source
impedance is large enough to sufficiently limit the current
on its own, no additional resistors are needed. The size of
any external resistors must be carefully chosen since they
will increase noise. See the Noise Performance section of
this data sheet for further information on noise calcula-
tion. Figure 2 shows an example implementing a current-
limiting feedback resistor.
OFFSET VOLTAGE ADJUSTMENT
The OPA227 and OPA228 series are laser-trimmed for
very low offset and drift so most applications will not
require external adjustment. However, the OPA227 and
OPA228 (single versions) provide offset voltage trim con-
nections on pins 1 and 8. Offset voltage can be adjusted by
connecting a potentiometer as shown in Figure 1. This
adjustment should be used only to null the offset of the op
®
OPA227, 2227, 4227
OPA228, 2228, 4228
11
INPUT BIAS CURRENT CANCELLATION
NOISE PERFORMANCE
The input bias current of the OPA227 and OPA228 series is
internally compensated with an equal and opposite cancella-
tion current. The resulting input bias current is the difference
between with input bias current and the cancellation current.
The residual input bias current can be positive or negative.
Figure 4 shows total circuit noise for varying source imped-
ances with the op amp in a unity-gain configuration (no
feedback resistor network, therefore no additional noise con-
tributions). Two different op amps are shown with total circuit
noise calculated. The OPA227 has very low voltage noise,
making it ideal for low source impedances (less than 20kΩ).
Asimilar precision op amp, the OPA277, has somewhat higher
voltage noise but lower current noise. It provides excellent
noise performance at moderate source impedance (10kΩ to
100kΩ). Above 100kΩ, a FET-input op amp such as the
OPA132 (very low current noise) may provide improved
performance. The equation is shown for the calculation of the
total circuit noise. Note that en = voltage noise, in = current
noise, RS = source impedance, k = Boltzmann’s constant =
1.38 • 10–23 J/K and T is temperature in K. For more details on
calculating noise, see the insert titled “Basic Noise Calcula-
tions.”
When the bias current is cancelled in this manner, the input
bias current and input offset current are approximately equal.
A resistor added to cancel the effect of the input bias current
(as shown in Figure 3) may actually increase offset and noise
and is therefore not recommended.
Conventional Op Amp Configuration
R2
R1
Op Amp
Not recommended
for OPA227
VOLTAGE NOISE SPECTRAL DENSITY
vs SOURCE RESISTANCE
1.00+03
RB = R2 || R1
External Cancellation Resistor
EO
OPA227
RS
Recommended OPA227 Configuration
1.00E+02
R2
OPA277
OPA277
R1
Resistor Noise
OPA227
1.00E+01
1.00E+00
Resistor Noise
EO2 = en2 + (in RS)2 + 4kTRS
OPA227
No cancellation resistor.
See text.
100
1k
10k
100k
10M
Source Resistance, RS (Ω)
FIGURE 4. Noise Performance of the OPA227 in Unity-
Gain Buffer Configuration.
FIGURE 3. Input Bias Current Cancellation.
BASIC NOISE CALCULATIONS
noise component. The voltage noise is commonly mod-
Design of low noise op amp circuits requires careful
consideration of a variety of possible noise contributors:
noise from the signal source, noise generated in the op
amp, and noise from the feedback network resistors. The
total noise of the circuit is the root-sum-square combina-
tion of all noise components.
eled as a time-varying component of the offset voltage.
The current noise is modeled as the time-varying compo-
nent of the input bias current and reacts with the source
resistance to create a voltage component of noise. Conse-
quently, the lowest noise op amp for a given application
depends on the source impedance. For low source imped-
ance, current noise is negligible and voltage noise gener-
ally dominates. For high source impedance, current noise
may dominate.
The resistive portion of the source impedance produces
thermal noise proportional to the square root of the
resistance. This function is shown plotted in Figure 4.
Since the source impedance is usually fixed, select the op
amp and the feedback resistors to minimize their contri-
bution to the total noise.
Figure 5 shows both inverting and noninverting op amp
circuit configurations with gain. In circuit configurations
with gain, the feedback network resistors also contribute
noise. The current noise of the op amp reacts with the
feedback resistors to create additional noise components.
The feedback resistor values can generally be chosen to
make these noise sources negligible. The equations for
total noise are shown for both configurations.
Figure 4 shows total noise for varying source imped-
ances with the op amp in a unity-gain configuration (no
feedback resistor network and therefore no additional
noise contributions). The operational amplifier itself con-
tributes both a voltage noise component and a current
®
OPA227, 2227, 4227
12
OPA228, 2228, 4228
Noise in Noninverting Gain Configuration
R2
Noise at the output:
2
2
R2
R2
R1
R1
2
2
2
2
2
2
2
EO = 1+
en + e1 + e2 + i R
+ eS + i R
1+
(
)
(
)
n
2
n
S
R1
EO
R2
R2
Where eS = √4kTRS •
= thermal noise of RS
1+
R1
RS
R2
R1
e1 = √4kTR1 •
e2 = √4kTR2
= thermal noise of R1
= thermal noise of R2
VS
Noise in Inverting Gain Configuration
R2
Noise at the output:
2
R1
R2
2
2
2
2
2
2
EO = 1+
en + e1 + e2 + i R
+ eS
(
)
n
2
R1 + RS
EO
RS
R2
Where eS = √4kTRS •
= thermal noise of RS
R1 + RS
VS
R2
e1 = √4kTR1 •
e2 = √4kTR2
= thermal noise of R1
= thermal noise of R2
R1 + RS
For the OPA227 and OPA228 series op amps at 1kHz, en = 3nV/√Hz and in = 0.4pA/√Hz.
FIGURE 5. Noise Calculation in Gain Configurations.
®
OPA227, 2227, 4227
OPA228, 2228, 4228
13
R1
2MΩ
R2
2MΩ
R8
402kΩ
R11
178kΩ
C6
10nF
C4
22nF
R3
1kΩ
R4
9.09kΩ
R6
R7
R9
R10
40.2kΩ
97.6kΩ
178kΩ
226kΩ
2
3
2
3
C1
1µF
C2
1µF
6
6
U2
VOUT
U3
U1
C3
C5
0.47µF
0.47µF
(OPA227)
(OPA227)
(OPA227)
Input from
Device
Under
R5
634kΩ
Test
FIGURE 6. 0.1Hz to 10Hz Bandpass Filter Used to Test Wideband Noise of the OPA227 and OPA228 Series.
USING THE OPA228 IN LOW GAINS
The OPA228 family is intended for applications with signal
gains of 5 or greater, but it is possible to take advantage of
their high speed in lower gains. Without external compen-
sation, the OPA228 has sufficient phase margin to maintain
stability in unity gain with purely resistive loads. However,
the addition of load capacitance can reduce the phase
margin and destabilize the op amp.
22pF
100kΩ
10Ω
2
3
6
VOUT
A variety of compensation techniques have been evaluated
specifically for use with the OPA228. The recommended
configuration consists of an additional capacitor (CF) in
parallel with the feedback resistance, as shown in Figures
8 and 11. This feedback capacitor serves two purposes in
compensating the circuit. The op amp’s input capacitance
and the feedback resistors interact to cause phase shift that
can result in instability. CF compensates the input capaci-
tance, minimizing peaking. Additionally, at high frequen-
cies, the closed-loop gain of the amplifier is strongly
influenced by the ratio of the input capacitance and the
feedback capacitor. Thus, CF can be selected to yield good
stability while maintaining high speed.
OPA227
Device
Under
Test
FIGURE 7. Noise Test Circuit.
Figure 6 shows the 0.1Hz 10Hz bandpass filter used to test
the noise of the OPA227 and OPA228. The filter circuit was
designed using Burr-Brown’s FilterPro software (available
at www.burr-brown.com). Figure 7 shows the configura-
tion of the OPA227 and OPA228 for noise testing.
®
OPA227, 2227, 4227
14
OPA228, 2228, 4228
Without external compensation, the noise specification of
the OPA228 is the same as that for the OPA227 in gains of
5 or greater. With the additional external compensation, the
output noise of the of the OPA228 will be higher. The
amount of noise increase is directly related to the increase
in high frequency closed-loop gain established by the CIN/
CF ratio.
values for CF. Because compensation is highly dependent
on circuit design, board layout, and load conditions, CF
should be optimized experimentally for best results. Fig-
ures 9 and 10 show the large- and small-signal step re-
sponses for the G = +2 configuration with 100pF load
capacitance. Figures 12 and 13 show the large- and small-
signal step responses for the G = –2 configuration with
100pF load capacitance.
Figures 8 and 11 show the recommended circuit for gains
of +2 and –2, respectively. The figures suggest approximate
15pF
22pF
1kΩ
2kΩ
2kΩ
2kΩ
OPA228
OPA228
100pF
2kΩ
100pF
2kΩ
FIGURE 8. Compensation of the OPA228 for G =+2.
FIGURE 11. Compensation for OPA228 for G = –2.
OPA228
OPA228
400ns/div
400ns/div
FIGURE 12. Large-Signal Step Response, G = –2, CLOAD
100pF, Input Signal = 5Vp-p.
=
FIGURE 9. Large-Signal Step Response, G = +2, CLOAD
100pF, Input Signal = 5Vp-p.
=
OPA228
OPA228
200ns/div
200ns/div
FIGURE 10. Small-Signal Step Response, G = +2, CLOAD
100pF, Input Signal = 50mVp-p.
=
FIGURE 13. Small-Signal Step Response, G = –2, CLOAD
100pF, Input Signal = 50mVp-p.
=
®
OPA227, 2227, 4227
OPA228, 2228, 4228
15
1.1kΩ
1.43kΩ
330pF
dc Gain = 1
2.2nF
1.1kΩ
1.65kΩ
VIN
1.43kΩ
1.91kΩ
OPA227
33nF
2.21kΩ
VOUT
10nF
OPA227
68nF
fN = 13.86kHz
Q = 1.186
fN = 20.33kHz
Q = 4.519
f = 7.2kHz
FIGURE 14. Three-Pole, 20kHz Low Pass, 0.5dB Chebyshev Filter.
20pF
0.1µF
TTL INPUT GAIN
9.76kΩ
“1”
“0”
+1
–1
100Ω
100kΩ
Balance
Trim
500Ω
2
3
Output
10kΩ
Input
6
2
3
OPA227
Output
6
8
4.99kΩ
OPA227
D1
D2
NOTE: Use metal film resistors
and plastic film capacitor. Circuit
must be well shielded to achieve
low noise.
S1
S2
Dexter 1M
Thermopile
Detector
1
4.75kΩ
4.75kΩ
1kΩ
Responsivity ≈ 2.5 x 104V/W
Output Noise ≈ 30µVrms, 0.1Hz to 10Hz
TTL
In
DG188
Offset
Trim
+VCC
FIGURE 16. High Performance Synchronous Demodulator.
FIGURE 15. Long-Wavelength Infrared Detector Amplifier.
®
OPA227, 2227, 4227
16
OPA228, 2228, 4228
+15V
0.1µF
1kΩ
1kΩ
Audio
In
1/2
OPA2227
200Ω
200Ω
To
Headphone
1/2
OPA2227
This application uses two op amps
in parallel for higher output current drive.
0.1µF
–15V
FIGURE 17. Headphone Amplifier.
Bass Tone Control
R2
50kΩ
CW
R1
7.5kΩ
R3
7.5kΩ
3
1
2
R10
100kΩ
Midrange Tone Control
C1
940pF
R5
50kΩ
CW
R4
2.7kΩ
R6
2.7kΩ
3
1
VIN
2
C2
0.0047µF
Treble Tone Control
R8
50kΩ
CW
R7
7.5kΩ
R9
7.5kΩ
R11
100kΩ
3
1
2
C3
680pF
2
6
VOUT
OPA227
3
FIGURE 18. Three-Band ActiveTone Control (bass, midrange and treble).
17
®
OPA227, 2227, 4227
OPA228, 2228, 4228
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