AD8541ART [ADI]
General Purpose CMOS Rail-to-Rail Amplifiers; 通用CMOS轨到轨放大器型号: | AD8541ART |
厂家: | ADI |
描述: | General Purpose CMOS Rail-to-Rail Amplifiers |
文件: | 总12页 (文件大小:171K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
General Purpose CMOS
Rail-to-Rail Amplifiers
a
AD8541/AD8542/AD8544
PIN CONFIGURATIONS
FEATURES
Single Supply Operation: +2.7 V to +5.5 V
Low Supply Current: 45 A/Amplifier
Wide Bandwidth: 1 MHz
No Phase Reversal
Low Input Currents: 4 pA
Unity Gain Stable
SO-8 (R)
SOT-23-5 (RT)
AD8541
V+
AD8541
NC
؊IN A
+IN A
V؊
NC
OUT A
V؊
1
2
3
4
8
7
6
5
1
2
5
V+
OUT A
NC
+IN A
؊IN A
3
4
Rail-to-Rail Input and Output
NC = NO CONNECT
APPLICATIONS
ASIC Input or Output Amplifier
Sensor Interface
SO-8 (R), RM-8, and RU-8
SO-14 (R) and RU-14
Piezo Electric Transducer Amplifier
Medical Instrumentation
Mobile Communication
Audio Output
OUT A
؊IN A
+IN A
V؊
V+
1
2
3
4
OUT A
؊IN A
+IN A
V+
8
7
6
5
1
2
3
4
5
6
7
14 OUT D
OUT B
؊IN D
13
12
AD8542
+IN D
؊IN B
AD8544
+IN B
11 V؊
Portable Systems
+IN C
+IN B
؊IN B
OUT B
10
9
؊IN C
OUT C
8
GENERAL DESCRIPTION
The AD8541/AD8542/AD8544 are single, dual and quad rail-
to-rail input and output single supply amplifiers featuring very
low supply current and 1 MHz bandwidth. All are guaranteed to
operate from a +2.7 V single supply as well as a +5 V supply.
These parts provide 1 MHz bandwidth at low current consump-
tion of 45 µA per amplifier.
Very low input bias currents enable the AD8541/AD8542/AD8544
to be used for integrators, photodiode amplifiers, piezo electric
sensors and other applications with high source impedance. Supply
current is only 45 µA per amplifier, ideal for battery operation.
Rail-to-rail inputs and outputs are useful to designers buffering
ASICs in single supply systems. The AD8541/AD8542/AD8544
are optimized to maintain high gains at lower supply voltages,
making them useful for active filters and gain stages.
The AD8541/AD8542/AD8544 are specified over the extended
industrial (–40°C to +125°C) temperature range. The AD8541
is available in 8-lead SO and 5-lead SOT-23 packages. The
AD8542 is available in 8-lead SO, 8-lead MSOP, and 8-lead
TSSOP surface mount packages. The AD8544 is available in
14-lead narrow SO-14 and 14-lead TSSOP surface mount pack-
ages. All TSSOP, MSOP, and SOT versions are available in tape
and reel only.
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2000
AD8541/AD8542/AD8544–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS (VS = +2.7 V, VCM = +1.35 V, TA = +25؇C unless otherwise noted)
Parameter
Symbol
Conditions
Min
Typ Max
Units
INPUT CHARACTERISTICS
Offset Voltage
VOS
IB
1
4
6
7
60
mV
mV
pA
–40°C ≤ TA ≤ +125°C
Input Bias Current
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
100
1,000
30
pA
pA
pA
Input Offset Current
IOS
0.1
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
50
500
+2.7
pA
pA
V
Input Voltage Range
0
Common-Mode Rejection Ratio
CMRR
AVO
VCM = 0 V to +2.7 V
40
38
100
50
2
45
dB
dB
–40°C ≤ TA ≤ +125°C
RL = 100 kΩ , VO = +0.5 V to +2.2 V
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
Large Signal Voltage Gain
500
V/mV
V/mV
V/mV
µV/°C
fA/°C
fA/°C
fA/°C
Offset Voltage Drift
Bias Current Drift
∆VOS/∆T
∆IB/∆T
4
100
2,000
25
Offset Current Drift
∆IOS/∆T
OUTPUT CHARACTERISTICS
Output Voltage High
VOH
VOL
IL = 1 mA
–40°C ≤ TA ≤ +125°C
IL = 1 mA
–40°C ≤ TA ≤ +125°C
VOUT = VS – 1 V
+2.575 +2.65
+2.550
V
V
Output Voltage Low
35
100
125
mV
mV
mA
mA
Ω
Output Current
IOUT
ISC
ZOUT
15
20
50
Closed Loop Output Impedance
f = 200 kHz, AV = 1
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
ISY
VS = +2.5 V to +6 V
–40°C ≤ TA ≤ +125°C
VO = 0 V
65
60
76
38
dB
dB
µA
µA
Supply Current/Amplifier
55
75
–40°C ≤ TA ≤ +125°C
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
Phase Margin
SR
tS
GBP
Φo
RL = 100 kΩ
To 0.1% (1 V Step)
0.4
0.75
5
980
63
V/µs
µs
kHz
Degrees
NOISE PERFORMANCE
Voltage Noise Density
en
en
in
f = 1 kHz
f = 10 kHz
40
38
<0.1
nV/√Hz
nV/√Hz
pA/√Hz
Current Noise Density
Specifications subject to change without notice.
–2–
REV. A
AD8541/AD8542/AD8544
ELECTRICAL CHARACTERISTICS (VS = +3.0 V, VCM = +1.5 V, TA = +25؇C unless otherwise noted)
Parameter
Symbol
Conditions
Min
Typ Max
Units
INPUT CHARACTERISTICS
Offset Voltage
VOS
IB
1
4
6
7
60
mV
mV
pA
–40°C ≤ TA ≤ +125°C
Input Bias Current
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
100
1,000
30
pA
pA
pA
Input Offset Current
IOS
0.1
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
50
500
+3
pA
pA
V
Input Voltage Range
0
Common-Mode Rejection Ratio
CMRR
AVO
V
CM = 0 V to +3 V
40
38
100
50
2
45
dB
dB
–40°C ≤ TA ≤ +125°C
RL = 100 kΩ , VO = +0.5 V to +2.2 V
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
Large Signal Voltage Gain
500
V/mV
V/mV
V/mV
µV/°C
fA/°C
fA/°C
fA/°C
Offset Voltage Drift
Bias Current Drift
∆VOS/∆T
∆IB/∆T
4
100
2,000
25
Offset Current Drift
∆IOS/∆T
OUTPUT CHARACTERISTICS
Output Voltage High
VOH
VOL
IL = 1 mA
–40°C ≤ TA ≤ +125°C
IL = 1 mA
–40°C ≤ TA ≤ +125°C
VOUT = VS – 1 V
+2.875 +2.955
+2.850
V
V
Output Voltage Low
32
100
125
mV
mV
mA
mA
Ω
Output Current
IOUT
ISC
ZOUT
18
25
50
Closed Loop Output Impedance
f = 200 kHz, AV = 1
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
ISY
VS = +2.5 V to +6 V
–40°C ≤ TA ≤ +125°C
VO = 0 V
65
60
76
40
dB
dB
µA
µA
Supply Current/Amplifier
60
75
–40°C ≤ TA ≤ +125°C
DYNAMIC PERFORMANCE
Slew Rate
Settling Time
Gain Bandwidth Product
Phase Margin
SR
tS
GBP
Φo
RL = 100 kΩ
To 0.01% (1 V Step)
0.4
0.8
5
980
64
V/µs
µs
kHz
Degrees
NOISE PERFORMANCE
Voltage Noise Density
en
en
in
f = 1 kHz
f = 10 kHz
42
38
<0.1
nV/√Hz
nV/√Hz
pA/√Hz
Current Noise Density
Specifications subject to change without notice.
REV. A
–3–
AD8541/AD8542/AD8544–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS (VS = +5.0 V, VCM = +2.5 V, TA = +25؇C unless otherwise noted)
Parameter
Symbol
Conditions
Min
Typ Max
Units
INPUT CHARACTERISTICS
Offset Voltage
VOS
IB
1
4
6
7
60
100
1,000
30
mV
mV
pA
pA
pA
pA
–40°C ≤ TA ≤ +125°C
Input Bias Current
Input Offset Current
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
IOS
0.1
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
50
500
+5
pA
pA
V
Input Voltage Range
0
Common-Mode Rejection Ratio
CMRR
AVO
VCM = 0 V to +5 V
40
38
20
10
2
48
40
dB
dB
–40°C ≤ TA ≤ +125°C
RL = 100 kΩ , VO = +0.5 V to +2.2 V
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +85°C
–40°C ≤ TA ≤ +125°C
–40°C ≤ TA ≤ +125°C
Large Signal Voltage Gain
V/mV
V/mV
V/mV
µV/°C
fA/°C
fA/°C
fA/°C
Offset Voltage Drift
Bias Current Drift
∆VOS/∆T
∆IB/∆T
4
100
2,000
25
Offset Current Drift
∆IOS/∆T
OUTPUT CHARACTERISTICS
Output Voltage High
VOH
VOL
IL = 1 mA
–40°C ≤ TA ≤ +125°C
IL = 1 mA
–40°C ≤ TA ≤ +125°C
VOUT = VS – 1 V
+4.9
+4.875
+4.965
25
V
V
Output Voltage Low
100
125
mV
mV
mA
mA
Ω
Output Current
IOUT
ISC
ZOUT
30
60
45
Closed Loop Output Impedance
f = 200 kHz, AV = 1
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
ISY
VS = +2.5 V to +6 V
–40°C ≤ TA ≤ +125°C
VO = 0 V
65
60
76
45
dB
dB
µA
µA
Supply Current/Amplifier
65
85
–40°C ≤ TA ≤ +125°C
DYNAMIC PERFORMANCE
Slew Rate
Full-Power Bandwidth
Settling Time
Gain Bandwidth Product
Phase Margin
SR
BWP
tS
GBP
Φo
RL = 100 kΩ, CL = 200 pF
1% Distortion
To 0.1% (1 V Step)
0.45
0.92
70
6
1,000
67
V/µs
kHz
µs
kHz
Degrees
NOISE PERFORMANCE
Voltage Noise Density
en
en
in
f = 1 kHz
f = 10 kHz
42
38
<0.1
nV/√Hz
nV/√Hz
pA/√Hz
Current Noise Density
Specifications subject to change without notice.
–4–
REV. A
AD8541/AD8542/AD8544
PACKAGE INFORMATION
ABSOLUTE MAXIMUM RATINGS1
Supply Voltage(VS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND to VS
1
Package Type
JA
Units
JC
Differential Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . .
6 V
5-Lead SOT-23 (RT)
8-Lead SOIC (R)
8-Lead MSOP (RM)
8-Lead TSSOP (RU)
14-Lead SOIC (R)
14-Lead TSSOP (RU)
256
158
210
240
120
240
81
43
45
43
36
43
°C/W
°C/W
°C/W
°C/W
°C/W
°C/W
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Operating Temperature Range . . . . . . . . . . –40°C to +125°C
Junction Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering, 60 sec) . . . . . . .+300°C
NOTES
1Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2For supplies less than +6 V, the differential input voltage is equal to VS.
NOTE
1θJA is specified for worst case conditions, i.e., θJA is specified for device soldered
onto a circuit board for surface mount packages.
ORDERING GUIDE
Temperature
Range
Package
Description
Package
Option
Branding
Information
Model
AD8541AR
AD8541ART*
AD8542AR
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
8-Lead SOIC
5-Lead SOT-23 RT-5
8-Lead SOIC
8-Lead MSOP
8-Lead TSSOP
14-Lead SOIC
SO-8
A4A
AVA
SO-8
AD8542ARM* –40°C to +125°C
RM-8
RU-8
SO-14
AD8542ARU* –40°C to +125°C
AD8544AR
–40°C to +125°C
AD8544ARU* –40°C to +125°C
14-Lead TSSOP RU-14
*Available in reels only.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD8541/AD8542/AD8544 features proprietary ESD protection circuitry, permanent damage
may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
WARNING!
ESD SENSITIVE DEVICE
REV. A
–5–
AD8541/AD8542/AD8544–Typical Performance Characteristics
180
160
140
120
100
80
1.0
9
8
7
6
5
4
3
2
1
V
V
= +5V
S
V
V
= +2.7V AND +5V
S
V
V
= +2.7V AND +5V
0.5
S
= +2.5V
CM
= V /2
CM
S
= V /2
CM
S
T
= +25؇C
A
0.0
؊0.5
؊1.0
؊1.5
؊2.0
؊2.5
؊3.0
؊3.5
؊4.0
60
40
20
0
0
؊4.5 ؊3.5؊2.5؊1.5؊0.5 0.5 1.5 2.5 3.5 4.5
INPUT OFFSET VOLTAGE – mV
؊55 ؊35 ؊15
5
25 45 65 85 105 125 145
؊0.5
0.5
1.5
2.5
3.5
4.5
5.5
TEMPERATURE – ؇C
COMMON-MODE VOLTAGE – V
Figure 2. Input Offset Voltage
vs. Temperature
Figure 1. Input Offset Voltage
Distribution
Figure 3. Input Bias Current vs.
Common-Mode Voltage
7
400
350
300
250
200
150
100
50
160
V
= +2.7V
S
= +25؇C
V
V
= +2.7V AND +5V
= V /2
V
V
= +2.7V AND +5V
= V /2
S
140
120
100
80
S
6
5
T
A
CM
S
CM
S
4
؊PSRR
+PSRR
3
60
40
2
20
1
0
0
؊20
؊40
0
؊1
؊40 ؊20
0
20 40 60 80 100 120 140
؊55 ؊35 ؊15
5
25 45 65 85 105 125 145
100
1k
10k
100k
1M
10M
TEMPERATURE – ؇C
TEMPERATURE – ؇C
FREQUENCY – Hz
Figure 4. Input Bias Current vs.
Temperature
Figure 5. Input Offset Current vs.
Temperature
Figure 6. Power Supply Rejection
Ratio vs. Frequency
10k
60
3.0
V
T
= +2.7V
= +25؇C
S
V
V
R
= +2.7V
= 2.5Vp-p
= 2k⍀
S
V
R
= +2.7V
=
S
A
IN
1k
100
10
2.5
2.0
1.5
1.0
0.5
0
50
40
30
20
L
L
T
= +25؇C
A
T
= +25؇C
A
+OS
SOURCE
SINK
؊OS
1
0.1
10
0
0.01
0.001
0.01
0.1
1
10
100
10
100
1k
10k
1k
10k
100k
FREQUENCY – Hz
1M
10M
LOAD CURRENT – mA
CAPACITANCE – pF
Figure 7. Output Voltage to Supply
Rail vs. Load Current
Figure 9. Small Signal Overshoot vs.
Load Capacitance
Figure 8. Closed-Loop Output
Voltage Swing vs. Frequency
–6–
REV. A
AD8541/AD8542/AD8544
60
60
50
40
30
20
10
0
V
= +2.7V
= 100k⍀
= 300pF
= +1
S
V
R
= +2.7V
= 10k⍀
= +25؇C
V
R
= +2.7V
= 2k⍀
= +25؇C
S
S
R
C
A
L
L
50
40
30
20
10
0
L
L
T
T
A
A
V
A
T
= +25؇C
+OS
+OS
؊OS
1.35V
؊OS
10s
50mV
10
100
1k
10k
10
100
1k
10k
CAPACITANCE – pF
CAPACITANCE – pF
Figure 10. Small Signal Overshoot
vs. Load Capacitance
Figure 11. Small Signal Overshoot
vs. Load Capacitance
Figure 12. Small Signal Transient
Response
160
V
R
= +2.7V
= NO LOAD
= +25؇C
V
T
= +5V
= +25؇C
S
S
A
140
120
100
80
L
T
A
80
60
40
20
0
45
90
؊PSRR
+PSRR
135
180
60
1.35V
40
V
= +2.7V
= 2k⍀
= +1
S
20
R
A
L
V
A
0
T
= +25؇C
؊20
؊40
10s
500mV
1k
10k
100k
FREQUENCY – Hz
1M
10M
100
1k
10k
100k
1M
10M
FREQUENCY – Hz
Figure 13. Large Signal Transient
Response
Figure 14. Open-Loop Gain and
Phase vs. Frequency
Figure 15. Power Supply Rejection
Ratio vs. Frequency
10k
5.0
90
V
V
R
= +5V
V
T
= +5V
= +25؇C
V
T
= +5V
= +25؇C
S
S
S
4.5
80
70
60
50
= +4.9Vp-p
= NO LOAD
= +25؇C
IN
A
A
1k
100
10
L
4.0
3.5
T
A
3.0
2.5
SOURCE
40
30
20
SINK
2.0
1.5
1
1.0
0.5
0
10
0.1
0
0.01
0.001
؊10
1k
10k
100k
FREQUENCY – Hz
1M
10M
1k
10k
100k
FREQUENCY – Hz
1M
10M
0.01
0.1
1
10
100
LOAD CURRENT – mA
Figure 16. Common-Mode Rejection
Ratio vs. Frequency
Figure 17. Output Voltage to Supply
Rail vs. Frequency
Figure 18. Closed Loop Output
Voltage Swing vs. Frequency
REV. A
–7–
AD8541/AD8542/AD8544
60
50
40
30
20
60
5.0
V
V
= +5V
= +4.9Vp-p
S
V
R
= +5V
= 10k⍀
= +25؇C
V
= +5V
4.5
S
S
IN
50
40
30
20
10
0
R
= 2k⍀
= +25؇C
L
L
R
= 2k⍀
= +25؇C
L
4.0
3.5
T
T
A
A
T
A
3.0
2.5
+OS
+OS
؊OS
؊OS
2.0
1.5
1.0
0.5
0
10
0
10
100
1k
10k
10
100
1k
10k
1k
10k
100k
FREQUENCY – Hz
1M
10M
CAPACITANCE – pF
CAPACITANCE – pF
Figure 19. Closed-Loop Output
Voltage Swing vs. Frequency
Figure 20. Small Signal Overshoot
vs. Load Capacitance
Figure 21. Small Signal Overshoot
vs. Load Capacitance
60
V
= +5V
S
V
R
= +5V
=
= +25؇C
S
R
C
A
= 100k⍀
= 300pF
= +1
L
L
50
40
30
20
10
0
L
T
A
V
A
T
= +25؇C
+OS
2.5V
2.5V
؊OS
V
= +5V
= 2k⍀
= +1
S
R
A
L
V
A
T
= +25؇C
10s
10s
50mV
1V
10
100
1k
10k
CAPACITANCE – pF
Figure 22. Small Signal Overshoot
vs. Load Capacitance
Figure 23. Small Signal Transient
Response
Figure 24. Large Signal Transient
Response
60
V
= +5V
= 10k⍀
= +1
S
V
R
= +5V
= NO LOAD
= +25؇C
S
T
= +25؇C
A
R
A
L
V
A
L
V
IN
50
40
30
20
10
0
T
A
T
= +25؇C
80
60
40
20
0
45
V
90
OUT
135
180
2.5V
20s
1V
0
1
2
3
4
5
6
1k
10k
100k
FREQUENCY – Hz
1M
10M
SUPPLY VOLTAGE – V
Figure 25. Open-Loop Gain & Phase
vs. Frequency
Figure 26. No Phase Reversal
Figure 27. Supply Current per
Amplifier vs. Supply Voltage
–8–
REV. A
AD8541/AD8542/AD8544
55
50
45
40
35
30
25
20
1,000
900
800
700
600
500
400
300
200
100
0
V
A
= +2.7V AND +5V
= +1
= +25؇C
V
A
= +5V
= +1
S
S
V
V
MARKER SET @ 10kHz
MARKER READING: 37.6V/ Hz
T
V
= +5V
A
S
T
= +25؇C
A
V
= +2.7V
S
؊55 ؊35؊15
5
25 45 65 85 105 125 145
0
5
10
15
20
25
1k
10k
100k
1M
10M
100M
TEMPERATURE – ؇C
FREQUENCY – Hz
FREQUENCY – kHz
Figure 28. Supply Current per
Amplifier vs. Temperature
Figure 29. Closed-Loop Output
Impedance vs. Frequency
Figure 30. Voltage Noise
NOTES ON THE AD854x AMPLIFIERS
the circuit to no longer attenuate at the ideal notch frequency.
To achieve desired performance, 1% or better component
tolerances or special component screens are usually required.
One method to desensitize the circuit-to-component mis-
match is to increase R2 with respect to R1, which lowers Q. A
lower Q increases attenuation over a wider frequency range,
but reduces attenuation at the peak notch frequency.
The AD8541/AD8542/AD8544 amplifiers are improved perfor-
mance general purpose operational amplifiers. Performance has
been improved over previous amplifiers in several ways.
Lower Supply Current for 1 MHz Gain Bandwidth
The AD854x series typically uses 45 microamps of current per
amplifier. This is much less than the 200 µA to 700 µA used in
earlier generation parts with similar performance. This makes
the AD854x series a good choice for upgrading portable designs
for longer battery life. Alternatively, additional functions and
performance can be added at the same current drain.
5.0V
R
R
8
100k⍀
100k⍀
1/2 AD8542
3
2
U1
VOUT
C2
1
4
53.6F
Higher Output Current
R/2
50k⍀
At +5 V single supply, the short circuit current is typically 60 µA.
Even 1 V from the supply rail, the AD854x amplifiers can provide
30 mA, sourcing or sinking.
R2
2.5k⍀
2.5V
REF
C
C
1/2 AD8542
26.7nF
26.7nF
5
6
Sourcing and sinking is strong at lower voltages, with 15 mA
available at +2.7 V, and 18 mA at 3.0 V. For even higher output
currents, please see the Analog Devices AD8531/AD853/AD8534
parts, with output currents to 250 mA. Information on these
parts is available from your Analog Devices representative, and
datasheets are available at the Analog Devices website at
www.analog.com.
7
U2
R1
97.5k⍀
1
f
=
0
2πRC
1
2.5V
REF
f
=
0
R1
1 ؊
4
[
]
R1+R2
Figure 31. 60 Hz Twin-T Notch Filter, Q = 10
Better Performance at Lower Voltages
The AD854x family parts have been designed to provide better ac
performance, at 3.0 V and 2.7 V, than previously available parts.
Typical gain-bandwidth product is close to 1 MHz at 2.7 V. Volt-
age gain at 2.7 V and 3.0 V is typically 500,000. Phase margin is
typically over +60°C, making the part easy to use.
5.0V
7
AD8541
R
R
3
2
VOUT
6
4
2C
V
IN
APPLICATIONS
Notch Filter
R/2
2.5V
REF
The AD8542 has very high open loop gain (especially with supply
voltage below 4 V), which makes it useful for active filters of all
types. For example, Figure 31 illustrates the AD8542 in the clas-
sic Twin-T Notch Filter design. The Twin-T Notch is desired for
simplicity, low output impedance and minimal use of op amps. In
fact, this notch filter may be designed with only one op amp if Q
adjustment is not required. Simply remove U2 as illustrated in
Figure 32. However, a major drawback to this circuit topology is
ensuring that all the Rs and Cs closely match. The components
must closely match or notch frequency offset and drift will cause
C
C
=
Figure 32. 60 Hz Twin-T Notch Filter, Q ∞ (Ideal)
Figure 33 diagrams another example of the AD8542 in a
notch filter circuit. The FNDR notch filter has several
unique features as compared to the Twin-T Notch including:
less critical matching requirements; Q is directly proportional
to a single resistor R1. While matching component values is
still important, it is also much easier and/or less expensive to
REV. A
–9–
AD8541/AD8542/AD8544
accomplish in the FNDR circuit. For example, the Twin-T
Notch uses three capacitors with two unique values, whereas the
FNDR circuit uses only two capacitors, which may be of the
same value. U3 is simply a buffer that is added to lower the out-
put impedance of the circuit.
Photodiode Application
The AD854x family has very high impedance with input bias
current typically around 4 pA. This characteristic allows the
AD854x op amps to be used in photodiode applications and
other applications that require high input impedance. Note that
the AD854x has significant voltage offset, which can be removed
by capacitive coupling or software calibration.
1/4 AD8544
R1
Q ADJUST
200⍀
9
8
Figure 35, illustrates a photodiode or current measurement
application. The feedback resistor is limited to 10 MΩ to avoid
excessive output offset. Also note that a resistor is not needed
on the noninverting input to cancel bias current offset, because
the bias current related output offset is not significant when
compared to the voltage offset contribution. For the best per-
formance follow the standard high impedance layout techniques
including: shield circuit, clean circuit board, put a trace con-
nected to the noninverting input around the inverting input,
and use separate analog and digital power supplies.
U3
VOUT
10
C1
1F
R
2.5V
REF
2.61k⍀
1/4 AD8544
1
4
3
C2
1F
U1
1/4 AD8544
2
6
11
7
U2
R
5
2.61k⍀
R
C
2.61k⍀
100pF
1/4 AD8544
R
13
1
f =
14
R
10M⍀
2.61k⍀
2π
LC1
U4
NC
12
2.5V
REF
SPARE
2
L =
R C2
V+
7
OR
2.5V
2
3
REF
6
V
OUT
Figure 33. FNDR 60 Hz Notch Filter with Output Buffer
4
D
AD8541
Comparator Function
A comparator function is a common application for a spare op
amp in a quad package. Figure 34 illustrates 1/4 of the AD8544
as a comparator in a standard overload detection application.
Unlike so many op amps, the AD854x family can double as
comparator because this op amp family has rail-to-rail differen-
tial input range, rail-to-rail output, and a great speed vs. power
ratio. R2 is used to introduce hysteresis. The AD854x when
used as comparators have 5 µs propagation delay @ 5 V and 5 µs
overload recovery time.
2.5V
2.5V
REF
REF
Figure 35. High Input Impedance Application–Photodiode
Amplifier
R2
1M⍀
R1
1k⍀
VOUT
V
IN
1/4 AD8544
2.5V
DC
2.5V
REF
Figure 34. The AD854x Comparator Application–Overload
Detector
–10–
REV. A
AD8541/AD8542/AD8544
* AD8542 SPICE Macro-model Typical Values
* VOLTAGE NOISE REFERENCE OF 35nV/rt(Hz)
* 6/98, Ver. 1
*
* TAM / ADSC
VN1 80 0 0
*
RN1 80 0 16.45E-3
* Copyright 1998 by Analog Devices
HN 81 0 VN1 35
*
RN2 81 0 1
* Refer to “README.DOC” file for License State-
ment. Use of this
*
* INTERNAL VOLTAGE REFERENCE
* model indicates your acceptance of the terms
and provisions in
*
VFIX 90 98 DC 1
* the License Statement.
*
S1
90 91 (50,99) VSY_SWITCH
VSN1 91 92 DC 0
* Node Assignments
RSY 92 98 1E3
*
*
*
*
*
*
*
noninverting input
EREF 98 0 POLY(2) (99,0) (50,0) 0 .5 .5
GSY 99 50 POLY(1) (99,50) 0 3.7E-6
*
* ADAPTIVE GAIN STAGE
* AT Vsy>+4.2, AVol=45 V/mv
* AT Vsy<+3.8, AVol=450 V/mv
*
|
|
|
|
|
|
1
inverting input
|
|
|
|
|
2
positive supply
|
|
|
|
negative supply
|
|
|
output
|
|
.SUBCKT AD8542
*
99 50 45
G1 98 30 POLY(2) (4,6) (11,12) 0 2.5E-5 2.5E-5
VR1 30 31 DC 0
* INPUT STAGE
*
H1 31 98 POLY(2) VR1 VSN1 0 5.45E6 0 0 49.05E9
CF 45 30 10E-12
M1
M2
4
6
1 8 8 PIX L=0.6E-6 W=16E-6
7 8 8 PIX L=0.6E-6 W=16E-6
D3 30 99 DX
D4 50 30 DX
M3 11 1 10 10 NIX L=0.6E-6 W=16E-6
M4 12 7 10 10 NIX L=0.6E-6 W=16E-6
RC1 4 50 20E3
*
* OUTPUT STAGE
*
RC2 6 50 20E3
RC3 99 11 20E3
RC4 99 12 20E3
M5 45 46 99 99 POX L=0.6E-6 W=375E-6
M6 45 47 50 50 NOX L=0.6E-6 W=500E-6
EG1 99 46 POLY(1) (98,30) 1.05 1
EG2 47 50 POLY(1) (30,98) 1.04 1
*
C1
4
6 1.5E-12
C2 11 12 1.5E-12
I1 99 8 1E-5
I2 10 50 1E-5
V1 99 9 0.2
V2 13 50 0.2
* MODELS
*
.MODEL POX PMOS (LEVEL=2,KP=20E-6,VTO=-
+1,LAMBDA=0.067)
D1
8
9 DX
.MODEL NOX NMOS (LEVEL=2,KP=20E-
+6,VTO=1,LAMBDA=0.067)
.MODEL PIX PMOS (LEVEL=2,KP=20E-6,VTO=-
+0.7,LAMBDA=0.01,KF=1E-31)
.MODEL NIX NMOS (LEVEL=2,KP=20E-
+6,VTO=0.7,LAMBDA=0.01,KF=1E-31)
.MODEL DX D(IS=1E-14)
.MODEL VSY_SWITCH VSWITCH(ROFF=100E3,RON=1,VOFF=-
+4.2,VON=-3.5)
D2 13 10 DX
EOS
1
IOS
*
* CMRR 64dB, ZERO AT 20kHz
*
ECM1 21 98 POLY(2) (1,98) (2,98) 0 .5 .5
7
1
2 POLY(3) (22,98) (73,98) (81,0) 1E-3 1 1
2 2.5E-12
RCM1 21 22 79.6E3
CCM1 21 22 100E-12
RCM2 22 98 50
.ENDS AD8542
*
* PSRR=90dB, ZERO AT 200Hz
*
RPS1 70 0 1E6
RPS2 71 0 1E6
CPS1 99 70 1E-5
CPS2 50 71 1E-5
EPSY 98 72 POLY(2) (70,0) (0,71) 0 1 1
RPS3 72 73 1.59E6
CPS3 72 73 500E-12
RPS4 73 98 25
*
REV. A
–11–
AD8541/AD8542/AD8544
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
8-Lead TSSOP
(RU-08)
14-Lead TSSOP
(RU-14)
0.122 (3.10)
0.114 (2.90)
0.201 (5.10)
0.193 (4.90)
14
8
7
8
5
1
4
1
PIN 1
PIN 1
0.0256 (0.65)
BSC
0.006 (0.15)
0.002 (0.05)
0.006 (0.15)
0.002 (0.05)
0.0433
(1.10)
MAX
0.0433
(1.10)
MAX
0.028 (0.70)
0.020 (0.50)
8؇
0؇
0.028 (0.70)
0.020 (0.50)
8؇
0؇
0.0118 (0.30)
0.0075 (0.19)
0.0118 (0.30)
0.0075 (0.19)
0.0256
(0.65)
BSC
SEATING
PLANE
0.0079 (0.20)
0.0035 (0.090)
SEATING
PLANE
0.0079 (0.20)
0.0035 (0.090)
8-Lead SOIC
(SO-8)
14-Lead SOIC
(SO-14)
0.1968 (5.00)
0.1890 (4.80)
0.3444 (8.75)
0.3367 (8.55)
8
1
5
4
14
8
0.1574 (4.00)
0.1497 (3.80)
0.1574 (4.00)
0.1497 (3.80)
0.2440 (6.20)
0.2284 (5.80)
0.2440 (6.20)
0.2284 (5.80)
1
7
PIN 1
0.0098 (0.25)
0.0040 (0.10)
0.0688 (1.75)
0.0532 (1.35)
0.0688 (1.75)
0.0532 (1.35)
PIN 1
0.0196 (0.50)
0.0099 (0.25)
0.0196 (0.50)
0.0099 (0.25)
x 45؇
x 45؇
0.0098 (0.25)
0.0040 (0.10)
8؇
0؇
8؇
0؇
0.0500
(1.27)
BSC
0.0192 (0.49)
0.0138 (0.35)
0.0500
(1.27)
BSC
0.0192 (0.49)
0.0138 (0.35)
SEATING
PLANE
0.0500 (1.27)
0.0160 (0.41)
SEATING
PLANE
0.0098 (0.25)
0.0075 (0.19)
0.0500 (1.27)
0.0160 (0.41)
0.0099 (0.25)
0.0075 (0.19)
8-Lead MSOP
(RM-8)
5-Lead SOT-23
(RT Suffix)
0.1181 (3.00)
0.1102 (2.80)
0.122 (3.10)
0.114 (2.90)
8
5
4
5
1
4
3
0.1181 (3.00)
0.1024 (2.60)
0.193
(4.90)
BSC
0.0669 (1.70)
0.0590 (1.50)
0.122 (3.10)
0.114 (2.90)
2
1
PIN 1
0.0374 (0.95) BSC
PIN 1
0.0256 (0.65) BSC
0.037 (0.95)
0.030 (0.75)
0.0748 (1.90)
BSC
0.043
(1.10)
MAX
0.006 (0.15)
0.002 (0.05)
0.0079 (0.20)
0.0031 (0.08)
6؇
0؇
0.0512 (1.30)
0.0354 (0.90)
0.0571 (1.45)
0.0374 (0.95)
0.016 (0.40)
0.010 (0.25)
SEATING
PLANE
0.028 (0.70)
0.016 (0.40)
0.009 (0.23)
0.005 (0.13)
10؇
0؇
SEATING
PLANE
0.0197 (0.50)
0.0138 (0.35)
0.0059 (0.15)
0.0019 (0.05)
0.0217 (0.55)
0.0138 (0.35)
–12–
REV. A
相关型号:
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