AD8047ARZ [ADI]
250 MHz, General Purpose Voltage Feedback Op Amps; 250兆赫，通用电压反馈运算放大器
| 型号： | AD8047ARZ |
| 厂家： | 
ADI |
| 描述： | 250 MHz, General Purpose Voltage Feedback Op Amps |
| 文件： | 总17页 (文件大小：516K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
250 MHz, General Purpose
Voltage Feedback Op Amps
AD8047/AD8048
FEATURES
Wide Bandwidth
Small Signal
FUNCTIONAL BLOCK DIAGRAM
AD8047, G = +1
250 MHz
AD8048, G = +2
260 MHz
160 MHz
8-Pin Plastic PDIP (N)
and SOIC (R) Packages
Large Signal (2 V p-p) 130 MHz
5.8 mA Typical Supply Current
Low Distortion, (SFDR) Low Noise
–66 dBc Typ @ 5 MHz
–54 dBc Typ @ 20 MHz
5.2 nV/√Hz (AD8047), 3.8 nV/√Hz (AD8048) Noise
Drives 50 pF Capacitive Load
AD8047/
AD8048
8
7
6
5
1
2
3
4
NC
–INPUT
+INPUT
NC
+V
S
OUTPUT
NC
–V
S
(TOP VIEW)
High Speed
NC = NO CONNECT
Slew Rate 750 V/ꢀs (AD8047), 1000 V/ꢀs (AD8048)
Settling 30 ns to 0.01%, 2 V Step
ꢁ3 V to ꢁ6 V Supply Operation
APPLICATIONS
Low Power ADC Input Driver
Differential Amplifiers
IF/RF Amplifiers
Pulse Amplifiers
Professional Video
DAC Current to Voltage Conversion
Baseband and Video Communications
Pin Diode Receivers
The AD8047 and AD8048’s low distortion and cap load drive
make the AD8047/AD8048 ideal for buffering high speed ADCs.
They are suitable for 12-bit/10 MSPS or 8-bit/60 MSPS ADCs.
Additionally, the balanced high impedance inputs of the voltage
feedback architecture allow maximum flexibility when designing
active filters.
The AD8047 and AD8048 are offered in industrial (–40°C to
+85°C) temperature ranges and are available in 8-lead PDIP
and SOIC packages.
Active Filters/Integrators
PRODUCT DESCRIPTION
The AD8047 and AD8048 are very high speed and wide band-
width amplifiers. The AD8047 is unity gain stable. The AD8048 is
stable at gains of two or greater. The AD8047 and AD8048,
which utilize a voltage feedback architecture, meet the require-
ments of many applications that previously depended on current
feedback amplifiers.
A proprietary circuit has produced an amplifier that combines
many of the best characteristics of both current feedback and
voltage feedback amplifiers. For the power (6.6 mA max), the
AD8047 and AD8048 exhibit fast and accurate pulse response
(30 ns to 0.01%) as well as extremely wide small signal and large
signal bandwidth and low distortion. The AD8047 achieves
–54 dBc distortion at 20 MHz, 250 MHz small signal, and
130 MHz large signal bandwidths.
1V
5ns
Figure 1. AD8047 Large Signal Transient Response,
VO = 4 V p-p, G = +1
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, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
www.analog.com
© 2003 Analog Devices, Inc. All rights reserved.
IMPORTANT LINKS for the AD8047_8048*
Last content update 08/19/2013 04:41 pm
PARAMETRIC SELECTION TABLES
DESIGN TOOLS, MODELS, DRIVERS & SOFTWARE
dBm/dBu/dBv Calculator
Find Similar Products By Operating Parameters
High Speed Amplifiers Selection Table
Analog Filter Wizard 2.0
Power Dissipation vs Die Temp
ADIsimOpAmp™
OpAmp Stability
DOCUMENTATION
AN-649: Using the Analog Devices Active Filter Design Tool
AD8047 SPICE Macro-Model
AN-581: Biasing and Decoupling Op Amps in Single Supply
Applications
AN-402: Replacing Output Clamping Op Amps with Input Clamping
Amps
DESIGN COLLABORATION COMMUNITY
AN-417: Fast Rail-to-Rail Operational Amplifiers Ease Design
Constraints in Low Voltage High Speed Systems
MT-060: Choosing Between Voltage Feedback and Current Feedback
Collaborate Online with the ADI support team and other designers
about select ADI products.
Op Amps
MT-059: Compensating for the Effects of Input Capacitance on VFB
and CFB Op Amps Used in Current-to-Voltage Converters
Follow us on Twitter: www.twitter.com/ADI_News
Like us on Facebook: www.facebook.com/AnalogDevicesInc
MT-058: Effects of Feedback Capacitance on VFB and CFB Op Amps
MT-056: High Speed Voltage Feedback Op Amps
MT-053: Op Amp Distortion: HD, THD, THD + N, IMD, SFDR, MTPR
MT-052: Op Amp Noise Figure: Don’t Be Mislead
DESIGN SUPPORT
Submit your support request here:
Linear and Data Converters
Embedded Processing and DSP
MT-050: Op Amp Total Output Noise Calculations for Second-Order
System
MT-049: Op Amp Total Output Noise Calculations for Single-Pole
System
Telephone our Customer Interaction Centers toll free:
MT-048: Op Amp Noise Relationships: 1/f Noise, RMS Noise, and
Americas:
Europe:
China:
1-800-262-5643
00800-266-822-82
4006-100-006
Equivalent Noise Bandwidth
MT-047: Op Amp Noise
India:
Russia:
1800-419-0108
8-800-555-45-90
MT-033: Voltage Feedback Op Amp Gain and Bandwidth
MT-032: Ideal Voltage Feedback (VFB) Op Amp
A Stress-Free Method for Choosing High-Speed Op Amps
UG-101: Evaluation Board User Guide
Quality and Reliability
Lead(Pb)-Free Data
Choosing High-Speed Signal Processing Components for Ultrasound
Systems
FOR THE AD8047
SAMPLE & BUY
AD8047
AN-214: Ground Rules for High Speed Circuits
AD8048
View Price & Packaging
Request Evaluation Board
Request Samples
Check Inventory & Purchase
EVALUATION KITS & SYMBOLS & FOOTPRINTS
View the Evaluation Boards and Kits page for the AD8047
View the Evaluation Boards and Kits page for the AD8048
Symbols and Footprints for the AD8047
Find Local Distributors
Symbols and Footprints for the AD8048
* This page was dynamically generated by Analog Devices, Inc. and inserted into this data sheet.
Note: Dynamic changes to the content on this page (labeled 'Important Links') does not
constitute a change to the revision number of the product data sheet.
This content may be frequently modified.
AD8047/AD8048–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS (ꢁVS = ꢁ5 V, RLOAD = 100 ꢂ, AV = 1 (AD8047), AV = 2 (AD8048), unless otherwise noted.)
AD8047A
AD8048A
Parameter
Conditions
Min Typ Max Min Typ Max Unit
DYNAMIC PERFORMANCE
Bandwidth (–3 dB)
Small Signal
VOUT ≤ 0.4 V p-p
VOUT = 2 V p-p
170
100
250
130
180 260
135 160
MHz
MHz
Large Signal1
Bandwidth for 0.1 dB Flatness
VOUT = 300 mV p-p
AD8047, RF = 0 Ω;
AD8048, RF = 200 Ω
VOUT = 4 V Step
VOUT = 0.5 V Step
VOUT = 4 V Step
35
50
740 1000
1.2
MHz
V/µs
ns
Slew Rate, Average +/–
Rise/Fall Time
475
750
1.1
4.3
3.2
ns
Settling Time
To 0.1%
To 0.01%
VOUT = 2 V Step
VOUT = 2 V Step
13
30
13
30
ns
ns
HARMONIC/NOISE PERFORMANCE
Second Harmonic Distortion
2 V p-p; 20 MHz
RL = 1 kΩ
–54
–64
–60
–61
5.2
–48
–60
–56
–65
3.8
dBc
dBc
dBc
dBc
nV/√Hz
pA/√Hz
Third Harmonic Distortion
2 V p-p; 20 MHz
RL = 1 kΩ
Input Voltage Noise
Input Current Noise
Average Equivalent Integrated
Input Noise Voltage
Differential Gain Error (3.58 MHz)
Differential Phase Error (3.58 MHz)
f = 100 kHz
f = 100 kHz
1.0
1.0
0.1 MHz to 10 MHz
RL = 150 Ω, G = +2
RL = 150 Ω, G = +2
16
0.02
0.03
11
0.01
0.02
µV rms
%
Degree
DC PERFORMANCE2, RL = 150 Ω
Input Offset Voltage3
1
3
4
1
3
4
mV
mV
µV/°C
µA
TMIN to TMAX
Offset Voltage Drift
Input Bias Current
5
1
5
1
3.5
6.5
2
3.5
6.5
2
TMIN to TMAX
TMIN to TMAX
µA
Input Offset Current
0.5
0.5
µA
3
3
µA
Common-Mode Rejection Ratio
Open-Loop Gain
VCM
VOUT
=
=
2.5 V
2.5 V
74
58
54
80
62
74
65
56
80
68
dB
dB
dB
TMIN to TMAX
INPUT CHARACTERISTICS
Input Resistance
Input Capacitance
500
1.5
3.4
500
1.5
3.4
kΩ
pF
V
Input Common-Mode Voltage Range
OUTPUT CHARACTERISTICS
Output Voltage Range, RL = 150 Ω
Output Current
Output Resistance
Short-Circuit Current
2.8
3.0
50
0.2
2.8
3.0
50
0.2
V
mA
Ω
mA
130
130
POWER SUPPLY
Operating Range
Quiescent Current
3.0
5.0 6.0
5.8 6.6
7.5
3.0
5.0 6.0
5.9 6.6
7.5
V
mA
mA
dB
TMIN to TMAX
Power Supply Rejection Ratio
72
78
72
78
NOTES
1See Absolute Maximum Ratings and Theory of Operation sections.
2Measured at AV = 50.
3Measured with respect to the inverting input.
Specifications subject to change without notice.
–2–
REV. A
AD8047/AD8048
MAXIMUM POWER DISSIPATION
ABSOLUTE MAXIMUM RATINGS1
Supply Voltage, (+VS) – (–VS) . . . . . . . . . . . . . . . . . . . . 12.6 V
Voltage Swing × Bandwidth Product
AD8047 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 V-MHz
AD8048 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 V-MHz
Internal Power Dissipation2
Plastic Package (N) . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 W
Small Outline Package (R) . . . . . . . . . . . . . . . . . . . . . 0.9 W
Input Voltage (Common Mode) . . . . . . . . . . . . . . . . . . . . VS
The maximum power that can be safely dissipated by these devices
is limited by the associated rise in junction temperature. The
maximum safe junction temperature for plastic encapsulated
devices is determined by the glass transition temperature of the
plastic, approximately 150°C. Exceeding this limit temporarily
may cause a shift in parametric performance due to a change in
the stresses exerted on the die by the package. Exceeding a
junction temperature of 175°C for an extended period can
result in device failure.
Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . .
1.2 V
Output Short-Circuit Duration . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . Observe Power Derating Curves
Storage Temperature Range (N, R) . . . . . . . –65°C to +125°C
Operating Temperature Range (A Grade) . . . –40°C to +85°C
Lead Temperature Range (Soldering 10 sec) . . . . . . . . . 300°C
While the AD8047 and AD8048 are internally short circuit
protected, this may not be sufficient to guarantee that the maxi-
mum junction temperature (150°C) is not exceeded under all
conditions. To ensure proper operation, it is necessary to observe
the maximum power derating curves.
NOTES
1 Stresses 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 indicated in the operational
section of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
2 Specification is for device in free air: 8-Lead PDIP Package, JA = 90°C/W; 8-Lead
SOIC Package, JA = 140°C/W
2.0
T
= +150ꢃC
J
8-PIN PDIP PACKAGE
1.5
1.0
0.5
METALLIZATION PHOTOS
Dimensions shown in inches and (mm)
Connect Substrate to –VS.
AD8047
8-PIN SOIC PACKAGE
+V
S
0
–50 –40 –30 –20 –10
0
10 20 30 40 50 60 70 80 90
C)
AMBIENT TEMPERATURE (
ꢃ
0.045
(1.14)
Figure 2. Plot of Maximum Power Dissipation vs.
Temperature
V
OUT
–IN
ORDERING GUIDE
–V
S
+IN
0.044
(1.13)
Temperature
Range
Package
Description
Package
Option*
Model
AD8048
AD8047AN
AD8047AR
AD8047AR-REEL
AD8047AR-REEL7 –40°C to +85°C SOIC
AD8048AN
AD8048AR
AD8048AR-REEL
AD8048AR-REEL7 –40°C to +85°C SOIC
–40°C to +85°C PDIP
–40°C to +85°C SOIC
–40°C to +85°C SOIC
N-8
R-8
R-8
R-8
N-8
R-8
R-8
R-8
+V
S
–40°C to +85°C PDIP
–40°C to +85°C SOIC
–40°C to +85°C SOIC
0.045
(1.14)
V
OUT
*N = PDIP, R= SOIC
–IN
–V
S
+IN
0.044
(1.13)
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
AD8047/AD8048 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.
REV. A
–3–
AD8047/AD8048–Typical Performance Characteristics
R
F
PULSE
10ꢀF
0.1ꢀF
10ꢀF
0.1ꢀF
+V
+V
7
S
S
GENERATOR
T
/T = 500ps
F
R
PULSE
R
T
IN
7
GENERATOR
2
3
2
3
V
IN
T
V
/T = 500ps
V
V
AD8047
4
6
AD8047
4
6
R
F
OUT
OUT
R = 100ꢂ
L
R
= 66.5ꢂ
0.1ꢀF
0.1ꢀF
R
= 100ꢂ
IN
L
R
= 49.9ꢂ
100ꢂ
T
10ꢀF
10ꢀF
–V
S
–V
S
TPC 1. AD8047 Noninverting Configuration, G = +1
TPC 4. AD8047 Inverting Configuration, G = –1
1V
5ns
1V
5ns
TPC 2. AD8047 Large Signal Transient Response;
VO = 4 V p-p, G = +1
TPC 5. AD8047 Large Signal Transient Response;
VO = 4 V p-p, G = –1, RF = RIN = 200 Ω
100mV
100mV
5ns
5ns
TPC 3. AD8047 Small Signal Transient Response;
VO = 400 mV p-p, G = +1
TPC 6. AD8047 Small Signal Transient Response;
VO = 400 mV p-p, G = –1, RF = RIN = 200 Ω
–4–
REV. A
AD8047/AD8048
R
F
R
F
PULSE
10ꢀF
PULSE
+V
7
10ꢀF
0.1ꢀF
S
+V
7
GENERATOR
S
GENERATOR
T
R
/T = 500ps
F
T
/T = 500ps
F
0.1ꢀF
R
R
IN
R
T
IN
2
3
V
2
3
IN
V
OUT
V
AD8048
4
AD8048
4
6
6
OUT
R
= 66.5ꢂ
0.1ꢀF
10ꢀF
0.1ꢀF
V
IN
R
R
= 100ꢂ
L
R
L
= 100ꢂ
R
= 100ꢂ
= 49.9ꢂ
S
10ꢀF
T
–V
S
–V
S
TPC 7. AD8048 Noninverting Configuration, G = +2
TPC 10. AD8048 Inverting Configuration, G= –1
1V
1V
5ns
5ns
TPC 8. AD8048 Large Signal Transient Response;
TPC 11. AD8048 Large Signal Transient Response;
VO = 4 V p-p, G = +2, RF = RIN = 200 Ω
VO = 4 V p-p, G = –1, RF = RIN = 200 Ω
100mV
100mV
5ns
5ns
TPC 9. AD8048 Small Signal Transient Response;
TPC 12. AD8048 Small Signal Transient Response;
VO = 400 mV p-p, G = +2, RF = RIN = 200 Ω
VO = 400 mV p-p, G = –1, RF = RIN = 200 Ω
REV. A
–5–
AD8047/AD8048
1
1
0
0
–1
R
R
R
V
= 100ꢂ
–1
–2
–3
–4
–5
–6
L
F
F
= 0ꢂ FOR DIP
= 66.5ꢂ FOR SOIC
= 2V p-p
R
R
R
V
= 100ꢂ
L
F
F
–2
–3
–4
–5
–6
= 0ꢂ FOR DIP
= 66.5ꢂ FOR SOIC
= 300mV p-p
OUT
OUT
–7
–8
–9
–7
–8
–9
1M
10M
100M
1G
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 13. AD8047 Small Signal Frequency Response,
G = +1
TPC 16. AD8047 Large Signal Frequency Response,
G = +1
0.1
0
1
0
R
R
R
V
= 100ꢂ
R
R
V
= 100ꢂ
–1
–2
–3
–4
–5
–6
–0.1
–0.2
–0.3
–0.4
L
F
F
L
F
= 0ꢂ FOR DIP
= 66.5ꢂ FOR SOIC
= 300mV p-p
= R = 200ꢂ
F
= 300mV p-p
OUT
OUT
–0.5
–0.6
–7
–8
–9
–0.7
–0.8
–0.9
1M
10M
100M
FREQUENCY (Hz)
1G
1M
10M
100M
1G
FREQUENCY (Hz)
TPC 14. AD8047 0.1 dB Flatness, G = +1
TPC 17. AD8047 Small Signal Frequency Response,
G = –1
100
70
60
–20
R
V
= 1kꢂ
80
L
–30
= 2V p-p
OUT
PHASE
MARGIN
60
40
20
0
50
40
–40
–50
–60
–70
–80
–90
30
GAIN
20
SECOND HARMONIC
–20
–40
10
0
THIRD HARMONIC
R
= 100ꢂ
L
–60
–80
–10
–20
–30
–100
–110
–120
–100
1k
10k
100k
1M
10M
100M
1G
10k
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 15. AD8047 Open-Loop Gain and Phase Margin
vs. Frequency
TPC 18. AD8047 Harmonic Distortion vs. Frequency,
G = +1
–6–
REV. A
AD8047/AD8048
0.5
–20
–30
R
V
= 100ꢂ
R
R
V
= 100ꢂ
= 0ꢂ
L
0.4
0.3
L
F
= 2V p-p
OUT
= 2V STEP
–40
–50
–60
–70
–80
–90
OUT
0.2
0.1
0.0
SECOND HARMONIC
–0.1
–0.2
–0.3
THIRD HARMONIC
–100
–110
–120
–0.4
–0.5
0
5
10
15
20
25
30
35
40
45
10k
100k
1M
FREQUENCY (Hz)
10M
100M
SETTLING TIME (ns)
TPC 22. AD8047 Short-Term Settling Time, G = +1
TPC 19. AD8047 Harmonic Distortion vs. Frequency,
G = +1
–25
0.25
f = 200MHz
–30
R
R
V
= 100ꢂ
= 0ꢂ
0.20
0.15
L
F
R
R
= 1kꢂ
L
F
= 0ꢂ FOR SOIC
= 2V STEP
OUT
–35
–40
–45
–50
–55
0.10
0.05
0.00
THIRD HARMONIC
–0.05
–0.10
–0.15
SECOND HARMONIC
–60
–65
–0.20
–0.25
0
2
4
6
8
10
12
14
16
18
1.5
2.5
3.5
4.5
5.5
6.5
SETTLING TIME (ꢀs)
OUTPUT SWING (V p-p)
TPC 20. AD8047 Harmonic Distortion vs. Output
Swing, G = +1
TPC 23. AD8047 Long-Term Settling Time, G = +1
0.04
0.02
17
15
13
11
9
0.00
–0.02
–0.04
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
0.04
0.02
7
0.00
5
–0.02
–0.04
3
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
10
100
1k
10k
100k
FREQUENCY (Hz)
TPC 21. AD8047 Differential Gain and Phase Error,
TPC 24. AD8047 Noise vs. Frequency
G = +2, RL = 150 Ω, RF = 200 Ω, RIN = 200 Ω
REV. A
–7–
AD8047/AD8048
7
6
5
7
6
R
R
V
= 100ꢂ
5
R
R
V
= 100ꢂ
L
F
L
F
= R = 200ꢂ
IN
= R = 200ꢂ
IN
= 300mV p-p
4
3
= 2V p-p
4
3
OUT
OUT
2
1
0
2
1
0
–1
–2
–3
–1
–2
–3
1M
10M
100M
FREQUENCY (Hz)
1G
1M
10M
100M
1G
FREQUENCY (Hz)
TPC 25. AD8048 Small Signal Frequency Response,
G = +2
TPC 28. AD8048 Large Signal Frequency Response,
G = +2
6.5
6.4
1
0
R
R
V
= 100ꢂ
L
F
= R = 200ꢂ
6.3
IN
–1
R
R
V
= 100ꢂ
L
F
= 300mV p-p
= R = 200ꢂ
OUT
IN
= 300mV p-p
6.2
6.1
–2
–3
OUT
6.0
5.9
5.8
–4
–5
–6
5.7
5.6
5.5
–7
–8
–9
1M
10M
100M
1G
1M
10M
100M
FREQUENCY (Hz)
1G
FREQUENCY (Hz)
TPC 26. AD8048 0.1 dB Flatness, G = +2
TPC 29. AD8048 Small Signal Frequency Response,
G = –1
100
–20
–30
90
80
70
80
60
40
20
R
V
= 1kꢂ
L
= 2V p-p
–40
–50
–60
–70
–80
–90
OUT
PHASE
60
50
40
30
0
SECOND HARMONIC
–20
–40
–60
–80
R
= 100ꢂ
L
20
10
0
THIRD HARMONIC
–100
–110
–120
–100
–120
–10
–20
10k
100k
1M
10M
100M
1k
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 30. AD8048 Harmonic Distortion vs. Frequency,
G = +2
TPC 27. AD8048 Open-Loop Gain and Phase Margin
vs. Frequency
–8–
REV. A
AD8047/AD8048
–20
–30
0.5
R
V
= 100ꢂ
L
0.4
0.3
= 2V p-p
R
R
V
= 100ꢂ
= 200ꢂ
OUT
L
F
–40
–50
–60
–70
–80
–90
= 2V STEP
OUT
0.2
0.1
0.0
SECOND HARMONIC
–0.1
–0.2
–0.3
THIRD HARMONIC
–100
–110
–120
–0.4
–0.5
0
5
10
15
20
25
30
35
40
45
10k
100k
1M
FREQUENCY (Hz)
10M
100M
SETTLING TIME (ns)
TPC 31. AD8048 Harmonic Distortion vs. Frequency,
G = +2
TPC 34. AD8048 Short-Term Settling Time, G = +2
–15
0.25
0.20
–20
f = 20MHz
R
R
V
= 100ꢂ
= 200ꢂ
L
F
R
R
= 1kꢂ
= 200ꢂ
–25
–30
L
F
0.15
0.10
THIRD HARMONIC
= 2V STEP
OUT
–35
–40
–45
–50
–55
–60
0.05
0.0
–0.05
–0.10
–0.15
SECOND HARMONIC
–0.20
–0.25
–65
–70
1.5
2.5
3.5
4.5
5.5
6.5
0
2
4
6
8
10
12
14
16
18
SETTLING TIME (ꢀs)
OUTPUT SWING (V p-p)
TPC 32. AD8048 Harmonic Distortion vs. Output
Swing, G = +2
TPC 35. AD8048 Long-Term Settling Time 2 V
Step, G = +2
17
0.04
0.02
15
13
11
9
0.00
–0.02
–0.04
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
0.04
0.02
7
0.00
5
–0.02
–0.04
3
1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th
10
100
1k
10k
100k
FREQUENCY (Hz)
TPC 33. AD8048 Differential Gain and Phase Error,
TPC 36. AD8048 Noise vs. Frequency
G = +2, RL = 150 Ω, RF = 200 Ω, RIN = 200 Ω
REV. A
–9–
AD8047/AD8048
100
90
100
ꢄV
= 1V
CM
= 100ꢂ
ꢄV
= 1V
CM
= 100ꢂ
90
R
L
R
L
80
70
80
70
60
50
40
60
50
40
30
20
30
20
100k
1M
10M
100M
1G
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 37. AD8047 CMRR vs. Frequency
TPC 40. AD8048 CMRR vs. Frequency
100
100
10
1
10
1
0.1
0.1
0.01
0.01
10k
100k
1M
10M
100M
1G
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 38. AD8047 Output Resistance vs. Frequency,
G = +1
TPC 41. AD8048 Output Resistance vs. Frequency,
G = +2
90
80
90
80
–PSRR
+PSRR
70
60
50
40
30
20
10
0
70
+PSRR
60
–
PSRR
50
40
30
20
10
0
10k
100k
1M
10M
100M
1G
3k
10k
100k
1M
100M
500M
FREQUENCY (Hz)
FREQUENCY (Hz)
TPC 39. AD8047 PSRR vs. Frequency
TPC 42. AD8048 PSRR vs. Frequency,
G = +2
–10–
REV. A
AD8047/AD8048
4.1
3.9
3.7
3.5
3.3
3.1
2.9
2.7
83.0
R
= 1kꢂ
+V
OUT
L
82.0
81.0
AD8047
AD8048
–V
OUT
80.0
79.0
78.0
+V
OUT
R
L
= 150ꢂ
–V
OUT
+V
OUT
77.0
76.0
R
= 50ꢂ
2.5
2.3
L
–V
OUT
–60 –40 –20
0
20
40
60
80
100 120 140
–60 –40 –20
0
20
40
60
80
C)
100 120 140
JUNCTION TEMPERATURE (ꢃC)
JUNCTION TEMPERATURE (
ꢃ
TPC 43. AD8047/AD8048 Output Swing vs. Temperature
TPC 46. AD8047/AD8048 CMRR vs. Temperature
8.0
2600
2400
AD8048
7.5
AD8047
AD8048
ꢁ6V
2200
7.0
2000
1800
1600
ꢁ6V
6.5
AD8048
6.0
AD8047
ꢁ5V
5.5
1400
ꢁ5V
AD8047
5.0
1200
1000
4.5
–60 –40 –20
0
20
40
60
80
C)
100 120 140
–60 –40 –20
0
20
40
60
80
C)
100 120 140
JUNCTION TEMPERATURE (
ꢃ
JUNCTION TEMPERATURE (
ꢃ
TPC 44. AD8047/AD8048 Open-Loop Gain vs.
Temperature
TPC 47. AD8047/AD8048 Supply Current vs.
Temperature
900
800
94
92
90
+PSRR
700
AD8048
88
AD8048
600
86
AD8047
500
AD8048
–PSRR
84
400
300
200
100
82
+PSRR
AD8047
AD8047
80
78
76
–PSRR
–60 –40 –20
0
20
40
60
80
100 120 140
–60 –40 –20
0
20
40
60
80
C)
100 120 140
JUNCTION TEMPERATURE (ꢃC)
JUNCTION TEMPERATURE (
ꢃ
TPC 45. AD8047/AD8048 PSRR vs. Temperature
TPC 48. AD8047/AD8048 Input Offset Voltage vs.
Temperature
REV. A
–11–
AD8047/AD8048
THEORY OF OPERATION
General
For general voltage gain applications, the amplifier bandwidth
can be closely estimated as
The AD8047 and AD8048 are wide bandwidth, voltage feed-
back amplifiers. Since their open-loop frequency response follows
the conventional 6 dB/octave roll-off, their gain bandwidth
product is basically constant. Increasing their closed-loop gain
results in a corresponding decrease in small signal bandwidth.
This can be observed by noting the bandwidth specification
between the AD8047 (gain of 1) and AD8048 (gain of 2).
ωO
f3 dB
≅
R
F
2π 1+
R
G
This estimation loses accuracy for gains of +2/–1 or lower due
to the amplifier’s damping factor. For these low gain cases, the
bandwidth will actually extend beyond the calculated value (see
Closed-Loop BW plots, TPCs 13 and 25).
Feedback Resistor Choice
The value of the feedback resistor is critical for optimum perfor-
mance on the AD8047 and AD8048. For maximum flatness at a
gain of 2, RF and RG should be set to 200 Ω for the AD8048.
When the AD8047 is configured as a unity gain follower, RF
should be set to 0 Ω (no feedback resistor should be used) for
the plastic DIP and 66.5 Ω for the SOIC.
As a general rule, capacitor CF will not be required if
NG
(RFꢀRG )× CI ≤
4 ωO
where NG is the Noise Gain (1 + RF/RG) of the circuit. For
most voltage gain applications, this should be the case.
R
F
10ꢀF
+V
R
R
S
F
+
G = 1
G
7
C
F
V
3
2
0.1ꢀF
IN
AD8047/
AD8048
V
R
6
OUT
TERM
0.1ꢀF
V
AD8047
4
OUT
C
I
I
I
R
G
10ꢀF
–V
S
R
F
Figure 5. Transimpedance Configuration
Pulse Response
Figure 3. Noninverting Operation
10ꢀF
Unlike a traditional voltage feedback amplifier, where the slew
speed is dictated by its front end dc quiescent current and gain
bandwidth product, the AD8047 and AD8048 provide on
demand current that increases proportionally to the input step
signal amplitude. This results in slew rates (1000 V/µs) compa-
rable to wideband current feedback designs. This, combined
with relatively low input noise current (1.0 pA/√Hz), gives the
AD8047 and AD8048 the best attributes of both voltage and
current feedback amplifiers.
+V
S
R
F
7
G =
–
3
2
0.1ꢀF
6
R
G
AD8047/
AD8048
V
OUT
0.1ꢀF
4
R
G
V
IN
R
TERM
10ꢀF
–V
S
R
F
Large Signal Performance
Figure 4. Inverting Operation
The outstanding large signal operation of the AD8047 and
AD8048 is due to a unique, proprietary design architecture.
In order to maintain this level of performance, the maximum
180 V-MHz product must be observed (e.g., @ 100 MHz,
VO ≤ 1.8 V p-p) on the AD8047 and the 250 V-MHz product
must be observed on the AD8048.
When the AD8047 is used in the transimpedance (I to V) mode,
such as in photodiode detection, the values of RF and diode
capacitance (CI) are usually known. Generally, the value of RF
selected will be in the kΩ range, and a shunt capacitor (CF)
across RF will be required to maintain good amplifier stability.
The value of CF required to maintain optimal flatness (<1 dB
Power Supply Bypassing
peaking) and settling time can be estimated as
1/2
Adequate power supply bypassing can be critical when optimiz-
ing the performance of a high frequency circuit. Inductance in
the power supply leads can form resonant circuits that produce
peaking in the amplifier’s response. In addition, if large current
transients must be delivered to the load, then bypass capacitors
(typically greater than 1 µF) will be required to provide the best
settling time and lowest distortion. A parallel combination of at
least 4.7 µF, and between 0.1 µF and 0.01 µF, is recommended.
Some brands of electrolytic capacitors will require a small series
damping resistor ≈4.7 Ω for optimum results.
2
2
CF ≅ (2 ωOCI RF –1)/ωO RF
[
]
where O is equal to the unity gain bandwidth product of
the amplifier in rad/sec, and CI is the equivalent total input
capacitance at the inverting input. Typically, O = 800 × 106 rad/sec
(see Open-Loop Frequency Response curve, TPC 15).
As an example, choosing RF = 10 kΩ and CI = 5 pF requires
CF to be 1.1 pF (Note: CI includes both source and parasitic
circuit capacitance). The bandwidth of the amplifier can be
estimated using the CF calculated as
Driving Capacitive Loads
The AD8047/AD8048 have excellent cap load drive capability
for high speed op amps, as shown in Figures 7 and 9. However,
when driving cap loads greater than 25 pF, the best frequency
response is obtained by the addition of a small series resistance.
1. 6
2πRF CF
f3 dB
≅
–12–
REV. A
AD8047/AD8048
It is worth noting that the frequency response of the circuit
when driving large capacitive loads will be dominated by the
passive roll-off of RSERIES and CL.
margin (65°), low noise current (1.0 pA/√Hz), and slew rate
(1000 V/µs) give higher performance capabilities to these appli-
cations over previous voltage feedback designs.
With a settling time of 30 ns to 0.01% and 13 ns to 0.1%, the
devices are an excellent choice for DAC I/V conversion. The
same characteristics along with low harmonic distortion make
them a good choice for ADC buffering/amplification. With
superb linearity at relatively high signal frequencies, the AD8047
and AD8048 are ideal drivers for ADCs up to 12 bits.
R
F
R
SERIES
AD8047
R
L
1kꢂ
C
L
Operation as a Video Line Driver
The AD8047 and AD8048 have been designed to offer out-
standing performance as video line drivers. The important
specifications of differential gain (0.01%) and differential phase
(0.02°) meet the most exacting HDTV demands for driving
video loads.
Figure 6. Driving Capacitive Loads
200ꢂ
200ꢂ
10ꢀF
0.1ꢀF
+V
S
7
75ꢂ
CABLE
2
3
75ꢂ
AD8047/
AD8048
75ꢂ
CABLE
V
6
OUT
0.1ꢀF
V
75ꢂ
IN
4
500mV
5ns
75ꢂ
10ꢀF
–V
S
Figure 7. AD8047 Large Signal Transient Response;
VO = 2 V p-p, G = +1, RF = 0 Ω, RSERIES = 0 Ω, CL = 27 pF
Figure 10. Video Line Driver
Active Filters
R
F
The wide bandwidth and low distortion of the AD8047 and
AD8048 are ideal for the realization of higher bandwidth active
filters. These characteristics, while being more common in many
current feedback op amps, are offered in the AD8047 and AD8048
in a voltage feedback configuration. Many active filter configu-
rations are not realizable with current feedback amplifiers.
R
SERIES
R
AD8048
IN
R
L
C
L
1kꢂ
A multiple feedback active filter requires a voltage feedback
amplifier and is more demanding of op amp performance than
other active filter configurations such as the Sallen-Key. In
general, the amplifier should have a bandwidth that is at least
10 times the bandwidth of the filter if problems due to phase
shift of the amplifier are to be avoided.
Figure 8. Driving Capacitive Loads
Figure 11 is an example of a 20 MHz low-pass multiple feed-
back active filter using an AD8048.
C1
50pF
10ꢀF
0.1ꢀF
+5V
R4
154ꢂ
1
R1
154ꢂ
R3
78.7ꢂ
7
2
3
V
IN
500mV
5ns
V
AD8048
4
6
C2
100pF
OUT
5
0.1ꢀF
Figure 9. AD8048 Large Signal Transient Response;
VO = 2 V p-p, G = +2, RF = RIN = 200 Ω, RSERIES = 0 Ω,
CL = 27 pF
100ꢂ
10ꢀF
–5V
Figure 11. Active Filter Circuit
APPLICATIONS
The AD8047 and AD8048 are voltage feedback amplifiers well
suited for such applications as photodetectors, active filters, and
log amplifiers. The devices’ wide bandwidth (260 MHz), phase
REV. A
–13–
AD8047/AD8048
Choose
Layout Considerations
The specified high speed performance of the AD8047 and
AD8048 requires careful attention to board layout and compo-
nent selection. Proper RF design techniques and low-pass
parasitic component selection are mandatory.
FO = Cutoff Frequency = 20 MHz
␣ = Damping Ratio = 1/Q = 2
–R4
R1
H = Absolute Value of Circuit Gain =
= 1
Then,
The PCB should have a ground plane covering all unused por-
tions of the component side of the board to provide a low
impedance path. The ground plane should be removed from the
area near the input pins to reduce stray capacitance.
k = 2 π FO C1
4 C1(H +1)
C2 =
R1=
R3 =
α2
α
Chip capacitors should be used for the supply bypassing (see
Figure 12). One end should be connected to the ground plane
and the other within 1/8 inch of each power pin. An additional
large (0.47 µF to 10 µF) tantalum electrolytic capacitor should
be connected in parallel, though not necessarily so close, to the
supply current for fast, large signal changes at the output.
2 HK
α
2 K (H +1)
R4 = H(R1)
The feedback resistor should be located close to the inverting
input pin in order to keep the stray capacitance at this node to a
minimum. Capacitance variations of less than 1 pF at the inverting
input will significantly affect high speed performance.
A/D Converter Driver
As A/D converters move toward higher speeds with higher reso-
lutions, there becomes a need for high performance drivers that
will not degrade the analog signal to the converter. It is desir-
able from a system’s standpoint that the A/D be the element in
the signal chain that ultimately limits overall distortion. This
places new demands on the amplifiers used to drive fast, high
resolution A/Ds.
Stripline design techniques should be used for long signal traces
(greater than about 1 inch). These should be designed with a
characteristic impedance of 50 Ω or 75 Ω and be properly termi-
nated at each end.
With high bandwidth, low distortion, and fast settling time,
the AD8047 and AD8048 make high performance A/D drivers
for advanced converters. Figure 12 is an example of an AD8047
used as an input driver for an AD872A, a 12-bit, 10 MSPS
A/D converter.
+5V DIGITAL
+5V ANALOG
10ꢂ
7
DV
DD
0.1ꢀF
0.1ꢀF
6
DGND
+5V DIGITAL
4
AV
DD
22
23
0.1ꢀF
+5V ANALOG
DRV
DD
5
AGND
DRGND
CLOCK INPUT
10ꢀF
0.1ꢀF
21
20
CLK
OTR
AD872A
49.9ꢂ
7
19
18
MSB
BIT2
2
3
1
V
AD8047
6
INA
17
16
15
14
13
12
11
10
ANALOG IN
BIT3
BIT4
BIT5
BIT6
0.1ꢀF
4
2
DIGITAL OUTPUT
10ꢀF
V
INB
BIT7
BIT8
BIT9
BIT10
BIT11
BIT12
27
REF GND
–5V
ANALOG
0.1ꢀF
1ꢀF
9
8
28
26
REF IN
24
AGND
REF OUT
AV
SS
AV
SS
3
25
0.1ꢀF
0.1ꢀF
–5V ANALOG
Figure 12. AD8047 Used as Driver for an AD872A, a 12-Bit, 10 MSPS A/D Converter
–14–
REV. A
AD8047/AD8048
OUTLINE DIMENSIONS
8-Lead Plastic Dual In-Line Package [PDIP]
(N-8)
Dimensions shown in inches and (millimeters)
0.375 (9.53)
0.365 (9.27)
0.355 (9.02)
8
1
5
0.295 (7.49)
0.285 (7.24)
0.275 (6.98)
4
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.100 (2.54)
BSC
0.150 (3.81)
0.135 (3.43)
0.120 (3.05)
0.015
(0.38)
MIN
0.180
(4.57)
MAX
0.015 (0.38)
0.010 (0.25)
0.008 (0.20)
0.150 (3.81)
0.130 (3.30)
0.110 (2.79)
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
SEATING
PLANE
0.060 (1.52)
0.050 (1.27)
0.045 (1.14)
COMPLIANT TO JEDEC STANDARDS MO-095AA
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
8-Lead Standard Small Outline Package [SOIC]
(R-8)
Dimensions shown in millimeters and (inches)
5.00 (0.1968)
4.80 (0.1890)
8
1
5
4
6.20 (0.2440)
5.80 (0.2284)
4.00 (0.1574)
3.80 (0.1497)
0.50 (0.0196)
0.25 (0.0099)
1.27 (0.0500)
BSC
ꢅ 45ꢃ
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
8ꢃ
0.51 (0.0201)
0.31 (0.0122)
0ꢃ 1.27 (0.0500)
COPLANARITY
0.10
0.25 (0.0098)
0.17 (0.0067)
SEATING
PLANE
0.40 (0.0157)
COMPLIANT TO JEDEC STANDARDS MS-012AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
REV. A
–15–
AD8047/AD8048
Revision History
Location
Page
7/03—Data Sheet changed from REV. 0 to REV. A.
Renumbered Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal
Deleted Evaluation Board Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Universal
Updated ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
–16–
REV. A
相关型号：
AD8047ARZ-REEL
IC OP-AMP, 4000 uV OFFSET-MAX, PDSO8, ROHS COMPLIANT, PLASTIC, SOIC-8, Operational Amplifier
ADI
©2020 ICPDF网 联系我们和版权申明