Data Sheet
FEATURES
±600 V common-mode voltage range
Rail-to-rail output
Fixed gain of 1
Wide power supply range of ±2.5 V to ±18 V
550 μA typical power supply current
Excellent ac specifications
90 dB minimum CMRR
130 kHz bandwidth
High accuracy dc performance
5 ppm maximum gain nonlinearity
10 µV/°C maximum offset voltage drift
5 ppm/°C maximum gain drift
Very High Common-Mode Voltage
Precision Difference Amplifier
AD8479
FUNCTIONAL BLOCK DIAGRAM
AD8479
REF(–)
1
8
NC
+V
S
OUTPUT
–IN
2
+IN
3
1MΩ
7
6
1MΩ
5
–V
S 4
REF(+)
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
APPLICATIONS
High voltage current sensing
Battery cell voltage monitors
Power supply current monitors
Motor controls
Isolation
Figure 1.
GENERAL DESCRIPTION
The
AD8479
is a difference amplifier with a very high input
common-mode voltage range. The
AD8479
is a precision device
that allows the user to accurately measure differential signals in
the presence of high common-mode voltages up to ±600 V.
The
AD8479
can replace costly isolation amplifiers in applications
that do not require galvanic isolation. The device operates over
a ±600 V common-mode voltage range and has inputs that are
protected from common-mode or differential mode transients
up to ±600 V.
The
AD8479
has low offset voltage, low offset voltage drift,
low gain drift, low common-mode rejection drift, and excellent
common-mode rejection ratio (CMRR) over a wide frequency
range.
The
AD8479
is available in a space-saving 8-lead SOIC package
and is operational over the −40°C to +125°C temperature range.
800
V
S
= ±15V
600
COMMON-MODE VOLTAGE (V)
400
V
S
= ±5V
200
0
–200
–400
–600
–800
–20
11118-001
–15
–10
–5
0
V
OUT
(V)
5
10
15
20
Figure 2. Input Common-Mode Voltage vs. Output Voltage
Rev. A
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11118-110
AD8479* PRODUCT PAGE QUICK LINKS
Last Content Update: 02/23/2017
COMPARABLE PARTS
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REFERENCE MATERIALS
Press
•
High Common-Mode Voltage Difference Amplifier
Enables Direct Interface to High Voltage Input up to ±600
V
EVALUATION KITS
•
AD8479 Evaulation Board for the Precision Difference
Amplifier
DESIGN RESOURCES
•
AD8479 Material Declaration
•
PCN-PDN Information
•
Quality And Reliability
•
Symbols and Footprints
DOCUMENTATION
Application Notes
•
AN-1308: Common-Mode Step Response of Current Sense
Amplifiers
•
AN-1344: High Common-Mode Voltage Current Loop
Transmitter Front End
•
AN-1375: Output Current Monitoring of High Voltage
Class D Amplifiers
Data Sheet
•
AD8479: Very High Common-Mode Voltage Precision
Difference Amplifier Data Sheet
Technical Books
•
A Designer's Guide to Instrumentation Amplifiers, 3rd
Edition, 2006
User Guides
•
AD8479: Evaluation Board for the Precision Difference
Amplifier (Wiki site)
DISCUSSIONS
View all AD8479 EngineerZone Discussions.
SAMPLE AND BUY
Visit the product page to see pricing options.
TECHNICAL SUPPORT
Submit a technical question or find your regional support
number.
DOCUMENT FEEDBACK
Submit feedback for this data sheet.
TOOLS AND SIMULATIONS
•
AD8479 SPICE Macro Model
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AD8479
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 11
Data Sheet
Applications Information .............................................................. 12
Basic Connections ...................................................................... 12
Single-Supply Operation ........................................................... 12
System-Level Decoupling and Grounding .............................. 12
Using a Large Shunt Resistor .................................................... 13
Output Filtering .......................................................................... 14
Gain of 60 Differential Amplifier ............................................. 14
Error Budget Analysis Example ............................................... 15
Outline Dimensions ....................................................................... 16
Ordering Guide .......................................................................... 16
REVISION HISTORY
9/15—Rev. 0 to Rev. A
Changes to Single-Supply Operation Section ............................. 12
4/13—Revision 0: Initial Version
Rev. A | Page 2 of 16
Data Sheet
SPECIFICATIONS
V
S
= ±15 V, REF(−) = REF(+) = 0 V, R
L
= 2 kΩ, T
A
= 25°C, unless otherwise noted.
Table 1.
Parameter
GAIN
Nominal Gain
Gain Error
Gain Nonlinearity
Gain Drift
OFFSET VOLTAGE
Offset Voltage
Offset Voltage Drift
Power Supply Rejection
Ratio (PSRR)
INPUT
Common-Mode Rejection
Ratio (CMRR)
Test Conditions/Comments
V
OUT
= ±10 V, R
L
= 2 kΩ
Min
A Grade
Typ
Max
1
0.01
4
3
0.5
0.5
3
100
Min
B Grade
Typ
Max
1
0.005
2
3
0.5
0.5
3
100
AD8479
Unit
V/V
%
ppm
ppm/°C
mV
mV
µV/°C
dB
T
A
= T
MIN
to T
MAX
V
S
= ±15 V
V
S
= ±5 V
T
A
= T
MIN
to T
MAX
V
S
= ±2.5 V to ±15 V
0.02
10
5
3
3
15
90
0.01
5
5
1
1
10
84
V
CM
= ±600 V dc
T
A
= 25°C
T
A
= T
MIN
to T
MAX
V
CM
= 1200 V p-p, dc to 12 kHz
Common-mode
Differential
Common-mode
Differential
80
80
80
90
90
90
80
±600
±14.7
500
2
−V
S
+ 0.3
±55
Stable operation
500
130
7.5
100
11
15.4
30
1.6
±2.5
V
OUT
= 0 V
T
A
= T
MIN
to T
MAX
T
A
= T
MIN
to T
MAX
−40
−40
550
850
8
+V
S
− 0.3
−V
S
+ 0.3
±55
500
130
7.5
100
11
15.4
30
1.6
±2.5
550
850
−40
−40
8
500
2
+V
S
− 0.3
96
dB
dB
dB
V
V
kΩ
MΩ
V
mA
pF
kHz
V/µs
kHz
µs
µs
µV p-p
μV/√Hz
V
μA
μA
°C
°C
Operating Voltage Range
Input Operating
Impedance
OUTPUT
Output Voltage Swing
Output Short-Circuit
Current
Capacitive Load
DYNAMIC RESPONSE
Small Signal −3 dB
Bandwidth
Slew Rate
Full Power Bandwidth
Settling Time
OUTPUT VOLTAGE NOISE
0.01 Hz to 10 Hz
Noise Spectral Density
POWER SUPPLY
Operating Voltage Range
Supply Current
TEMPERATURE RANGE
Specified Performance
Operational
±600
±14.7
R
L
= 2 kΩ
V
OUT
= 20 V p-p
0.01%, V
OUT
= 10 V step
0.001%, V
CM
= 10 V step
35
35
f ≥ 100 Hz
±18
650
±18
650
+85
+125
+85
+125
Rev. A | Page 3 of 16
AD8479
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Supply Voltage, V
S
Input Voltage Range
Continuous
Common-Mode and Differential,
10 sec
Output Short-Circuit Duration
REF(−) and REF(+)
Maximum Junction Temperature
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 60 sec)
Rating
±18 V
±600 V
±900 V
Indefinite
−V
S
− 0.3 V to +V
S
+ 0.3 V
150°C
−40°C to +125°C
−65°C to +150°C
300°C
Data Sheet
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
ESD CAUTION
Rev. A | Page 4 of 16
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