INA280
INA280
SBOSA19 – OCTOBER
2020
SBOSA19 – OCTOBER 2020
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INA280 2.7-V to 120-V, 1.1-MHz, High Precision Current Sense Amplifier in Small
(SC-70) Package
1 Features
3 Description
•
The INA280 is a current sense amplifier that can
measure voltage drops across shunt resistors over a
wide common-mode range from 2.7 V to 120 V. It is in
a highly space-efficient SC-70 package with a PCB
footprint of only 2.0 mm × 2.1 mm. The current
measurement accuracy is achieved thanks to the
combination of an ultra-low offset voltage of ±150 µV
(maximum), a small gain error of ±0.5% (maximum),
and a high DC CMRR of 140 dB (typical). The INA280
is not only designed for DC current measurement, but
also for high-speed applications (like fast overcurrent
protection, for example) with a high bandwidth of 1.1
MHz (at gain of 20 V/V) and an 85-dB AC CMRR (at
50 kHz).
•
•
•
•
•
•
Wide common-mode voltage:
– Operational voltage: 2.7 V to 120 V
– Survival voltage: −20 V to +122 V
Excellent CMRR:
– 120-dB DC (Minimum)
– 85-dB AC at 50 kHz
Accuracy
– Gain:
• Gain error: ±0.5% (maximum)
• Gain drift: ±20 ppm/°C (maximum)
– Offset:
• Offset voltage: ±150 µV (maximum)
• Offset drift: ±1 µV/°C (maximum)
Available gains:
– INA280A1: 20 V/V
– INA280A2: 50 V/V
– INA280A3: 100 V/V
– INA280A4: 200 V/V
– INA280A5: 500 V/V
High bandwidth: 1.1 MHz
Slew rate: 2 V/µs
Quiescent current: 370 µA
The INA280 operates from a single 2.7-V to 20-V
supply and draws a 370-μA supply current (typical).
The INA280 available with five gain options: 20 V/V,
50 V/V, 100 V/V, 200 V/V, and 500 V/V. The low offset
and drift of the INA280 enables accurate current
sensing over the extended operating temperature
range of −40°C to +125°C.
Device Information
PART NUMBER
INA280
2 Applications
•
•
•
•
•
Active antenna system mMIMO (AAS)
Macro remote radio unit (RRU)
48-V rack server
48-V merchant network & server power supply
Test and measurement
(1)
PACKAGE(1)
SC-70 (5)
BODY SIZE (NOM)
2.00 mm × 1.25 mm
For all available packages, see the package option
addendum at the end of the data sheet.
VS
VCM
ISENSE
R1
IN+
±
RSENSE
Bias
R1
IN±
Load
Current
Feedback
OUT
+
Buffer
SAR
ADC
RL
GND
Typical Application
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
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Copyright
© 2020 Texas
Instruments
Incorporated
intellectual
property
matters
and other important disclaimers. PRODUCTION DATA.
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Table of Contents
1 Features............................................................................1
2 Applications..................................................................... 1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Pin Configuration and Functions ..................................3
6 Specifications.................................................................. 4
6.1 Absolute Maximum Ratings ....................................... 4
6.2 ESD Ratings .............................................................. 4
6.3 Recommended Operating Conditions ........................4
6.4 Thermal Information ...................................................4
6.5 Electrical Characteristics ............................................5
6.6 Typical Characteristics................................................ 6
7 Detailed Description...................................................... 11
7.1 Overview................................................................... 11
7.2 Functional Block Diagram......................................... 11
7.3 Feature Description...................................................11
7.4 Device Functional Modes..........................................13
8 Application and Implementation.................................. 14
8.1 Application Information............................................. 14
8.2 Typical Application.................................................... 16
9 Power Supply Recommendations................................18
10 Layout...........................................................................18
10.1 Layout Guidelines................................................... 18
10.2 Layout Example...................................................... 18
11 Device and Documentation Support..........................19
11.1 Documentation Support.......................................... 19
11.2 Receiving Notification of Documentation Updates.. 19
11.3 Support Resources................................................. 19
11.4 Trademarks............................................................. 19
11.5 Electrostatic Discharge Caution.............................. 19
11.6 Glossary.................................................................. 19
12 Mechanical, Packaging, and Orderable
Information.................................................................... 19
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
2
DATE
REVISION
NOTES
October 2020
*
Initial Release
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5 Pin Configuration and Functions
OUT
1
GND
2
VS
3
5
IN±
4
IN+
Not to scale
Figure 5-1. DCK Package 5-Pin SC-70 Top View
Pin Functions
PIN
TYPE
NAME
NO.
GND
2
Ground
DESCRIPTION
Ground
IN–
5
Input
Connect to load side of shunt resistor
IN+
4
Input
Connect to supply side of shunt resistor
OUT
1
Output
Output voltage
VS
3
Power
Power supply
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
MIN
MAX
UNIT
Vs
Supply Voltage
–0.3
22
V
Analog Inputs,
VIN+, VIN– (2)
Differential (VIN+) – (VIN–)
–30
30
V
Common - mode
Output
TA
Operating Temperature
TJ
Junction temperature
Tstg
Storage temperature
(1)
(2)
–20
122
V
GND – 0.3
Vs + 0.3
V
–55
150
°C
150
°C
150
°C
–65
Stresses beyond those listed under Absolute Maximum Rating may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating Condition. Exposure to absolute-maximum-rated conditions for extended periods may affect device
reliability.
VIN+ and VIN– are the voltages at the VIN+ and VIN– pins, respectively.
6.2 ESD Ratings
VALUE
pins(1)
V(ESD)
(1)
(2)
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all
Electrostatic discharge Charged device model (CDM), per JEDEC specification JESD22-C101, all
pins(2)
UNIT
±2000
V
±1000
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
Common-mode input range(1)
VCM
MIN
NOM
MAX
UNIT
VS
48
120
V
5
VS
Operating supply range
2.7
TA
Ambient temperature
–40
(1)
20
V
125
°C
Common-mode voltage can go below VS under certain conditions. See Figure 7-1 for additional infromation on operating range.
6.4 Thermal Information
INA280
THERMAL METRIC(1)
DCK (SC-70)
UNIT
5 PINS
RθJA
Junction-to-ambient thermal resistance
191.6
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
144.4
°C/W
RθJB
Junction-to-board thermal resistance
69.2
°C/W
ΨJT
Junction-to-top characterization parameter
46.2
°C/W
ΨJB
Junction-to-board characterization parameter
69.0
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
N/A
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
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6.5 Electrical Characteristics
at TA = 25 °C, VS = 5 V, VSENSE = VIN+ – VIN– = 0.5 V / Gain, VCM = VIN– = 48 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
120
140
MAX
UNIT
INPUT
CMRR
Common-mode rejection ratio
VCM = 2.7 V to 120 V, TA = –40 °C to +125 °C
f = 50 kHz
dB
85
Vos
Offset voltage, input referred
dVos/dT
Offset voltage drift
TA = –40 °C to +125 °C
15
PSRR
Power supply rejection ratio,
input refered
VS = 2.7 V to 20 V, TA = –40 °C to +125 °C
IB
Input bias current
±150
µV
1
µV/℃
1
±10
µV/V
IB+, VSENSE = 0 mV
10
20
30
IB–, VSENSE = 0 mV
10
20
30
µA
OUTPUT
A1 devices
G
20
A2 devices
50
A3 devices
100
A4 devices
200
A5 devices
500
Gain error
GND + 50 mV ≤ VOUT ≤ VS – 200 mV
0.1
Gain error drift
TA = –40 °C to +125 °C
2.5
Gain
Nonlinearity error
Maximum capacitive load
No sustained oscillations, no isolation resistor
V/V
±0.5
%
20 ppm/°C
0.01
%
500
pF
VOLTAGE OUTPUT
Swing to VS power supply rail
RLOAD = 10 kΩ, TA = –40 °C to +125 °C
VS – 0.07
VS – 0.2
V
Swing to ground
RLOAD = 10 kΩ, VSENSE = 0 V, TA = –40 °C to
+125 °C
0.005
0.025
V
A1 devices, CLOAD = 5 pF, VSENSE = 200 mV
1100
A2 devices, CLOAD = 5 pF, VSENSE = 80 mV
1100
A3 devices, CLOAD = 5 pF, VSENSE = 40 mV
900
A4 devices, CLOAD = 5 pF, VSENSE = 20 mV
850
A5 devices, CLOAD = 5 pF, VSENSE = 8 mV
800
FREQUENCY RESPONSE
BW
SR
Bandwidth
Slew rate
Settling time
kHz
2
VOUT =4 V ± 0.1 V step, output settles to 0.5%
9
VOUT =4 V ± 0.1 V step, output settles to 1%
5
V/µs
µs
NOISE
Ven
Voltage noise density
50
nV/√Hz
POWER SUPPLY
VS
Supply voltage
IQ
Quiescent current
TA = –40 °C to +125 °C
2.7
20
370
TA = –40 °C to +125 °C
500
600
V
µA
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6.6 Typical Characteristics
All specifications at TA = 25 °C, VS = 5 V, VSENSE = VIN+ – VIN– = 0.5 V / Gain, and VCM = VIN– = 48 V, unless
otherwise noted.
160
Common-Mode Rejection Ratio (dB)
Common-Mode Rejection Ratio (nV/V)
200
100
0
G
G
G
G
G
-100
-200
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
=
=
=
=
=
20
50
100
200
500
150
140
120
100
80
60
40
20
0
10
175
Figure 6-1. Common-Mode Rejection Ratio vs
Temperature
100
1k
10k
Frequency (Hz)
100k
Figure 6-2. Common-Mode Rejection Ratio vs
Frequency
60
0.250
G
G
G
G
G
50
0.125
Gain Error (%)
Gain (dB)
40
30
20
10
0
-10
10
1M
G
G
G
G
G
=
=
=
=
=
20
50
100
200
500
100
=
=
=
=
=
20
50
100
200
500
0.000
-0.125
1k
10k
100k
Frequency (Hz)
1M
10M
-0.250
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
175
VSENSE = 4 V / Gain
Figure 6-4. Gain Error vs Temperature
25
25
20
20
15
VS
VS
VS
VS
10
=
=
=
=
5V
20V
2.7V
0V
5
VS
VS
VS
VS
VS
VS
VS
VS
15
10
5
=
=
=
=
=
=
=
=
2.7 to 20V, VCM = 48V
2.7 to 20V, VCM = 120V
2.7 to 5V, VCM = 2.7V
20V, VCM = 7V
2.7 to 20V, VCM = 0V
0V, VCM = 48V
0V, VCM = 120V
0 to 20V, VCM = -20V
0
0
-5
-20
Input Bias Current (PA)
Input Bias Current (PA)
Figure 6-3. Gain vs Frequency
0
20
40
60
80
Common-Mode Voltage (V)
100
120
-5
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
175
VSENSE = 0 V
Figure 6-5. Input Bias Current vs Common-Mode
Voltage
6
Figure 6-6. Input Bias Current vs Temperature
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140
240
IB+
IBIB+, VS = 0V
IB-, VS = 0V
Input Bias Current (PA)
160
100
120
80
40
0
-40
-80
80
60
40
20
0
-20
-40
-120
-60
-160
0
200
400
600
VSENSE (mV)
800
-80
1000
Figure 6-7. Input Bias Current vs VSENSE, A1
devices
0
100
200
VSENSE (mV)
300
400
Figure 6-8. Input Bias Current vs VSENSE, A2 and
A3 devices
100
VS
IB+, G=200
IB+, G=500
IBIB+, VS = 0V
IB-, VS = 0V
60
25qC
125qC
-40qC
VS - 1
Output Voltage (V)
80
Input Bias Current (PA)
IB+
IBIB+, VS = 0V
IB-, VS = 0V
120
Input Bias Current (PA)
200
40
20
VS - 2
GND + 2
GND + 1
0
GND
0
-20
0
20
40
60
VSENSE (mV)
80
10
15
20
25
Output Current (mA)
30
35
40
VS = 2.7 V
Figure 6-9. Input Bias Current vs VSENSE, A4 and
A5 devices
Figure 6-10. Output Voltage vs Output Current
VS
VS
25qC
125qC
-40qC
VS - 1
VS - 2
VS - 3
GND + 3
VS - 2
VS - 3
GND + 3
GND + 2
GND + 2
GND + 1
GND + 1
GND
25qC
125qC
-40qC
VS - 1
Output Voltage (V)
Output Voltage (V)
5
100
GND
0
5
10
15
20
25
Output Current (mA)
30
35
40
VS = 5 V
0
5
10
15
20
25
Output Current (mA)
30
35
40
VS = 20 V
Figure 6-11. Output Voltage vs Output Current
Figure 6-12. Output Voltage vs Output Current
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0.00
200
100
50
-0.10
20
10
5
Swing to VS (V)
Output Impedance (:)
1000
500
2
1
0.5
0.2
0.1
0.05
-0.20
-0.30
-0.40
0.02
0.01
10
100
1k
10k
100k
Frequency (Hz)
1M
-0.50
-75
10M
VS = 5V
VS = 20V
VS = 2.7V
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
175
RL = 10 kΩ
Figure 6-13. Output Impedance vs Frequency
Figure 6-14. Swing to Supply vs Temperature
0.020
100
Input-Referred Voltage Noise (nV/—Hz)
VS = 5V
VS = 20V
VS = 2.7V
Swing to GND (V)
0.015
0.010
0.005
0.000
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
G = 20
G = 500
80
70
60
50
40
30
20
10
10
175
100
1k
10k
Frequency (Hz)
100k
1M
RL = 10 kΩ
Figure 6-15. Swing to GND vs Temperature
Figure 6-16. Input Referred Noise vs Frequency
400
Quiescent Current (PA)
Referred-to-Input
Voltage Noise (200 nV/div)
375
350
325
300
275
250
225
VS = 5V
VS = 20V
VS = 2.7V
200
175
0
Time (1 s/div)
Figure 6-17. Input Referred Noise
8
2.5
5
7.5
10
12.5
Output Voltage (V)
15
17.5
20
Figure 6-18. Quiescent Current vs Output Voltage
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50
425
375
350
325
VS = 5V
VS = 20V
VS = 2.7V
300
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
40
Short Circuit Current (mA)
Quiescent Current (PA)
400
30
0
-75
-50
-25
0
25
50
75 100
Temperature (qC)
125
150
175
Figure 6-20. Short-Circuit Current vs Temperature
425
VS = 5V
VS = 20V
VS = 2.7V
400
Quiescent Current (PA)
400
Quiescent Current (PA)
5V, Sourcing
5V, Sinking
20V, Sourcing
20V, Sinking
2.7V, Sourcing
2.7V, Sinking
10
425
375
350
325
375
350
325
25qC
125qC
-40qC
300
-20
300
4
6
8
10
12
14
Supply Voltage (V)
16
18
20
Figure 6-21. Quiescent Current vs Supply Voltage
2.7V
2.5V
Output Voltage (2.5V/div)
VCM
VOUT
Time (12.5Ps/div)
RL = 10 kΩ
0
20
40
60
80
Common-Mode Voltage (V)
100
120
Figure 6-22. Quiescent Current vs Common-Mode
Voltage
Output Voltage
500 mV/div
2
0V
Input Voltage
5 mV/div
0
Common-Mode Voltage (20V/div)
=
=
=
=
=
=
20
175
Figure 6-19. Quiescent Current vs Temperature
VS
VS
VS
VS
VS
VS
0V
VSENSE = 5 mV
Time (10 Ps/div)
Figure 6-23. Common-Mode Voltage Fast Transient
Pulse, A5 devices
Figure 6-24. Step Response, A3 devices
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Voltage (1 V/div)
Voltage (1 V/div)
Supply Voltage
Output Voltage
0V
0V
Time (5 Ps/div)
Time (25 Ps/div)
VSENSE = 0 mV
VSENSE = 5 mV
Figure 6-25. Start-Up Response
10
Supply Voltage
Output Voltage
Figure 6-26. Supply Transient Response, A5
devices
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7 Detailed Description
7.1 Overview
The INA280 is a high-side only current-sense amplifier that offers a wide common-mode range, excellent
common-mode rejection ratio (CMRR), high bandwidth, and fast slew rate. Different gain versions are available
to optimize the output dynamic range based on the application. The INA280 is designed using a
transconductance architecture with a current-feedback amplifier that enables low bias currents of 20 µA and a
common-mode voltage of 120 V.
7.2 Functional Block Diagram
VS
VCM
ISENSE
R1
IN+
±
RSENSE
Current
Feedback
Bias
R1
OUT
+
IN±
Buffer
Load
RL
GND
7.3 Feature Description
7.3.1 Amplifier Input Common-Mode Range
Minimum Common-Mode Input Voltage (V)
The INA280 supports large input common-mode voltages from 2.7 V to 120 V and features a high DC CMRR of
140 dB (typical) and a 85-dB AC CMRR at 50 kHz. The minimum common-mode voltage is restricted by the
supply voltage as shown in Figure 7-1. The topology of the internal amplifiers INA280 restricts operation to highside, current-sensing applications.
8
7
6
5
4
3
2
VCM = 2.7V
1
0
0
2.5
5
7.5
10
12.5
Supply Voltage (V)
15
17.5
20
Figure 7-1. Minimum Common-Mode Voltage vs Supply
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7.3.1.1 Input-Signal Bandwidth
The INA280 –3-dB bandwidth is gain dependent with several gain options of 20 V/V, 50 V/V, 100 V/V, 200 V/V,
and 500 V/V as shown in Figure 6-2. The unique multistage design enables the amplifier to achieve high
bandwidth at all gains. This high bandwidth provides the throughput and fast response that is required for the
rapid detection and processing of overcurrent events.
The bandwidth of the device also depends on the applied VSENSE voltage. Figure 7-2 shows the bandwidth
performance profile of the device over frequency as output voltage increases for each gain variation. As shown
in Figure 7-2, the device exhibits the highest bandwidth with higher VSENSE voltages, and the bandwidth is higher
with lower device gain options. Individual requirements determine the acceptable limits of error for highfrequency, current-sensing applications. Testing and evaluation in the end application or circuit is required to
determine the acceptance criteria and validate whether or not the performance levels meet the system
specifications.
1200
1100
Bandwidth (kHz)
1000
900
800
700
600
500
G
G
G
G
G
400
300
=
=
=
=
=
20
50
100
200
500
200
0
0.5
1
1.5
2
2.5
Output Voltage (V)
3
3.5
4
Figure 7-2. Bandwidth vs Output Voltage
7.3.1.2 Low Input Bias Current
The INA280 input bias current draws 20 μA (typical) even with common-mode voltages as high as 120 V. This
enables precision current sensing in applications where the sensed current is small or applications that require
lower input leakage current.
7.3.1.3 Multiple Fixed Gain Outputs
The INA280 gain error is < 0.5% at room temperature for all gain options, with a maximum drift of 20ppm/°C over
the full temperature range of –40 °C to +125 °C. The INA280 is available in multiple gain options of 20 V/V, 50
V/V, 100 V/V, 200 V/V, and 500 V/V, which the system designer should select based on their desired signal-tonoise ratio and other system requirements.
The INA280 closed-loop gain is set by a precision, low-drift internal resistor network. Even though the ratio of
these resistors are well matched, the absolute value of these reisistors may vary significantly. TI does not
recommend adding additional resistance around the INA280 to change the effective gain because of this
variation, however. The typical values of the gain resistors are described in Table 7-1.
Table 7-1. Fixed Gain Resistor
12
GAIN
R1
RL
20 (V/V)
25 kΩ
500 kΩ
50 (V/V)
10 kΩ
500 kΩ
100 (V/V)
10 kΩ
1000 kΩ
200 (V/V)
5 kΩ
1000 kΩ
500 (V/V)
2 kΩ
1000 kΩ
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7.3.1.4 Wide Supply Range
The INA280 operates with a wide supply range from a 2.7 V to 20 V. The output stage supports a full-scale
output voltage range of up to VS. Wide output range can enable very-wide dynamic range current
measurements. For a gain of 20 V/V, the maximum differential input acceptable is 1 V.
7.4 Device Functional Modes
7.4.1 Unidirectional Operation
The INA280 measures the differential voltage developed by current flowing through a resistor that is commonly
referred to as a current-sensing resistor or a current-shunt resistor. The INA280 operates in unidirectional mode
only, meaning it only senses current sourced from a power supply to a system load as shown in Figure 7-3.
5V
48-V
Supply
ISENSE
R1
IN+
±
RSENSE
Bias
R1
Current
Feedback
+
IN±
Buffer
OUT
RL
Load
GND
Figure 7-3. Unidirectional Application
The linear range of the output stage is limited to how close the output voltage can approach ground under zeroinput conditions. The zero current output voltage of the INA280 is very small, with a maximum of GND + 25 mV.
Make sure to apply a sense voltage of (25 mV / Gain) or greater to keep the INA280 output in the linear region of
operation.
7.4.2 High Signal Throughput
With a bandwidth of 1.1 MHz at a gain of 20 V/V and a slew rate of 2 V/µs, the INA280 is specifically designed
for detecting and protecting applications from fast inrush currents. As shown in Table 7-2, the INA280 responds
in less than 2 µs for a system measuring a 75-A threshold on a 2-mΩ shunt.
Table 7-2. Response Time
PARAMETER
G
EQUATION
INA280
AT VS = 5 V
Gain
20 V/V
IMAX
Maximum current
100 A
IThreshold
Threshold current
75 A
RSENSE
Current sense resistor value
VOUT_MAX
Output voltage at maximum current
VOUT = IMAX × RSENSE × G
VOUT_THR
Output voltage at threshold current
VOUT_THR = ITHR × RSENSE × G
SR
Slew rate
Output response time
2 mΩ
4V
3V
2 V/µs
Tresponse = VOUT_THR / SR
< 2 µs
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8 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification, and TI
does not warrant its accuracy or completeness. TI’s customers are responsible for determining
suitability of components for their purposes. Customers should validate and test their design
implementation to confirm system functionality.
8.1 Application Information
The INA280 amplifies the voltage developed across a current-sensing resistor as current flows through the
resistor to the load. The wide input common-mode voltage range and high common-mode rejection of the
INA280 allows use over a wide range of voltage rails while still maintaining an accurate current measurement.
8.1.1 RSENSE and Device Gain Selection
The accuracy of any current-sense amplifier is maximized by choosing the current-sense resistor to be as large
as possible. A large sense resistor maximizes the differential input signal for a given amount of current flow and
reduces the error contribution of the offset voltage. However, there are practical limits as to how large the
current-sense resistor can be in a given application because of the resistor size and maximum allowable power
dissipation. Equation 1 gives the maximum value for the current-sense resistor for a given power dissipation
budget:
RSENSE
PDMAX
IMAX2
(1)
where:
•
•
PDMAX is the maximum allowable power dissipation in RSENSE.
IMAX is the maximum current that will flow through RSENSE.
An additional limitation on the size of the current-sense resistor and device gain is due to the power-supply
voltage, VS, and device swing-to-rail limitations. To make sure that the current-sense signal is properly passed to
the output, both positive and negative output swing limitations must be examined. Equation 2 provides the
maximum values of RSENSE and GAIN to keep the device from exceeding the positive swing limitation.
IMAX ª RSENSE ª *$,1 < VSP
(2)
where:
•
•
•
IMAX is the maximum current that will flow through RSENSE.
GAIN is the gain of the current-sense amplifier.
VSP is the positive output swing as specified in the data sheet.
To avoid positive output swing limitations when selecting the value of RSENSE, there is always a trade-off
between the value of the sense resistor and the gain of the device under consideration. If the sense resistor
selected for the maximum power dissipation is too large, then it is possible to select a lower-gain device in order
to avoid positive swing limitations.
The negative swing limitation places a limit on how small the sense resistor value can be for a given application.
Equation 3 provides the limit on the minimum value of the sense resistor.
IMIN ª RSENSE ª *$,1 > VSN
(3)
where:
•
•
14
IMIN is the minimum current that will flow through RSENSE.
GAIN is the gain of the current-sense amplifier.
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VSN is the negative output swing of the device.
Table 8-1 shows an example of the different results obtained from using five different gain versions of the
INA280. From the table data, the highest gain device allows a smaller current-shunt resistor and decreased
power dissipation in the element.
Table 8-1. RSENSE Selection and Power Dissipation
PARAMETER(1)
G
Gain
VSENSE
Ideal differential input voltage (Ignores
swing limitation and power supply
variation.)
RSENSE
Current sense resistor value
PSENSE
Current-sense resistor power dissipation
(1)
RESULTS AT VS = 5 V
EQUATION
INA280A1
INA280A2
INA280A3
INA280A4
INA280A5
20 V/V
50 V/V
100 V/V
200 V/V
500 V/V
VSENSE = VOUT / G
250 mV
100 mV
50 mV
25 mV
10 mV
RSENSE = VSENSE / IMAX
25 mΩ
10 mΩ
5 mΩ
2.5 mΩ
1 mΩ
RSENSE x IMAX2
2.5 W
1W
0.5W
0.25 W
0.1 W
Design example with 10-A full-scale current with maximum output voltage set to 5 V.
8.1.2 Input Filtering
Note
Input filters are not required for accurate measurements using the INA280, and use of filters in this
location is not recommended. If filter components are used on the input of the amplifier, follow the
guidelines in this section to minimize the effects on performance.
Based strictly on user design requirements, external filtering of the current signal may be desired. The initial
location that can be considered for the filter is at the output of the current-sense amplifier. Although placing the
filter at the output satisfies the filtering requirements, this location changes the low output impedance measured
by any circuitry connected to the output voltage pin. The other location for filter placement is at the current-sense
amplifier input pins. This location also satisfies the filtering requirement, but the components must be carefully
selected to minimally impact device performance. Figure 8-1 shows a filter placed at the input pins.
VS
VCM
f3dB =
1
4ŒRINCIN
ISENSE
RIN
R1
IN+
+
CIN
RSENSE
Bias
RIN
R1
IN±
Current
Feedback
OUT
-
Load
Buffer
RL
GND
Figure 8-1. Filter at Input Pins
External series resistance provides a source of additional measurement error, so keep the value of these series
resistors to 10 Ω or less to reduce loss of accuracy. The internal bias network shown in Figure 38 creates a
mismatch in input bias currents (see Figure 6-7, Figure 6-8, and Figure 6-9) when a differential voltage is applied
between the input pins. If additional external series filter resistors are added to the circuit, a mismatch is created
in the voltage drop across the filter resistors. This voltage is a differential error voltage in the shunt resistor
voltage. In addition to the absolute resistor value, mismatch resulting from resistor tolerance can significantly
impact the error because this value is calculated based on the actual measured resistance.
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The measurement error expected from the additional external filter resistors can be calculated using Equation 4,
where the gain error factor is calculated using Equation 5.
Gain Error (%) = 100 x (Gain Error Factor í 1)
(4)
The gain error factor, shown in Equation 4, can be calculated to determine the gain error introduced by the
additional external series resistance. Equation 4 calculates the deviation of the shunt voltage, resulting from the
attenuation and imbalance created by the added external filter resistance. Table 8-2 provides the gain error
factor and gain error for several resistor values.
Gain Error Factor =
RB × R1
(RB × R1) + (RB × RIN) + (2 × RIN × R1)
(5)
Where:
• RIN is the external filter resistance value.
• R1 is the INA280 input resistance value specified in Table 7-1.
• RB in the internal bias resistance, which is 6600 Ω ± 20%.
Table 8-2. Example Gain Error Factor and Gain Error for 10-Ω External Filter Input Resistors
DEVICE (GAIN)
GAIN ERROR FACTOR
GAIN ERROR (%)
A1 devices (20)
0.99658
–0.34185
A2 devices (50)
0.99598
–0.40141
A3 devices (100)
0.99598
–0.40141
A4 devices (200)
0.99499
–0.50051
A5 devices (500)
0.99203
–0.79663
8.2 Typical Application
The INA280 is a unidirectional, current-sense amplifier capable of measuring currents through a resistive shunt
with shunt common-mode voltages from 2.7 V to 120 V. The circuit configuration for monitoring current in a highside radio frequency (RF) power amplifier (PA) application is shown in Figure 8-2.
54 V
+
ADC
INA280
±
RF
Out
GND
Microprocessor
RF
DAC
GND
Figure 8-2. Current Sensing in a PA Application
16
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8.2.1 Design Requirements
VSUPPLY is set to 5 V, and the common-mode voltage set to 54 V. Table 8-3 lists the design setup for this
application.
Table 8-3. Design Parameters
DESIGN PARAMETERS
EXAMPLE VALUE
INA280 supply voltage
5V
High-side supply voltage
5V
Maximum sense current (IMAX)
5A
Gain option
50 V/V
8.2.2 Detailed Design Procedure
The maximum value of the current-sense resistor is calculated based choice of gain, value of the maximum
current the be sensed (IMAX), and the power-supply voltage (VS). When operating at the maximum current, the
output voltage must not exceed the positive output swing specification, VSP. Under the given design parameters,
Equation 6 calculates the maximum value for RSENSE as 19.2 mΩ.
RSENSE <
VSP
IMAX u GAIN
(6)
For this design example, a value of 15 mΩ is selected because, while the 15 mΩ is less than the maximum value
calculated, 15 mΩ is still large enough to give adequate signal at the current-sense amplifier output.
8.2.2.1 Overload Recovery With Negative VSENSE
The INA280 is a unidirectional current-sense amplifier that is meant to operate with a positive differential input
voltage (VSENSE). If negative VSENSE is applied, the device is placed in an overload condition and requires time to
recover once VSENSE returns positive. The required overload recovery time increases with more negative
VSENSE.
8.2.3 Application Curve
Figure 8-3 shows the output response of the device to a high frequency sinusoidal current.
VSENSE (20 mV/div)
A2 Device VOUT (1 V/div)
Time (10Ps/div)
INA2
Figure 8-3. INA280 Output Response
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9 Power Supply Recommendations
The input circuitry of the INA280 device can accurately measure beyond the power-supply voltage. The power
supply can be 20 V, whereas the load power-supply voltage at IN+ and IN– can go up to 120 V. The output
voltage range of the OUT pin is limited by the voltage on the VS pin and the device swing to supply specification.
10 Layout
10.1 Layout Guidelines
TI always recommends to follow good layout practices:
• Connect the input pins to the sensing resistor using a Kelvin or 4-wire connection. This connection technique
makes sure that only the current-sensing resistor impedance is detected between the input pins. Poor routing
of the current-sensing resistor commonly results in additional resistance present between the input pins.
Given the very low ohmic value of the current resistor, any additional high-current carrying impedance can
cause significant measurement errors.
• Place the power-supply bypass capacitor as close to the device power supply and ground pins as possible.
The recommended value of this bypass capacitor is 0.1 µF. Additional decoupling capacitance can be added
to compensate for noisy or high-impedance power supplies.
• When routing the connections from the current-sense resistor to the device, keep the trace lengths as short
as possible.
10.2 Layout Example
Load
RSENSE
TI Device
Current Sense
Output
OUT 1
5 IN±
Direction of
Current Flow
GND 2
Power Supply, VS
(2.7 V to 20 V)
VS 3
4 IN+
CBYPASS
VIA to Ground
Plane
Bus Voltage
Figure 10-1. Recommended Layout for INA280
18
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
For related documentation, see the following:
Texas Instruments, INA280EVM User's Guide
11.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
11.3 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
11.4 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
11.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
11.6 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
INA280A1IDCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HP
INA280A1IDCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HP
INA280A2IDCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HQ
INA280A2IDCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HQ
INA280A3IDCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HR
INA280A3IDCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HR
INA280A4IDCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HS
INA280A4IDCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HS
INA280A5IDCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HT
INA280A5IDCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-40 to 125
1HT
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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