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INA219
SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015
INA219 Zerø-Drift, Bidirectional Current/Power Monitor With I2C Interface
1 Features
3 Description
•
•
•
•
The INA219 is a current shunt and power monitor
with an I2C- or SMBUS-compatible interface. The
device monitors both shunt voltage drop and bus
supply voltage, with programmable conversion times
and filtering. A programmable calibration value,
combined with an internal multiplier, enables direct
readouts of current in amperes. An additional
multiplying register calculates power in watts. The
I2C- or SMBUS-compatible interface features 16
programmable addresses.
1
•
•
•
Senses Bus Voltages from 0 to 26 V
Reports Current, Voltage, and Power
16 Programmable Addresses
High Accuracy: 0.5% (Maximum) Over
Temperature (INA219B)
Filtering Options
Calibration Registers
SOT23-8 and SOIC-8 Packages
The INA219 is available in two grades: A and B. The
B grade version has higher accuracy and higher
precision specifications.
2 Applications
•
•
•
•
•
•
•
•
Servers
Telecom Equipment
Notebook Computers
Power Management
Battery Chargers
Welding Equipment
Power Supplies
Test Equipment
The INA219 senses across shunts on buses that can
vary from 0 to 26 V. The device uses a single 3- to
5.5-V supply, drawing a maximum of 1 mA of supply
current. The INA219 operates from –40°C to 125°C.
Device Information(1)
PART NUMBER
INA219
PACKAGE
BODY SIZE (NOM)
SOIC (8)
3.91 mm × 4.90 mm
SOT-23 (8)
1.63 mm × 2.90 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
VS
(Supply Voltage)
VIN+ VIN-
INA219
´
Power Register
Data
2
Current Register
PGA
I C-/SMBUSCompatible
Interface
CLK
A0
ADC
Voltage Register
A1
GND
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
INA219
SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Related Products ...................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
3
4
7.1
7.2
7.3
7.4
7.5
7.6
7.7
4
4
4
4
5
6
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics:..........................................
Bus Timing Diagram Definitions................................
Typical Characteristics ..............................................
Detailed Description .............................................. 9
8.1 Overview ................................................................... 9
8.2 Functional Block Diagram ......................................... 9
8.3
8.4
8.5
8.6
9
Feature Description................................................... 9
Device Functional Modes........................................ 11
Programming........................................................... 12
Register Maps ........................................................ 18
Application and Implementation ........................ 25
9.1 Application Information............................................ 25
9.2 Typical Application ................................................. 25
10 Power Supply Recommendations ..................... 27
11 Layout................................................................... 27
11.1 Layout Guidelines ................................................. 27
11.2 Layout Example .................................................... 27
12 Device and Documentation Support ................. 28
12.1
12.2
12.3
12.4
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
28
28
28
28
13 Mechanical, Packaging, and Orderable
Information ........................................................... 28
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision F (September 2011) to Revision G
Page
•
Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section ................................................................................................. 1
•
Updated Bus Timing Diagram Definitions table. I2C timing table values were previously based on simulation and not
characterized .......................................................................................................................................................................... 6
Changes from Revision E (September 2010) to Revision F
•
Changed step 5 and step 6 values in Table 8...................................................................................................................... 26
Changes from Revision D (September 2010) to Revision E
•
2
Page
Page
Updated Packaging Information table .................................................................................................................................... 3
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SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015
5 Related Products
DEVICE
DESCRIPTION
INA209
Current/power monitor with watchdog, peak-hold, and fast comparator functions
INA210, INA211, INA212, INA213, INA214
Zerø-drift, low-cost, analog current shunt monitor series in small package
6 Pin Configuration and Functions
DCN Package
8-Pin SOT-23
Top View
D Package
8-Pin SOIC
Top View
IN+
1
8
A1
IN–
2
7
A0
GND
3
6
SDA
VS
4
5
SCL
A1
1
8
IN+
A0
2
7
IN–
SDA
3
6
GND
SCL
4
5
VS
Pin Functions
PIN
NAME
I/O
DESCRIPTION
SOT-23
SOIC
IN+
1
8
Analog
Input
Positive differential shunt voltage. Connect to positive side of shunt resistor.
IN–
2
7
Analog
Input
Negative differential shunt voltage. Connect to negative side of shunt resistor. Bus voltage is
measured from this pin to ground.
GND
3
6
Analog
Ground
VS
4
5
Analog
Power supply, 3 to 5.5 V
Serial bus clock line
SCL
5
4
Digital
Input
SDA
6
3
Digital
I/O
Serial bus data line
A0
7
2
Digital
Input
Address pin. Table 1 shows pin settings and corresponding addresses.
A1
8
1
Digital
Input
Address pin. Table 1 shows pin settings and corresponding addresses.
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SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015
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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
MIN
VS
Supply voltage
UNIT
6
V
–26
26
V
-0.3
26
V
SDA
GND – 0.3
6
V
SCL
GND – 0.3
Analog Inputs
IN+, IN–
Differential (VIN+ – VIN–)
(2)
MAX
Common-mode(VIN+ + VIN–) / 2
VS + 0.3
V
Input current into any pin
5
mA
Open-drain digital output current
10
mA
125
°C
150
°C
150
°C
Operating temperature
–40
TJ
Junction temperature
Tstg
Storage temperature
(1)
(2)
–65
Stresses beyond those listed under Absolute Maximum Ratings 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 Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
VIN+ and VIN– may have a differential voltage of –26 to 26 V; however, the voltage at these pins must not exceed the range –0.3 to 26 V.
7.2 ESD Ratings
VALUE
Electrostatic
discharge
V(ESD)
(1)
(2)
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins (1)
±4000
Charged device model (CDM), per JEDEC specification JESD22-C101, all pins (2)
±750
Machine Model (MM)
±200
UNIT
V
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.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
VCM
MAX
12
VS
V
3.3
TA
UNIT
V
–25
85
ºC
7.4 Thermal Information
INA219
THERMAL METRIC (1)
D (SOIC)
DCN (SOT)
UNIT
8 PINS
8 PINS
RθJA
Junction-to-ambient thermal resistance
111.3
135.4
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
55.9
68.1
°C/W
RθJB
Junction-to-board thermal resistance
52
48.9
°C/W
ψJT
Junction-to-top characterization parameter
10.7
9.9
°C/W
ψJB
Junction-to-board characterization parameter
51.5
48.4
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
N/A
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, SPRA953.
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SBOS448G – AUGUST 2008 – REVISED DECEMBER 2015
7.5 Electrical Characteristics:
At TA = 25°C, VS = 3.3 V, VIN+ = 12V, VSHUNT = (VIN+ – VIN–) = 32 mV, PGA = /1, and BRNG (1) = 1, unless otherwise noted.
PARAMETER
TEST CONDITIONS
INA219A
MIN
INA219B
TYP
MAX
MIN
TYP
MAX
UNIT
INPUT
VSHUNT
Full-scale current sense (input) voltage
range
Bus voltage (input voltage) range (2)
CMRR
Common-mode rejection
PGA = /1
0
±40
0
±40
mV
PGA = /2
0
±80
0
±80
mV
PGA = /4
0
±160
0
±160
mV
PGA = /8
0
±320
0
±320
mV
BRNG = 1
0
32
0
32
BRNG = 0
0
16
0
16
VIN+ = 0 to 26 V
100
PGA = /1
Offset voltage, RTI (3)
VOS
vs Temperature
PSRR
vs Power Supply
±10
IN– pin input bias current || VIN– pin input
impedance
±100
120
±10
±50 (4)
μV
(4)
μV
μV
±20
±125
±20
±75
±30
±150
±30
±75 (4)
PGA = /8
±40
±200
±40
±100 (4)
TA = –25°C to 85°C
0.1
TA = –25°C to 85°C
Active mode
Active mode
μV
0.1
μV/°C
μV/V
10
10
±40
±40
1
1
20
20
20 || 320
V
dB
PGA = /4
VS = 3 to 5.5 V
IN+ pin input bias current
100
PGA = /2
Current sense gain error
vs Temperature
120
V
m%
m%/°C
μA
μA ||
kΩ
20 || 320
(5)
Power-down mode
0.1
±0.5
0.1
±0.5
μA
IN– pin input leakage (5)
Power-down mode
0.1
±0.5
0.1
±0.5
μA
IN+ pin input leakage
DC ACCURACY
ADC basic resolution
12
12
Shunt voltage, 1 LSB step size
10
10
μV
4
4
mV
Bus voltage, 1 LSB step size
Current measurement error
over Temperature
±0.2%
TA = –25°C to 85°C
±0.2%
±0.2%
TA = –25°C to 85°C
4)
4)
±0.5%
±0.2%
±1%
Differential nonlinearity
±0.3% (
±0.5% (
±1%
Bus voltage measurement error
over Temperature
±0.5%
bits
±0.5%
±1%
±0.1
±0.1
LSB
ADC TIMING
ADC conversion time
12 bit
532
586
532
586
μs
11 bit
276
304
276
304
μs
10 bit
148
163
148
163
μs
9 bit
84
93
84
93
μs
Minimum convert input low time
4
μs
4
SMBus
SMBus timeout (6)
28
35
28
1
0.1
35
ms
1
μA
6
V
0.3 (VS)
V
DIGITAL INPUTS (SDA as Input, SCL, A0, A1)
Input capacitance
Leakage input current
(1)
(2)
(3)
(4)
(5)
(6)
3
0 ≤ VIN ≤ VS
0.1
VIH input logic level
0.7 (VS)
VIL input logic level
–0.3
3
6 0.7 (VS)
0.3 (VS)
–0.3
pF
BRNG is bit 13 of the Configuration register 00h in Figure 19.
This parameter only expresses the full-scale range of the ADC scaling. In no event should more than 26 V be applied to this device.
Referred-to-input (RTI)
Indicates improved specifications of the INA219B.
Input leakage is positive (current flowing into the pin) for the conditions shown at the top of the table. Negative leakage currents can
occur under different input conditions.
SMBus timeout in the INA219 resets the interface any time SCL or SDA is low for over 28 ms.
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Electrical Characteristics: (continued)
At TA = 25°C, VS = 3.3 V, VIN+ = 12V, VSHUNT = (VIN+ – VIN–) = 32 mV, PGA = /1, and BRNG(1) = 1, unless otherwise noted.
PARAMETER
INA219A
TEST CONDITIONS
MIN
INA219B
TYP
Hysteresis
MAX
MIN
500
TYP
UNIT
MAX
500
mV
OPEN-DRAIN DIGITAL OUTPUTS (SDA)
Logic 0 output level
ISINK = 3 mA
High-level output leakage current
VOUT = VS
0.15
0.4
0.15
0.4
V
0.1
1
0.1
1
μA
POWER SUPPLY
Operating supply range
3
5.5
Quiescent current
3
5.5
V
0.7
1
0.7
1
mA
Quiescent current, power-down mode
6
15
6
15
μA
Power-on reset threshold
2
2
V
7.6 Bus Timing Diagram Definitions (1)
FAST MODE
HIGH-SPEED MODE
MIN
MAX
MIN
MAX
0.4
0.001
2.56
UNIT
ƒ(SCL)
SCL operating frequency
0.001
t(BUF)
Bus free time between STOP and START
condition
1300
160
ns
t(HDSTA)
Hold time after repeated START condition.
After this period, the first clock is generated.
600
160
ns
t(SUSTA)
Repeated START condition setup time
600
160
ns
t(SUSTO)
STOP condition setup time
600
t(HDDAT)
Data hold time
t(SUDAT)
Data setup time
t(LOW)
t(HIGH)
tF DA
Data fall time
300
150
ns
tFCL
Clock fall time
300
40
ns
tRCL
Clock rise time
300
40
ns
tRCL
Clock rise time for SCLK ≤ 100kHz
(1)
MHz
160
0
900
0
ns
90
ns
100
10
ns
SCL clock LOW period
1300
250
ns
SCL clock HIGH period
600
60
ns
1000
ns
Values based on a statistical analysis of a one-time sample of devices. Minimum and maximum values are not ensured and not
production tested.
t(LOW)
tF
tR
t(HDSTA)
SCL
t(HDSTA)
t(HIGH)
t(HDDAT)
t(SUSTO)
t(SUSTA)
t(SUDAT)
SDA
t(BUF)
P
S
S
P
Figure 1. Bus Timing Diagram
6
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7.7 Typical Characteristics
0
100
-10
80
-20
60
-30
40
Offset (mV)
Gain (dB)
At TA = 25°C, VS = 3.3 V, VIN+ = 12 V, VSHUNT = (VIN+ – VIN–) = 32 mV, PGA = /1, and BRNG = 1, unless otherwise noted.
-40
-50
-60
0
-20
-40
-80
-60
-90
-80
-100
-100
100
1k
10k
100k
160mV Range
20
-70
10
320mV Range
1M
80mV Range
-40 -25
0
Input Frequency (Hz)
80
45
60
40
40
35
160mV Range
0
-20
-40
75
100
125
30
25
20
16V Range
32V Range
15
80mV Range 40mV Range
-60
10
-80
5
0
-100
-40 -25
0
25
50
75
100
-40 -25
125
0
Temperature (°C)
25
50
75
100
125
Temperature (°C)
Figure 4. ADC Shunt Gain Error vs Temperature
Figure 5. ADC Bus Voltage Offset vs Temperature
100
20
80
15
60
10
40
16V
20
INL (mV)
Gain Error (m%)
50
Figure 3. ADC Shunt Offset vs Temperature
50
Offset (mV)
Gain Error (m%)
Figure 2. Frequency Response
320mV Range
25
Temperature (°C)
100
20
40mV Range
0
-20
0
-5
32V
-40
5
-10
-60
-15
-80
-100
-40 -25
0
25
50
75
100
125
-20
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Input Voltage (V)
Temperature (°C)
Figure 6. ADC Bus Gain Error vs Temperature
Figure 7. Integral Nonlinearity vs Input Voltage
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Typical Characteristics (continued)
At TA = 25°C, VS = 3.3 V, VIN+ = 12 V, VSHUNT = (VIN+ – VIN–) = 32 mV, PGA = /1, and BRNG = 1, unless otherwise noted.
2.0
1.2
VS+ = 5V
1.0
1.0
VS = 5V
0.8
0.5
IQ (mA)
Input Currents (mA)
1.5
VS+ = 3V
0
VS+ = 3V
0.6
VS = 3V
0.4
-0.5
0.2
-1.0
VS+ = 5V
0
-1.5
10
5
0
15
20
25
30
0
-40 -25
25
VIN- Voltage (V)
Figure 8. Input Currents With Large Differential
Voltages(VIN+ at 12 V, Sweep Of VIN–)
75
100
125
Figure 9. Active IQ vs Temperature
16
1.0
14
0.9
VS = 5V
0.8
12
0.7
IQ (mA)
10
IQ (mA)
50
Temperature (°C)
VS = 5V
8
6
VS = 3V
4
0.6
VS = 3V
0.5
0.4
0.3
0.2
2
0.1
0
0
-40 -25
0
25
50
75
100
125
100k
10k
1k
1M
Temperature (°C)
SCL Frequency (Hz)
Figure 10. Shutdown IQ vs Temperature
Figure 11. Active IQ vs I2C Clock Frequency
10M
300
250
VS = 5V
IQ (mA)
200
150
100
50
VS = 3V
0
1k
10k
100k
1M
10M
SCL Frequency (Hz)
Figure 12. Shutdown IQ vs I2C Clock Frequency
8
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8 Detailed Description
8.1 Overview
The INA219 is a digital current sense amplifier with an I2C- and SMBus-compatible interface. It provides digital
current, voltage, and power readings necessary for accurate decision-making in precisely-controlled systems.
Programmable registers allow flexible configuration for measurement resolution as well as continuous-versustriggered operation. Detailed register information appears at the end of this data sheet, beginning with Table 2.
See the Functional Block Diagram section for a block diagram of the INA219 device.
8.2 Functional Block Diagram
Power
(1)
Bus Voltage
(1)
´
Shunt Voltage
Channel
Current
(1)
ADC
Bus Voltage
Channel
Full-Scale Calibration
(2)
´
Shunt Voltage
(1)
PGA
(In Configuration Register)
NOTES:
(1) Read-only
(2) Read/write
Data Registers
8.3 Feature Description
8.3.1 Basic ADC Functions
The two analog inputs to the INA219, IN+ and IN–, connect to a shunt resistor in the bus of interest. The INA219
is typically powered by a separate supply from 3 to 5.5 V. The bus being sensed can vary from 0 to
26 V. There are no special considerations for power-supply sequencing (for example, a bus voltage can be
present with the supply voltage off, and vice-versa). The INA219 senses the small drop across the shunt for
shunt voltage, and senses the voltage with respect to ground from IN– for the bus voltage. Figure 13 shows this
operation.
When the INA219 is in the normal operating mode (that is, MODE bits of the Configuration register are set to
111), it continuously converts the shunt voltage up to the number set in the shunt voltage averaging function
(Configuration register, SADC bits). The device then converts the bus voltage up to the number set in the bus
voltage averaging (Configuration register, BADC bits). The Mode control in the Configuration register also
permits selecting modes to convert only voltage or current, either continuously or in response to an event
(triggered).
All current and power calculations are performed in the background and do not contribute to conversion time;
conversion times shown in the Electrical Characteristics: can be used to determine the actual conversion time.
Power-Down mode reduces the quiescent current and turns off current into the INA219 inputs, avoiding any
supply drain. Full recovery from Power-Down requires 40 μs. ADC Off mode (set by the Configuration register,
MODE bits) stops all conversions.
Writing any of the triggered convert modes into the Configuration register (even if the desired mode is already
programmed into the register) triggers a single-shot conversion. Table 6 lists the triggered convert mode settings.
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Feature Description (continued)
VSHUNT = VIN+ - VINTypically < 50mV
+
-
RSHUNT
Supply
Load
INA219 Power-Supply Voltage
3V to 5.5V
3.3V Supply
VIN+
VS
VIN-
INA219
´
Power Register
Data (SDA)
Clock (SCL)
2
VBUS = VIN- - GND
Current Register
Range of 0V to 26V
Typical Application 12V
PGA
ADC
Voltage Register
I C-/SMBUSCompatible
Interface
A0
A1
GND
Figure 13. INA219 Configured for Shunt and Bus Voltage Measurement
Although the INA219 can be read at any time, and the data from the last conversion remain available, the
conversion ready bit (Status register, CNVR bit) is provided to help coordinate one-shot or triggered conversions.
The conversion ready bit is set after all conversions, averaging, and multiplication operations are complete.
The conversion ready bit clears under any of these conditions:
• Writing to the Configuration register, except when configuring the MODE bits for power down or ADC off
(disable) modes
• Reading the Status register
• Triggering a single-shot conversion with the convert pin
8.3.1.1 Power Measurement
Current and bus voltage are converted at different points in time, depending on the resolution and averaging
mode settings. For instance, when configured for 12-bit and 128 sample averaging, up to 68 ms in time between
sampling these two values is possible. Again, these calculations are performed in the background and do not add
to the overall conversion time.
8.3.1.2 PGA Function
If larger full-scale shunt voltages are desired, the INA219 provides a PGA function that increases the full-scale
range up to 2, 4, or 8 times (320 mV). Additionally, the bus voltage measurement has two full-scale ranges: 16 or
32 V.
8.3.1.3 Compatibility With TI Hot Swap Controllers
The INA219 is designed for compatibility with hot swap controllers such the TI TPS2490. The TPS2490 uses a
high-side shunt with a limit at 50 mV; the INA219 full-scale range of 40 mV enables the use of the same shunt for
current sensing below this limit. When sensing is required at (or through) the 50-mV sense point of the TPS2490,
the PGA of the INA219 can be set to /2 to provide an 80-mV full-scale range.
10
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8.4 Device Functional Modes
8.4.1 Filtering and Input Considerations
Measuring current is often noisy, and such noise can be difficult to define. The INA219 offers several options for
filtering by choosing resolution and averaging in the Configuration register. These filtering options can be set
independently for either voltage or current measurement.
The internal ADC is based on a delta-sigma (ΔΣ) front-end with a 500-kHz (±30%) typical sampling rate. This
architecture has good inherent noise rejection; however, transients that occur at or very close to the sampling
rate harmonics can cause problems. Because these signals are at 1 MHz and higher, they can be dealt with by
incorporating filtering at the input of the INA219. The high frequency enables the use of low-value series resistors
on the filter for negligible effects on measurement accuracy. In general, filtering the INA219 input is only
necessary if there are transients at exact harmonics of the 500-kHz (±30%) sampling rate (>1 MHz). Filter using
the lowest possible series resistance and ceramic capacitor. Recommended values are 0.1 to 1 μF. Figure 14
shows the INA219 with an additional filter added at the input.
RSHUNT
Load
Supply
RFILTER 10W
RFILTER 10W
Supply Voltage
3.3V Supply
0.1mF to 1mF
Ceramic Capacitor
VIN+ VIN-
VS
INA219
´
Power Register
Data (SDA)
Clock (SCL)
2
Current Register
PGA
I C-/SMBUSCompatible
Interface
A0
ADC
Voltage Register
A1
GND
Figure 14. INA219 With Input Filtering
Overload conditions are another consideration for the INA219 inputs. The INA219 inputs are specified to tolerate
26 V across the inputs. A large differential scenario might be a short to ground on the load side of the shunt. This
type of event can result in full power-supply voltage across the shunt (as long the power supply or energy
storage capacitors support it). It must be remembered that removing a short to ground can result in inductive
kickbacks that could exceed the 26-V differential and common-mode rating of the INA219. Inductive kickback
voltages are best dealt with by zener-type transient-absorbing devices combined with sufficient energy storage
capacitance.
In applications that do not have large energy storage electrolytics on one or both sides of the shunt, an input
overstress condition may result from an excessive dV/dt of the voltage applied to the input. A hard physical short
is the most likely cause of this event, particularly in applications with no large electrolytics present. This problem
occurs because an excessive dV/dt can activate the ESD protection in the INA219 in systems where large
currents are available. Testing has demonstrated that the addition of 10-Ω resistors in series with each input of
the INA219 sufficiently protects the inputs against dV/dt failure up to the 26-V rating of the INA219. These
resistors have no significant effect on accuracy.
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8.5 Programming
An important aspect of the INA219 device is that it measure current or power if it is programmed based on the
system. The device measures both the differential voltage applied between the IN+ and IN- input pins and the
voltage at IN- pin. In order for the device to report both current and power values, the user must program the
resolution of the Current Register (04h) and the value of the shunt resistor (RSHUNT) present in the application to
develop the differential voltage applied between the input pins. Both the Current_LSB and shunt resistor value
are used in the calculation of the Calibration Register value that the device uses to calculate the corresponding
current and power values based on the measured shunt and bus voltages.
After programming the Calibration Register, the Current Register (04h) and Power Register (03h) update
accordingly based on the corresponding shunt voltage and bus voltage measurements. Until the Calibration
Register is programmed, the Current Register (04h) and Power Register (03h) remain at zero.
8.5.1 Programming the Calibration Register
The Calibration Register is calculated based on Equation 1. This equation includes the term Current_LSB, which
is the programmed value for the LSB for the Current Register (04h). The user uses this value to convert the
value in the Current Register (04h) to the actual current in amperes. The highest resolution for the Current
Register (04h) can be obtained by using the smallest allowable Current_LSB based on the maximum expected
current as shown in Equation 2. While this value yields the highest resolution, it is common to select a value for
the Current_LSB to the nearest round number above this value to simplify the conversion of the Current Register
(04h) and Power Register (03h) to amperes and watts respectively. The RSHUNT term is the value of the external
shunt used to develop the differential voltage across the input pins. The Power Register (03h) is internally set to
be 20 times the programmed Current_LSB see Equation 3.
0.04096
Cal = trunc Current_LSB ´ R
SHUNT
where
•
0.04096 is an internal fixed value used to ensure scaling is maintained properly
Maximum Expected Current
215
Power_LSB = 20 Current_LSB
Current_LSB =
(1)
(2)
(3)
Shunt voltage is calculated by multiplying the Shunt Voltage Register contents with the Shunt Voltage LSB of 10
µV.
The Bus Voltage register bits are not right-aligned. In order to compute the value of the Bus Voltage, Bus Voltage
Register contents must be shifted right by three bits. This shift puts the BD0 bit in the LSB position so that the
contents can be multiplied by the Bus Voltage LSB of 4-mV to compute the bus voltage measured by the device.
After programming the Calibration Register, the value expected in the Current Register (04h) can be calculated
by multiplying the Shunt Voltage register contents by the Calibration Register and then dividing by 4096 as
shown in Equation 4. To obtain a value in amperes the Current register value is multiplied by the programmed
Current_LSB.
Current Register =
Shunt Voltage Re gister ´ Calibration Re gister
4096
(4)
The value expected in the Power register (03h) can be calculated by multiplying the Current register value by the
Bus Voltage register value and then dividing by 5000 as shown in Equation 5. Power Register content is
multiplied by Power LSB which is 20 times the Current_LSB for a power value in watts.
Current Re gister ´ Bus Voltage Re gister
Power Register =
5000
(5)
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Programming (continued)
8.5.2 Programming the Power Measurement Engine
8.5.2.1 Calibration Register and Scaling
The Calibration Register enables the user to scale the Current Register (04h) and Power Register (03h) to the
most useful value for a given application. For example, set the Calibration Register such that the largest possible
number is generated in the Current Register (04h) or Power Register (03h) at the expected full-scale point. This
approach yields the highest resolution using the previously calculated minimum Current_LSB in the equation for
the Calibration Register. The Calibration Register can also be selected to provide values in the Current Register
(04h) and Power Register (03h) that either provide direct decimal equivalents of the values being measured, or
yield a round LSB value for each corresponding register. After these choices have been made, the Calibration
Register also offers possibilities for end user system-level calibration. After determining the exact current by
using an external ammeter, the value of the Calibration Register can then be adjusted based on the measured
current result of the INA219 to cancel the total system error as shown in Equation 6.
Corrected_Full_Scale_Cal = trunc
Cal ´ MeasShuntCurrent
INA219_Current
(6)
8.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
The INA219 can be used without any programming if it is only necessary to read a shunt voltage drop and bus
voltage with the default 12-bit resolution, 320-mV shunt full-scale range (PGA = /8), 32-V bus full-scale range,
and continuous conversion of shunt and bus voltage.
Without programming, current is measured by reading the shunt voltage. The Current register and Power register
are only available if the Calibration register contains a programmed value.
8.5.4 Default Settings
The default power-up states of the registers are shown in the Register Details section of this data sheet. These
registers are volatile, and if programmed to other than default values, must be re-programmed at every device
power-up. Detailed information on programming the Calibration register specifically is given in the section,
Programming the Calibration Register.
8.5.5 Bus Overview
The INA219 offers compatibility with both I2C and SMBus interfaces. The I2C and SMBus protocols are
essentially compatible with one another.
The I2C interface is used throughout this data sheet as the primary example, with SMBus protocol specified only
when a difference between the two systems is being addressed. Two bidirectional lines, SCL and SDA, connect
the INA219 to the bus. Both SCL and SDA are open-drain connections.
The device that initiates the transfer is called a master, and the devices controlled by the master are slaves. The
bus must be controlled by a master device that generates the serial clock (SCL), controls the bus access, and
generates START and STOP conditions.
To address a specific device, the master initiates a START condition by pulling the data signal line (SDA) from a
HIGH to a LOW logic level while SCL is HIGH. All slaves on the bus shift in the slave address byte on the rising
edge of SCL, with the last bit indicating whether a read or write operation is intended. During the ninth clock
pulse, the slave being addressed responds to the master by generating an Acknowledge and pulling SDA LOW.
Data transfer is then initiated and eight bits of data are sent, followed by an Acknowledge bit. During data
transfer, SDA must remain stable while SCL is HIGH. Any change in SDA while SCL is HIGH is interpreted as a
START or STOP condition.
Once all data have been transferred, the master generates a STOP condition, indicated by pulling SDA from
LOW to HIGH while SCL is HIGH. The INA219 includes a 28-ms timeout on its interface to prevent locking up an
SMBus.
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Programming (continued)
8.5.5.1 Serial Bus Address
To communicate with the INA219, the master must first address slave devices through a slave address byte. The
slave address byte consists of seven address bits, and a direction bit indicating the intent of executing a read or
write operation.
The INA219 has two address pins, A0 and A1. Table 1 describes the pin logic levels for each of the 16 possible
addresses. The state of pins A0 and A1 is sampled on every bus communication and should be set before any
activity on the interface occurs. The address pins are read at the start of each communication event.
Table 1. INA219 Address Pins and Slave Addresses
A1
A0
SLAVE ADDRESS
GND
GND
1000000
GND
VS+
1000001
GND
SDA
1000010
GND
SCL
1000011
VS+
GND
1000100
VS+
VS+
1000101
VS+
SDA
1000110
VS+
SCL
1000111
SDA
GND
1001000
SDA
VS+
1001001
SDA
SDA
1001010
SDA
SCL
1001011
SCL
GND
1001100
SCL
VS+
1001101
SCL
SDA
1001110
SCL
SCL
1001111
8.5.5.2 Serial Interface
The INA219 operates only as a slave device on the I2C bus and SMBus. Connections to the bus are made
through the open-drain I/O lines SDA and SCL. The SDA and SCL pins feature integrated spike suppression
filters and Schmitt triggers to minimize the effects of input spikes and bus noise. The INA219 supports the
transmission protocol for fast (1- to 400-kHz) and high-speed (1-kHz to 2.56-MHz) modes. All data bytes are
transmitted most significant byte first.
8.5.6 Writing to and Reading from the INA219
Accessing a particular register on the INA219 is accomplished by writing the appropriate value to the register
pointer. Refer to Table 2 for a complete list of registers and corresponding addresses. The value for the register
pointer as shown in Figure 18 is the first byte transferred after the slave address byte with the R/W bit LOW.
Every write operation to the INA219 requires a value for the register pointer.
Writing to a register begins with the first byte transmitted by the master. This byte is the slave address, with the
R/W bit LOW. The INA219 then acknowledges receipt of a valid address. The next byte transmitted by the
master is the address of the register to which data will be written. This register address value updates the
register pointer to the desired register. The next two bytes are written to the register addressed by the register
pointer. The INA219 acknowledges receipt of each data byte. The master may terminate data transfer by
generating a START or STOP condition.
When reading from the INA219, the last value stored in the register pointer by a write operation determines
which register is read during a read operation. To change the register pointer for a read operation, a new value
must be written to the register pointer. This write is accomplished by issuing a slave address byte with the R/W
bit LOW, followed by the register pointer byte. No additional data are required. The master then generates a
START condition and sends the slave address byte with the R/W bit HIGH to initiate the read command. The
next byte is transmitted by the slave and is the most significant byte of the register indicated by the register
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pointer. This byte is followed by an Acknowledge from the master; then the slave transmits the least significant
byte. The master acknowledges receipt of the data byte. The master may terminate data transfer by generating a
Not-Acknowledge after receiving any data byte, or generating a START or STOP condition. If repeated reads
from the same register are desired, it is not necessary to continually send the register pointer bytes; the INA219
retains the register pointer value until it is changed by the next write operation.
Figure 15 and Figure 16 show write and read operation timing diagrams, respectively. Note that register bytes
are sent most-significant byte first, followed by the least significant byte. Figure 17 shows the timing diagram for
the SMBus Alert response operation. Figure 18 shows a typical register pointer configuration.
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1
9
1
9
1
9
1
9
SCL
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
P7
P6
P5
P4
P3
P2
P1
ACK By
INA219
Frame 1 Two-Wire Slave Address Byte
P0
D15 D14
D13
D12 D11 D10
D9
D8
(1)
D7
D6
D5
D4
D3
D2
D1
D0
ACK By
INA219
ACK By
INA219
Frame 2 Register Pointer Byte
ACK By
INA219
Frame 3 Data MSByte
Stop By
Master
Frame 4 Data LSByte
NOTE (1): The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 1.
Figure 15. Timing Diagram for Write Word Format
1
9
1
9
1
9
SCL
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
D15 D14
ACK By
INA219
Frame 1 Two-Wire Slave Address Byte
(1)
D13
D12
D11 D10
D9
From
INA219
Frame 2 Data MSByte
D7
D8
D6
ACK By
Master
(2)
D5
D4
D3
D2
D1
From
INA219
Frame 3 Data LSByte
D0
NoACK By
Master
(3)
Stop
(2)
NOTES: (1) The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins.
Refer to Table 1.
(2) Read data is from the last register pointer location. If a new register is desired, the register
pointer must be updated. See Figure 19.
(3) ACK by Master can also be sent.
Figure 16. Timing Diagram for Read Word Format
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ALERT
1
9
1
9
SCL
SDA
0
0
0
1
1
0
0
1
R/W
Start By
Master
0
0
A3
A2
ACK By
INA219
A1
A0
0
From
INA219
Frame 1 SMBus ALERT Response Address Byte
Frame 2 Slave Address Byte
NACK By
Master
Stop By
Master
(1)
NOTE (1): The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 1.
Figure 17. Timing Diagram for SMBus Alert
1
9
1
9
SCL
¼
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
P7
P6
P5
P4
P3
P2
P1
ACK By
INA219
Frame 1 Two-Wire Slave Address Byte
(1)
P0
Stop
ACK By
INA219
Frame 2 Register Pointer Byte
NOTE (1): The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 1.
Figure 18. Typical Register Pointer Set
8.5.6.1 High-Speed I2C Mode
When the bus is idle, both the SDA and SCL lines are pulled high by the pull-up devices. The master generates
a start condition followed by a valid serial byte containing high-speed (HS) master code 00001XXX. This
transmission is made in fast (400 kbps) or standard (100 kbps) (F/S) mode at no more than 400 kbps. The
INA219 does not acknowledge the HS master code, but does recognize it and switches its internal filters to
support 2.56 Mbps operation.
The master then generates a repeated start condition (a repeated start condition has the same timing as the start
condition). After this repeated start condition, the protocol is the same as F/S mode, except that transmission
speeds up to 2.56 Mbps are allowed. Instead of using a stop condition, repeated start conditions should be used
to secure the bus in HS-mode. A stop condition ends the HS-mode and switches all the internal filters of the
INA219 to support the F/S mode. For bus timing, see Bus Timing Diagram Definitions (1) and Figure 1.
8.5.6.2 Power-Up Conditions
Power-up conditions apply to a software reset through the RST bit (bit 15) in the Configuration register, or the I2C
bus General Call Reset.
(1)
Values based on a statistical analysis of a one-time sample of devices. Minimum and maximum values are not ensured and not
production tested.
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8.6 Register Maps
8.6.1 Register Information
The INA219 uses a bank of registers for holding configuration settings, measurement results, maximum/minimum
limits, and status information. Table 2 summarizes the INA219 registers; Functional Block Diagram shows
registers.
Register contents are updated 4 μs after completion of the write command. Therefore, a 4-μs delay is required
between completion of a write to a given register and a subsequent read of that register (without changing the
pointer) when using SCL frequencies in excess of 1 MHz.
Table 2. Summary of Register Set
POINTER
ADDRESS
REGISTER NAME
FUNCTION
HEX
(1)
(2)
18
POWER-ON RESET
TYPE (1)
BINARY
HEX
00
Configuration
All-register reset, settings for bus
voltage range, PGA Gain, ADC
resolution/averaging.
00111001 10011111
399F
R/W
01
Shunt voltage
Shunt voltage measurement data.
Shunt voltage
—
R
02
Bus voltage
03
Power (2)
Bus voltage measurement data.
Bus voltage
—
R
Power measurement data.
00000000 00000000
0000
R
04
Current
(2)
Contains the value of the current flowing
through the shunt resistor.
00000000 00000000
0000
R
05
Calibration
Sets full-scale range and LSB of current
and power measurements. Overall
system calibration.
00000000 00000000
0000
R/W
Type: R = Read only, R/W = Read/Write.
The Power register and Current register default to 0 because the Calibration register defaults to 0, yielding a zero current value until the
Calibration register is programmed.
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8.6.2 Register Details
All INA219 16-bit registers are actually two 8-bit bytes through the I2C interface.
8.6.2.1 Configuration Register (address = 00h) [reset = 399Fh]
Figure 19. Configuration Register
15
14
13
12
11
RST
—
BRNG
PG1
PG0
R/W-0
R/W-0
R/W-1
R/W-1
R/W-1
10
BADC
4
R/W-0
9
BADC
3
R/W-0
8
BADC
2
R/W-1
7
BADC
1
R/W-1
6
SADC
4
R/W-0
5
SADC
3
R/W-0
4
SADC
2
R/W-1
3
SADC
1
R/W-1
2
1
0
MODE MODE MODE
3
2
1
R/W-1 R/W-1 R/W-1
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 3. Bit Descriptions
RST:
Reset Bit
Bit 15
Setting this bit to '1' generates a system reset that is the same as power-on reset. Resets all registers to default
values; this bit self-clears.
BRNG:
Bus Voltage Range
Bit 13
0 = 16V FSR
1 = 32V FSR (default value)
PG:
PGA (Shunt Voltage Only)
Bits 11, 12
Sets PGA gain and range. Note that the PGA defaults to ÷8 (320mV range). Table 4 shows the gain and range for
the various product gain settings.
Table 4. PG Bit Settings (1)
(1)
PG1
PG0
GAIN
Range
0
0
0
1
±40 mV
1
/2
±80 mV
1
0
/4
±160 mV
1
1
/8
±320 mV
Shaded values are default.
BADC:
BADC Bus ADC Resolution/Averaging
Bits 7–10
These bits adjust the Bus ADC resolution (9-, 10-, 11-, or 12-bit) or set the number of samples used when
averaging results for the Bus Voltage Register (02h).
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SADC:
SADC Shunt ADC Resolution/Averaging
Bits 3–6
These bits adjust the Shunt ADC resolution (9-, 10-, 11-, or 12-bit) or set the number of samples used when
averaging results for the Shunt Voltage Register (01h).
BADC (Bus) and SADC (Shunt) ADC resolution/averaging and conversion time settings are shown in Table 5.
Table 5. ADC Settings (1)
(1)
(2)
ADC4
ADC3
ADC2
ADC1
Mode/Samples
Conversion Time
0
X (2)
0
0
9 bit
84 μs
0
X
(2)
0
1
10 bit
148 μs
0
X (2)
1
0
11 bit
276 μs
0
X (2)
1
1
12 bit
532 μs
1
0
0
0
12 bit
532 μs
1
0
0
1
2
1.06 ms
1
0
1
0
4
2.13 ms
1
0
1
1
8
4.26 ms
1
1
0
0
16
8.51 ms
1
1
0
1
32
17.02 ms
1
1
1
0
64
34.05 ms
1
1
1
1
128
68.10 ms
Shaded values are default.
X = Don't care
MODE:
Operating Mode
Bits 0–2
Selects continuous, triggered, or power-down mode of operation. These bits default to continuous shunt and bus
measurement mode. The mode settings are shown in Table 6.
Table 6. Mode Settings (1)
(1)
MODE3
MODE2
MODE1
MODE
0
0
0
Power-down
0
0
1
Shunt voltage, triggered
0
1
0
Bus voltage, triggered
0
1
1
Shunt and bus, triggered
1
0
0
ADC off (disabled)
1
0
1
Shunt voltage, continuous
1
1
0
Bus voltage, continuous
1
1
1
Shunt and bus, continuous
Shaded values are default.
8.6.3 Data Output Registers
8.6.3.1 Shunt Voltage Register (address = 01h)
The Shunt Voltage register stores the current shunt voltage reading, VSHUNT. Shunt Voltage register bits are
shifted according to the PGA setting selected in the Configuration register (00h). When multiple sign bits are
present, they will all be the same value. Negative numbers are represented in 2's complement format. Generate
the 2's complement of a negative number by complementing the absolute value binary number and adding 1.
Extend the sign, denoting a negative number by setting the MSB = 1. Extend the sign to any additional sign bits
to form the 16-bit word.
Example: For a value of VSHUNT = –320 mV:
1. Take the absolute value (include accuracy to 0.01 mV) → 320.00
2. Translate this number to a whole decimal number → 32000
3. Convert it to binary → 111 1101 0000 0000
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4. Complement the binary result : 000 0010 1111 1111
5. Add 1 to the Complement to create the Two’s Complement formatted result → 000 0011 0000 0000
6. Extend the sign and create the 16-bit word: 1000 0011 0000 0000 = 8300h (Remember to extend the sign to
all sign-bits, as necessary based on the PGA setting.)
At PGA = /8, full-scale range = ±320 mV (decimal = 32000). For VSHUNT = +320 mV, Value = 7D00h; For VSHUNT
= –320 mV, Value = 8300h; and LSB = 10µV.
Figure 20. Shunt Voltage Register at PGA = /8
15
SIGN
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SD14_ SD13_ SD12_ SD11_ SD10_
SD9_8 SD8_8 SD7_8 SD6_8 SD5_8 SD4_8 SD3_8 SD2_8 SD1_8 SD0_8
8
8
8
8
8
At PGA = /4, full-scale range = ±160 mV (decimal = 16000). For VSHUNT = +160 mV, Value = 3E80h; For VSHUNT
= –160 mV, Value = C180h; and LSB = 10µV.
Figure 21. Shunt Voltage Register at PGA = /4
15
14
SIGN
SIGN
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SD13_ SD12_ SD11_ SD10_
SD9_4 SD8_4 SD7_4 SD6_4 SD5_4 SD4_4 SD3_4 SD2_4 SD1_4 SD0_4
4
4
4
4
At PGA = /2, full-scale range = ±80 mV (decimal = 8000). For VSHUNT = +80 mV, Value = 1F40h; For VSHUNT =
–80 mV; Value = E0C0h; and LSB = 10µV.
Figure 22. Shunt Voltage Register at PGA = /2
15
14
13
SIGN
SIGN
SIGN
12
11
10
9
8
7
6
5
4
3
2
1
0
SD12_ SD11_ SD10_
SD9_2 SD8_2 SD7_2 SD6_2 SD5_2 SD4_2 SD3_2 SD2_2 SD1_2 SD0_2
2
2
2
At PGA = /1, full-scale range = ±40 mV (decimal = 4000). For VSHUNT = +40 mV, Value = 0FA0h; For VSHUNT =
–40 mV, Value = F060h; and LSB = 10µV.
Figure 23. Shunt Voltage Register at PGA = /1
15
14
13
12
SIGN
SIGN
SIGN
SIGN
11
10
9
8
7
6
5
4
3
2
1
0
SD11_ SD10_
SD9_1 SD8_1 SD7_1 SD6_1 SD5_1 SD4_1 SD3_1 SD2_1 SD1_1 SD0_1
1
1
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Table 7. Shunt Voltage Register Format (1)
VSHUNT
Reading (mV)
Decimal
Value
PGA = /8
(D15:D0)
PGA = /4
(D15:D0)
PGA = /2
(D15:D0)
PGA = /1
(D15:D0)
320.02
32002
0111 1101 0000 0000
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
320.01
32001
0111 1101 0000 0000
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
320.00
32000
0111 1101 0000 0000
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
319.99
31999
0111 1100 1111 1111
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
319.98
31998
0111 1100 1111 1110
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
160.02
16002
0011 1110 1000 0010
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
160.01
16001
0011 1110 1000 0001
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
160.00
16000
0011 1110 1000 0000
0011 1110 1000 0000
0001 1111 0100 0000
0000 1111 1010 0000
159.99
15999
0011 1110 0111 1111
0011 1110 0111 1111
0001 1111 0100 0000
0000 1111 1010 0000
159.98
15998
0011 1110 0111 1110
0011 1110 0111 1110
0001 1111 0100 0000
0000 1111 1010 0000
80.02
8002
0001 1111 0100 0010
0001 1111 0100 0010
0001 1111 0100 0000
0000 1111 1010 0000
80.01
8001
0001 1111 0100 0001
0001 1111 0100 0001
0001 1111 0100 0000
0000 1111 1010 0000
80.00
8000
0001 1111 0100 0000
0001 1111 0100 0000
0001 1111 0100 0000
0000 1111 1010 0000
79.99
7999
0001 1111 0011 1111
0001 1111 0011 1111
0001 1111 0011 1111
0000 1111 1010 0000
79.98
7998
0001 1111 0011 1110
0001 1111 0011 1110
0001 1111 0011 1110
0000 1111 1010 0000
40.02
4002
0000 1111 1010 0010
0000 1111 1010 0010
0000 1111 1010 0010
0000 1111 1010 0000
40.01
4001
0000 1111 1010 0001
0000 1111 1010 0001
0000 1111 1010 0001
0000 1111 1010 0000
40.00
4000
0000 1111 1010 0000
0000 1111 1010 0000
0000 1111 1010 0000
0000 1111 1010 0000
39.99
3999
0000 1111 1001 1111
0000 1111 1001 1111
0000 1111 1001 1111
0000 1111 1001 1111
39.98
3998
0000 1111 1001 1110
0000 1111 1001 1110
0000 1111 1001 1110
0000 1111 1001 1110
0.02
2
0000 0000 0000 0010
0000 0000 0000 0010
0000 0000 0000 0010
0000 0000 0000 0010
0.01
1
0000 0000 0000 0001
0000 0000 0000 0001
0000 0000 0000 0001
0000 0000 0000 0001
0
0
0000 0000 0000 0000
0000 0000 0000 0000
0000 0000 0000 0000
0000 0000 0000 0000
–0.01
–1
1111 1111 1111 1111
1111 1111 1111 1111
1111 1111 1111 1111
1111 1111 1111 1111
–0.02
–2
1111 1111 1111 1110
1111 1111 1111 1110
1111 1111 1111 1110
1111 1111 1111 1110
–39.98
–3998
1111 0000 0110 0010
1111 0000 0110 0010
1111 0000 0110 0010
1111 0000 0110 0010
–39.99
–3999
1111 0000 0110 0001
1111 0000 0110 0001
1111 0000 0110 0001
1111 0000 0110 0001
–40.00
–4000
1111 0000 0110 0000
1111 0000 0110 0000
1111 0000 0110 0000
1111 0000 0110 0000
–40.01
–4001
1111 0000 0101 1111
1111 0000 0101 1111
1111 0000 0101 1111
1111 0000 0110 0000
–40.02
–4002
1111 0000 0101 1110
1111 0000 0101 1110
1111 0000 0101 1110
1111 0000 0110 0000
–79.98
–7998
1110 0000 1100 0010
1110 0000 1100 0010
1110 0000 1100 0010
1111 0000 0110 0000
–79.99
–7999
1110 0000 1100 0001
1110 0000 1100 0001
1110 0000 1100 0001
1111 0000 0110 0000
–80.00
–8000
1110 0000 1100 0000
1110 0000 1100 0000
1110 0000 1100 0000
1111 0000 0110 0000
–80.01
–8001
1110 0000 1011 1111
1110 0000 1011 1111
1110 0000 1100 0000
1111 0000 0110 0000
–80.02
–8002
1110 0000 1011 1110
1110 0000 1011 1110
1110 0000 1100 0000
1111 0000 0110 0000
–159.98
–15998
1100 0001 1000 0010
1100 0001 1000 0010
1110 0000 1100 0000
1111 0000 0110 0000
–159.99
–15999
1100 0001 1000 0001
1100 0001 1000 0001
1110 0000 1100 0000
1111 0000 0110 0000
–160.00
–16000
1100 0001 1000 0000
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–160.01
–16001
1100 0001 0111 1111
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–160.02
–16002
1100 0001 0111 1110
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–319.98
–31998
1000 0011 0000 0010
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–319.99
–31999
1000 0011 0000 0001
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–320.00
–32000
1000 0011 0000 0000
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–320.01
–32001
1000 0011 0000 0000
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
–320.02
–32002
1000 0011 0000 0000
1100 0001 1000 0000
1110 0000 1100 0000
1111 0000 0110 0000
(1)
22
Out-of-range values are shown in gray shading.
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8.6.3.2 Bus Voltage Register (address = 02h)
The Bus Voltage register stores the most recent bus voltage reading, VBUS.
At full-scale range = 32 V (decimal = 8000, hex = 1F40), and LSB = 4 mV.
Figure 24. Bus Voltage Register
15
BD12
14
BD11
13
BD10
12
BD9
11
BD8
10
BD7
9
BD6
8
BD5
7
BD4
6
BD3
5
BD2
4
BD1
3
BD0
2
—
1
CNVR
0
OVF
At full-scale range = 16 V (decimal = 4000, hex = 0FA0), and LSB = 4 mV.
CNVR:
Conversion Ready
Bit 1
Although the data from the last conversion can be read at any time, the INA219 Conversion Ready bit (CNVR)
indicates when data from a conversion is available in the data output registers. The CNVR bit is set after all
conversions, averaging, and multiplications are complete. CNVR will clear under the following conditions:
1.) Writing a new mode into the Operating Mode bits in the Configuration Register (except for Power-Down or
Disable)
2.) Reading the Power Register
OVF:
Math Overflow Flag
Bit 0
The Math Overflow Flag (OVF) is set when the Power or Current calculations are out of range. It indicates that
current and power data may be meaningless.
8.6.3.3 Power Register (address = 03h) [reset = 00h]
Full-scale range and LSB are set by the Calibration register. See the Programming the Calibration Register.
Figure 25. Power Register
15
PD15
R-0
14
PD14
R-0
13
PD13
R-0
12
PD12
R-0
11
PD11
R-0
10
PD10
R-0
9
PD9
R-0
8
PD8
R-0
7
PD7
R-0
6
PD6
R-0
5
PD5
R-0
4
PD4
R-0
3
PD3
R-0
2
PD2
R-0
1
PD1
R-0
0
PD0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
The Power register records power in watts by multiplying the values of the current with the value of the bus
voltage according to the equation Equation 5:
8.6.3.4 Current Register (address = 04h) [reset = 00h]
Full-scale range and LSB depend on the value entered in the Calibration register. See Programming the
Calibration Register for more information. Negative values are stored in 2's complement format.
Figure 26. Current Register
15
CSIGN
R-0
14
CD14
R-0
13
CD13
R-0
12
CD12
R-0
11
CD11
R-0
10
CD10
R-0
9
CD9
R-0
8
CD8
R-0
7
CD7
R-0
6
CD6
R-0
5
CD5
R-0
4
CD4
R-0
3
CD3
R-0
2
CD2
R-0
1
CD1
R-0
0
CD0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
The value of the Current register is calculated by multiplying the value in the Shunt Voltage register with the
value in the Calibration register according to the Equation 4:
8.6.4 Calibration Register
8.6.4.1 Calibration Register (address = 05h) [reset = 00h]
Current and power calibration are set by bits FS15 to FS1 of the Calibration register. Note that bit FS0 is not
used in the calculation. This register sets the current that corresponds to a full-scale drop across the shunt. Fullscale range and the LSB of the current and power measurement depend on the value entered in this register.
See the Programming the Calibration Register. This register is suitable for use in overall system calibration. Note
that the 0 POR values are all default.
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Figure 27. Calibration Register (1)
15
FS15
R/W-0
14
FS14
R/W-0
13
FS13
R/W-0
12
FS12
R/W-0
11
FS11
R/W-0
10
FS10
R/W-0
9
FS9
R/W-0
8
FS8
R/W-0
7
FS7
R/W-0
6
FS6
R/W-0
5
FS5
R/W-0
4
FS4
R/W-0
3
FS3
R/W-0
2
FS2
R/W-0
1
FS1
R/W-0
0
FS0
R-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
(1)
24
FS0 is a void bit and will always be 0. It is not possible to write a 1 to FS0. CALIBRATION is the value stored in FS15:FS1.
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9 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.
9.1 Application Information
The INA219 is a current shunt and power monitor with an I2C- and SMBus-compatible interface. The device
monitors both a shunt voltage drop and bus supply voltage. Programmable calibration value, combined with an
internal multiplier, enable readouts of current and power.
9.2 Typical Application
Figure 28 shows a typical application circuit for the INA219. Use a 0.1-μF ceramic capacitor for power-supply
bypassing, placed as closely as possible to the supply and ground pins.
The input filter circuit consisting of RF1, RF2, and CF is not necessary in most applications. If the need for filtering
is unknown, reserve board space for the components and install 0-Ω resistors for RF1 and RF2 and leave CF
unpopulated, unless a filter is needed (see Filtering and Input Considerations).
The pull-up resistors shown on the SDA and SCL lines are not needed if there are pullup resistors on these
same lines elsewhere in the system. Resistor values shown are typical: consult either the I2C or SMBus
specification to determine the acceptable minimum or maximum values and also refer to the Specifications for
Output Current Limitations.
Supply Voltage
(INA219 Power Supply Range is
3V to 5.5V)
RSHUNT
Power Bus
(0V to 26V)
Load
RF1
RF2
CBYPASS
0.1mF
(typical)
CF
VIN+
RPULLUP
3.3kW
(typical)
VIN-
INA219
´
RPULLUP
3.3kW
(typical)
SDA
Power Register
SCL
2
Current Register
PGA
IC
Interface
ADC
Data (SDA)
Clock (SCL)
A0
A1
Voltage Register
GND
Figure 28. Typical Application Circuit
9.2.1 Design Requirements
The INA219 measures the voltage across a current-sensing resistor (RSHUNT) when current passes through the
resistor. The device also measures the bus supply voltage, and calculates power when calibrated. This section
goes through the steps to program the device for power measurements, and shows the register results Table 8.
The Conditions for the example circuit is: Maximum expected load current = 15 A, Nominal load current = 10 A,
VCM = 12 V, RSHUNT = 2 mΩ, VSHUNT FSR = 40 mV (PGA = /1), and BRNG = 0 (VBUS range = 16 V).
9.2.2 Detailed Design Procedure
Figure 29 shows a nominal 10-A load that creates a differential voltage of 20 mV across a 2-mΩ shunt resistor.
The common mode is at 12 volts and the voltage present at the IN– pin is equal to the common-mode voltage
minus the differential drop across the resistor.
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Typical Application (continued)
For this example, the minimum-current LSB is calculated to be 457.78 µA/bit, assuming a maximum expected
current of 15 A using Equation 2. This value is rounded up to 1 mA/bit and is chosen for the current LSB. Setting
the current LSB to this value allows for sufficient precision while serving to simplify the math as well. Using
Equation 1 results in a calibration value of 20480 (5000h). This value is then programmed into the Calibration
register.
+3.3V to +5V
+12V
VCM
RSHUNT
2mW
10µF
10A
Load
0.1µF
VS (Supply Voltage)
´
Power Register
V
VIN+
Current Register
VIN-
Voltage Register
I2C-/
SMBUSCompatible
Interface
SDA
SCL
A0
I
A1
GND
Figure 29. Example Circuit Configuration
The bus voltage is internally measured at the IN– pin to calculate the voltage level delivered to the load. The Bus
Voltage register bits are not right-aligned; therefore, they must be shifted right by three bits. Multiply the shifted
contents by the 4-mV LSB to compute the bus voltage measured by the device in volts. The shifted value of the
Bus Voltage register contents is equal to BB3h, the decimal equivalent of 2995. This value of 2995 is multiplied
by the 4-mV LSB, and results in a value of 11.98 V. As shown, the voltage at the IN– pin is 11.98 V. For a 40mV, full-scale range, this small difference is not a significant deviation from the 12-V common-mode voltage.
However, at larger full-scale ranges, this deviation can be much larger.
The Current register content is internally calculated using Equation 4, and the result of 10000 (2710h) is
automatically loaded into the register. Current in amperes is equal to 1 mA/bit times 10000, and results in a 10-A
load current.
The Power register content is internally calculated using Equation 5 and the result of 5990 (1766h) is
automatically loaded into the register. Multiplying this result by the Power register LSB 20 × 10–3(20 times 1 ×
10–3 current LSB using Equation 3), results in a power calculation of 5990 × 20 mW/bit, and equals 119.8 W.
This result matches what is expected for this register. A calculation for the power delivered to the load uses
11.98 V (12 VCM – 20-mV shunt drop) multiplied by the load current of 10 A to give a 119.8-W result.
9.2.2.1 Register Results for the Example Circuit
Table 8 shows the register readings for the Calibration example.
Table 8. Register Results (1)
(1)
26
REGISTER NAME
ADDRESS
CONTENTS
ADJ
Configuration
00h
019Fh
Shunt
01h
07D0h
Bus
02h
5D98h
Calibration
05h
5000h
20480
Current
04h
2710h
10000
1 mA
10.0 A
Power
03h
1766h
5990
20 mW
119.8 W
0BB3
DEC
LSB
VALUE
2000
10 µV
20 mV
2995
4 mV
11.98 V
Conditions: load = 10 A, VCM = 12 V, RSHUNT = 2 mΩ, VSHUNT FSR = 40 mV, and VBUS = VIN-, BRNG = 0 (VBUS range = 16 V).
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10 Power Supply Recommendations
The input circuitry of the device can accurately measure signals on common-mode voltages beyond its power
supply voltage, VS. For example, the voltage applied to the VS power supply terminal can be 5 V, whereas the
load power-supply voltage being monitored (the common-mode voltage) can be as high as 26 V. Note also that
the device can withstand the full 0-V to 26-V range at the input terminals, regardless of whether the device has
power applied or not.
Place the required power-supply bypass capacitors as close as possible to the supply and ground terminals of
the device to ensure stability. A typical value for this supply bypass capacitor is 0.1 μF. Applications with noisy or
high-impedance power supplies may require additional decoupling capacitors to reject power-supply noise.
11 Layout
11.1 Layout Guidelines
Connect the input pins (IN+ and IN–) to the sensing resistor using a Kelvin connection or a 4-wire connection.
These connection techniques ensure 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-sensing resistor, any additional high-current carrying
impedance causes significant measurement errors. Place the power-supply bypass capacitor as close as
possible to the supply and ground pins.
11.2 Layout Example
A1
A0
IN+
Sense/Shunt
Resistor
IN±
SDA
GND
SCL
VS
2
I C-/
SMBUS compatible
interface
Supply bypass
capacitor
Via to Ground Plane
Via to Power Plane
Figure 30. Recommended Layout
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12 Device and Documentation Support
12.1 Community Resources
The following links connect to TI community resources. Linked contents are 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.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
12.2 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.3 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
12.4 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 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.
28
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PACKAGE OPTION ADDENDUM
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6-Feb-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
INA219AID
ACTIVE
SOIC
D
8
75
Green (RoHS
& no Sb/Br)
NIPDAU
Level-1-260C-UNLIM
-40 to 125
I219A
INA219AIDCNR
ACTIVE
SOT-23
DCN
8
3000
Green (RoHS
& no Sb/Br)
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
A219
INA219AIDCNT
ACTIVE
SOT-23
DCN
8
250
Green (RoHS
& no Sb/Br)
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
A219
INA219AIDR
ACTIVE
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
NIPDAU
Level-1-260C-UNLIM
-40 to 125
I219A
INA219BID
ACTIVE
SOIC
D
8
75
Green (RoHS
& no Sb/Br)
NIPDAU
Level-1-260C-UNLIM
-40 to 125
I219B
INA219BIDCNR
ACTIVE
SOT-23
DCN
8
3000
Green (RoHS
& no Sb/Br)
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
B219
INA219BIDCNT
ACTIVE
SOT-23
DCN
8
250
Green (RoHS
& no Sb/Br)
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
B219
INA219BIDR
ACTIVE
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
NIPDAU
Level-1-260C-UNLIM
-40 to 125
I219B
(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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