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INA226
SBOS547A – JUNE 2011 – REVISED AUGUST 2015
INA226 High-Side or Low-Side Measurement,
Bi-Directional Current and Power Monitor with I2C Compatible Interface
1 Features
3 Description
•
•
•
•
The INA226 is a current shunt and power monitor
with an I2C™- or SMBUS-compatible interface. The
device monitors both a shunt voltage drop and bus
supply voltage. Programmable calibration value,
conversion times, and averaging, combined with an
internal multiplier, enable direct readouts of current in
amperes and power in watts.
1
•
•
•
•
Senses Bus Voltages From 0 V to 36 V
High-Side or Low-Side Sensing
Reports Current, Voltage, and Power
High Accuracy:
– 0.1% Gain Error (Max)
– 10 μV Offset (Max)
Configurable Averaging Options
16 Programmable Addresses
Operates from 2.7-V to 5.5-V Power Supply
10-Pin, DGS (VSSOP) Package
The INA226 senses current on common-mode bus
voltages that can vary from 0 V to 36 V, independent
of the supply voltage. The device operates from a
single 2.7-V to 5.5-V supply, drawing a typical of 330
μA of supply current. The device is specified over the
operating temperature range between –40°C and
125°C and features up to 16 programmable
addresses on the I2C-compatible interface.
2 Applications
•
•
•
•
•
•
•
Servers
Telecom Equipment
Computing
Power Management
Battery Chargers
Power Supplies
Test Equipment
Device Information(1)
PART NUMBER
INA226
PACKAGE
VSSOP (10)
BODY SIZE (NOM)
3.00 mm x 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
High-Side or Low-Side Sensing Application
Power Supply
(0 V to 36 V)
CBYPASS
0.1 mF
HighSide
Shunt
VS
(Supply Voltage)
VBUS
SDA
SCL
´
Load
Power Register
V
2
VIN+
LowSide
Shunt
Current Register
ADC
I
VIN–
Voltage Register
I C or SMBus
Compatible
Interface
Alert
A0
Alert 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.
INA226
SBOS547A – JUNE 2011 – REVISED AUGUST 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
6.1
6.2
6.3
6.4
6.5
6.6
4
4
4
4
5
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description ............................................ 10
7.1
7.2
7.3
7.4
Overview .................................................................
Functional Block Diagram .......................................
Feature Description.................................................
Device Functional Modes........................................
10
10
10
13
7.5 Programming .......................................................... 15
7.6 Register Maps ......................................................... 21
8
Application and Implementation ........................ 28
8.1 Application Information............................................ 28
8.2 Typical Applications ................................................ 28
9 Power Supply Recommendations...................... 30
10 Layout................................................................... 30
10.1 Layout Guidelines ................................................. 30
10.2 Layout Example .................................................... 30
11 Device and Documentation Support ................. 31
11.1
11.2
11.3
11.4
11.5
Device Support ....................................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
31
31
31
31
31
12 Mechanical, Packaging, and Orderable
Information ........................................................... 31
4 Revision History
Changes from Original (June 2011) to Revision A
•
2
Page
Added Handling Rating 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
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5 Pin Configuration and Functions
DGS Package
10-Pin VSSOP
Top View
A1 1
10 IN+
A0
2
9 IN–
Alert
3
8 VBUS
SDA
4
7 GND
SCL
5
6 VS
Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
A0
2
Digital input
Address pin. Connect to GND, SCL, SDA, or VS. Table 2 shows pin settings and corresponding addresses.
A1
1
Digital input
Address pin. Connect to GND, SCL, SDA, or VS. Table 2 shows pin settings and corresponding addresses.
Alert
3
Digital output
GND
7
Analog
IN+
10
Analog input
Connect to supply side of shunt resistor.
IN–
9
Analog input
Connect to load side of shunt resistor.
SCL
5
Digital input
Serial bus clock line, open-drain input.
SDA
4
Digital I/O
VBUS
8
Analog input
VS
6
Analog
Multi-functional alert, open-drain output.
Ground.
Serial bus data line, open-drain input/output.
Bus voltage input.
Power supply, 2.7 V to 5.5 V.
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
MIN
VVS
MAX
UNIT
6
V
Supply voltage
–40
40
–0.3
40
VVBUS
–0.3
40
V
VSDA
GND – 0.3
6
V
VSCL
GND – 0.3
VVS + 0.3
V
5
mA
Analog Inputs,
IN+, IN–
Differential (VIN+ – VIN-)
(2)
Common-Mode (VIN+ + VIN-) / 2
V
IIN
Input current into any pin
IOUT
Open-drain digital output current
10
mA
TJ
Junction temperature
150
°C
Tstg
Storage temperature range
150
°C
(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.
IN+ and IN– may have a differential voltage between –40 V and 40 V. However, the voltage at these pins must not exceed the range
–0.3 V to 40 V.
6.2 ESD Ratings
VALUE
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins
Electrostatic
discharge
V(ESD)
(1)
(2)
(1)
UNIT
±2500
Charged device model (CDM), per JEDEC specification JESD22-C101, all
pins (2)
±1000
Machine model (MM)
±150
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.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
VCM
Common-mode input voltage
12
VVS
Operating supply voltage
3.3
TA
Operating free-air temperature
MAX
UNIT
V
V
–40
125
°C
6.4 Thermal Information
INA226
THERMAL METRIC
(1)
DGS (VSSOP)
UNIT
10 PINS
RθJA
Junction-to-ambient thermal resistance
171.4
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
42.9
°C/W
RθJB
Junction-to-board thermal resistance
91.8
°C/W
ψJT
Junction-to-top characterization parameter
1.5
°C/W
ψJB
Junction-to-board characterization parameter
90.2
°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, SPRA953.
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6.5 Electrical Characteristics
TA = 25°C, VVS = 3.3 V, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 0 mV and VVBUS = 12 V, unless otherwise noted
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
mV
INPUT
Shunt voltage input range
–81.9175
81.92
Bus voltage input range (1)
0
36
0 V ≤ VIN+ ≤ 36 V
CMRR
Common-mode rejection
VOS
Shunt offset voltage, RTI (2)
PSRR
VOS
Shunt offset voltage, RTI (2) vs
temperature
–40°C ≤ TA ≤ 125°C
Shunt offset voltage, RTI (2) vs
Power supply
2.7 V ≤ VS ≤ 5.5 V
Bus offset voltage, RTI
(2)
Bus offset voltage, RTI (2) vs
temperature
(2)
PSRR
Bus offset voltage, RTI
supply
IB
Input bias current (IIN+, IIN– pins)
–40°C ≤ TA ≤ 125°C
vs power
VBUS input impedance
Input leakage
(3)
126
V
140
dB
±2.5
±10
μV
0.02
0.1
μV/°C
μV/V
2.5
±1.25
±7.5
10
40
mV
μV/°C
0.5
mV/V
10
μA
830
kΩ
(IN+ pin) + (IN– pin),
Power-down mode
0.1
16
Bits
Shunt voltage
2.5
μV
μA
0.5
DC ACCURACY
ADC native resolution
1 LSB step size
Bus voltage
Shunt voltage gain error
Shunt voltage gain error vs
temperature
–40°C ≤ TA ≤ 125°C
Bus voltage gain error
Bus voltage gain error vs
temperature
–40°C ≤ TA ≤ 125°C
Differential nonlinearity
tCT
ADC conversion time
1.25
mV
0.02%
0.1%
10
50
0.02%
0.1%
10
50
±0.1
ppm/°C
ppm/°C
LSB
CT bit = 000
140
154
CT bit = 001
204
224
CT bit = 010
332
365
CT bit = 011
588
646
CT bit = 100
1.1
1.21
CT bit = 101
2.116
2.328
CT bit = 110
4.156
4.572
CT bit = 111
8.244
9.068
28
35
μs
ms
SMBus
SMBus timeout (4)
(1)
(2)
(3)
(4)
ms
While the input range is 36 V, the full-scale range of the ADC scaling is 40.96 V. See the Basic ADC Functions section. Do not apply
more than 36 V.
RTI = Referred-to-input.
Input leakage is positive (current flowing into the pin) for the conditions shown at the top of this table. Negative leakage currents can
occur under different input conditions.
SMBus timeout in the INA226 resets the interface any time SCL is low for more than 28 ms.
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Electrical Characteristics (continued)
TA = 25°C, VVS = 3.3 V, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 0 mV and VVBUS = 12 V, unless otherwise noted
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
DIGITAL INPUT/OUTPUT
Input capacitance
Leakage input current
3
0 V ≤ VSCL ≤ VVS ,
0 V ≤ VSDA ≤ VVS,
0 V ≤ VAlert ≤ VVS ,
0 V ≤ VA0 ≤ VVS ,
0 V ≤ VA1 ≤ VVS
0.1
pF
1
μA
VIH
High-level input voltage
0.7×VVS
6
V
VIL
Low-level input voltage
–0.5
0.3×VVS
V
VOL
Low-level output voltage, SDA, Alert
0
0.4
IOL = 3 mA
Hysteresis
500
V
mV
POWER SUPPLY
Operating supply range
IQ
VPOR
6
5.5
V
Quiescent current
2.7
330
420
μA
Quiescent current, power-down
(shutdown) mode
0.5
2
μA
Power-on reset threshold
2
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6.6 Typical Characteristics
At TA = 25°C, VVS = 3.3 V, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 0 mV and VVBUS = 12 V, unless otherwise noted.
0
−10
Population
Gain (dB)
−20
−30
−40
G001
10
8
6
4
Input Offset Voltage (mV)
Figure 2. Shunt Input Offset Voltage Production Distribution
Figure 1. Frequency Response
170
Common−Mode Rejection Ratio (dB)
−1
−1.2
−1.4
Offset (µV)
2
100k
0
10k
-2
100
1k
Frequency (Hz)
-4
10
-6
1
-10
−60
-8
−50
−1.6
−1.8
−2
−2.2
−2.4
−50
−25
0
25
50
Temperature (°C)
75
100
160
150
140
−50
125
−25
0
G003
Figure 3. Shunt Input Offset Voltage vs Temperature
25
50
Temperature (°C)
75
100
125
G004
Figure 4. Shunt Input Common-Mode Rejection Ratio vs
Temperature
600
Population
Gain Error (m%)
500
400
300
200
100
80
60
40
20
0
-20
-40
-60
-80
-100
100
0
−50
−25
0
25
50
Temperature (°C)
75
100
125
G007
Input Gain Error (m%)
Figure 5. Shunt Input Gain Error Production Distribution
Figure 6. Shunt Input Gain Error vs Temperature
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Typical Characteristics (continued)
At TA = 25°C, VVS = 3.3 V, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 0 mV and VVBUS = 12 V, unless otherwise noted.
300
200
Population
Gain Error (m%)
250
150
100
50
G008
7.5
6
4.5
3
1.5
36
0
32
-1.5
8
12
16
20
24
28
Common−Mode Input Voltage (V)
-3
4
-4.5
0
-7.5
−50
-6
0
Input Offset Voltage (mV)
Figure 8. Bus Input Offset Voltage Production Distribution
Figure 7. Shunt Input Gain Error vs Common-Mode Voltage
−0.6
Population
Offset (mV)
−0.8
−1.0
G009
100
80
60
40
125
20
100
0
75
-20
25
50
Temperature (°C)
-40
0
-60
−25
-100
−1.4
−50
-80
−1.2
Input Gain Error (m%)
Figure 10. Bus Input Gain Error Production Distribution
Figure 9. Bus Input Offset Voltage vs Temperature
600
25
Input Bias Current (µA)
Gain Error (m%)
500
400
300
200
100
0
−50
−25
0
25
50
Temperature (°C)
75
100
15
10
5
0
0
G012
Figure 11. Bus Input Gain Error vs Temperature
8
125
20
4
8
12
16
20
24
28
Common−Mode Input Voltage (V)
32
36
G012
Figure 12. Input Bias Current vs Common-Mode Voltage
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Typical Characteristics (continued)
At TA = 25°C, VVS = 3.3 V, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 0 mV and VVBUS = 12 V, unless otherwise noted.
260
Input Bias Current − Shutdown (nA)
Input Bias Current (µA)
24
22
20
18
16
−50
−25
0
25
50
Temperature (°C)
75
100
140
100
60
−25
0
G013
Figure 13. Input Bias Current vs Temperature
25
50
Temperature (°C)
75
100
125
G014
Figure 14. Input Bias Current vs Temperature, Shutdown
1.2
Quiescent Current − Shutdown (µA)
Quiescent Current (µA)
180
20
−50
125
500
400
300
200
100
−50
220
−25
0
25
50
Temperature (°C)
75
100
1
0.8
0.6
0.4
0.2
−50
125
−25
0
G015
Figure 15. Active IQ vs Temperature
25
50
Temperature (°C)
75
100
125
G016
Figure 16. Shutdown IQ vs Temperature
500
300
250
Shutdown IQ (mA)
IQ (mA)
450
400
200
150
100
350
50
300
0
1
10
100
1,000
10,000
1
10
100
1,000
10,000
Frequency (kHz)
Frequency (kHz)
Figure 17. Active IQ vs I2C Clock Frequency
Figure 18. Shutdown IQ vs I2C Clock Frequency
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7 Detailed Description
7.1 Overview
The INA226 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 4.
See the Functional Block Diagram section for a block diagram of the INA226 device.
7.2 Functional Block Diagram
Power
(1)
Bus Voltage
(1)
´
Shunt Voltage
Channel
Current
(1)
ADC
Bus Voltage
Channel
Calibration
(2)
´
Shunt Voltage
(1)
Data Registers
(1) Read-only
(2) Read/write
7.3 Feature Description
7.3.1 Basic ADC Functions
The INA226 device performs two measurements on the power-supply bus of interest. The voltage developed
from the load current that flows through a shunt resistor creates a shunt voltage that is measured at the IN+ and
IN– pins. The device can also measure the power supply bus voltage by connecting this voltage to the VBUS pin.
The differential shunt voltage is measured with respect to the IN– pin while the bus voltage is measured with
respect to ground.
The device is typically powered by a separate supply that can range from 2.7 V to 5.5 V. The bus that is being
monitored can range in voltage from 0 V to 36 V. Based on the fixed 1.25-mV LSB for the Bus Voltage Register
that a full-scale register results in a 40.96 V value.
NOTE
Do not apply more than 36 V of actual voltage to the input pins.
There are no special considerations for power-supply sequencing because the common-mode input range and
power-supply voltage are independent of each other; therefore, the bus voltage can be present with the supply
voltage off, and vice-versa.
The device takes two measurements, shunt voltage and bus voltage. It then converts these measurements to
current, based on the Calibration Register value, and then calculates power. Refer to the Programming the
Calibration Register section for additional information on programming the Calibration Register.
10
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Feature Description (continued)
The device has two operating modes, continuous and triggered, that determine how the ADC operates following
these conversions. When the device is in the normal operating mode (that is, MODE bits of the Configuration
Register (00h) are set to '111'), it continuously converts a shunt voltage reading followed by a bus voltage
reading. After the shunt voltage reading, the current value is calculated (based on Equation 3). This current value
is then used to calculate the power result (using Equation 4). These values are subsequently stored in an
accumulator, and the measurement/calculation sequence repeats until the number of averages set in the
Configuration Register (00h) is reached. Following every sequence, the present set of values measured and
calculated are appended to previously collected values. After all of the averaging has been completed, the final
values for shunt voltage, bus voltage, current, and power are updated in the corresponding registers that can
then be read. These values remain in the data output registers until they are replaced by the next fully completed
conversion results. Reading the data output registers does not affect a conversion in progress.
The mode control in the Conversion Register (00h) also permits selecting modes to convert only the shunt
voltage or the bus voltage in order to further allow the user to configure the monitoring function to fit the specific
application requirements.
All current and power calculations are performed in the background and do not contribute to conversion time.
In triggered mode, writing any of the triggered convert modes into the Configuration Register (00h) (that is,
MODE bits of the Configuration Register (00h) are set to ‘001’, ‘010’, or ‘011’) triggers a single-shot conversion.
This action produces a single set of measurements; thus, to trigger another single-shot conversion, the
Configuration Register (00h) must be written to a second time, even if the mode does not change.
In addition to the two operating modes (continuous and triggered), the device also has a power-down mode that
reduces the quiescent current and turns off current into the device inputs, reducing the impact of supply drain
when the device is not being used. Full recovery from power-down mode requires 40µs. The registers of the
device can be written to and read from while the device is in power-down mode. The device remains in powerdown mode until one of the active modes settings are written into the Configuration Register (00h) .
Although the device can be read at any time, and the data from the last conversion remain available, the
Conversion Ready flag bit (Mask/Enable Register, CVRF bit) is provided to help coordinate one-shot or triggered
conversions. The Conversion Ready flag (CVRF) bit is set after all conversions, averaging, and multiplication
operations are complete.
The Conversion Ready flag (CVRF) bit clears under these conditions:
• Writing to the Configuration Register (00h), except when configuring the MODE bits for power-down mode; or
• Reading the Mask/Enable Register (06h)
7.3.1.1 Power Calculation
The Current and Power are calculated following shunt voltage and bus voltage measurements as shown in
Figure 19. Current is calculated following a shunt voltage measurement based on the value set in the Calibration
Register. If there is no value loaded into the Calibration Register, the current value stored is zero. Power is
calculated following the bus voltage measurement based on the previous current calculation and bus voltage
measurement. If there is no value loaded in the Calibration Register, the power value stored is also zero. Again,
these calculations are performed in the background and do not add to the overall conversion time. These current
and power values are considered intermediate results (unless the averaging is set to 1) and are stored in an
internal accumulation register, not the corresponding output registers. Following every measured sample, the
newly-calculated values for current and power are appended to this accumulation register until all of the samples
have been measured and averaged based on the number of averages set in the Configuration Register (00h).
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Feature Description (continued)
Bus and Power Limit Detect
Following Every Bus Voltage Conversion
Current Limit Detect Following
Every Shunt Voltage Conversion
I
V
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
I
V
P
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
I
P
V
P
Power Average
Bus Voltage Average
Shunt Voltage Average
Figure 19. Power Calculation Scheme
In addition to the current and power accumulating after every sample, the shunt and bus voltage measurements
are also collected. After all of the samples have been measured and the corresponding current and power
calculations have been made, the accumulated average for each of these parameters is then loaded to the
corresponding output registers, where they can then be read.
7.3.1.2 Alert Pin
The INA226 has a single Alert Limit Register (07h), that allows the Alert pin to be programmed to respond to a
single user-defined event or to a Conversion Ready notification if desired. The Mask/Enable Register allows the
user to select from one of the five available functions to monitor and/or set the Conversion Ready bit to control
the response of the Alert pin. Based on the function being monitored, the user would then enter a value into the
Alert Limit Register to set the corresponding threshold value that asserts the Alert pin.
The Alert pin allows for one of several available alert functions to be monitored to determine if a user-defined
threshold has been exceeded. The five alert functions that can be monitored are:
• Shunt Voltage Over-Limit (SOL)
• Shunt Voltage Under-Limit (SUL)
• Bus Voltage Over-Limit (BOL)
• Bus Voltage Under-Limit (BUL)
• Power Over-Limit (POL)
The Alert pin is an open-drain output. This pin is asserted when the alert function selected in the Mask/Enable
Register exceeds the value programmed into the Alert Limit Register. Only one of these alert functions can be
enabled and monitored at a time. If multiple alert functions are enabled, the selected function in the highest
significant bit position takes priority and responds to the Alert Limit Register value. For example, if the Shunt
Voltage Over-Limit function and the Shunt Voltage Under-Limit function are both selected, the Alert pin asserts
when the Shunt Voltage Register exceeds the value in the Alert Limit Register.
The Conversion Ready state of the device can also be monitored at the Alert pin to inform the user when the
device has completed the previous conversion and is ready to begin a new conversion. Conversion Ready can
be monitored at the Alert pin along with one of the alert functions. If an alert function and the Conversion Ready
are both enabled to be monitored at the Alert pin, after the Alert pin is asserted, the Mask/Enable Register must
be read following the alert to determine the source of the alert. By reading the Conversion Ready Flag (CVRF, bit
3), and the Alert Function Flag (AFF, bit 4) in the Mask/Enable Register, the source of the alert can be
determined. If the Conversion Ready feature is not desired and the CNVR bit is not set, the Alert pin only
responds to an exceeded alert limit based on the alert function enabled.
If the alert function is not used, the Alert pin can be left floating without impacting the operation of the device.
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Feature Description (continued)
Refer to Figure 19 to see the relative timing of when the value in the Alert Limit Register is compared to the
corresponding converted value. For example, if the alert function that is enabled is Shunt Voltage Over-Limit
(SOL), following every shunt voltage conversion the value in the Alert Limit Register is compared to the
measured shunt voltage to determine if the measurements has exceeded the programmed limit. The AFF, bit 4 of
the Mask/Enable Register, asserts high any time the measured voltage exceeds the value programmed into the
Alert Limit Register. In addition to the AFF being asserted, the Alert pin is asserted based on the Alert Polarity Bit
(APOL, bit 1 of the Mask/Enable Register). If the Alert Latch is enabled, the AFF and Alert pin remain asserted
until either the Configuration Register (00h) is written to or the Mask/Enable Register is read.
The Bus Voltage alert functions compare the measured bus voltage to the Alert Limit Register following every
bus voltage conversion and assert the AFF bit and Alert pin if the limit threshold is exceeded.
The Power Over-Limit alert function is also compared to the calculated power value following every bus voltage
measurement conversion and asserts the AFF bit and Alert pin if the limit threshold is exceeded.
7.4 Device Functional Modes
7.4.1 Averaging and Conversion Time Considerations
The INA226 device offers programmable conversion times (tCT) for both the shunt voltage and bus voltage
measurements. The conversion times for these measurements can be selected from as fast as 140 μs to as long
as 8.244 ms. The conversion time settings, along with the programmable averaging mode, allow the device to be
configured to optimize the available timing requirements in a given application. For example, if a system requires
that data be read every 5ms, the device could be configured with the conversion times set to 588 μs for both
shunt and bus voltage measurements and the averaging mode set to 4. This configuration results in the data
updating approximately every 4.7ms. The device could also be configured with a different conversion time setting
for the shunt and bus voltage measurements. This type of approach is common in applications where the bus
voltage tends to be relatively stable. This situation can allow for the time focused on the bus voltage
measurement to be reduced relative to the shunt voltage measurement. The shunt voltage conversion time could
be set to 4.156 ms with the bus voltage conversion time set to 588 μs, with the averaging mode set to 1. This
configuration also results in data updating approximately every 4.7 ms.
There are trade-offs associated with the settings for conversion time and the averaging mode used. The
averaging feature can significantly improve the measurement accuracy by effectively filtering the signal. This
approach allows the device to reduce any noise in the measurement that may be caused by noise coupling into
the signal. A greater number of averages enables the device to be more effective in reducing the noise
component of the measurement.
The conversion times selected can also have an impact on the measurement accuracy. Figure 20 shows multiple
conversion times to illustrate the impact of noise on the measurement. In order to achieve the highest accuracy
measurement possible, use a combination of the longest allowable conversion times and highest number of
averages, based on the timing requirements of the system.
10mV/div
Conversion Time: 140ms
Conversion Time: 1.1ms
Conversion Time: 8.244ms
0
200
400
600
800
1000
Number of Conversions
Figure 20. Noise vs Conversion Time
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Device Functional Modes (continued)
7.4.2 Filtering and Input Considerations
Measuring current is often noisy, and such noise can be difficult to define. The INA226 device offers several
options for filtering by allowing the conversion times and number of averages to be selected independently in the
Configuration Register (00h). The conversion times can be set independently for the shunt voltage and bus
voltage measurements to allow added flexibility in configuring the monitoring of the power-supply bus.
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 managed by
incorporating filtering at the input of the device. The high frequency enables the use of low-value series resistors
on the filter with negligible effects on measurement accuracy. In general, filtering the device input is only
necessary if there are transients at exact harmonics of the 500 kHz (±30%) sampling rate (greater than 1 MHz).
Filter using the lowest possible series resistance (typically 10 Ω or less) and a ceramic capacitor. Recommended
values for this capacitor are between 0.1 μF and 1 μF. Figure 21 shows the device with a filter added at the
input.
Overload conditions are another consideration for the device inputs. The device inputs are specified to tolerate
40 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). Removing a short to ground can result in inductive kickbacks that could exceed
the 40-V differential and common-mode rating of the device. Inductive kickback voltages are best controlled by
Zener-type transient-absorbing devices (commonly called transzorbs) combined with sufficient energy storage
capacitance. See the TI Design, Transient Robustness for Current Shunt Monitors (TIDU473), which describes a
high-side current shunt monitor used to measure the voltage developed across a current-sensing resistor when
current passes through it.
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 device in systems where large
currents are available. Testing demonstrates that the addition of 10-Ω resistors in series with each input of the
device sufficiently protects the inputs against this dV/dt failure up to the 40-V rating of the device. Selecting these
resistors in the range noted has minimal effect on accuracy.
Power Supply
(0 V to 36 V)
CBYPASS
0.1 µF
VS
(Supply Voltage)
VBUS
CFILTER
0.1 µF to 1 µF
Ceramic
Capacitor
SDA
SCL
X
Power Register
RFILTER
≤ 10 Ω
VIN+
V
2
Current Register
ADC
I
RFILTER
Load
Voltage Register
I C or SMBus
Compatible
Interface
Alert
A0
VINAlert Register
≤ 10 Ω
A1
GND
Figure 21. Input Filtering
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7.5 Programming
An important aspect of the INA226 device is that it does not necessarily measure current or power. The device
measures both the differential voltage applied between the IN+ and IN- input pins and the voltage applied to the
VBUS 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 present in the application to develop the
differential voltage applied between the input pins. The Power Register (03h) is internally set to be 25 times the
programmed Current_LSB. Both the Current_LSB and shunt resistor value are used in the calculation of the
Calibration Register value the device uses to calculate the corresponding current and power values based on the
measured shunt and bus voltages.
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.
0.00512
CAL = Current_LSB · R
SHUNT
where
•
0.00512 is an internal fixed value used to ensure scaling is maintained properly
Current_LSB =
Maximum Expected Current
215
(1)
(2)
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.
7.5.1 Programming the Calibration Register
Figure 27 shows a nominal 10-A load that creates a differential voltage of 20 mV across a 2-mΩ shunt resistor.
The bus voltage for the INA226 is measured at the external VBUS input pin, which in this example is connected
to the IN– pin to measure the voltage level delivered to the load. For this example, the VBUS pin measures less
than 12 V because the voltage at the IN– pin is 11.98 V as a result of the voltage drop across the shunt resistor.
For this example, assuming a maximum expected current of 15 A, the Current_LSB is calculated to be 457.7
μA/bit using Equation 2. Using a value for the Current_LSB of 500 μA/Bit or 1 mA/Bit would significantly simplify
the conversion from the Current Register (04h) and Power Register (03h) to amperes and watts. For this
example, a value of 1 mA/bit was chosen for the Current_LSB. Using this value for the Current_LSB does trade a
small amount of resolution for having a simpler conversion process on the user side. Using Equation 1 in this
example with a Current_LSB value of 1 mA/bit and a shunt resistor of 2 mΩ results in a Calibration Register
value of 2560, or A00h.
The Current Register (04h) is then calculated by multiplying the decimal value of the Shunt Voltage Register
(01h) contents by the decimal value of the Calibration Register and then dividing by 2048, as shown in
Equation 3. For this example, the Shunt Voltage Register contains a value of 8,000 (representing 20 mV), which
is multiplied by the Calibration Register value of 2560 and then divided by 2048 to yield a decimal value for the
Current Register (04h) of 10000, or 2710h. Multiplying this value by 1 mA/bit results in the original 10-A level
stated in the example.
Current =
ShuntVoltage · CalibrationRegister
2048
(3)
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Programming (continued)
The LSB for the Bus Voltage Register (02h) is a fixed 1.25 mV/bit, which means that the 11.98 V present at the
VBUS pin results in a register value of 2570h, or a decimal equivalent of 9584. Note that the MSB of the Bus
Voltage Register (02h) is always zero because the VBUS pin is only able to measure positive voltages.
The Power Register (03h) is then be calculated by multiplying the decimal value of the Current Register, 10000,
by the decimal value of the Bus Voltage Register (02h), 9584, and then dividing by 20,000, as defined in
Equation 4. For this example, the result for the Power Register (03h) is 12B8h, or a decimal equivalent of 4792.
Multiplying this result by the power LSB (25 times the [1 × 10–3 Current_LSB]) results in a power calculation of
(4792 × 25 mW/bit), or 119.82 W. The power LSB has a fixed ratio to the Current_LSB of 25. For this example, a
programmed 1 mA/bit Current_LSB results in a power LSB of 25 mW/bit. This ratio is internally programmed to
ensure that the scaling of the power calculation is within an acceptable range. A manual calculation for the power
being delivered to the load would use a bus voltage of 11.98 V (12 VCM – 20 mV shunt drop) multiplied by the
load current of 10 A to give a result of 119.8 W.
Power =
Current · BusVoltage
20,000
(4)
Table 1 lists the steps for configuring, measuring, and calculating the values for current and power for this
device.
Table 1. Calculating Current and Power (1)
(1)
STEP
REGISTER NAME
ADDRESS
CONTENTS
DEC
LSB
VALUE
Step 1
Configuration Register
00h
4127h
—
—
—
Step 2
Shunt Register
01h
1F40h
8000
2.5 µV
20 mV
Step 3
Bus Voltage Register
02h
2570h
9584
1.25 mV
11.98 V
Step 4
Calibration Register
05h
A00h
2560
—
—
Step 5
Current Register
04h
2710
10000
1 mA
10 A
Step 6
Power Register
03h
12B8h
4792
25 mW
119.82 W
Conditions: Load = 10 A, VCM = 12 V, RSHUNT = 2 mΩ, and VVBUS = 12 V.
7.5.2 Programming the Power Measurement Engine
7.5.2.1 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 INA226 to cancel the total system error as shown in Equation 5.
Corrected_Full_Scale_Cal = trunc
Cal ´ MeasShuntCurrent
INA226_Current
(5)
7.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
The device can be used without any programming if it is only necessary to read a shunt voltage drop and bus
voltage with the default power-on reset configuration and continuous conversion of shunt and bus voltages.
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Without programming the device Calibration Register, the device is unable to provide either a valid current or
power value, because these outputs are both derived using the values loaded into the Calibration Register.
7.5.4 Default Settings
The default power-up states of the registers are shown in the Register Maps section of this data sheet. These
registers are volatile, and if programmed to a value other than the default values shown in Table 4, they must be
re-programmed at every device power-up. Detailed information on programming the Calibration Register
specifically is given in the Programming section and calculated based on Equation 1.
7.5.5 Bus Overview
The INA226 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 discussed. Two lines, SCL and SDA, connect the device to the
bus. Both SCL and SDA are open-drain connections.
The device that initiates a data 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.
After all data have been transferred, the master generates a stop condition, indicated by pulling SDA from low to
high while SCL is high. The device includes a 28 ms timeout on its interface to prevent locking up the bus.
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7.5.5.1 Serial Bus Address
To communicate with the INA226, the master must first address slave devices via a slave address byte. The
slave address byte consists of seven address bits and a direction bit that indicates whether the action is to be a
read or write operation.
The device has two address pins, A0 and A1. Table 2 lists the pin logic levels for each of the 16 possible
addresses. The device samples the state of pins A0 and A1 on every bus communication. Establish the pin
states before any activity on the interface occurs.
Table 2. 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
7.5.5.2 Serial Interface
The INA226 operates only as a slave device on both the I2C bus and the SMBus. Connections to the bus are
made via the open-drain SDA and SCL lines. The SDA and SCL pins feature integrated spike suppression filters
and Schmitt triggers to minimize the effects of input spikes and bus noise. Although the device integrates spike
suppression into the digital I/O lines, proper layout techniques help minimize the amount of coupling into the
communication lines. This noise introduction could occur from capacitively coupling signal edges between the
two communication lines themselves or from other switching noise sources present in the system. Routing traces
in parallel with ground in between layers on a printed circuit board (PCB) typically reduces the effects of coupling
between the communication lines. Shielded communication lines reduces the possibility of unintended noise
coupling into the digital I/O lines that could be incorrectly interpreted as start or stop commands.
The INA226 supports the transmission protocol for fast mode (1 kHz to 400 kHz) and high-speed mode (1 kHz to
2.94 MHz). All data bytes are transmitted most significant byte first.
7.5.5.3 Writing to and Reading from the INA226
Accessing a specific register on the INA226 is accomplished by writing the appropriate value to the register
pointer. Refer to Table 4 for a complete list of registers and corresponding addresses. The value for the register
pointer (as shown in Figure 25) is the first byte transferred after the slave address byte with the R/W bit low.
Every write operation to the device 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 device then acknowledges receipt of a valid address. The next byte transmitted by the master is
the address of the register which data is written to. 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 device
acknowledges receipt of each data byte. The master may terminate data transfer by generating a start or stop
condition.
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When reading from the device , 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 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 NotAcknowledge 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 device retains the
register pointer value until it is changed by the next write operation.
Figure 22 shows the write operation timing diagram. Figure 23 shows the read operation timing diagram.
NOTE
Register bytes are sent most-significant byte first, followed by the least significant byte.
1
9
9
1
9
1
9
1
SCL
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
P7
P6
P4
P3
P2
P1
D15 D14
P0
D13
D12 D11 D10
D9
D8
(1)
D7
D6
D5
D4
D3
D2
D1
D0
ACK By
Slave
ACK By
Slave
Frame 1 Two-Wire Slave Address Byte
(1)
P5
ACK By
Slave
Frame 2 Register Pointer Byte
ACK By
Slave
Frame 3 Data MSByte
Stop By
Master
Frame 4 Data LSByte
The value of the Slave Address byte is determined by the settings of the A0 and A1 pins. Refer to Table 2.
Figure 22. Timing Diagram for Write Word Format
1
9
1
1
9
9
SCL
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
D15 D14
ACK By
Slave
(1)
Frame 1 Two-Wire Slave Address Byte
D13
D12
D11 D10
D9
D8
From
Slave
Frame 2 Data MSByte
D7
D6
D5
D4
D3
D2
D1
From
Slave
ACK By
Master
(2)
D0
No ACK By
Master
(3)
Stop
(2)
Frame 3 Data LSByte
(1)
The value of the Slave Address byte is determined by the settings of the A0 and A1 pins. Refer to Table 2.
(2)
Read data is from the last register pointer location. If a new register is desired, the register pointer must be updated.
See Figure 25.
(3)
ACK by Master can also be sent.
Figure 23. Timing Diagram for Read Word Format
Figure 24 shows the timing diagram for the SMBus Alert response operation. Figure 25 illustrates a typical
register pointer configuration.
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ALERT
1
9
1
9
SCL
SDA
0
0
0
1
1
0
0
R/W
Start By
Master
1
0
0
A2
ACK By
Slave
A1
A0
0
From
Slave
Frame 1 SMBus ALERT Response Address Byte
(1)
A3
Frame 2 Slave Address Byte
NACK By
Master
Stop By
Master
(1)
The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 2.
Figure 24. Timing Diagram for SMBus ALERT
1
9
1
9
¼
SCL
SDA
1
0
0
A3
A2
A1
A0
R/W
Start By
Master
P7
P6
P5
P3
P2
P1
P0
Stop
ACK By
Slave
(1)
Frame 2 Register Pointer Byte
Frame 1 Two-Wire Slave Address Byte
(1)
P4
ACK By
Slave
The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 2.
Figure 25. Typical Register Pointer Set
7.5.5.3.1 High-Speed I2C Mode
When the bus is idle, both the SDA and SCL lines are pulled high by the pullup resistors. 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 kHz) or standard (100 kHz) (F/S) mode at no more than 400 kHz. The device
does not acknowledge the HS master code, but does recognize it and switches its internal filters to support 2.94
MHz 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 2.94 MHz are allowed. Instead of using a stop condition, use repeated start conditions to secure
the bus in HS-mode. A stop condition ends the HS-mode and switches all the internal filters of the device to
support the F/S mode.
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 26. Bus Timing Diagram
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Table 3. Bus Timing Diagram Definitions (1)
FAST MODE
PARAMETER
HIGH-SPEED MODE
MIN
MAX
MIN
MAX
UNIT
0.4
0.001
2.94
MHz
SCL operating frequency
f(SCL)
0.001
Bus free time between stop and start
conditions
t(BUF)
600
160
ns
t(HDSTA)
100
100
ns
Repeated start condition setup time
t(SUSTA)
100
100
ns
STOP condition setup time
t(SUSTO)
100
100
ns
Data hold time
t(HDDAT)
10
Data setup time
t(SUDAT)
100
20
ns
SCL clock low period
t(LOW)
1300
200
ns
SCL clock high period
t(HIGH)
600
60
ns
Hold time after repeated START condition.
After this period, the first clock is generated.
900
10
100
ns
Data fall time
tF
300
80
ns
Clock fall time
tF
300
40
ns
Clock rise time
tR
300
40
ns
Clock/data rise time for SCLK ≤ 100kHz
tR
1000
(1)
ns
Values based on a statistical analysis of a one-time sample of devices. Minimum and maximum values are not guaranteed and not
production tested.
7.5.5.4 SMBus Alert Response
The INA226 is designed to respond to the SMBus Alert Response address. The SMBus Alert Response provides
a quick fault identification for simple slave devices. When an Alert occurs, the master can broadcast the Alert
Response slave address (0001 100) with the Read/Write bit set high. Following this Alert Response, any slave
device that generates an alert identifies itself by acknowledging the Alert Response and sending its address on
the bus.
The Alert Response can activate several different slave devices simultaneously, similar to the I2C General Call. If
more than one slave attempts to respond, bus arbitration rules apply. The losing device does not generate an
Acknowledge and continues to hold the Alert line low until the interrupt is cleared.
7.6 Register Maps
The INA226 uses a bank of registers for holding configuration settings, measurement results, minimum/maximum
limits, and status information. Table 4 summarizes the device registers; refer to the Functional Block Diagram
section for an illustration of the registers.
All 16-bit device registers are two 8-bit bytes via the I2C interface.
Table 4. Register Set Summary
POINTER
ADDRESS
(1)
(2)
POWER-ON RESET
HEX
REGISTER NAME
FUNCTION
BINARY
HEX
TYPE (1)
00h
Configuration Register
All-register reset, shunt voltage and bus
voltage ADC conversion times and
averaging, operating mode.
01000001 00100111
4127
R/W
01h
Shunt Voltage Register
Shunt voltage measurement data.
00000000 00000000
0000
R
02h
Bus Voltage Register
Bus voltage measurement data.
00000000 00000000
0000
R
03h
Power Register (2)
Contains the value of the calculated
power being delivered to the load.
00000000 00000000
0000
R
04h
Current Register (2)
Contains the value of the calculated
current flowing through the shunt
resistor.
00000000 00000000
0000
R
Type: R = Read-Only, R/W = Read/Write.
The Current Register (04h) and Power Register (03h) default to '0' because the Calibration register defaults to '0', yielding zero current
and power values until the Calibration register is programmed.
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Register Maps (continued)
Table 4. Register Set Summary (continued)
POINTER
ADDRESS
POWER-ON RESET
HEX
REGISTER NAME
FUNCTION
BINARY
HEX
TYPE (1)
05h
Calibration Register
Sets full-scale range and LSB of current
and power measurements. Overall
system calibration.
00000000 00000000
0000
R/W
06h
Mask/Enable Register
Alert configuration and Conversion
Ready flag.
00000000 00000000
0000
R/W
07h
Alert Limit Register
Contains the limit value to compare to
the selected Alert function.
00000000 00000000
0000
R/W
FEh
Manufacturer ID Register
Contains unique manufacturer
identification number.
0101010001001001
5449
R
FFh
Die ID Register
Contains unique die identification
number.
0010001001100000
2260
R
7.6.1 Configuration Register (00h) (Read/Write)
Table 5. Configuration Register (00h) (Read/Write) Descriptions
BIT NO.
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
RST
—
—
—
AVG2
AVG1
AVG0
VBUSCT2
VBUSCT1
VBUSCT0
VSHCT2
VSHCT1
VSHCT0
MODE3
MODE2
MODE1
POR
VALUE
0
1
0
0
0
0
0
1
0
0
1
0
0
1
1
1
The Configuration Register settings control the operating modes for the device. This register controls the
conversion time settings for both the shunt and bus voltage measurements as well as the averaging mode used.
The operating mode that controls what signals are selected to be measured is also programmed in the
Configuration Register .
The Configuration Register can be read from at any time without impacting or affecting the device settings or a
conversion in progress. Writing to the Configuration Register halts any conversion in progress until the write
sequence is completed resulting in a new conversion starting based on the new contents of the Configuration
Register (00h). This halt prevents any uncertainty in the conditions used for the next completed conversion.
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.
AVG:
Averaging Mode
Bits 9–11
Determines the number of samples that are collected and averaged. Table 6 shows all the AVG bit settings and
related number of averages for each bit setting.
Table 6. AVG Bit Settings[11:9] Combinations
(1)
22
AVG2
D11
AVG1
D10
AVG0
D9
NUMBER OF
AVERAGES (1)
0
0
0
1
0
0
1
4
0
1
0
16
0
1
1
64
1
0
0
128
1
0
1
256
1
1
0
512
1
1
1
1024
Shaded values are default.
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VBUSCT:
Bus Voltage Conversion Time
Bits 6–8
Sets the conversion time for the bus voltage measurement. Table 7 shows the VBUSCT bit options and related
conversion times for each bit setting.
Table 7. VBUSCT Bit Settings [8:6] Combinations
(1)
VBUSCT2
D8
VBUSCT1
D7
VBUSCT0
D6
CONVERSION
TIME (1)
0
0
0
140 µs
0
0
1
204 µs
0
1
0
332 µs
0
1
1
588 µs
1
0
0
1.1 ms
1
0
1
2.116 ms
1
1
0
4.156 ms
1
1
1
8.244 ms
Shaded values are default.
VSHCT:
Shunt Voltage Conversion Time
Bits 3–5
Sets the conversion time for the shunt voltage measurement. Table 8 shows the VSHCT bit options and related
conversion times for each bit setting.
Table 8. VSHCT Bit Settings [5:3] Combinations
(1)
VSHCT2
D8
VSHCT1
D7
VSHCT0
D6
CONVERSION
TIME (1)
0
0
0
140 µs
0
0
1
204 µs
0
1
0
332 µs
0
1
1
588 µs
1
0
0
1.1 ms
1
0
1
2.116 ms
1
1
0
4.156 ms
1
1
1
8.244 ms
Shaded values are default.
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 9.
Table 9. Mode Settings [2:0] Combinations
(1)
MODE3
D2
MODE2
D1
MODE1
D0
MODE (1)
0
0
0
Power-Down (or Shutdown)
0
0
1
Shunt Voltage, Triggered
0
1
0
Bus Voltage, Triggered
0
1
1
Shunt and Bus, Triggered
1
0
0
Power-Down (or Shutdown)
1
0
1
Shunt Voltage, Continuous
1
1
0
Bus Voltage, Continuous
1
1
1
Shunt and Bus, Continuous
Shaded values are default.
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7.6.2 Shunt Voltage Register (01h) (Read-Only)
The Shunt Voltage Register stores the current shunt voltage reading, VSHUNT. Negative numbers are represented
in two's complement format. Generate the two's complement of a negative number by complementing the
absolute value binary number and adding 1. An MSB = '1' denotes a negative number.
Example: For a value of VSHUNT = –80 mV:
1. Take the absolute value: 80 mV
2. Translate this number to a whole decimal number (80 mV ÷ 2.5 µV) = 32000
3. Convert this number to binary = 0111 1101 0000 0000
4. Complement the binary result = 1000 0010 1111 1111
5. Add '1' to the complement to create the two's complement result = 1000 0011 0000 0000 = 8300h
If averaging is enabled, this register displays the averaged value.
Full-scale range = 81.92 mV (decimal = 7FFF); LSB: 2.5 μV.
Table 10. Shunt Voltage Register (01h) (Read-Only) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SIGN
SD14
SD13
SD12
SD11
SD10
SD9
SD8
SD7
SD6
SD5
SD4
SD3
SD2
SD1
SD0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.6.3 Bus Voltage Register (02h) (Read-Only)
(1)
The Bus Voltage Register stores the most recent bus voltage reading, VBUS.
If averaging is enabled, this register displays the averaged value.
Full-scale range = 40.96 V (decimal = 7FFF); LSB = 1.25 mV.
Table 11. Bus Voltage Register (02h) (Read-Only) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
—
BD14
BD13
BD12
BD11
BD10
BD9
BD8
BD7
BD6
BD5
BD4
BD3
BD2
BD1
BD0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(1)
D15 is always zero because bus voltage can only be positive.
7.6.4 Power Register (03h) (Read-Only)
If averaging is enabled, this register displays the averaged value.
The Power Register LSB is internally programmed to equal 25 times the programmed value of the Current_LSB.
The Power Register records power in Watts by multiplying the decimal values of the Current Register with the
decimal value of the Bus Voltage Register according to Equation 4.
Table 12. Power Register (03h) (Read-Only) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
PD15
PD14
PD13
PD12
PD11
PD10
PD9
PD8
PD7
PD6
PD5
PD4
PD3
PD2
PD1
PD0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.6.5 Current Register (04h) (Read-Only)
If averaging is enabled, this register displays the averaged value.
The value of the Current Register is calculated by multiplying the decimal value in the Shunt Voltage Register
with the decimal value of the Calibration Register, according to Equation 3.
24
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Table 13. Current Register (04h) (Read-Only) Register Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
CSIGN
CD14
CD13
CD12
CD11
CD10
CD9
CD8
CD7
CD6
CD5
CD4
CD3
CD2
CD1
CD0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.6.6 Calibration Register (05h) (Read/Write)
This register provides the device with the value of the shunt resistor that was present to create the measured
differential voltage. It also sets the resolution of the Current Register. Programming this register sets the
Current_LSB and the Power_LSB. This register is also suitable for use in overall system calibration. See the
Programming the Calibration Register for additional information on programming the Calibration Register.
Table 14. Calibration Register (05h) (Read/Write) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
—
FS14
FS13
FS12
FS11
FS10
FS9
FS8
FS7
FS6
FS5
FS4
FS3
FS2
FS1
FS0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.6.7 Mask/Enable Register (06h) (Read/Write)
The Mask/Enable Register selects the function that is enabled to control the Alert pin as well as how that pin
functions. If multiple functions are enabled, the highest significant bit position Alert Function (D15-D11) takes
priority and responds to the Alert Limit Register.
Table 15. Mask/Enable Register (06h) (Read/Write)
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SOL
SUL
BOL
BUL
POL
CNVR
—
—
—
—
—
AFF
CVRF
OVF
APOL
LEN
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
SOL:
Shunt Voltage Over-Voltage
Bit 15
Setting this bit high configures the Alert pin to be asserted if the shunt voltage measurement following a conversion
exceeds the value programmed in the Alert Limit Register.
SUL:
Shunt Voltage Under-Voltage
Bit 14
Setting this bit high configures the Alert pin to be asserted if the shunt voltage measurement following a conversion
drops below the value programmed in the Alert Limit Register.
BOL:
Bus Voltage Over-Voltage
Bit 13
Setting this bit high configures the Alert pin to be asserted if the bus voltage measurement following a conversion
exceeds the value programmed in the Alert Limit Register.
BUL:
Bus Voltage Under-Voltage
Bit 12
Setting this bit high configures the Alert pin to be asserted if the bus voltage measurement following a conversion
drops below the value programmed in the Alert Limit Register.
POL:
Power Over-Limit
Bit 11
Setting this bit high configures the Alert pin to be asserted if the Power calculation made following a bus voltage
measurement exceeds the value programmed in the Alert Limit Register.
CNVR:
Conversion Ready
Bit 10
Setting this bit high configures the Alert pin to be asserted when the Conversion Ready Flag, Bit 3, is asserted
indicating that the device is ready for the next conversion.
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AFF:
Alert Function Flag
Bit 4
While only one Alert Function can be monitored at the Alert pin at a time, the Conversion Ready can also be
enabled to assert the Alert pin. Reading the Alert Function Flag following an alert allows the user to determine if the
Alert Function was the source of the Alert.
When the Alert Latch Enable bit is set to Latch mode, the Alert Function Flag bit clears only when the Mask/Enable
Register is read. When the Alert Latch Enable bit is set to Transparent mode, the Alert Function Flag bit is cleared
following the next conversion that does not result in an Alert condition.
CVRF:
Conversion Ready Flag
Bit 3
Although the device can be read at any time, and the data from the last conversion is available, the Conversion
Ready Flag bit is provided to help coordinate one-shot or triggered conversions. The Conversion Ready Flag bit is
set after all conversions, averaging, and multiplications are complete. Conversion Ready Flag bit clears under the
following conditions:
1.) Writing to the Configuration Register (except for Power-Down selection)
2.) Reading the Mask/Enable Register
OVF:
Math Overflow Flag
Bit 2
This bit is set to '1' if an arithmetic operation resulted in an overflow error. It indicates that current and power data
may be invalid.
APOL:
Alert Polarity bit; sets the Alert pin polarity.
Bit 1
1 = Inverted (active-high open collector)
0 = Normal (active-low open collector) (default)
LEN:
Alert Latch Enable; configures the latching feature of the Alert pin and Alert Flag bits.
Bit 0
1 = Latch enabled
0 = Transparent (default)
When the Alert Latch Enable bit is set to Transparent mode, the Alert pin and Flag bit resets to the idle states when
the fault has been cleared. When the Alert Latch Enable bit is set to Latch mode, the Alert pin and Alert Flag bit
remains active following a fault until the Mask/Enable Register has been read.
7.6.8 Alert Limit Register (07h) (Read/Write)
The Alert Limit Register contains the value used to compare to the register selected in the Mask/Enable Register
to determine if a limit has been exceeded.
Table 16. Alert Limit Register (07h) (Read/Write) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
AUL15
AUL14
AUL13
AUL12
AUL11
AUL10
AUL9
AUL8
AUL7
AUL6
AUL5
AUL4
AUL3
AUL2
AUL1
AUL0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7.6.9 Manufacturer ID Register (FEh) (Read-Only)
The Manufacturer ID Register stores a unique identification number for the manufacturer.
Table 17. Manufacturer ID Register (FEh) (Read-Only) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
ID15
ID14
ID13
ID12
ID11
ID10
ID9
ID8
ID7
ID6
ID5
ID4
ID3
ID2
ID1
ID0
POR
VALUE
0
1
0
1
0
1
0
0
0
1
0
0
1
0
0
1
ID:
Manufacturer ID Bits
Bits 0-15
Stores the manufacturer identification bits
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7.6.10 Die ID Register (FFh) (Read-Only)
The Die ID Register stores a unique identification number and the revision ID for the die.
Table 18. Die ID Register (FFh) (Read-Only) Description
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
DID11
DID10
DID9
DID8
DID7
DID6
DID5
DID4
DID3
DID2
DID1
DID0
RID3
RID2
RID1
RID0
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DID:
Device ID Bits
Bits 4-15
Stores the device identification bits
RID:
Die Revision ID Bits
Bit 0-3
Stores the device revision identification bits
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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. Validate and test
the design implementation to confirm system functionality.
8.1 Application Information
The INA226 is a current shunt and power monitor with an I2C™ compatible interface. The device monitors both a
shunt voltage drop and bus supply voltage. Programmable calibration value, conversion times, and averaging,
combined with an internal multiplier, enable direct readouts of current in amperes and power in watts.
8.2 Typical Applications
8.2.1 High-Side Sensing Circuit Application
CBYPASS
0.1 µF
+12-V Supply
Pullup Resistors
VS
(Supply Voltage)
VBUS
SDA
SCL
´
VIN+
Power Register
V
2
Current Register
ADC
RSHUNT
2 mW
I
IC
Interface
Alert
Voltage Register
A0
VIN-
A1
Alert Register
10-A
Load
GND
Figure 27. Typical Circuit Configuration, INA226
8.2.1.1 Design Requirements
INA226 measures the voltage developed across a current-sensing resistor (RSHUNT) when current passes through
it. The device also measures the bus supply voltage and can calculate power when calibrated. It comes with alert
capability where the alert pin can be programmed to respond to a user-defined event or to a conversion ready
notification. This design illustrates the ability of the alert pin to respond to a set threshold.
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Typical Applications (continued)
8.2.1.2 Detailed Design Procedure
The Alert pin can be configured to respond to one of the five alert functions described in the Alert Pin section.
The alert pin must to be pulled up to the VVS pin voltage via the pull-up resistors. The configuration register is set
based on the required conversion time and averaging. The Mask/Enable Register is set to identify the required
alert function and the Alert Limit Register is set to the limit value used for comparison.
8.2.1.3 Application Curves
Figure 28 shows the Alert pin response to a shunt voltage over-limit of 80 mV for a conversion time (tCT) of 1.1
ms and averaging set to 1. Figure 29 shows the response for the same limit but with the conversion time reduced
to 140 µs.
Alert
(2 V/div)
ALERT
INPUT
LIMIT
Input/Limit
(50 mV/div)
Input/Limit
(50 mV/div)
Alert
(2 V/div)
ALERT
INPUT
LIMIT
Time (20 Ps/div)
Time (200 Ps/div)
D002
See Table 19
See Table 21
D002
tCT = 1.1 ms
See Table 22
See Table 20
See Table 21
Figure 28. Alert Response
tCT = 140 µs
See Table 22
Figure 29. Alert Response
Table 19. Configuration Register (00h) Settings for Figure 28 (Value = 4025h)
BIT #
D15
D14
D13
D12
D11
BIT
NAME
RST
—
—
—
AVG2
POR
VALUE
0
1
0
0
0
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
AVG1
AVG0
VBUSC
T2
VBUSC
T1
VBUSC
T0
VSHCT2
VSHCT1
VSHCT0
MODE3
MODE2
MODE1
0
0
0
0
0
1
0
0
1
0
1
Table 20. Configuration Register (00h) Settings for Figure 29 (Value = 4005h)
BIT #
D15
D14
D13
D12
D11
BIT
NAME
RST
—
—
—
AVG2
POR
VALUE
0
1
0
0
0
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
AVG1
AVG0
VBUSC
T2
VBUSC
T1
VBUSC
T0
VSHCT2
VSHCT1
VSHCT0
MODE3
MODE2
MODE1
0
0
0
0
0
0
0
0
1
0
1
Table 21. Mask/Enable Register (06h) Settings for Figure 28 and Figure 29 (Value = 8000h)
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SOL
SUL
BOL
BUL
POL
CNVR
—
—
—
—
—
AFF
CVRF
OVF
APOL
LEN
POR
VALUE
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 22. Alert Limit Register (07h) Settings for Figure 28 and Figure 29 (Value = 7D00)
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
AUL15
AUL14
AUL13
AUL12
AUL11
AUL10
AUL9
AUL8
AUL7
AUL6
AUL5
AUL4
AUL3
AUL2
AUL1
AUL0
POR
VALUE
0
1
1
1
1
1
0
1
0
0
0
0
0
0
0
0
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9 Power Supply Recommendations
The input circuitry of the device can accurately measure signals on common-mode voltages beyond its power
supply voltage, VVS. For example, the voltage applied to the VVS power supply terminal can be 5 V, whereas the
load power-supply voltage being monitored (the common-mode voltage) can be as high as 36 V. Note also that
the device can withstand the full 0-V to 36-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.
10 Layout
10.1 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.
10.2 Layout Example
A1
IN+
A0
IN±
Sense/Shunt
Resistor
(1)
Alert output
(Can be left floating if unused)
Alert
VBUS
SDA
GND
SCL
VS
2
I C/SMBUS
interface
Supply bypass
capacitor
Via to Ground Plane
Via to Power Plane
(1) connect the VBUS pin to the power supply rail.
Figure 30. INA226 Layout Example
30
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Copyright © 2011–2015, Texas Instruments Incorporated
Product Folder Links: INA226
INA226
www.ti.com
SBOS547A – JUNE 2011 – REVISED AUGUST 2015
11 Device and Documentation Support
11.1 Device Support
11.1.1 Development Support
• INA226EVM Evaluation Board and Software Tutorial (SBOU113)
11.2 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.
11.3 Trademarks
E2E is a trademark of Texas Instruments.
I2C is a trademark of NXP Semiconductors.
All other trademarks are the property of their respective owners.
11.4 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.
11.5 Glossary
SLYZ022 — 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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Copyright © 2011–2015, Texas Instruments Incorporated
Product Folder Links: INA226
31
PACKAGE OPTION ADDENDUM
www.ti.com
19-Sep-2014
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)
INA226AIDGSR
ACTIVE
VSSOP
DGS
10
2500
Green (RoHS
& no Sb/Br)
CU NIPDAUAG
Level-2-260C-1 YEAR
-40 to 125
226
INA226AIDGST
ACTIVE
VSSOP
DGS
10
250
Green (RoHS
& no Sb/Br)
CU NIPDAUAG
Level-2-260C-1 YEAR
-40 to 125
226
(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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
(6)
Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish
value exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
Addendum-Page 1
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
19-Sep-2014
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
19-Sep-2014
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
INA226AIDGSR
VSSOP
DGS
10
2500
330.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
INA226AIDGST
VSSOP
DGS
10
250
330.0
12.4
5.3
3.4
1.4
8.0
12.0
Q1
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
19-Sep-2014
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
INA226AIDGSR
VSSOP
DGS
10
2500
366.0
364.0
50.0
INA226AIDGST
VSSOP
DGS
10
250
366.0
364.0
50.0
Pack Materials-Page 2
PACKAGE OUTLINE
DGS0010A
VSSOP - 1.1 mm max height
SCALE 3.200
SMALL OUTLINE PACKAGE
C
5.05
TYP
4.75
SEATING PLANE
PIN 1 ID
AREA
A
0.1 C
10
1
3.1
2.9
NOTE 3
8X 0.5
2X
2
5
6
B
10X
3.1
2.9
NOTE 4
SEE DETAIL A
0.27
0.17
0.1
C A
1.1 MAX
B
0.23
TYP
0.13
0.25
GAGE PLANE
0 -8
0.15
0.05
0.7
0.4
DETAIL A
TYPICAL
4221984/A 05/2015
NOTES:
1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not
exceed 0.15 mm per side.
4. This dimension does not include interlead flash. Interlead flash shall not exceed 0.25 mm per side.
5. Reference JEDEC registration MO-187, variation BA.
www.ti.com
EXAMPLE BOARD LAYOUT
DGS0010A
VSSOP - 1.1 mm max height
SMALL OUTLINE PACKAGE
10X (0.3)
10X (1.45)
(R0.05)
TYP
SYMM
1
10
SYMM
8X (0.5)
6
5
(4.4)
LAND PATTERN EXAMPLE
SCALE:10X
SOLDER MASK
OPENING
METAL
SOLDER MASK
OPENING
METAL UNDER
SOLDER MASK
0.05 MAX
ALL AROUND
0.05 MIN
ALL AROUND
SOLDER MASK
DEFINED
NON SOLDER MASK
DEFINED
SOLDER MASK DETAILS
NOT TO SCALE
4221984/A 05/2015
NOTES: (continued)
6. Publication IPC-7351 may have alternate designs.
7. Solder mask tolerances between and around signal pads can vary based on board fabrication site.
www.ti.com
EXAMPLE STENCIL DESIGN
DGS0010A
VSSOP - 1.1 mm max height
SMALL OUTLINE PACKAGE
10X (1.45)
10X (0.3)
SYMM
1
(R0.05) TYP
10
SYMM
8X (0.5)
6
5
(4.4)
SOLDER PASTE EXAMPLE
BASED ON 0.125 mm THICK STENCIL
SCALE:10X
4221984/A 05/2015
NOTES: (continued)
8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
9. Board assembly site may have different recommendations for stencil design.
www.ti.com
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