TI INA220B-Q1

INA220B-Q1
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SLOS785A – JUNE 2012 – REVISED JUNE 2012
High- or Low-Side, Bidirectional
Current Power Monitor with 2-Wire Interface
Check for Samples: INA220B-Q1
FEATURES
DESCRIPTION
•
•
The INA220B-Q1 device is a current shunt and power
monitor with an 2-wire interface. The INA220B-Q1
device monitors both shunt drop and supply voltage.
A programmable calibration value, combined with an
internal multiplier, enables direct readouts in
amperes. An additional multiplying register calculates
power in watts. The 2-wire interface features 16
programmable addresses. The separate shunt input
on the INA220B-Q1 device allows it to be used in
systems with low-side sensing.
1
•
•
•
•
•
•
•
•
Qualified for Automotive Applications
AEC-Q100 Qualified with the following results:
– Device Temperature Grade 1: –40°C to
125°C Ambient Operating Temperature
Range
– Device HBM ESD Classification Level H2
– Device CDM ESD Classification Level C3B
High- or Low-Side Sensing
Senses Bus Voltages From 0 V to 26 V
Reports Current, Voltage, and Power
16 Programmable Addresses
High Accuracy: 0.5% (Max) Over Temperature
(INA220B-Q1)
User-Programmable Calibration
Fast (3.4 MHz) 2-Wire Mode
MSOP-10 Package
APPLICATIONS
•
•
•
•
•
•
•
•
Automotive
Servers
Telecom Equipment
Notebook Computers
Power Management
Battery Chargers
Power Supplies
Test Equipment
The INA220B-Q1 device is available in two grades: A
and B. The B grade version has higher accuracy and
higher precision specifications.
The INA220B-Q1 device senses across shunts on
buses that can vary from 0 V to 26 V, useful for lowside sensing or CPU power supplies. The device
uses a single 3 V to 5.5 V supply, drawing a
maximum of 1 mA of supply current. The INA220BQ1 device operates from –40°C to 125°C.
RELATED PRODUCTS
DESCRIPTION
DEVICE
Current/Power Monitor with Watchdog, Peak-Hold,
and Fast Comparator Functions
INA209
Zero-Drift, Low-Cost, Analog Current Shunt Monitor
Series in Small Package
INA210, INA211,
INA212, INA213,
INA214
Zero-Drift, Bidirectional Current Power Monitor with
2-Wire Interface
INA219
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2012, Texas Instruments Incorporated
INA220B-Q1
SLOS785A – JUNE 2012 – REVISED JUNE 2012
www.ti.com
Supply (0 to 26 V)
CBYPASS
0.1 mF
HighSide
Shunt
3.3 V to
5V
Bus Voltage Input
VS (Supply Voltage)
INA220B-Q1
´
Load
SDA
Power Register
DATA
SCL
R2F
LowSide
Shunt
V
VIN+
2-Wire
Interface
Current Register
ADC
R1F CF
CLK
A0
A1
Voltage Register
I
VIN-
GND
General Load, Low- or High-Side Sensing
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ORDERING INFORMATION
PACKAGE (2)
TA
–40°C to 125°C
(1)
(2)
VSSOP-DGS
Reel of 2500
(1)
ORDERABLE PART
NUMBER
TOP-SIDE MARKING
INA220BQDGSRQ1
IPUQ
For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the
INA220B-Q1 product folder at www.ti.com.
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging
ABSOLUTE MAXIMUM RATINGS (1)
Over operating free-air temperature range (unless otherwise noted).
INA220B-Q1
UNIT
6
V
Differential (VIN+) – (VIN–) (2)
–26 to 26
V
Common-Mode
Supply Voltage, VS
Analog Inputs,
VIN+, VIN–
–0.3 to 26
V
VBUS
–0.3 to 26
V
SDA
GND – 0.3 to 6
V
SCL
GND – 0.3 to VS 0.3
V
Input Current Into Any Pin
5
mA
Open-Drain Digital Output Current
10
mA
Operating Temperature
–40 to 125
°C
Storage Temperature
–65 to 150
°C
Junction Temperature
150
°C
2
kV
750
V
ESD Ratings
(1)
(2)
2
Human Body Model (HBM) AEC-Q100 Classification Level
H2
Charged Device Model (CDM) AEC-Q100 Classification
Level C3B
Stresses above Absolute Maximum Ratings may cause permanent damage. Exposure to absolute maximum conditions for extended
periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other
conditions beyond those specified is not implied.
VIN+ and VIN– may have a differential voltage of –26 V to 26 V; however, the voltage at these pins must not exceed the range –0.3 V to
26 V.
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RECOMMENDED OPERATING CONDITIONS
Boldface limits apply over the specified temperature range, TA = –40°C to 125°C
At TA = 25°C, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 32 mV, VBUS = 12 V, PGA = ÷ 1, and BRNG (1) = 1, unless otherwise noted.
PARAMETER
TEST CONDITIONS
MIN
NOM
MAX
UNIT
DIGITAL INPUTS
(SDA as Input, SCL, A0, A1)
Input Capacitance
Leakage Input Current
Input Logic Levels:
3
pF
0.1
0 ≤ VIN ≤ VS
1
μA
V
MMMVIH
0.7 (VS)
6
MMMVIL
–0.3
0.3 (VS)
Hysteresis
500
V
mV
OPEN-DRAIN DIGITAL OUTPUTS
(SDA)
Logic '0' Output Level
ISINK = 3mA
0.15
0.4
V
High-Level Output Leakage Current
VOUT = VS
0.1
1
μA
POWER SUPPLY
Operating Supply Range
3
Quiescent Current
5.5
V
0.7
1
mA
Quiescent Current, Power-Down Mode
6
15
μA
Power-On Reset (POR) Threshold
2
V
TEMPERATURE RANGE
Specified Temperature Range
–40
85
°C
Operating Temperature Range
–40
125
°C
Thermal Resistance (2)MMMMMMMθJA
MMMMSOP-10
(1)
(2)
200
°C/W
BRNG is bit 13 of the Configuration Register.
θJA value is based on JEDEC low-K board.
THERMAL INFORMATION
THERMAL METRIC (1)
INA220B-Q1
DGS (10 PINS)
θJA
Junction-to-ambient thermal resistance
165.4
θJCtop
Junction-to-case (top) thermal resistance
53.2
θJB
Junction-to-board thermal resistance
86.6
ψJT
Junction-to-top characterization parameter
6.4
ψJB
Junction-to-board characterization parameter
84.9
θJCbot
Junction-to-case (bottom) thermal resistance
N/A
(1)
UNIT
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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ELECTRICAL CHARACTERISTICS: VS = 3.3V
Boldface limits apply over the specified temperature range, TA = –40°C to 125°C.
At TA = 25°C, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 32 mV, VBUS = 12 V, PGA = ÷ 1, and BRNG (1) = 1, unless otherwise noted.
INA220B-Q1
PARAMETER
TEST CONDITIONS
MIN
PGA = ÷ 1
PGA = ÷ 2
TYP
MAX
UNIT
0
±40
mV
0
±80
mV
PGA = ÷ 4
0
±160
mV
PGA = ÷ 8
0
±320
mV
BRNG = 1
0
32
V
BRNG = 0
0
16
VIN+ = 0 V to 26 V
100
INPUT
Full-Scale Current Sense (Input) Voltage Range
Bus Voltage (Input Voltage) Range (2)
Common-Mode Rejection
Offset Voltage, RTI (3)
CMRR
VOS
PSRR
V
dB
PGA = ÷ 1
±10
±50 (4)
μV
PGA = ÷ 2
±20
±75
μV
PGA = ÷ 4
±30
±75
μV
PGA = ÷ 8
±40
±100
versus Temperature
versus Power Supply
120
VS = 3 V to 5.5 V
Current Sense Gain Error
μV
0.16
μV/°C
10
μV/V
±40
m%
1
m%/°C
VIN+ Pin
20
μA
VIN– Pin
20
μA
VBUS Pin (5)
320
kΩ
versus Temperature, MSOP-10
Input Impedance
Input Leakage (6)
Active Mode
Power-Down Mode
VIN+ Pin
0.1
±0.5
μA
VIN– Pin
0.1
±0.5
μA
DC ACCURACY
ADC Basic Resolution
12
Bits
1LSB Step Size
Shunt Voltage
10
μV
Bus Voltage
4
mV
Current Measurement Error
±0.2
over Temperature
Bus Voltage Measurement Error
VBUS = 12 V
±0.2
over Temperature
±0.3
%
±0.5
%
±0.5
%
±1
Differential Nonlinearity
±0.1
%
LSB
ADC TIMING
ADC Conversion Time
12-Bit
532
586
μs
11-Bit
276
304
μs
10-Bit
148
163
μs
9-Bit
84
93
μs
Minimum Convert Input Low Time
μs
4
SMBus
SMBus Timeout (7)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
4
28
35
ms
BRNG is bit 13 of the Configuration Register.
This parameter only expresses the full-scale range of the analog-to-digital converter (ADC) scaling. In no event should more than 26 V
be applied to this device.
Referred-to-input (RTI).
Shaded cells indicate improved specifications of the INA220B-Q1.
The input impedance of this pin may vary approximately ±15%.
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.
System management bus (SMBus) timeout in the INA220B-Q1 resets the interface any time SCL or SDA is low for over 28 ms.
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SLOS785A – JUNE 2012 – REVISED JUNE 2012
PIN CONFIGURATIONS
DGS PACKAGE
MSOP-10
(Top View)
A1
1
10 VIN+
A0
2
9
VIN-
NC
3
8
VBUS
SDA
4
7
GND
SCL
5
6
VS
PIN DESCRIPTIONS: MSOP-10
MSOP-10
(DGS)
PIN NO
NAME
DESCRIPTION
1
A1
Address pin. Connect to GND, SCL, SDA, or VS. Table 1 shows pin settings and corresponding
addresses.
2
A0
Address pin. Connect to GND, SCL, SDA, or VS. Table 1 shows pin settings and corresponding
addresses.
3
NC
No internal connection
4
SDA
Serial bus data line.
5
SCL
Serial bus clock line.
6
VS
7
GND
Ground.
8
VBUS
Bus voltage input.
9
VIN–
Negative differential shunt voltage. Connect to negative side of shunt resistor. Bus voltage is measured
from this pin to ground.
10
VIN+
Positive differential shunt voltage. Connect to positive side of shunt resistor.
Power supply, 3 V to 5.5 V.
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TYPICAL CHARACTERISTICS
At TA = 25°C, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 32 mV, PGA = ÷ 1, and BRNG = 1, unless otherwise noted.
ADC SHUNT OFFSET
vs
TEMPERATURE
100
-10
80
-20
60
-30
40
Offset (mV)
Gain (dB)
FREQUENCY RESPONSE
0
-40
-50
-60
20
0
-20
-70
-40
-80
-60
-90
-80
-100
-100
1k
100
10
10k
100k
320 mV Range
160 mV Range
1M
80 mV Range
-50
-25
0
Input Frequency (Hz)
75
Figure 1.
Figure 2.
ADC SHUNT GAIN ERROR
vs
TEMPERATURE
ADC BUS VOLTAGE OFFSET
vs
TEMPERATURE
100
125
45
160 mV Range
320 mV Range
60
40
35
40
Offset (mV)
Gain Error (m%)
50
50
80
20
0
80 mV Range
-20
40 mV Range
30
25
20
-60
10
-80
5
16 V Range
32 V Range
15
0
-100
-50
-25
0
25
50
75
100
125
-50
-25
0
25
50
75
100
125
Temperature (°C)
Temperature (°C)
Figure 3.
6
25
Temperature (°C)
100
-40
40 mV Range
Figure 4.
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TYPICAL CHARACTERISTICS (continued)
At TA = 25°C, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 32 mV, PGA = ÷ 1, and BRNG = 1, unless otherwise noted.
ADC BUS GAIN ERROR
vs
TEMPERATURE
INTEGRAL NONLINEARITY
vs
INPUT VOLTAGE
100
20
80
15
10
40
16 V
20
INL (mV)
Gain Error (m%)
60
0
-20
0
-5
32 V
-40
5
-10
-60
-15
-80
-100
-50
-25
0
25
50
75
100
-20
-0.4
125
-0.3
-0.2
2.0
INPUT CURRENTS WITH LARGE DIFFERENTIAL
VOLTAGES
(VIN+ at 12 V, Sweep of VIN–)
ACTIVE IQ
vs
TEMPERATURE
0.2
0.3
0.4
1.2
VS+ = 5 V
1.0
VS = 5 V
0.8
IQ (mA)
Input Currents (mA)
0.1
Figure 6.
1.0
0
0
Figure 5.
1.5
0.5
-0.1
Input Voltage (V)
Temperature (°C)
VS+ = 3 V
VS+ = 3 V
0.6
VS = 3 V
0.4
-0.5
0.2
-1.0
VS+ = 5 V
0
-1.5
0
5
10
15
20
25
30
-50
VIN- Voltage (V)
-25
0
25
50
75
100
125
Temperature (°C)
Figure 7.
Figure 8.
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TYPICAL CHARACTERISTICS (continued)
At TA = 25°C, VIN+ = 12 V, VSENSE = (VIN+ – VIN–) = 32 mV, PGA = ÷ 1, and BRNG = 1, unless otherwise noted.
SHUTDOWN IQ
vs
TEMPERATURE
ACTIVE IQ
vs
2-WIRE CLOCK FREQUENCY
16
1.0
14
0.9
12
0.7
10
IQ (mA)
IQ (mA)
VS = 5 V
0.8
VS = 5 V
8
6
VS = 3 V
4
0.6
VS = 3 V
0.5
0.4
0.3
0.2
2
0.1
0
0
-50
-25
0
25
50
75
100
1k
125
10k
Temperature (°C)
100k
Figure 9.
Figure 10.
TOTAL PERCENT BUS VOLTAGE ERROR
vs
SUPPLY VOLTAGE
SHUTDOWN IQ
vs
2-WIRE CLOCK FREQUENCY
4
5 V +Error
250
VS = 5 V
3
3.3 V +Error
2
200
IQ (mA)
% Bus Voltage Error
10M
300
5
1
0
-1
150
100
-2
-3
50
5 V -Error
-4
VS = 3 V
3.3 V -Error
0
-5
0
1
2
3
4
5
24
25
26
1k
10k
100k
1M
10M
SCL Frequency (Hz)
VBUS (V)
Figure 11.
8
1M
SCL Frequency (Hz)
Figure 12.
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REGISTER BLOCK DIAGRAM
Power
(1)
Bus Voltage
(1)
´
Shunt Voltage
Channel
Current
(1)
ADC
Bus Voltage
Channel
Calibration
(2)
´
Shunt Voltage
(1)
PGA
(In Configuration Register)
Data Registers
(1)
Read-only.
(2)
Write-only.
Figure 13. INA220B-Q1 Register Block Diagram
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APPLICATION INFORMATION
The INA220B-Q1 device is a digital current shunt
monitor with an 2-wire 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, and continuous versus
triggered operation. Detailed register information
appears at the end of this data sheet, beginning with
Table 3. See the Register Block Diagram for a block
diagram of the INA220B-Q1 device.
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
INA220B-Q1 device includes a 28 ms timeout on its
interface to prevent locking up an SMBus.
INA220B-Q1 TYPICAL APPLICATION
Serial Bus Address
The figure on the front page shows a typical
application circuit for the INA220B-Q1 device. Use a
0.1 μF ceramic capacitor for power-supply bypassing,
placed as closely as possible to the supply and
ground pins.
To communicate with the INA220B-Q1 device, 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 indicating the
intent of executing a read or write operation.
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 unless a filter is
needed. See the Filtering and Input Considerations
section.
The INA220B-Q1 device 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.
BUS OVERVIEW
The INA220B-Q1 device offers compatibility with both
2-wire and SMBus interfaces. The 2-wire and SMBus
protocols are essentially compatible with one another.
The 2-wire 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,
serial bus clock line (SCL) and serial bus data line
(SDA), connect the INA220B-Q1 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 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 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.
10
Table 1. INA220B-Q1 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
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Serial Interface
The INA220B-Q1 device operates only as a slave
device on the 2-wire 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 INA220B-Q1 device supports the
transmission protocol for fast (1 kHz to 400 kHz) and
high-speed (HS) (1 kHz to 3.4 MHz) modes. All data
bytes are transmitted most significant byte first.
WRITING TO AND READING FROM THE
INA220B-Q1 DEVICE
Accessing a particular register on the INA220B-Q1
device is accomplished by writing the appropriate
value to the register pointer. Refer to Table 3 for a
complete list of registers and corresponding
addresses. The value for the register pointer as
shown in Figure 17 is the first byte transferred after
the slave address byte with the R/W bit LOW. Every
write operation to the INA220B-Q1 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 INA220B-Q1
device 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 INA220B-Q1 device acknowledges
receipt of each data byte. The master may terminate
data transfer by generating a START or STOP
condition.
When reading from the INA220B-Q1 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 INA220B-Q1 device retains the register
pointer value until it is changed by the next write
operation.
Figure 14 and Figure 15 show read and write
operation timing diagrams, respectively. Note that
register bytes are sent most significant byte first,
followed by the least significant byte. Figure 16
shows the timing diagram for the SMBus ALERT
response operation. Figure 17 illustrates a typical
register pointer configuration.
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Start By
Master
1
1
1
1
0
A3
0
A2
A3
A1
A2
A0
A1
R/W
9
A0
1
P7
ACK By
INA220B-Q1
9
1
D15 D14
ACK By
INA220B-Q1
R/W
(1)
P6
P5
P4
P3
P2
D13
P1
Frame 2 Register Pointer Byte
D12
D11 D10
D9
(2)
From
INA220B-Q1
Frame 2 Data MSByte
P0
9
1
D15 D14
ACK By
INA220B-Q1
D13
D8
9
D9
1
D6
9
ACK By
INA220B-Q1
D8
D7
ACK By
Master
D12 D11 D10
Frame 3 Data MSByte
D5
1
D7
D4
D3
D2
From
INA220B-Q1
D5
D4
D3
(2)
D1
D2
Frame 3 Data LSByte
D6
9
9
ACK By
INA220B-Q1
D0
(3)
No ACK By
Master
D0
D1
Frame 4 Data LSByte
Stop
Stop By
Master
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Frame 1 2-Wire Slave Address Byte
0
(1)
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.
0
Frame 1 2-Wire Slave Address Byte
Figure 15. Timing Diagram for Read Word Format
Figure 14. Timing Diagram for Write Word Format
SCL
SDA
SCL
SDA
Start By
Master
NOTE (1): The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins. Refer to Table 1.
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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
A3
A2
ACK By
INA220B-Q1
A1
A0
0
From
INA220B-Q1
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 16. 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
P4
P3
P2
P1
ACK By
INA220B-Q1
Frame 1 2-Wire Slave Address Byte
(1)
P0
Stop
ACK By
INA220B-Q1
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 17. Typical Register Pointer Set
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HS 2-Wire Mode
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 3.4
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 INA220B-Q1 device to support
the F/S 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 the 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 INA220B-Q1 device does not acknowledge
the HS master code, but does recognize it and
switches its internal filters to support 3.4 Mbps
operation.
t(LOW)
tF
tR
t(HDSTA)
SCL
t(HDSTA)
t(HIGH)
t(SUSTO)
t(SUSTA)
t(HDDAT)
t(SUDAT)
SDA
t(BUF)
P
S
S
P
Figure 18. Bus Timing Diagram
Bus Timing Diagram Definitions
FAST MODE
PARAMETER
HIGH-SPEED MODE
MIN
MAX
MIN
MAX
UNITS
0.4
0.001
3.4
MHz
SCL Operating Frequency
f(SCL)
0.001
Bus Free Time Between STOP and START
Condition
t(BUF)
600
160
ns
Hold time after repeated START condition.
After this period, the first clock is generated.
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)
0
0
ns
Data Setup Time
t(SUDAT)
100
10
ns
SCL Clock LOW Period
t(LOW)
1300
160
ns
SCL Clock HIGH Period
t(HIGH)
600
60
Clock/Data Fall Time
tF
Clock/Data Rise Time
Clock/Data Rise Time for SCLK ≤ 100kHz
14
ns
300
160
ns
tR
300
160
ns
tR
1000
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Power-Up Conditions
Power-up conditions apply to a software reset via the
RST bit (bit 15) in the Configuration Register, or the
2-wire bus general call reset.
BASIC ADC FUNCTIONS
The two analog inputs to the INA220B-Q1 device,
VIN+ and VIN–, connect to a shunt resistor in the bus
of interest. Bus voltage is measured at VBUS pin. The
INA220B-Q1 device is typically powered by a
separate supply from 3 V to 5.5 V. The bus being
sensed can vary from 0 V 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 INA220B-Q1
device senses the small drop across the shunt for
shunt voltage, and senses the voltage with respect to
ground from VBUS for the bus voltage.
When the INA220B-Q1 device 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 table can be used to determine the
actual conversion time.
Power-down mode reduces the quiescent current and
turns off current into the INA220B-Q1 device inputs,
avoiding any supply drain. Full recovery from powerdown requires 40 μs. ADC off mode (set by the
Configuration Register, MODE bits) stops all
conversions.
In triggered mode, 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.
Although the INA220B-Q1 device 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.
space
The conversion ready bit clears under these
conditions:
1. Writing to the Configuration Register, except
when configuring the MODE bits for power-down
or ADC off (Disable) modes;
2. Reading the Status Register; or
3. Triggering a single-shot conversion with the
convert pin.
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.
PGA Function
If larger full-scale shunt voltages are desired, the
INA220B-Q1 device 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 V or 32 V.
Compatibility with TI Hot Swap Controllers
The INA220B-Q1 device 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 INA220B-Q1 device 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 INA220B-Q1 device can be set to ÷2
to provide an 80mV full-scale range.
Filtering and Input Considerations
Measuring current is often noisy, and such noise can
be difficult to define. The INA220B-Q1 device 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 INA220B-Q1 device. The
high frequency enables the use of low-value series
resistors on the filter for negligible effects on
measurement accuracy. In general, filtering the
INA220B-Q1 device input is only necessary if there
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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 μF to 1 μF.
Figure 19 shows the INA220B-Q1 device with an
additional filter added at the input.
Overload conditions are another consideration for the
INA220B-Q1 device inputs. The INA220B-Q1 device
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 INA220B-Q1 device.
Inductive kickback voltages are best dealt with by
zener-type transient-absorbing devices (commonly
called transzorbs) 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 INA220B-Q1 device in systems where large
currents are available. Testing has demonstrated that
the addition of 10 Ω resistors in series with each input
of the INA220B-Q1 device sufficiently protects the
inputs against dV/dt failure up to the 26 V rating of
the INA220B-Q1 device. These resistors have no
significant effect on accuracy.
Simple Current Shunt Monitor Usage
(No Programming Necessary)
The INA220B-Q1 device 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.
Programming the INA220B-Q1
The default power-up states of the registers are
shown in the INA220 register descriptions section of
this data sheet. These registers are volatile, and if
programmed to other than default values, must be
reprogrammed at every device power-up. Detailed
information on programming the Calibration Register
specifically is given in the section, Programming the
INA220 Power Measurement Engine.
Current
Shunt
Load
Supply
RFILTER 10 W
RFILTER 10 W
Supply Voltage
3.3 V Supply
VBUS
0.1 mF to 1 mF
Ceramic Capacitor
VIN+ VIN-
VS
INA220B-Q1
´
Power Register
Current Register
Data (SDA)
2-Wire
Interface
Clock (SCL)
A0
ADC
A1
Voltage Register
GND
Figure 19. INA220B-Q1 Device With Input Filtering
16
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PROGRAMMING THE INA220B-Q1 DEVICE
POWER MEASUREMENT ENGINE
Calibration Register and Scaling
The Calibration Register makes it possible to set the
scaling of the Current and Power Registers to
whatever values are most useful for a given
application. One strategy may be to set the
Calibration Register such that the largest possible
number is generated in the Current Register or Power
Register at the expected full-scale point; this
approach yields the highest resolution. The
Calibration Register can also be selected to provide
values in the Current and Power Registers that either
provide direct decimal equivalents of the values being
measured, or yield a round LSB number. After these
choices have been made, the Calibration Register
also offers possibilities for end user system-level
calibration, where the value is adjusted slightly to
cancel total system error.
Below are two examples for configuring the INA220BQ1 device calibration. Both examples are written so
the information directly relates to the calibration setup
found in the INA220B-Q1 EVM software.
Calibration Example 1: Calibrating the INA220B-Q1 device with no possibility for overflow. (Note that the
numbers used in this example are the same used with the INA220B-Q1 EVM software as shown in
Figure 20)
1. Establish the following parameters:
VBUS_MAX = 32
VSHUNT_MAX = 0.32
RSHUNT = 0.5
2. Using Equation 1, determine the maximum possible current.
VSHUNT_MAX
MaxPossible_I =
RSHUNT
MaxPossible_I = 0.64
(1)
3. Choose the desired maximum current value. This value is selected based on system expectations.
Max_Expected_I = 0.6
4. Calculate the possible range of current LSBs. To calculate this range, first compute a range of LSBs that is
appropriate for the design. Next, select an LSB within this range. Note that the results will have the most
resolution when the minimum LSB is selected. Typically, an LSB is selected to be the nearest round number
to the minimum LSB value.
Max_Expected_I
Minimum_LSB =
32767
Minimum_LSB = 18.311 ´ 10-6
(2)
Max_Expected_I
4096
Maximum_LSB = 146.520 ´ 10-6
Maximum_LSB =
(3)
Choose an LSB in the range: Minimum_LSB<Selected_LSB < Maximum_LSB
Current_LSB = 20 × 10–6
Note:
This value was selected to be a round number near the Minimum_LSB. This selection allows for
good resolution with a rounded LSB.
5. Compute the Calibration Register value using Equation 4:
0.04096
Cal = trunc Current_LSB ´ R
SHUNT
Cal = 4096
(4)
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6. Calculate the Power LSB, using Equation 5. Equation 5 shows a general formula; because the bus voltage
measurement LSB is always 4 mV, the power formula reduces to the calculated result.
Power_LSB = 20 Current_LSB
Power_LSB = 400 ´ 10-6
(5)
7. Compute the maximum current and shunt voltage values (before overflow), as shown by Equation 6 and
Equation 7. Note that both Equation 6 and Equation 7 involve an If - then condition:
Max_Current = Current_LSB ´ 32767
Max_Current = 0.65534
(6)
If Max_Current ≥ Max Possible_I then
Max_Current_Before_Overflow = MaxPossible_I
Else
Max_Current_Before_Overflow = Max_Current
End If
(Note that Max_Current is greater than MaxPossible_I in this example.)
Max_Current_Before_Overflow = 0.64 (Note: This result is displayed by software as seen in Figure 20)
Max_ShuntVoltage = Max_Current_Before_Overflow ´ RSHUNT
Max_ShuntVoltage = 0.32
(7)
If Max_ShuntVoltage ≥ VSHUNT_MAX
Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
Else
Max_ShuntVoltage_Before_Overflow= Max_ShuntVoltage
End If
(Note that Max_ShuntVoltage is greater than VSHUNT_MAX in this example.)
Max_ShuntVoltage_Before_Overflow = 0.32 (Note: This result is displayed by software as seen in
Figure 20)
8. Compute the maximum power with Equation 8.
MaximumPower = Max_Current_Before_Overflow ´ VBUS_MAX
MaximumPower = 20.48
(8)
9. (Optional second calibration step) Compute corrected full-scale calibration value based on measured current.
INA220B-Q1_Current = 0.63484
MeasShuntCurrent = 0.55
Corrected_Full_Scale_Cal = trunc
Cal ´ MeasShuntCurrent
INA220_Current
Corrected_Full_Scale_Cal = 3548
18
(9)
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Figure 20 illustrates how to perform the same
procedure discussed in this example using the
automated INA220B-Q1 EVM software. Note that the
same numbers used in the nine-step example are
used in the software example in Figure 20. Also note
that Figure 20 illustrates which results correspond to
which step (for example, the information entered in
step 1 is enclosed in a box in Figure 20 and labeled).
Step1
Optional
Step9
Equ9
Step2
Equ1
Step3
Step4
Equ2, 3
Step5
Equ4
Step7
Equ6, 7
Step6
Equ4
Step8
Equ8
Figure 20. INA220B-Q1 EVM Calibration Software Automatically Computes Calibration Steps 1-9
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Calibration Example 2 (Overflow Possible)
This design example uses the nine-step procedure for
calibrating the INA220B-Q1 device where overflow is
possible. Figure 21 illustrates how the same
procedure is performed using the automated
INA220B-Q1 EVM software. Note that the same
numbers used in the nine-step example are used in
the software example in Figure 21. Also note that
Figure 21 illustrates which results correspond to
which step (for example, the information entered in
step 1 is circled in Figure 21 and labeled).
1. Establish the following parameters:
VBUS_MAX = 32
VSHUNT_MAX = 0.32
RSHUNT = 5
2. Determine the maximum possible current using Equation 10:
VSHUNT_MAX
MaxPossible_I =
RSHUNT
MaxPossible_I = 0.064
(10)
3. Choose the desired maximum current value: Max_Expected_I, ≤ MaxPossible_I. This value is selected
based on system expectations.
Max_Expected_I = 0.06
4. Calculate the possible range of current LSBs. This calculation is done by first computing a range of LSBs
that is appropriate for the design. Next, select an LSB withing this range. Note that the results will have the
most resolution when the minimum LSB is selected. Typically, an LSB is selected to be the nearest round
number to the minimum LSB.
Max_Expected_I
Minimum_LSB =
32767
Minimum_LSB = 1.831 ´ 10-6
(11)
Max_Expected_I
4096
Maximum_LSB = 14.652 ´ 10-6
Maximum_LSB =
(12)
Choose an LSB in the range: Minimum_LSB<Selected_LSB<Maximum_LSB
Current_LSB = 1.9 × 10–6
Note:
This value was selected to be a round number near the Minimum_LSB. This section allows for good
resolution with a rounded LSB.
5. Compute the Calibration Register using Equation 13:
Cal = trunc
0.04096
Current_LSB ´ RSHUNT
Cal = 4311
(13)
6. Calculate the Power_LSB using Equation 14. Equation 14 shows a general formula; because the bus voltage
measurement LSB is always 4 mV, the power formula reduces to calculate the result.
Power_LSB = 20 Current_LSB
Power_LSB = 38 ´ 10-6
20
(14)
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7. Compute the maximum current and shunt voltage values (before overflow), as shown by Equation 15 and
Equation 16. Note that both Equation 15 and Equation 16 involve an If - then condition.
Max_Current = Current_LSB ´ 32767
Max_Current = 0.06226
(15)
If Max_Current ≥ Max Possible_I then
Max_Current_Before_Overflow = MaxPossible_I
Else
Max_Current_Before_Overflow = Max_Current
End If
(Note that Max_Current is less than MaxPossible_I in this example.)
Max_Current_Before_Overflow = 0.06226 (Note: This result is displayed by software as seen in Figure 21)
Max_ShuntVoltage = Max_Current_Before_Overflow ´ RSHUNT
Max_ShuntVoltage = 0.3113
(16)
If Max_ShuntVoltage ≥ VSHUNT_MAX
Max_ShuntVoltage_Before_Overflow = VSHUNT_MAX
Else
Max_ShuntVoltage_Before_Overflow = Max_ShuntVoltage
End If
(Note that Max_ShuntVoltage is less than VSHUNT_MAX in this example)
Max_ShuntVoltage_Before_Overflow = 0.3113 (Note: This result is displayed by software as seen in
Figure 21)
8. Compute the maximum power with equation 8.
MaximumPower = Max_Current_Before_Overflow ´ VBUS_MAX
MaximumPower = 1.992
(17)
9. (Optional second calibration step) Compute the corrected full-scale calibration value based on measured
current.
INA220B-Q1_Current = 0.06226
MeaShuntCurrent = 0.05
Corrected_Full_Scale_Cal = trunc
Cal ´ MeasShuntCurrent
INA220_Current
Corrected_Full_Scale_Cal = 3462
(18)
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Figure 21 illustrates how to perform the same
procedure discussed in this example using the
automated INA220B-Q1 EVM software. Note that the
same numbers used in the nine-step example are
used in the software example in Figure 21.
Also note that Figure 21 illustrates which results
correspond to which step (for example, the
information entered in step 1 is enclosed in a box in
Figure 21 and labeled).
Step1
Optional
Step9
Equ18
Step2
Equ10
Step3
Step4
Equ11, 12
Step5
Equ13
Step7
Equ15, 16
Step6
Equ14
Step8
Equ17
Figure 21. INA220B-Q1 EVM Calibration Software Automatically Computes Calibration Steps 1-9
22
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CONFIGURE, MEASURE, AND CALCULATE
EXAMPLE
shunt voltage. By knowing the value of the shunt
resistor, the device can then calculate the amount of
current that created the measured shunt voltage drop.
The first step when calculating the calibration value is
setting the current LSB. The Calibration Register
value is based on a calculation that has its precision
capability limited by the size of the register and the
Current Register LSB. The device can measure
bidirectional current; thus, the MSB of the Current
Register is a sign bit that allows for the rest of the 15
bits to be used for the Current Register value. It is
common when using the current value calculations to
use a resolution between 12 bits and 15 bits.
Calculating the current LSB for each of these
resolutions provides minimum and maximum values.
These values are calculated assuming the maximum
current that will be expected to flow through the
current shunt resistor, as shown in Equation 2 and
Equation 3. To simplify the mathematics, it is
common to choose a round number located between
these two points. For this example, the maximum
current LSB is 3.66 mA/bit and the minimum current
LSB would be 457.78 µA/bit assuming a maximum
expected current of 15 A. For this example, a value of
1 mA/bit was 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 4 results in a Calibration Register
value of 20480, or 5000h.
In this example, the 10 A load creates a differential
voltage of 20 mV across a 2 mΩ shunt resistor. The
voltage present at the VIN– pin is equal to the
common-mode voltage minus the differential drop
across the resistor. The bus voltage for the INA220BQ1 device is measured at the external VBUS input pin,
which in this example is connected to the VIN– pin to
measure the voltage level delivered to the load. For
this example, the voltage at the VIN– pin is 11.98 V.
For this particular range (40 mV full-scale), 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.
Note that the Bus Voltage Register bits are not rightaligned. In order to compute the value of the Bus
Voltage Register contents using the LSB of 4 mV, the
register 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 4 mV LSB value to
compute the bus voltage measured by the device.
The shifted value of the Bus Voltage Register
contents is now equal to BB3h, a decimal equivalent
of 2995. This value of 2995 multiplied by the 4 mV
LSB results in a value of 11.98 V.
The Calibration Register (05h) is set in order to
provide the device information about the current
shunt resistor that was used to create the measured
3.3 V to 5 V
12 V
VCM
RSHUNT
2 mW
10 mF
10 A
Load
0.1 mF
VS (Supply Voltage)
x
V
VIN+
VIN-
SDA
Power Register
Current Register
Voltage Register
I
I2C
Interface
SCK
A0
A1
GND
Figure 22. Example Circuit Configuration
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The Current Register (04h) is then calculated by
multiplying the shunt voltage contents by the
Calibration Register and then dividing by 4095. For
this example, the shunt voltage of 2000 is multiplied
by the Calibration Register of 20480 and then divided
by 4095 to yield a Current Register of 2712h.
this result by the power LSB that is 20 times the
1 × 10-3 current LSB, or 20 × 10-3, results in a power
calculation of 5991 × 20 mW/bit, which equals 119.82
W. This result matches what is expected for this
register. A manual calculation for the power being
delivered to the load would use 11.98 V (12VCM – 20
mV shunt drop) multiplied by the load current of 10 A
to give a 119.8 W result.
The Power Register (03h) is then be calculated by
multiplying the Current Register of 10002 by the Bus
Voltage Register of 2995 and then dividing by 5000.
For this example, the Power Register contents are
1767h, or a decimal equivalent of 5991. Multiplying
Table 2 shows the steps for configuring, measuring,
and calculating the values for current and power for
this device.
Table 2. Configure, Measure, and Calculate Example (1)
(1)
24
STEP #
REGISTER NAME
ADDRESS
CONTENTS
Step 1
Configuration
00h
019Fh
ADJ
Step 2
Shunt
01h
07D0h
Step 3
Bus
02h
5D98h
Step 4
Calibration
05h
5000h
20480
Step 5
Current
04h
2712h
10002
1 mA
10.002 A
Step 6
Power
03h
1767h
5991
20 mW
119.82 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 = 16 V.
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REGISTER INFORMATION
The INA220B-Q1 device uses a bank of registers for
holding configuration settings, measurement results,
maximum and minimum limits, and status information.
Table 3 summarizes the INA220B-Q1 device
registers; Figure 13 illustrates the 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 3. Summary of Register Set
POINTER
ADDRESS
(1)
(2)
POWER-ON RESET
BINARY
HEX
TYPE (1)
All-register reset, settings for bus
voltage range, PGA Gain, ADC
resolution and averaging
00111001 10011111
399F
R/W
Shunt voltage measurement data
Shunt voltage
—
R
Bus voltage
—
R
00000000 00000000
0000
R
00000000 00000000
0000
R
00000000 00000000
0000
R/W
HEX
REGISTER NAME
FUNCTION
00
Configuration Register
01
Shunt Voltage
02
Bus Voltage
03
Power (2)
Power measurement data
04
Current (2)
Contains the value of the current flowing
through the shunt resistor
05
Calibration
Sets full-scale range and LSB of current
and power measurements; overall
system calibration
Bus voltage measurement data
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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REGISTER DETAILS
All INA220B-Q1 device registers 16-bit registers are actually two 8-bit bytes through the 2-wire interface.
Configuration Register 00h (Read/Write)
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
RST
—
BRNG
PG1
PG0
BADC4
BADC3
BADC2
BADC1
SADC4
SADC3
SADC2
SADC1
MODE3
MODE2
MODE1
POR
VALUE
0
0
1
1
1
0
0
1
1
0
0
1
1
1
1
1
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 = 16 V FSR
1 = 32 V FSR (default value)
PG:
PGA (Shunt Voltage Only)
Bits 11, 12
Sets PGA gain and range. Note that the PGA defaults to ÷8 (320 mV range). Table 4 shows the gain and range for
the various product gain settings.
Table 4. PG Bit Settings [12:11]
(1)
(1)
PG1
PG0
GAIN
RANGE
0
0
1
±40 mV
0
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).
26
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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 (SADC [6:3], BADC [10:7]) (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 [2:0] (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.
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DATA OUTPUT REGISTERS
Shunt Voltage Register 01h (Read-Only)
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 twos complement format.
Generate the twos 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
4. Complement the binary result : 000 0010 1111 1111
5. Add 1 to the complement to create the twos 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, positive value hex = 7D00, negative value hex =
8300), and LSB = 10 μV.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SIGN
SD14_8
SD13_8
SD12_8
SD11_8
SD10_8
SD9_8
SD8_8
SD7_8
SD6_8
SD5_8
SD4_8
SD3_8
SD2_8
SD1_8
SD0_8
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
At PGA = ÷4, full-scale range = ±160 mV (decimal = 16000, positive value hex = 3E80, negative value hex =
C180), and LSB = 10 μV.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SIGN
SIGN
SD13_4
SD12_4
SD11_4
SD10_4
SD9_4
SD8_4
SD7_4
SD6_4
SD5_4
SD4_4
SD3_4
SD2_4
SD1_4
SD0_4
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
At PGA = ÷2, full-scale range = ±80 mV (decimal = 8000, positive value hex = 1F40, negative value hex =
E0C0), and LSB = 10 μV.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SIGN
SIGN
SIGN
SD12_2
SD11_2
SD10_2
SD9_2
SD8_2
SD7_2
SD6_2
SD5_2
SD4_2
SD3_2
SD2_2
SD1_2
SD0_2
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
At PGA = ÷1, full-scale range = ±40 mV (decimal = 4000, positive value hex = 0FA0, negative value hex = F060),
and LSB = 10 μV.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
SIGN
SIGN
SIGN
SIGN
SD11_1
SD10_1
SD9_1
SD8_1
SD7_1
SD6_1
SD5_1
SD4_1
SD3_1
SD2_1
SD1_1
SD0_1
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
28
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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)
Out-of-range values are shown in grey shading.
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Bus Voltage Register 02h (Read-Only)
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.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
BD12
BD11
BD10
BD9
BD8
BD7
BD6
BD5
BD4
BD3
BD2
BD1
BD0
—
CNVR
OVF
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
At full-scale range = 16 V (decimal = 4000, hex = 0FA0), and LSB = 4 mV.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
BIT
NAME
0
BD11
BD10
BD9
BD8
BD7
BD6
BD5
BD4
BD3
BD2
BD1
BD0
—
CNVR
OVF
POR
VALUE
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
CNVR:
Conversion Ready
Bit 1
Although the data from the last conversion can be read at any time, the INA220B-Q1 device conversion ready
(CNVR) bit 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.
Power Register 03h (Read-Only)
Full-scale range and LSB are set by the Calibration Register. See the Programming the INA220 Power
Measurement Engine section.
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
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:
Power =
30
Current ´ BusVoltage
5000
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Current Register 04h (Read-Only)
Full-scale range and LSB depend on the value entered in the Calibration Register. See the Programming the
INA220 Power Measurement Engine section. Negative values are stored in twos complement format.
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
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:
Current =
ShuntVoltage ´ Calibration Register
4096
CALIBRATION REGISTER
Calibration Register 05h (Read/Write)
Current and power calibration are set by bits D15 to D1 of the Calibration Register. Note that bit D0 is not used in
the calculation. This register sets the current that corresponds to a full-scale drop across the shunt. Full-scale
range and the LSB of the current and power measurement depend on the value entered in this register. See the
Programming the INA220 Power Measurement Engine section. This register is suitable for use in overall system
calibration. Note that the '0' POR values are all default.
BIT #
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0 (1)
BIT
NAME
FS15
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
(1)
D0 is a void bit and will always be '0'. It is not possible to write a '1' to D0. CALIBRATION is the value stored in D15:D1.
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ADDITIONAL APPLICATION IDEAS
Figure 23, Figure 24, and Figure 25 show the INA220B-Q1 device in additional circuit configurations for current,
voltage, and power monitoring applications.
HCPL2300
0.1 mF
3.3 V to 5 V
1/4 W Zener
or shunt reg
0.1 mF
4.3 kW
4.3 kW
1W
10 mF
-48V
Supply
8
1
7
2
6
3
5
4
SDA
0.1mF
35.7 kW
5V
HCPL2300
1
8
VS (Supply Voltage)
2
7
INA220B-Q1
3
6
4
5
VBUS (Bus Voltage Input)
13.7 kW
24 V
Tranzorb
0.1 mF
4.3 kW
Power Register
Data
V
VIN+
Current Register
2-Wire
Interface
Clock
A0
ADC
VIN-
Voltage Register
A1
I
GND
-48 V
Supply
HCPL2300
0.1 mF
4.3 kW
8
1
7
2
6
3
5
4
4.3 kW
SCL
-48 V
to Load
Shunt
(40 mV max
for 12-bit)
Figure 23. –48 V Telecom Current, Voltage, and Power Sense with Isolation
Shunt
RSHUNT
From
Supply
Load
RG
3.3 V to
5V
100 W
MOSFET rated to
standoff supply voltage
such as BSS84 for
up to 50 V
10 kW
5.1 V
Zener
0.1 mF
35.7 kW
OPA333
10 mF
VBUS (Bus Voltage Input)
VS (Supply Voltage)
INA220B-Q1
13.7 kW
24 V
Tranzorb
´
V
VIN+
RL
100 W
Power Register
Current Register
2-Wire
Interface
Data
(SDA)
Clock
(SCL)
A0
ADC
VIN-
Voltage Register
A1
I
GND
Figure 24. 48 V Telecom Current, Voltage, and Power Sense
32
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Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): INA220B-Q1
INA220B-Q1
www.ti.com
SLOS785A – JUNE 2012 – REVISED JUNE 2012
CBYPASS
0.1 mF
3.3 V to
5V
Bus Voltage Input
VS (Supply Voltage)
Load
INA220B-Q1
Battery
´
SDA
Power Register
DATA
SCL
Shunt
(40 mV
max
for
12-bit)
R2F
R1F
V
VIN+
Current Register
2-Wire
Interface
ADC
CF
CLK
A0
A1
Voltage Register
VIN-
I
Address
Select
GND
Figure 25. General Source Low-Side Sensing
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Copyright © 2012, Texas Instruments Incorporated
Product Folder Link(s): INA220B-Q1
33
INA220B-Q1
SLOS785A – JUNE 2012 – REVISED JUNE 2012
www.ti.com
REVISION HISTORY
Changes from Original (June 2012) to Revision A
•
34
Page
Device went from preview to production ............................................................................................................................... 1
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Product Folder Link(s): INA220B-Q1
PACKAGE OPTION ADDENDUM
www.ti.com
2-Jul-2012
PACKAGING INFORMATION
Orderable Device
INA220BQDGSRQ1
Status
(1)
ACTIVE
Package Type Package
Drawing
MSOP
DGS
Pins
Package Qty
10
2500
Eco Plan
(2)
Green (RoHS
& no Sb/Br)
Lead/
Ball Finish
MSL Peak Temp
(3)
Samples
(Requires Login)
CU NIPDAU Level-2-260C-1 YEAR
(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.
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.
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 1
PACKAGE MATERIALS INFORMATION
www.ti.com
2-Jul-2012
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
INA220BQDGSRQ1
Package Package Pins
Type Drawing
MSOP
DGS
10
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
2500
330.0
12.4
Pack Materials-Page 1
5.3
B0
(mm)
K0
(mm)
P1
(mm)
3.4
1.4
8.0
W
Pin1
(mm) Quadrant
12.0
Q1
PACKAGE MATERIALS INFORMATION
www.ti.com
2-Jul-2012
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
INA220BQDGSRQ1
MSOP
DGS
10
2500
366.0
364.0
50.0
Pack Materials-Page 2
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any product or service without notice, and advise customers to obtain the latest version of relevant information
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pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
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