INA199-Q1
SBOS781E – MARCH 2016 – REVISED MAY 2021
INA199-Q1 Automotive, 26-V, Bidirectional, Zero-Drift, Low-Side or High-Side,
Voltage-Output, Current-Shunt Monitor
1 Features
3 Description
•
The INA199-Q1 is a voltage-output, current-sense
amplifier that can sense drops across shunts
at common-mode voltages from –0.1 V to 26V,
independent of the supply voltage. Three fixed gains
are available: 50V/V, 100V/V, and 200V/V. The low
offset of the zero-drift architecture enables current
sensing with maximum drops across the shunt as low
as 10-mV full-scale.
•
•
•
•
•
•
•
AEC-Q100 qualified for automotive applications:
– Temperature grade 1: –40°C to 125°C, TA
Functional Safety-Capable
– Documentation available to aid functional safety
system design
Wide common-mode range: –0.1 V to 26 V
Offset voltage: ±150 μV (maximum)
(enables shunt drops of 10-mV full-scale)
Accuracy:
– Gain error (maximum over temperature):
• ±1% (C version)
• ±1.5% (B version)
– Offset drift: 0.5-μV/°C (maximum)
– Gain drift: 10-ppm/°C (maximum)
Choice of gains:
– INA199x1-Q1: 50 V/V
– INA199x2-Q1: 100 V/V
– INA199x3-Q1: 200 V/V
Quiescent current: 100 μA (maximum)
Package: 6-pin SC70
This device operates from a single 2.7-V to 26-V
power supply, drawing a maximum of 100 μA of
supply current. All gain options are specified from
–40°C to +125°C, and are offered in a 6-pin SC70
package.
Device Information(1)
PART NUMBER
INA199-Q1
(1)
Mirrors
Brake systems
EGR valves
Power seats
Body control modules
Electric windows
Seat heaters
Wireless charging
BODY SIZE (NOM)
SC70 (6)
2.00 mm × 1.25 mm
For all available packages, see the package option
addendum at the end of the data sheet.
2 Applications
•
•
•
•
•
•
•
•
PACKAGE
RSHUNT
Supply
Reference
Voltage
OUT
REF
GND
2.7 V to 26 V
CBYPASS
0.01 mF
to
0.1 mF
R1
R3
R2
R4
Load
Output
IN-
IN+
V+
Copyright © 2016, Texas Instruments Incorporated
Simplified Schematic
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.
INA199-Q1
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SBOS781E – MARCH 2016 – REVISED MAY 2021
Table of Contents
1 Features............................................................................1
2 Applications..................................................................... 1
3 Description.......................................................................1
4 Revision History.............................................................. 2
5 Device Comparison......................................................... 3
6 Pin Configuration and Functions...................................3
7 Specifications.................................................................. 4
7.1 Absolute Maximum Ratings........................................ 4
7.2 ESD Ratings............................................................... 4
7.3 Recommended Operating Conditions.........................4
7.4 Thermal Information....................................................4
7.5 Electrical Characteristics.............................................5
7.6 Typical Characteristics................................................ 6
8 Detailed Description......................................................10
8.1 Overview................................................................... 10
8.2 Functional Block Diagram......................................... 10
8.3 Feature Description...................................................10
8.4 Device Functional Modes..........................................10
9 Application and Implementation.................................. 11
9.1 Application Information..............................................11
9.2 Typical Applications.................................................. 17
10 Power Supply Recommendations..............................19
11 Layout........................................................................... 19
11.1 Layout Guidelines................................................... 19
11.2 Layout Example...................................................... 19
12 Device and Documentation Support..........................20
12.1 Documentation Support.......................................... 20
12.2 Receiving Notification of Documentation Updates..20
12.3 Support Resources................................................. 20
12.4 Trademarks............................................................. 20
12.5 Electrostatic Discharge Caution..............................20
12.6 Glossary..................................................................20
13 Mechanical, Packaging, and Orderable
Information.................................................................... 20
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision D (August 2019) to Revision E (May 2021)
Page
• Updated the numbering format for tables, figures, and cross-references throughout the document..................1
• Added Functional Safety bullets......................................................................................................................... 1
Changes from Revision C (August 2017) to Revision D (August 2019)
Page
• Changed VS and VIN maximum values from 26 V to 28 V in Absolute Maximum Ratings table.........................4
• Changed differential VIN minimum value from –26 V to –28 V in Absolute Maximum Ratings table.................. 4
• Added new Note 2 with caution regarding operation between 26 V and 28 V....................................................4
Changes from Revision B (July 2016) to Revision C (August 2017)
Page
• Added C version devices and associated content to data sheet ....................................................................... 1
• Changed location of VS voltage range from Electrical Characteristics table to Recommended Operating
Conditions table.................................................................................................................................................. 5
• Deleted redundant Temperature Range section from Electrical Characteristics table; all information already
shown in Thermal Information and Recommended Operating Conditions tables...............................................5
Changes from Revision A (May 2016) to Revision B (July 2016)
Page
• Changed ESD Ratings table: changed HBM value and deleted machine model row ....................................... 4
Changes from Revision * (March 2016) to Revision A (May 2016)
Page
• Released to production ......................................................................................................................................1
2
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5 Device Comparison
Table 5-1. Device Comparison
PRODUCT
INA199B1-Q1
INA199C1-Q1
INA199B2-Q1
INA199C2-Q1
INA199B3-Q1
INA199C3-Q1
GAIN
R3 AND R4
R1 AND R2
50 V/V
20 kΩ
1 MΩ
100 V/V
10 kΩ
1 MΩ
200 V/V
5 kΩ
1 MΩ
6 Pin Configuration and Functions
REF
1
6
OUT
GND
2
5
IN-
V+
3
4
IN+
Figure 6-1. DCK Package 6-Pin SC70 Top View
Table 6-1. Pin Functions
PIN
NAME
NO.
I/O
DESCRIPTION
GND
2
Analog
IN–
5
Analog input
Ground
Connect to load side of shunt resistor
IN+
4
Analog input
Connect to supply side of shunt resistor
OUT
6
Analog output
REF
1
Analog input
Reference voltage, 0 V to V+
V+
3
Analog
Power supply, 2.7 V to 26 V
Output voltage
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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
MIN
MAX
Supply voltage(2)
28
V
–28
28
GND – 0.1
28
REF input
GND – 0.3
(V+) + 0.3
V
Output
GND – 0.3
(V+) + 0.3
V
–40
125
Analog inputs, VIN+, VIN– (2) (3)
Differential (VIN+) – (VIN–)
UNIT
Common-mode
Operating, TA
Temperature
Junction, TJ
150
Storage, Tstg
(1)
(2)
(3)
–65
V
°C
150
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.
Sustained operation between 26 V and 28 V for more than a few minutes may cause permanent damage to the device.
VIN+ and VIN– are the voltages at the IN+ and IN– pins, respectively.
7.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge
Human-body model (HBM), per AEC Q100-002(1)
HBM ESD classification level 2
±3500
Charged-device model (CDM), per AEC Q100-002
CDM ESD classification level C6
±1000
UNIT
V
AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
VCM
Common-mode input voltage
VS
Operating supply voltage (applied to V+)
2.7
TA
Operating free-air temperature
–40
NOM
MAX
12
UNIT
V
5
26
V
125
°C
7.4 Thermal Information
INA199-Q1
THERMAL METRIC(1)
DCK (SC70)
UNIT
6 PINS
RθJA
Junction-to-ambient thermal resistance
227.3
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
79.5
°C/W
RθJB
Junction-to-board thermal resistance
72.1
°C/W
ψJT
Junction-to-top characterization parameter
3.6
°C/W
ψJB
Junction-to-board characterization parameter
70.4
°C/W
RθJC(bot)
Junction-to-case (bottom) thermal resistance
N/A
°C/W
(1)
4
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.
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7.5 Electrical Characteristics
at TA = 25°C, VS = 5 V, VIN+ = 12 V, VSENSE = VIN+ – VIN–, and VREF = VS / 2 (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
INPUT
VCM
Common-mode input voltage
TA = –40°C to +125°C
–0.1
26
CMR
Common-mode rejection
VIN+ = 0 V to 26 V, VSENSE = 0 mV,
TA = –40°C to +125°C
100
VOS
Offset voltage, RTI(1)
VSENSE = 0 mV
±5
±150
dVOS/dT
VOS vs. temperature
TA = –40°C to +125°C
0.1
0.5
PSR
Power-supply rejection
VS = 2.7 V to 18 V,
VIN+ = 18 V, VSENSE = 0 mV
IB
Input bias current
VSENSE = 0 mV
28
μA
IOS
Input offset current
VSENSE = 0 mV
±0.02
μA
120
V
dB
±0.1
μV
μV/°C
μV/V
OUTPUT
G
Gain
INA199x1-Q1
50
INA199x2-Q1
100
INA199x3-Q1
VOLTAGE
Gain error
VSENSE = –5 mV to 5 mV,
TA = –40°C to +125°C
Gain error vs. temperature
TA = –40°C to +125°C
Nonlinearity error
VSENSE = –5 mV to +5 mV
Maximum capacitive load
No sustained oscillation
V/V
200
B version
±0.03%
±1.5%
C version
±0.03%
±1%
3
10
ppm/°C
±0.01%
1
nF
OUTPUT(2)
Swing to V+ power-supply rail
RL = 10 kΩ to GND,
TA = –40°C to +125°C
(V+) – 0.05
(V+) – 0.2
V
Swing to GND
RL = 10 kΩ to GND,
TA = –40°C to +125°C
(VGND) +
0.005
(VGND) +
0.05
V
FREQUENCY RESPONSE
GBW
SR
Bandwidth
CLOAD = 10 pF
INA199x1-Q1
80
INA199x2-Q1
30
INA199x3-Q1
14
Slew rate
kHz
0.4
V/µs
25
nV/√ Hz
NOISE, RTI(1)
Voltage noise density
POWER SUPPLY
IQ
(1)
(2)
Quiescent current
VSENSE = 0 mV
IQ over temperature
TA = –40°C to +125°C
65
100
µA
115
µA
RTI = referred-to-input.
See typical characteristic curve, Output Voltage Swing vs. Output Current (Figure 7-6).
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7.6 Typical Characteristics
performance measured with the INA199B3-Q1 at TA = 25°C, VS = 5 V, VIN+ = 12 V, and VREF = VS / 2 (unless otherwise
noted)
20
1
15
0.8
0.6
0.4
CMRR (mV/V)
Offset Voltage (mV)
10
5
0
-5
0.2
0
-0.2
-0.4
-10
-0.6
-15
-0.8
-20
-50
-25
0
25
50
75
100
-1
-50
125
-25
0
25
60
125
140
G = 200
50
120
40
100
|PSR| (dB)
Gain (dB)
100
160
70
30
G = 50
G = 100
20
80
60
10
40
0
20
0
-10
10
100
1k
10k
100k
1M
1
10M
10
100
VCM = 0 V, VDIF = 15-mVPP sine
Figure 7-3. Gain vs. Frequency
Figure 7-4. Power-Supply Rejection Ratio vs. Frequency
160
Output Voltage Swing (V)
140
120
100
80
60
40
20
0
10
100
1k
100k
10k
VS = 5 V + 250-mV sine disturbance, VCM = 0 V, VDIF =
shorted, VREF = 2.5 V
.
1
1k
Frequency (Hz)
Frequency (Hz)
|CMRR| (dB)
75
Figure 7-2. Common-Mode Rejection Ratio vs. Temperature
Figure 7-1. Offset Voltage vs. Temperature
10k
100k
V+
(V+) - 0.5
(V+) - 1
(V+) - 1.5
(V+) - 2
(V+) - 2.5
(V+) - 3
VS = 5 V to 26 V
VS = 2.7 V
to 26 V
VS = 2.7 V
GND + 3
GND + 2.5
GND + 2
GND + 1.5
GND + 1
GND + 0.5
GND
0
1M
TA = -40°C
TA = +25°C
TA = +105°C
VS = 2.7 V to 26 V
Frequency (Hz)
5
10
15
20
25
30
35
40
Output Current (mA)
VS = 5 V, VCM = 1-V sine, VDIF = shorted, VREF = 2.5 V
Figure 7-5. Common-Mode Rejection Ratio vs. Frequency
6
50
Temperature (°C)
Temperature (°C)
.
Figure 7-6. Output Voltage Swing vs. Output Current
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7.6 Typical Characteristics (continued)
V+
(V+) - 0.25
(V+) - 0.5
(V+) - 0.75
(V+) - 1
(V+) - 1.25
(V+) - 1.5
50
25°C
40
-20°C
Input Bias Current (mA)
Output Voltage (V)
performance measured with the INA199B3-Q1 at TA = 25°C, VS = 5 V, VIN+ = 12 V, and VREF = VS / 2 (unless otherwise
noted)
85°C
GND + 1.5
GND + 1.25
GND + 1
GND + 0.75
GND + 0.5
GND + 0.25
GND
85°C
25°C
IB+, IB-, VREF = 0 V
30
20
IB+, IB-, VREF = 2.5 V
10
0
-20°C
-10
0
2
4
5
8
10
12
14
16
0
18
5
10
15
20
25
30
Common-Mode Voltage (V)
Output Current (mA)
.
Figure 7-8. Input Bias Current vs. Common-Mode Voltage With
Supply Voltage = 5 V
VS = 2.5 V
Figure 7-7. Output Voltage Swing vs. Output Current
30
30
IB+, IB-, VREF = 0 V
and
IB-, VREF = 2.5 V
20
Input Bias Current (mA)
Input Bias Current (mA)
25
15
10
5
IB+, VREF = 2.5 V
10
15
27
25
-50
-5
5
28
26
0
0
29
20
25
30
-25
0
Common-Mode Voltage (V)
Figure 7-9. Input Bias Current vs. Common-Mode Voltage With
Supply Voltage = 0 V (Shutdown)
50
75
100
125
Figure 7-10. Input Bias Current vs. Temperature
Input-Referred Voltage Noise (nV/ÖHz)
Quiescent Current (mA)
70
68
66
64
62
60
-50
25
Temperature (°C)
100
G = 50
G = 200
G = 100
10
1
-25
0
25
50
75
100
125
10
Temperature (°C)
100
1k
10k
100k
Frequency (Hz)
.
VS = ±2.5 V, VREF = 0 V, VIN– and VIN+ = 0 V
Figure 7-11. Quiescent Current vs. Temperature
Figure 7-12. Input-Referred Voltage Noise vs. Frequency
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7.6 Typical Characteristics (continued)
2-VPP Output Signal
10-mVPP Input Signal
Input Voltage
(5 mV/diV)
Referred-to-Input
Voltage Noise (200 nV/div)
Output Voltage
(0.5 V/diV)
performance measured with the INA199B3-Q1 at TA = 25°C, VS = 5 V, VIN+ = 12 V, and VREF = VS / 2 (unless otherwise
noted)
Time (100 ms/div)
Time (1 s/div)
.
VS = ±2.5 V, VCM = 0 V, VDIF = 0 V, VREF = 0 V
Figure 7-13. 0.1-Hz to 10-Hz Voltage Noise (Referred-to-Input)
Figure 7-14. Step Response (10-mVPP Input Step)
Output Voltage
0V
2 V/div
0V
Output Voltage (40 mV/div)
Common-Mode Voltage (1 V/div)
Inverting Input Overload
Common Voltage Step
Output
0V
Time (50 ms/div)
Time (250 ms/div)
.
Figure 7-15. Common-Mode Voltage Transient Response
VS = 5 V, VCM = 12 V, VREF = 2.5 V
Figure 7-16. Inverting Differential Input Overload
Supply Voltage
1 V/div
2 V/div
Noninverting Input Overload
Output
Output Voltage
0V
0V
Time (250 ms/div)
Time (100 ms/div)
VS = 5 V, VCM = 12 V, VREF = 2.5 V
VS = 5 V, 1-kHz step with VDIF = 0 V, VREF = 2.5 V
Figure 7-17. Noninverting Differential Input Overload
8
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Figure 7-18. Start-Up Response
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7.6 Typical Characteristics (continued)
performance measured with the INA199B3-Q1 at TA = 25°C, VS = 5 V, VIN+ = 12 V, and VREF = VS / 2 (unless otherwise
noted)
1 V/div
Supply Voltage
Output Voltage
0V
Time (100 ms/div)
VS = 5 V, 1-kHz step with VDIF = 0 V, VREF = 2.5 V
Figure 7-19. Brownout Recovery
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8 Detailed Description
8.1 Overview
The INA199-Q1 is a 26-V, common-mode, zero-drift topology, current-sensing amplifier that can be used in both
low-side and high-side configurations. The device is a specially-designed, current-sensing amplifier that is able
to accurately measure voltages developed across a current-sensing resistor on common-mode voltages that far
exceed the supply voltage powering the device. Current can be measured on input voltage rails as high as 26 V
and the device can be powered from supply voltages as low as 2.7 V.
The zero-drift topology enables high-precision measurements with maximum input offset voltages as low as
150 µV with a maximum temperature contribution of 0.5 µV/°C over the full temperature range of –40°C to
+125°C.
8.2 Functional Block Diagram
V+
IN-
-
IN+
+
OUT
REF
GND
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8.3 Feature Description
8.3.1 Zero-Drift Offset
The zero-drift offset performance of the INA199-Q1 offers several benefits. Most often, the primary advantage
of the low offset characteristic enables lower full-scale drops across the shunt. For example, non-zero-drift
current-shunt monitors typically require a full-scale range of 100 mV.
8.3.2 Accuracy
The INA199-Q1 series gives equivalent accuracy at a full-scale range on the order of 10 mV. This accuracy
reduces shunt dissipation by an order of magnitude with many additional benefits.
8.3.3 Choice of Gain Options
The INA199-Q1 series provides three gain options: 50 V/V, 100 V/V, and 200 V/V, Some applications must
measure current over a wide dynamic range that can take advantage of the low offset on the low end of the
measurement. Most often, these applications use the lower gain of 50 V/V or 100 V/V to accommodate larger
shunt drops on the upper end of the scale. For instance, the INA199B1-Q1 (with a factory-set gain of 50 V/V)
operating on a 3.3-V supply can easily handle a full-scale shunt drop of 60 mV, with only 150 μV of offset. See
the Electrical Characteristics for more information.
8.4 Device Functional Modes
The INA199-Q1 has a single functional mode and is operational when the power-supply voltage is greater than
2.7 V. The maximum power supply voltage for this device is 26 V.
10
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9 Application and Implementation
Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.
9.1 Application Information
The INA199-Q1 measures the voltage developed across a current-sensing resistor when current passes
through it. The ability to drive the reference pin to adjust the functionality of the output signal offers multiple
configurations, as discussed throughout this section.
9.1.1 Basic Connections
Figure 9-1 shows the basic connections for the INA199-Q1. The input pins, IN+ and IN–, must be connected as
close as possible to the shunt resistor to minimize any resistance in series with the shunt resistor.
Power
Supply
RSHUNT
5-V
Supply
Load
CBYPASS
0.1 µF
V+
IN±
OUT
ADC
Microcontroller
+
REF
IN+
GND
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Figure 9-1. Typical Application
Power-supply bypass capacitors are required for stability. Applications with noisy or high-impedance power
supplies may require additional decoupling capacitors to reject power-supply noise. Connect bypass capacitors
close to the device pins.
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9.1.2 Input Filtering
An obvious and straightforward filtering location is at the device output. However, this location negates the
advantage of the low output impedance of the internal buffer. The only other filtering option is at the device input
pins. This location, though, does require consideration of the ±30% tolerance of the internal resistances. Figure
9-2 shows a filter placed at the inputs pins.
RSHUNT
Power
Supply
Load
Bus Supply
CBYPASS
0.1 µF
V+
RINT
INRS < 10 Ÿ
±
Bias
CF
OUT
Output
+
IN+
RINT
RS < 10 Ÿ
REF
GND
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Figure 9-2. Filter at Input Pins
The addition of external series resistance, however, creates an additional error in the measurement so the
value of these series resistors must be 10 Ω (or less if possible) to reduce any affect to accuracy. The internal
bias network shown in Figure 9-2 present at the input pins creates a mismatch in input bias currents when a
differential voltage is applied between the input pins. If additional external series filter resistors are added to
the circuit, the mismatch in bias currents results in a mismatch of voltage drops across the filter resistors. This
mismatch creates a differential error voltage that subtracts from the voltage developed at the shunt resistor. This
error results in a voltage at the device input pins that is different than the voltage developed across the shunt
resistor. Without the additional series resistance, the mismatch in input bias currents has little effect on device
operation. The amount of error these external filter resistor add to the measurement can be calculated using
Equation 1, where the gain error factor is calculated using Equation 2.
Gain Error (%) = 100 - (100 ´ Gain Error Factor)
(1)
(1250 ´ RINT)
Gain Error Factor =
(1250 ´ RS) + (1250 ´ RINT) + (RS ´ RINT)
(2)
where:
•
•
RINT is the internal input resistor (R3 and R4) and
RS is the external series resistance
The amount of variance in the differential voltage present at the device input relative to the voltage developed at
the shunt resistor is based on both the external series resistance value and the internal input resistors, R3 and
R4 (or RINT, as shown in Figure 9-2). The reduction of the shunt voltage reaching the device input pins appears
as a gain error when comparing the output voltage relative to the voltage across the shunt resistor. A factor
can be calculated to determine the amount of gain error that is introduced by the addition of external series
resistance. The equation used to calculate the expected deviation from the shunt voltage to what is measured at
the device input pins is given in Equation 2.
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With the adjustment factor equation including the device internal input resistance, this factor varies with each
gain version, as listed in Table 9-1. Each individual device gain error factor is listed in Table 9-2.
Table 9-1. Input Resistance
PRODUCT
INA199B1-Q1
INA199C1-Q1
INA199B2-Q1
INA199C2-Q1
INA199B3-Q1
INA199C3-Q1
GAIN (V/V)
RINT (kΩ)
50
20
100
10
200
5
Table 9-2. Device Gain Error Factor
PRODUCT
SIMPLIFIED GAIN ERROR FACTOR
INA199B1-Q1
20,000
INA199C1-Q1
(17 ´ RS) + 20,000
INA199B2-Q1
10,000
INA199C2-Q1
(9 ´ RS) + 10,000
INA199B3-Q1
1000
RS + 1000
INA199C3-Q1
The gain error that can be expected from the addition of the external series resistors can then be calculated
based on Equation 1.
For example, when using an INA199B2-Q1 and the corresponding gain error equation from Table 9-2, a series
resistance of 10-Ω results in a gain error factor of 0.991. The corresponding gain error is then calculated using
Equation 1, resulting in a gain error of approximately 0.89% solely because of the external 10-Ω series resistors.
Using an INA199B1-Q1 with the same 10-Ω series resistor results in a gain error factor of 0.991 and a gain error
of 0.84% again solely because of these external resistors.
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9.1.3 Shutting Down the INA199-Q1
Although the INA199-Q1 series does not have a shutdown pin, the low power consumption of the device allows
the output of a logic gate or transistor switch to power the INA199-Q1. This gate or switch turns on and turns off
the INA199-Q1 power-supply quiescent current.
However, in current-shunt monitoring applications, there is also a concern for how much current is drained
from the shunt circuit in shutdown conditions. Evaluating this current drain involves considering the simplified
schematic of the INA199-Q1 in shutdown mode as shown in Figure 9-3.
RSHUNT
Supply
Reference
Voltage
OUT
REF
GND
Shutdown
Control
1 MW
R3
1 MW
R4
Load
Output
IN-
IN+
V+
CBYPASS
DEVICE
R3, R4
INA199x1-Q1
INA199x2-Q1
INA199x3-Q1
20 kW
10 kW
5 kW
Copyright © 2016, Texas Instruments Incorporated
1-MΩ paths from shunt inputs to the reference and the INA199-Q1 outputs.
Figure 9-3. Basic Circuit for Shutting Down the INA199-Q1 With a Grounded Reference
There is typically slightly more than a 1-MΩ impedance (from the combination of the 1-MΩ feedback and
5-kΩ input resistors) from each input of the INA199-Q1 to the OUT pin and to the REF pin. The amount of
current flowing through these pins depends on the respective ultimate connection. For example, if the REF pin
is grounded, the calculation of the effect of the 1-MΩ impedance from the shunt to ground is straightforward.
However, if the reference or operational amplifier is powered when the INA199-Q1 is shut down, then the
calculation is direct; instead of assuming a 1-MΩ impedance to ground, assume a 1-MΩ impedance to the
reference voltage. If the reference or operational amplifier is also shut down, some knowledge of the reference
or operational amplifier output impedance under shutdown conditions is required. For instance, if the reference
source functions as an open circuit when not powered, little or no current flows through the 1-MΩ path.
Regarding the 1-MΩ path to the output pin, the output stage of a disabled INA199-Q1 does constitute a good
path to ground. Consequently, this current is directly proportional to a shunt common-mode voltage applied
across a 1-MΩ resistor.
Note
When the device is powered up, an additional, nearly constant, and well-matched 25 μA of current
flows in each of the inputs as long as the shunt common-mode voltage is 3 V or higher. Below 2-V
common-mode, the resulting 1-MΩ resistors are the only effects from this current.
14
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9.1.4 REF Input Impedance Effects
As with any difference amplifier, the INA199-Q1 series common-mode rejection ratio is affected by any
impedance present at the REF input. This concern is not a problem when the REF pin is connected directly
to most references or power supplies. When using resistive dividers from the power supply or a reference
voltage, the REF pin must be buffered by an operational amplifier.
In systems where the INA199-Q1 output can be sensed differentially, such as by a differential input analog-todigital converter (ADC) or by using two separate ADC inputs, the effects of the external impedance on the REF
input can be cancelled. Figure 9-4 shows a method of capturing the output from the INA199-Q1 by using the
REF pin as a reference.
RSHUNT
Supply
Load
ADC
OUT
REF
GND
2.7 V to 26 V
CBYPASS
0.01 mF
to
0.1 mF
R1
R3
R2
R4
Output
IN-
IN+
V+
Copyright © 2016, Texas Instruments Incorporated
Figure 9-4. Sensing the INA199-Q1 to Cancel Effects of Impedance on the REF Input
9.1.5 Using the INA199-Q1 With Common-Mode Transients Above 26 V
With a small amount of additional circuitry, the INA199-Q1 series can be used in circuits subject to transients
higher than 26 V, such as automotive applications. Use only zener diodes or zener-type transient absorbers
(sometimes referred to as transzorbs); any other type of transient absorber has an unacceptable time delay.
Start by adding a pair of resistors (as shown in Figure 9-5) as a working impedance for the zener. Keeping
these resistors as small as possible is preferable, most often approximately 10 Ω. Larger values can be used
with an affect on gain as discussed in the Input Filtering section. Many applications are satisfied with a 10-Ω
resistor along with conventional zener diodes of the lowest power rating that can be found because this circuit
limits only short-term transients. This combination uses the least amount of board space. These diodes can be
found in packages as small as SOT-523 or SOD-523. See the TIDA-00302 Transient Robustness for Current
Shunt Monitor TI design (TIDU473) for more information on transient robustness and current-shunt monitor input
protection.
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RSHUNT
Supply
RPROTECT
10 W
Load
RPROTECT
10 W
Reference
Voltage
GND
1 MW
R3
1 MW
R4
V+
Shutdown
Control
Output
OUT
REF
IN-
IN+
CBYPASS
Copyright © 2016, Texas Instruments Incorporated
Figure 9-5. INA199-Q1 Transient Protection Using Dual Zener Diodes
In the event that low-power zeners do not have sufficient transient absorption capability and a higher power
transzorb must be used, the most package-efficient solution then involves using a single transzorb and back-toback diodes between the device inputs. The most space-efficient solutions are dual series-connected diodes in
a single SOT-523 or SOD-523 package. This method is illustrated in Figure 9-6. In either of these examples, the
total board area required by the INA199-Q1 with all protective components is less than that of an 8-pin SOIC
package, and only slightly greater than that of an 8-pin VSSOP package.
RSHUNT
Supply
RPROTECT
10 W
Load
RPROTECT
10 W
Reference
Voltage
OUT
REF
GND
1 MW
R3
1 MW
R4
V+
Shutdown
Control
Output
IN-
IN+
CBYPASS
Copyright © 2016, Texas Instruments Incorporated
Figure 9-6. INA199-Q1 Transient Protection Using a Single Transzorb and Input Clamps
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9.2 Typical Applications
9.2.1 Unidirectional Operation
Bus
Supply
Power
Supply
Load
CBYPASS
0.1 µF
V+
INOUT
Output
±
+
REF
IN+
GND
Copyright © 2016, Texas Instruments Incorporated
Figure 9-7. Unidirectional Application Schematic
9.2.1.1 Design Requirements
The device can be configured to monitor current flowing in one direction (unidirectional) or in both directions
(bidirectional), depending on how the REF pin is configured. The most common case is unidirectional where the
output is set to ground when current is not flowing by connecting the REF pin to ground; see Figure 9-7. When
the input signal increases, the output voltage at the OUT pin increases.
9.2.1.2 Detailed Design Procedure
The linear range of the output stage is limited in how close the output voltage can approach ground under
zero input conditions. In unidirectional applications where measuring very low input currents is desirable, bias
the REF pin to a convenient value above 50 mV to get the output into the linear range of the device. To limit
common-mode rejection errors, buffering the reference voltage connected to the REF pin is recommended.
A less frequently-used output biasing method is to connect the REF pin to the supply voltage, V+. This method
results in the output voltage saturating at 200 mV below the supply voltage when a differential input signal is not
present. This method is similar to the output-saturated low condition without an input signal when the REF pin
is connected to ground. The output voltage in this configuration only responds to negative currents that develop
negative differential input voltage relative to the device IN– pin. Under these conditions, when the differential
input signal increases negatively, the output voltage moves downward from the saturated supply voltage. The
voltage applied to the REF pin must not exceed the device supply voltage.
9.2.1.3 Application Curve
Output Voltage
(1 V/div)
An example output response of a unidirectional configuration is shown in Figure 9-8. With the REF pin
connected directly to ground, the output voltage is biased to this zero output level. The output rises above
the reference voltage for positive differential input signals but cannot fall below the reference voltage for negative
differential input signals because of the grounded reference voltage.
0V
Output
VREF
Time (500 µs /div)
C001
Figure 9-8. Unidirectional Application Output Response
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9.2.2 Bidirectional Operation
Bus
Supply
Power
Supply
Load
Reference
Voltage
CBYPASS
0.1 µF
V+
INOUT
Output
±
+
+
REF
IN+
±
GND
Copyright © 2016, Texas Instruments Incorporated
Figure 9-9. Bidirectional Application Schematic
9.2.2.1 Design Requirements
The device is a bidirectional, current-sense amplifier capable of measuring currents through a resistive shunt
in two directions. This bidirectional monitoring is common in applications that include charging and discharging
operations where the current flow-through resistor can change directions.
9.2.2.2 Detailed Design Procedure
The ability to measure this current flowing in both directions is enabled by applying a voltage on the REF pin, as
shown in Figure 9-9. The voltage applied to REF (VREF) sets the output state that corresponds to the zero-input
level state. The output then responds by rising above VREF for positive differential signals (relative to the IN– pin)
and falling below VREF for negative differential signals. This reference voltage applied to the REF pin can be set
anywhere between 0 V to V+. For bidirectional applications, VREF is typically set at mid-scale for an equal signal
range in both current directions. In some cases, however, VREF is set at a voltage other than mid-scale when the
bidirectional current and corresponding output signal do not need to be symmetrical.
Output Voltage
(1 V/div)
9.2.2.3 Application Curve
VOUT
VREF
0V
Time (500 µs/div)
C002
Figure 9-10. Bidirectional Application Output Response
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10 Power Supply Recommendations
The input circuitry of the INA199-Q1 can accurately measure beyond its power-supply voltage, V+. For example,
the V+ power supply can be 5 V, whereas the load power-supply voltage can be as high as 26 V. However,
the output voltage range of the OUT pin is limited by the voltages on the power-supply pin. Furthermore, the
INA199-Q1 can withstand the full input signal range up to the 26-V range in the input pins, regardless of whether
the device has power applied or not.
11 Layout
11.1 Layout Guidelines
•
•
Connect the input pins to the sensing resistor using a kelvin or 4-wire connection. This connection technique
makes certain that only the current-sensing resistor impedance is detected between the input pins. Poor
routing of the current-sensing resistor commonly results in additional resistance present between the input
pins. Given the very low ohmic value of the current resistor, any additional high-current carrying impedance
can cause significant measurement errors.
Place the power-supply bypass capacitor as close as possible to the supply and ground pins. Using a
bypass capacitor with a value of 0.1 μF is recommended. Additional decoupling capacitance can be added to
compensate for noisy or high-impedance power supplies.
11.2 Layout Example
Output Signal
Trace
IN+
VIA to Ground Plane
V+
INGND
REF
OUT
VIA to Power or
Ground Plane
Supply
Voltage
Supply Bypass
Capacitor
Copyright © 2017, Texas Instruments Incorporated
Figure 11-1. Recommended Layout
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12 Device and Documentation Support
12.1 Documentation Support
12.1.1 Related Documentation
For related documentation see the following:
•
•
Texas Instruments, INA199B1-B3EVM user's guide
Texas Instruments, TIDA-00302 Transient Robustness for Current Shunt Monitor TI design
12.2 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
12.3 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
12.4 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
12.5 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled
with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may
be more susceptible to damage because very small parametric changes could cause the device not to meet its published
specifications.
12.6 Glossary
TI Glossary
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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23-Mar-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
INA199B1QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
13C
INA199B2QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
13D
INA199B3QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
13E
INA199C1QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
17A
INA199C2QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
17B
INA199C3QDCKRQ1
ACTIVE
SC70
DCK
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 125
17C
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
