1.99

1.995

2

2.005

±50

±25

0

25

50

75

100

125

150

Temperature (

ƒC)

C030

14

INA253

SLOS954A – JULY 2018 – REVISED DECEMBER 2018

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Copyright © 2018, Texas Instruments Incorporated

Feature Description (continued)

8.3.3 Temperature Stability

System calibration is common for many industrial applications in order to eliminate initial component and system-

level errors that can be present. A system-level calibration reduces the initial accuracy requirement for many of

the individual components because the errors associated with these components are effectively eliminated

through the calibration procedure. This calibration enables precise measurements at the temperature in which

the system is calibrated. As the system temperature changes because of external ambient changes or self

heating, measurement errors are reintroduced. Without accurate temperature compensation used in addition to

the initial adjustment, the calibration procedure is not effective. The user must account for temperature-induced

changes. One of the primary benefits of the low temperature coefficient of the INA253 (including both the

integrated current-sensing resistor and current-sensing amplifier) is that the device measurement remains

accurate, even when the temperature changes throughout the specified temperature range of the device.

Figure 31 shows the drift performance for the integrated current-sensing resistor. Use Figure 31 to determine the

typical variance in the shunt resistor value at various temperatures. As with any resistive element, the tolerance

of the component varies when exposed to different temperature conditions.

For the current-sensing resistor

integrated in the INA253, the resistor does vary slightly more when operated in temperatures ranging from –40°C

to 0°C than when operated from 0°C to 125°C. Even in the –40°C to 0°C temperature range, the drift is still low

at 25 ppm/°C.

Figure 31. Sensing Resistor vs Temperature

An additional aspect to consider is that when current flows through the current-sensing resistor, power is

dissipated across this component. This dissipated power results in an increase in the internal temperature of the

package, including the integrated sensing resistor. This resistor self-heating effect results in an increase of the

resistor temperature helping to move the component out of the colder, wider drift temperature region.

8.3.4 Enhanced PWM Rejection Operation

The enhanced PWM rejection feature of the INA253 provides increased attenuation of large common-mode

ΔV/Δt transients. Large ΔV/Δt common-mode transients associated with PWM signals are employed in

applications such as motor or solenoid drive and switching power supplies. Traditionally, large ΔV/Δt common-

mode transitions are handled strictly by increasing the amplifier signal bandwidth, which can increase chip size,

complexity and ultimately cost. The INA253 is designed with high common-mode rejection techniques to reduce

large ΔV/Δt transients before the system is disturbed as a result of these large signals. The high ac CMRR, in

conjunction with signal bandwidth, allows the INA253 to provide minimal output transients and ringing compared

with standard circuit approaches.