Frequency (Hz)

0.01%

0.1%

1%

10%

1

10

100

1k

10k

100k

1M

D006

90% FS Input

15

INA253

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SLOS954A – JULY 2018 – REVISED DECEMBER 2018

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Feature Description (continued)

8.3.5 Input Signal Bandwidth

The INA253 input signal, which represents the current being measured, is accurately measured with minimal

disturbance from large ΔV/Δt common-mode transients as previously described. For PWM signals typically

associated with motors, solenoids, and other switching applications, the current being monitored varies at a

significantly slower rate than the faster PWM frequency.

The INA253 bandwidth is defined by the –3-dB bandwidth of the current-sense amplifier inside the device; see

the Electrical Characteristics for more information. The device bandwidth provides fast throughput and fast

response required for the rapid detection and processing of overcurrent events. Without the higher bandwidth,

protection circuitry may not have adequate response time, and damage may occur to the monitored application

or circuit.

Figure 32 shows the performance profile of the device over frequency. Harmonic distortion increases at the

upper end of the amplifier bandwidth with no adverse change in detection of overcurrent events. However,

increased distortion at the highest frequencies must be considered when the measured current bandwidth begins

to approach the INA253 bandwidth.

Figure 32. Amplifier Performance Over Frequency

For applications requiring distortion sensitive signals, Figure 32 provides information to show that there is an

optimal frequency performance range for the amplifier. The full amplifier bandwidth is always available for fast

overcurrent events at the same time that the lower-frequency signals are amplified at a low distortion level. The

output signal accuracy is reduced for frequencies closer to the maximum bandwidth. Individual requirements

determine the acceptable limits of distortion for high-frequency, current-sensing applications. Testing and

evaluation in the end application or circuit are required to determine the acceptance criteria, and to validate the

performance levels meet the system specifications.