not keep track of elapsed time. For applications that require critical measurements in regards to accumulation of

time for energy and charge measurements, the device must be configured to use continuous conversion mode,

as the accumulated results are continuously updated and can provide true system representation of charge and

energy consumption in a system. All of the calculations are performed in the background and do not contribute to

conversion time.

For applications that must synchronize with other components in the system, the INA700 conversion can be

delayed by programming the CONVDLY bits in CONFIG register in the range between 0 ms (no delay) and 510

ms. The resolution in programming the conversion delay is 2 ms. The conversion delay is set to 0 by default.

Conversion delay can assist in measurement synchronization when multiple external devices are used for

voltage or current monitoring purposes. In applications where time aligned voltage and current measurements

are needed, two devices can be used with the current measurement delayed such that the external voltage and

current measurements will occur at approximately the same time. Keep in mind that even though the internal

time base for the ADC is precise, synchronization will be lost over time due to internal and external time base

mismatch.

7.3.5.1 Low Latency Digital Filter

The device integrates a low-pass digital filter that performs both decimation and filtering on the ADC output data,

which helps with noise reduction. The digital filter is automatically adjusted for the different output data rates

and always settles within one conversion cycle. The user has the flexibility to choose different output conversion

time periods TCT from 50 µs to 4.12 ms. With this configuration the first amplitude notch appears at the Nyquist

frequency of the output signal which is determined by the selected conversion time period (see Equation 1).

fNOTCH= 12×TCT

(1)

This means that the filter cut-off frequency will scale proportionally with the data output rate as described. Figure

7-6 shows the filter response when the 1.052 ms conversion time period is selected.

−60

−50

−40

−30

−20

−10

0

1

10

100

1k

10k

100k

Frequency (Hz)

G001

Conversion time = 1.052 ms, single

conversion only

Figure 7-6. ADC Frequency Response

7.3.5.2 Flexible Conversion Times and Averaging

ADC conversion times for shunt voltage, bus voltage and temperature can be set independently from 50 μs to

4.12 ms. The flexibility in conversion time allows for robust operation in a variety of noisy environments. The

device also allows for programmable averaging times from a single conversion all the way to an average of

1024 conversions. The amount of averaging selected applies uniformly to all active measurement inputs. The

ADC_CONFIG register shown in Table 7-6 shows additional details on the supported conversion times and

averaging modes. The INA700 effective resolution of the ADC can be increased by increasing the conversion

time and increasing the number of averages. Figure 7-7 and Figure 7-8 both show the effect of conversion time

and averaging on a constant input signal.

INA700

SBOSAB4 – MAY 2023

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