Although the INA232 can be read at any time, and the data from the last conversion remain available, the

conversion ready flag bit (CVRF bit, Mask/Enable register) is provided to help coordinate single-shot or triggered

conversions. The CVRF bit is set after all conversions, averaging, and multiplication operations are complete for

a single cycle.

The CVRF bit clears under these conditions:

1. Writing to the Configuration register, except when configuring the MODE bits for power-down mode; or

2. Reading the Mask/Enable register.

7.4.2 Device Shutdown

In addition to the two operating modes (continuous and triggered), the INA232 also has a power-down mode

that reduces the quiescent current and input bias current. The power-down mode reduces supply drain when

the device is not being used. Full recovery from power-down mode requires 100 µs. The device remains in

power-down mode until one of the active modes settings are written into the Configuration register.

7.4.3 Power-On Reset

Power-on reset (POR) is asserted when VS drops below 0.95 V (typical) at which all of the registers are reset

to their default values. The default power-up register values are shown in the reset column for each register

description. Table 7-2 provides links to the register descriptions.

7.4.4 Averaging and Conversion Time Considerations

The INA232 has programmable conversion times for both the shunt voltage and bus voltage measurements. The

conversion times for these measurements can be selected from as fast as 140 μs to as long as 8.244 ms. The

conversion time settings, along with the programmable averaging mode, allow the INA232 to be configured to

optimize the available timing requirements in a given application. For example, if a system requires that data

be read every 5 ms, the INA232 can be configured with the conversion times set to 588 μs and the averaging

mode set to 4. This configuration results in the data updating approximately every 4.7 ms. The INA232 can also

be configured with a different conversion time setting for the shunt and bus voltage measurements. This type of

approach is common in applications where the bus voltage tends to be relatively stable. This situation allows for

the time spent measuring the bus voltage to be reduced relative to the shunt voltage measurement. The shunt

voltage conversion time can be set to 4.156 ms with the bus voltage conversion time set to 588 μs, and the

averaging mode set to 1. This configuration also results in data updating approximately every 4.7 ms.

There are trade-offs associated with the conversion time settings and the averaging mode used. The averaging

feature can significantly improve the measurement accuracy by effectively filtering the signal. This approach

allows the INA232 to reduce noise in the measurement that may be caused by noise coupling into the signal.

A greater number of averages enables the INA232 to be more effective in reducing the noise component of the

measurement.

The conversion times selected can also have an effect on the measurement accuracy. Figure 7-2 shows

multiple conversion times to illustrate the effect of noise on the measurement. To achieve the highest accuracy

measurement possible, use a combination of the longest allowable conversion times and highest number of

averages, based on the timing requirements of the system.

INA232

SBOSAA2 – DECEMBER 2022

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