SBOS825D September 2019 – July 2021 TMCS1101

PRODUCTION DATA

- 1 Features
- 2 Applications
- 3 Description
- 4 Revision History
- 5 Device Comparison
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Parameter Measurement Information
- 9 Detailed Description
- 10Application and Implementation
- 11Power Supply Recommendations
- 12Layout
- 13Device and Documentation Support
- 14Mechanical, Packaging, and Orderable Information

Refer to the PDF data sheet for device specific package drawings

- D|8

Total error can be calculated for any
arbitrary device condition and current level. Error sources considered should include
input-referred offset current, power-supply rejection, input common-mode rejection,
sensitivity error, nonlinearity, and the error caused by any
external fields. Compare each of these error sources in percentage terms, as some are
significant drivers of error and some have inconsequential impact to current error. Offset
(Equation 22), CMRR (Equation 24), PSRR (Equation 23), and external field error (Equation 25) are all referred to the input, and so, are divided by the actual input current
I_{IN} to calculate percentage errors. For calculations of sensitivity error and
nonlinearity error, the percentage limits explicitly specified in the *Section 7.9* table can be used.

Equation 22.

Equation 23.

Equation 24.

Equation 25.

When calculating error contributions across temperature, only the input offset current and sensitivity error contributions vary significantly. For determining offset error over a given temperature range (ΔT), use Equation 26 to calculate total offset error current. Sensitivity error is specified for both –40°C to 85°C and –40°C to 125°C. The appropriate specification should be used based on application operating ambient temperature range.

Equation 26.

To accurately calculate the total expected
error of the device, the contributions from each of the individual components above must be
understood in reference to operating conditions. To account for the individual error sources
that are statistically uncorrelated, a root sum square (RSS) error calculation should be
used to calculate total error. For the TMCS1101, only the input referred
offset current (I_{OS}), CMRR, and PSRR are statistically correlated. These error
terms are lumped in an RSS calculation to reflect this nature, as shown in Equation 27 for room temperature and Equation 28 for across a given temperature range. The same methodology can be applied for
calculating typical total error by using the appropriate error term specification.

Equation 27.

Equation 28.

The total error calculation has a strong
dependence on the actual input current; therefore, always calculate total error across the
dynamic range that is required. These curves asymptotically approach the sensitivity and
nonlinearity error at high current levels, and approach infinity at low current levels due
to offset error terms with input current in the denominator. Key figures of merit for any
current-measurement system include the total error percentage at full-scale current, as well
as the dynamic range of input current over which the error remains below some key level.
Figure 10-1 illustrates the RSS maximum total error as a function of input current for a TMCS1101A2B at room temperature
and across the full temperature range with V_{S} of 5 V.