The TPS7H1121 features an accurate
voltage reference, which is essential in minimizing the intrinsic error of the LDO.
Output voltage accuracy specifies
minimum and maximum output voltage error, relative to the expected nominal output
voltage. The accuracy specification in the Section 6.5 table presents two operating
regions, one in which the VIN is above 3V and one when VIN is
in the "low-input" voltage region (2.25V ≤ VIN ≤ 3V).
The ±1.5% specification applies across
the complete temperature range of –55°C to 125°C, across the input voltage range of
3V ≤ VIN ≤ 14V, when the dissipated power is ≤3W, and up to the full load
(10mA ≤ IOUT ≤ 2A).
When VIN is below 3V
(2.25V ≤ VIN ≤ 3V), the output voltage accuracy is adjusted to ±1.8%.
A few additional details to the measurement are noted:
- The range of VIN,
IOUT and temperature mean the specification applies across all
load and temperature combinations. This is accomplished by testing multiple bias
conditions that cover various corners.
- Footnote 3 in Section 6.5 specifies that the
measurement is done with a power dissipation limit that is limited to a maximum
3W. This is due to tester thermal limitations.
- The test conditions specify a
minimum of 10mA and not 0mA for more robust accuracy measurements. However, in a
normal application the TPS7H1121 device does not have a minimum load current for
stability
- TI does not recommend including
the following error terms into the VACC specification as the
following terms are inherently covered by the VACC parameter:
- VFB
accuracy
- ΔVOUT/ΔVIN (line regulation)
- ΔVOUT/ΔIOUT (load regulation)
- VOUT
tempco
- The error due to the feedback
resistors, such as the specified tolerances can be added to the VACC
specification.
- For additional information on
determining accuracy see Section 9.2.2.2.