Other Parts Discussed in Thread: LM706A0
Tool/software:
Dear Texas Instruments,
It appears 2 tools are provided to assist with the LM70880 and LM706A0 design calculations. The tools provided are Webench Power Designer and the LM70XX0_quickstart_calculator_A1.xlsm.
When these 2 tools are provided with identical ambient temperature, input voltage, output voltage and output current, they produce substantially differing values for DC converter efficiency and IC power dissipation.
The IC power dissipation calculated by the provided tools can differ by approximately 1 Watt. Resulting in estimated junction temperature differing by as much as 18.6 degrees.
For example, with high ambient temperature and current, webench sets the switching frequency to 200KHz and this can't be changed. Webench seems to limit the switching frequency at 200KHz due to junction temperature concerns that are based on the calculated IC power dissipation. However, the IC power dissipation figures don't match the quick start calculator.
Questions:
1. Could Texas Instruments clarify, which of these 2 tools is recommended for the required design calculations? The webench Power Designer or the LM70XX0_quickstart_calculator_A1.xlsm?
Kind regards,
Mark.
