SLUS634F November 2004 – January 2022 TPS2384
PRODUCTION DATA
PMM Discovery 1 function waveforms for the N and CINT pins are shown in Figure 8-12. The measurement is being performed using 25-kΩ impedance between the P and N pin. The Discovery 1 voltage is allowed to settle for approximately 5 ms before the A/D begins integrating. The voltage on the CINT pin shows the A/D cycle. There are four distinct regions to any A/D cycle: precharge (to a known starting voltage), charge, coarse discharge, and fine discharge. CINT pin is very high impedance therefore extreme care must be taken to avoid any noise or leakage affecting this pin. For the measurements where CINT voltage is shown a buffer was used to prevent performance degradation. The A/D measurement time is approximately 18 ms. The entire Discovery 1 function takes approximately 22 ms to complete. At the end of the A/D cycle the Discovery 1 current is stored in the Discovery Current Register and the function done bit is set. The applied Discovery 1 voltage level remains until a new function is called. The data for this measurement remains stored in the Discovery Current Register until another Discovery 1 or 2 function is called.