SNVS276I April 2004 – February 2019 LM2743
PRODUCTION DATA.
When connecting a resistor divider to the SD pin of the LM2743 some care has to be taken. Once the SD voltage goes above VSD-IH, a 17-µA pull-up current is activated as shown in Figure 24. This current is used to create the internal hysteresis (≊170 mV); however, high external impedances will affect the SD pin logic thresholds as well. The external impedance used for the sequencing divider network should preferably be a small fraction of the impedance of the SD pin for good performance (around 1 kΩ).