SNAS714C November 2016 – August 2021 LMS3635-Q1 , LMS3655-Q1
PRODUCTION DATA
Start-up and shutdown of the LMS36x5-Q1 are controlled by the EN input. Applying a voltage of ≥ 2 V activates the device, while a voltage of ≤ 1.45 V is required for shutdown. The EN input may also be connected directly to the input voltage supply. This input must not be left floating. The LMS36x5-Q1 uses a reference-based soft start that prevents output voltage overshoots and large inrush currents as the regulator is starting up.
A typical start-up waveform is shown in Figure 8-4 along with timing definitions. This waveform indicates the sequence and timing between the enable input, output voltage, and RESET. From the figure, the user can define several different start-up times depending on what is relevant to the application. Table 8-1 lists the timing definitions and typical values.
PARAMETER | DEFINITION | VALUE | UNIT | |
---|---|---|---|---|
tRESET-READY | Total start-up sequence time | Time from EN to RESET released | 7.5 | ms |
tPOWER-UP | Start-up time | Time from EN to 90% of VOUT | 4 | ms |
tSS | Soft-start time | Rise time of VOUT from 10% to 90% | 3.2 | ms |
tEN | Delay time | Time from EN to start of VOUT rising | 1 | ms |
tRESET-ACT | RESET time | Time from output voltage within 94% and RESET released | 3 | ms |