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LM3017

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SNOSC66D – MARCH 2012 – REVISED SEPTEMBER 2016

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Device Functional Modes (continued)

7.4.6 Start-Up Pass-Through Mode

During start-up in pass mode, the current limit is defined by VLIM2 = 100 mV (typical) in Electrical Characteristics,

for the first TLIM2 = 3.6 ms (typical). The current is limited to VLIM2 / RSEN, for this period. Once the TLIM2 = 3.6 ms

(typical) timer has finished, the current limit is reduced to VLIM1 = 85 mV (typical). For the first TLIM2 = 3.6 ms

(typical) of the start-up, the latch-off feature is not enabled; however, the current is always limited to VLIM2 / RSEN.

This higher limit allows the part to start up normally. If the current limit is still tripped at the end of TLIM2 = 3.6 ms

(typical), the TLIM1 = 900 µs (typical) timer is started. Once the TLIM1= 900 µs time has expired, the pass FET(Q2)

is latched off. This gives a total current-limited time of TLIM1+ TLIM2 = 4.5 ms (typical), in cases where the LM3017

is started into a short circuit at the output.

Figure 15. Current Limit and Short-Circuit Protection