VS6955CA datasheet(19/90 Pages) STMICROELECTRONICS

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VS6955CA

Functional description

3.4

Internal power-on reset (POR)

The VS6955CA internally performs a power-on reset (POR) when the 1V2 VDD digital

supply rises through the trigger level, Vtrig_rising. Similarly, if the 1V2 VDD digital power

supply falls through the trigger level, Vtrig_falling, then the power-on reset also triggers.

Definitions

Figure 8. POR timing

Rise threshold voltage (VTRIGR)

This is the supply voltage level that is recognized by the

POR as voltage “HIGH”. Only after the supply reaches

this level does the output of POR change to high level if

it is off, after a specified amount of delay.

Fall threshold voltage (VTRIGF)

This is the supply voltage level that is recognized by the

POR as voltage “LOW”. Only after the supply reaches

this level does the output of POR change to low

(ground) level if it is on.

Burst width (pw)

Burst is the negative pulse riding the supply signal. The

burst width is measured as the amount of duration for

which the supply signal dropped beyond the threshold

levels.

Delay duration (TPOR)

Delay duration is defined as the time duration for which

POR stays off before re-powering. Each reset of POR

imparts a specified delay duration before POR re-

powers.

VS6955CA Datasheet(PDF) 19 Page - STMicroelectronics