L9678P datasheet(32/203 Pages) STMICROELECTRONICS

No. de pieza	L9678P

Descripción Electrónicos	Automotive user configurable airbag IC

PDF	203 Pages

Scroll/Zoom	100%

Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	http://www.st.com

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32 / 203 page

Start-up power control

L9678P, L9678P-S

32/203

DocID029274 Rev 3

4.3.5

VDD3V3 linear regulator

The fully integrated VDD3V3 linear regulator provides 3.3 V system voltage derived directly

from VDD5. This voltage rail is used in case a 3.3 V micro-controller is adopted. The stability

of the regulation loop is guaranteed by use of a small external capacitor. Current limitation is

implemented and its maximum current capability on VDD3V3 is 125 mA. The VDD3V3

regulator is enabled in the ACTIVE mode and continues operation in the PASSIVE mode

using power from energy reserve. VDD3V3 supply is monitored for system reset (see Power

On Reset and Reset in Section 4.4); voltage monitoring is based on a second redundant

bandgap voltage reference.

Note that if the VDDQ pin (digital outputs supply) is connected to the VDD3V3, and any of

the digital output pins are connected to 5 V logic, there is no internal blocking diode to

prevent back-feeding this 3.3 V supply.

Figure 15. VDD3V3 control behaviour

L9678P Datasheet(PDF) 32 Page - STMicroelectronics