AN2559 datasheet(17/35 Pages) STMICROELECTRONICS

Part #	AN2559

Description	System power supply board for digital solutions

PDF	35 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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17 / 35 page

AN2559

PM6680A block

17/35

Figure 14 shows the schematic and placement of the reset part on the board. Typically in

real applications the reset circuit senses if the supply voltage drops below about 10% of

nominal value. This feature cannot be implemented on the System Supply board due to the

fact that the output voltage is selectable, while the reset voltage is factory set. There are

several types of reset circuits in the STM6719 family (see datasheet). Of these, the

STM6719TGWB6F was selected as optimal. The voltage thresholds of this device are

3.075 V, 1.11 V and 0.626 V.

Figure 14.

Schematic of the reset circuit and board placement

R209

110 k

Ω

Vcore

Vsys

C32

1 nF

C33

1 nF

Vio

J14

Reset

VCC1

VCC2

VSS

RSTIN

RST

STM6719TEWB6F

J15

Reset GND

AI12695

AN2559 Datasheet(PDF) 17 Page - STMicroelectronics