AN4488 datasheet(13/44 Pages) STMICROELECTRONICS

Part #	AN4488

Description	Getting started with STM32F4xxxx MCU hardware development

PDF	44 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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13 / 44 page

DocID026304 Rev 3

13/44

AN4488

Power supplies

Figure 6. PDR_ON timings example

(not to scale, not needed for STM32F411xx and STM32F446xx)

Selection of PDR_ON voltage supervisor

Voltage supervisor should have the following characteristics

•

Reset output active-high push-pull (output driving high when voltage is below trip

point)

•

Supervisor trip point including tolerances and hysteresis should fit the expected VDD

range.

Notice that supervisor spec usually specify trip point for falling supply, so hysteresis

should be added to check the power on phase.

Example:

–

Voltage regulator 1.8V +/- 5% mean VDD min1.71V

–

Supervisor specified at 1.66V +/- 2.5% with an hysteresis of 0.5% mean

- rising trip max = 1.71V (1.66V + 2.5% + 0.5%)

- falling trip min = 1.62V (1.66V - 2.5%).

AN4488 Datasheet(PDF) 13 Page - STMicroelectronics