DocID027559 Rev 1

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AN4661

Reference design

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1. PC13, PC14, PC15 and PI8 are supplied through the power switch. Since the switch only sinks a limited

amount of current (3 mA), the use of GPIOs PC13 to PC15 and PI8 in output mode is limited:

- The speed should not exceed 2 MHz with a maximum load of 30 pF.

- These I/Os must not be used as a current source (e.g. to drive an LED).

2. 5 V tolerant except when in analog mode or oscillator mode for PC14, PC15, PH0 and PH1.

3. If the device is delivered in an WLCSP143, UFBGA176, LQFP176 or TFBGA216 package, and the

BYPASS_REG pin is set to VDD (Regulator OFF/internal reset ON mode), then PA0-WKUP is used as an

internal reset (active low).