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STM32F722xx STM32F723xx Functional overview

2.16.2 Regulator OFF

This feature is available only on packages featuring the BYPASS_REG pin. The regulator is

disabled by holding BYPASS_REG high. The regulator OFF mode allows to supply

externally a V

voltage source through V

CAP_1

and V

CAP_2

pins.

Since the internal voltage scaling is not managed internally, the external voltage value must

be aligned with the targeted maximum frequency.The two 2.2

µF ceramic capacitors should

be replaced by two 100

nF decoupling capacitors.

When the regulator is OFF, there is no more internal monitoring on V

. An external power

supply supervisor should be used to monitor the V

of the logic power domain. The PA0 pin

should be used for this purpose, and act as power-on reset on V

power domain.

In regulator OFF mode, the following features are no more supported:

• PA0 cannot be used as a GPIO pin since it allows to reset a part of the V

logic power

domain which is not reset by the NRST pin.

• As long as PA0 is kept low, the debug mode cannot be used under power-on reset. As

a consequence, PA0 and NRST pins must be managed separately if the debug

connection under reset or pre-reset is required.

• The over-drive and under-drive modes are not available.

• The Standby mode is not available.

Table 3. Voltage regulator configuration mode versus device operating mode

(1)

1. ‘-’ means that the corresponding configuration is not available.

Voltage regulator

configuration

Run mode Sleep mode Stop mode Standby mode

Normal mode MR MR MR or LPR -

Over-drive

mode

(2)

2. The over-drive mode is not available when V

= 1.7 to 2.1 V.

MR MR - -

Under-drive mode - - MR or LPR -

Power-down

mode

---Yes

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