STM32F405XX_13 Datasheet, PDF (25/185 Pages) STMicroelectronics – ARM Cortex-M4 32b MCU+FPU, 210DMIPS, up to 1MB Flash/192+4KB RAM, USB OTG HS/FS

STM32F405xx, STM32F407xx
Description
Figure 8. PDR_ON and NRST control with internal reset OFF
V _DD
PDR = 1.7 V or 1.8 V ⁽¹⁾
time
Reset by other source than
power supply supervisor
NRST
PDR_ON
PDR_ON
2.2.16
1. PDR = 1.7 V for reduce temperature range; PDR = 1.8 V for all temperature range.
time
MS19009V6
Voltage regulator
The regulator has four operating modes:
• Regulator ON
– Main regulator mode (MR)
– Low power regulator (LPR)
– Power-down
• Regulator OFF
Regulator ON
On packages embedding the BYPASS_REG pin, the regulator is enabled by holding
BYPASS_REG low. On all other packages, the regulator is always enabled.
There are three power modes configured by software when regulator is ON:
• MR is used in the nominal regulation mode (With different voltage scaling in Run)
In Main regulator mode (MR mode), different voltage scaling are provided to reach the
best compromise between maximum frequency and dynamic power consumption.
Refer to Table 14: General operating conditions.
• LPR is used in the Stop modes
The LP regulator mode is configured by software when entering Stop mode.
• Power-down is used in Standby mode.
The Power-down mode is activated only when entering in Standby mode. The regulator
output is in high impedance and the kernel circuitry is powered down, inducing zero
consumption. The contents of the registers and SRAM are lost)
DocID022152 Rev 4
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