Table 4. Cpu Frequency Range Depending On Dynamic Voltage Scaling - STMicroelectronics STM32L151RE Manual

Functional overview
Table 3. Functionalities depending on the operating power supply range (continued)
Operating power supply
range
V =V = 2.0 to 2.4 V
DD DDA
V =V = 2.4 to 3.6 V
DD DDA
1. CPU frequency changes from initial to final must respect "F
consumption peak when frequency increases. It must also respect 5 µs delay between two changes. For example to switch
from 4.2 MHz to 32 MHz, the user can switch from 4.2 MHz to 16 MHz, wait 5 µs, then switch from 16 MHz to 32 MHz.
2. Should be USB compliant from I/O voltage standpoint, the minimum V

Table 4. CPU frequency range depending on dynamic voltage scaling

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Functionalities depending on the operating power supply range
DAC and ADC
operation
Conversion time up
to 500 Ksps
Conversion time up
to 1 Msps
CPU frequency range
16 MHz to 32 MHz (1ws)
32 kHz to 16 MHz (0ws)
8 MHz to 16 MHz (1ws)
32 kHz to 8 MHz (0ws)
2.1MHz to 4.2 MHz (1ws)
32 kHz to 2.1 MHz (0ws)
DocID025433 Rev 8
Dynamic voltage
USB
scaling range
Range 1, Range 2
(2)
Functional
or Range 3
Range 1, Range 2
(2)
Functional
or Range 3
initial < 4*F final" to limit V
CPU CPU
is 3.0 V.
DD
Dynamic voltage scaling range
STM32L151xE STM32L152xE
I/O operation
Full speed operation
Full speed operation
drop due to current
CORE
Range 1
Range 2
Range 3