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I'm designing a USB-powered microcontroller board, and I'm considering choosing a Cortex-M7-based microcontroller for it (I want a double-precision FPU, along with other features M7 offers). Currently, there are 2 MCU families commercially available:

  • STMicroelectronics STM32F7,
  • Atmel SAM S70 / E70 / V70.

Because my board will only be powered by USB cable (through Type-C connector / USB 3.1 PD chip), I thought of choosing a MCU based on their power consumption - but I couldn't find any numbers.

STM manufactures it's MCUs using pretty aged 90 nm process; Atmel doesn't disclose any manufacturing details, but collective consciousness of the Internet says it's 55 nm process - thus it should be more power-efficient.

Are there any figures/estimates publicly available on the power consumption of the above MCUs? Any measurements of yours?

I totally understand that there are different usage scenarios possible; also, each MCU comes in a variety of variants among which power drain may vary. I'm not looking for comparisons, but rather for various measurements or different chips, which will help me estimate.

Thank you in advance.

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    \$\begingroup\$ Using a typical device datasheet, there are numerous current tables: st.com/resource/en/datasheet/stm32f745ie.pdf - starts at page 104. \$\endgroup\$ – Peter Smith Jun 19 '16 at 11:17
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    \$\begingroup\$ @PeterSmith wonderful. Any way you can find the same for Atmel S70, E70 or V70 please? \$\endgroup\$ – Dmitriy Khudorozhkov Jun 19 '16 at 11:29
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    \$\begingroup\$ @PeterSmith nevermind, found: atmel.com/Images/… (starting page 1458). \$\endgroup\$ – Dmitriy Khudorozhkov Jun 19 '16 at 11:31
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    \$\begingroup\$ The Atmel documentation breaks out all the peripherals more precisely from a first glance. Be careful of power sequencing requirements. \$\endgroup\$ – Peter Smith Jun 19 '16 at 11:37
  • \$\begingroup\$ PIC32MZ have double precision Floating point unit \$\endgroup\$ – ElectronS Jun 20 '18 at 11:42
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Converted to answer.

There are numerous devices in each family, so I took a typical device from each one:

Atmel typical device: ATSAME70 series

Tables are in section 56.3.4 for active mode.

For ST: STM32F745. Tables start at page 104.

Be careful of power sequencing requirements in the Atmel device; see section 6.2

According to these documents, SAME70 draws 90mA at 300 mhz and 77mA at 250 mhz, and STM32F7 draws 178mA at its top speed of 216 mhz.

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  • \$\begingroup\$ The chapters for power consumption in the linked Microchip SAM devices are 58 and 59. \$\endgroup\$ – minghua May 6 '18 at 2:20

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