SAM L10/L11 Power Supplies

Last modified by Microchip on 2023/11/21 21:37

Contents

Power Supplies Overview

The SAM L10/L11 has three different power supply pins:

  • VDDANA
  • VDDIO
  • VDDCORE

The same voltage source must be applied to both VDDIO and VDDANA. The maximum supply falling and rising rates of the different power supplies must not exceed the values described in the Supply Characteristics section of the Product Datasheet Electrical Characteristics section.

Refer to the product datasheet for power-up and power-down sequences and for the min/max rise time of the supply voltages.

Related Peripherals

The related peripherals to control the power supplies are the following:

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Power Domains

In order to offer high flexibility in terms of power consumption, the device is divided into three different power domains:

  • VDDANA Domain powers all the Analog peripherals (Analog-to-Digital Converter (ADC), Digital-to-Analog Converter (DAC), Peripheral Touch Controller (PTC), Operational Amplifier Controller (OPAMP), Analog Comparator (AC), Analog IOs PA00 to PA07) of the device, plus the 32 kHz clock sources (OSCULP32K & XOSC32K), the Power-On Reset (POR) and the 3.3V Brown-out Detector (BOD33).
  • VDDIO Domain powers all the IOs plus the internal voltage regulators, the main oscillators (OSC16M and XOSC), and the 1 V2 Brown-out Detector (BOD12).
  • VDDCORE domain powers all the Digital Logic (CPU) Peripherals (except analog), memories, plus the FDPLL96M and the DFLLULP oscillators.

The three different power domains

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Typical Power Supply Schemes

Switching (Buck) / Linear (LDO) Power Scheme

The SAM L10/L11 embeds a flexible regulator able to operate in two different modes: Buck mode or Low Dropout (LDO) mode. The mode selection can be done on the fly by software. By default, LDO mode is selected after a device reset. Changing to Buck mode is then required to benefit from its power efficiency.

Linear (LDO) power scheme

Linear (LDO) Mode Only

In this scheme the Buck mode (Switching) is not considered, therefore no inductor is required and the Bill of Materials (BOM) is reduced. This configuration also has the advantage of avoiding the resulting switching noise of the Buck mode. Note that in this mode, no further on-the-fly mode selection is possible.

Linear (LDO) Mode Only

Refer to the Voltage Regulators section for more details.

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Power-On Reset and Brown-Out Detectors

The SAM L10/L11 embeds three features to monitor, warn, and reset the device:

  • A Power-on Reset (POR) on VDD (VDDANA and VDDIO):
    • Monitoring is always activated, including during device startup or during any Sleep modes.
    • Having VDD below a fixed threshold voltage will reset the whole device.

Refer to the product datasheet for the rising and falling threshold voltages.

  • A Brown-out Detector (BOD33) on VDD (VDDANA and VDDIO):
    • The BOD33 can monitor VDD continuously (Continuous mode) or periodically (Sampled mode) with a programmable sample frequency in Active mode as in any Sleep mode.
    • A programmable threshold loaded from the NVM User Row is used to trigger an interrupt and/or reset the whole device.
  • A Brown-out Detector (BOD12) on VDDCORE.

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Related Sections

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