This application note describes the STR91xFA low power modes and provides an overview of the hardware implementation. It also includes details on the power supply circuitry and components, clock systems, register settings and power management.
This application note provides a hardware implementation overview of the STR91xFA microcontroller family's low power modes. It details power supply circuitry, clock systems, register settings, and power management techniques to help system designers optimize power consumption.
The document covers main operating voltages, independent A/D converter supplies, battery backup options, and low voltage detectors. It also explains the clock control unit, master clock sources, and various peripheral clock gating mechanisms. Additionally, it includes information on software library functions for configuring low power modes and provides operating measurements with typical values.
| CPU and memories operating voltage | 1.65 V to 2.0 V |
|---|---|
| I/O ring operating voltage | 2.7 V to 3.6 V |
| Main oscillator frequency range | 4 to 25 MHz |
| RTC crystal frequency | 32.768 kHz |
| Maximum PLL output frequency | 96 MHz |
| AVREF voltage range | 1.0 V to Vppq |
The LVD circuit monitors Vpp and Vppq supplies and generates a global reset whenever either voltage drops below the configured levels.
Yes, in STR91xFA low power modes, the Flash automatically reduces its power consumption and can be read immediately after wake-up.
The VBATT pin supplies power to the RTC unit, allowing it to function even when the main digital supplies are switched off.