STM32L471

The STM32L471xx devices are the ultra-low-power microcontrollers based on the highperformance ARM ® Cortex ® -M4 32-bit RISC core operating at a frequency of up to 80 MHz. The Cortex-M4 core features a Floating point unit (FPU) single precision which supports all ARM single-precision data-processing instructions and data types. It also implements a full set of DSP instructions and a memory protection unit (MPU) which enhances application security.

The STM32L471xx devices embed high-speed memories (Flash memory up to 1 Mbyte, up to 128 Kbyte of SRAM), a flexible external memory controller (FSMC) for static memories (for devices with packages of 100 pins and more), a Quad SPI flash memories interface (available on all packages) and an extensive range of enhanced I/Os and peripherals connected to two APB buses, two AHB buses and a 32-bit multi-AHB bus matrix.

The STM32L471xx devices embed several protection mechanisms for embedded Flash memory and SRAM: readout protection, write protection, proprietary code readout protection and Firewall.

The devices offer up to three fast 12-bit ADCs (5 Msps), two comparators, two operational amplifiers, two DAC channels, an internal voltage reference buffer, a low-power RTC, two general-purpose 32-bit timer, two 16-bit PWM timers dedicated to motor control, seven general-purpose 16-bit timers, and two 16-bit low-power timers. The devices support four digital filters for external sigma delta modulators (DFSDM).

In addition, up to 24 capacitive sensing channels are available.

They also feature standard and advanced communication interfaces.

• Three I2Cs
• Three SPIs
• Three USARTs, two UARTs and one Low-Power UART.
• Two SAIs (Serial Audio Interfaces)
• One SDMMC
• One CAN
• One SWPMI (Single Wire Protocol Master Interface)

The STM32L471xx operates in the -40 to +85 °C (+105 °C junction), -40 to +105 °C (+125 °C junction) and -40 to +125 °C (+130 °C junction) temperature ranges from a 1.71 to 3.6 V power supply. A comprehensive set of power-saving modes allows the design of lowpower applications.

Some independent power supplies are supported: analog independent supply input for ADC, DAC, OPAMPs and comparators, and up to 14 I/Os can be supplied independently down to 1.08V. A VBAT input allows to backup the RTC and backup registers.

The STM32L471xx family offers four packages from 64-pin to 144-pin packages.

Table 2. STM32L471xx family device features and peripheral counts

Table 2. STM32L471xx family device features and peripheral counts

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Table 2. STM32L471xx family device features and peripheral counts (continued)

Table 2. STM32L471xx family device features and peripheral counts (continued)

Figure 1. STM32L471xx block diagram

Note:

AF: alternate function on I/O pins.

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• Ultra-low-power with FlexPowerControl
• -1.71 V to 3.6 V power supply
• --40 °C to 85/105/125 °C temperature range
• -300 nA in V BAT mode: supply for RTC and 32x32-bit backup registers
• -30 nA Shutdown mode (5 wakeup pins)
• -120 nA Standby mode (5 wakeup pins)
• -420 nA Standby mode with RTC
• -1.1 μA Stop 2 mode, 1.4 μA Stop 2 with RTC
• -100 μA/MHz run mode
• -Batch acquisition mode (BAM)
• -4 μs wakeup from Stop mode
• -Brown out reset (BOR) in all modes except shutdown
• -Interconnect matrix
• Core: ARM ® 32-bit Cortex ® -M4 CPU with FPU, Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait-state execution from Flash memory, frequency up to 80 MHz, MPU, 100DMIPS/1.25DMIPS/MHz (Dhrystone 2.1), and DSP instructions
• Clock Sources
• -4 to 48 MHz crystal oscillator
• -32 kHz crystal oscillator for RTC (LSE)
• -Internal 16 MHz factory-trimmed RC (±1%)
• -Internal low-power 32 kHz RC (±5%)
• -Internal multispeed 100 kHz to 48 MHz oscillator, auto-trimmed by LSE (better than ±0.25 % accuracy)
• -3 PLLs for system clock, audio, ADC
• RTC with HW calendar, alarms and calibration
• Up to 24 capacitive sensing channels: support touchkey, linear and rotary touch sensors
• 16x timers: 2 x 16-bit advanced motor-control, 2 x 32-bit and 5 x 16-bit general purpose, 2x 16-bit basic, 2x low-power 16-bit timers (available in Stop mode), 2x watchdogs, SysTick timer
• Up to 114 fast I/Os, most 5 V-tolerant, up to 14 I/Os with independent supply down to 1.08 V

February 2016

DocID027226 Rev 1

Figure 5. STM32L471Zx LQFP144 pinout (1)

The definition and values of input/output AC characteristics are given in Figure 22 and Table 60 , respectively.

Unless otherwise specified, the parameters given are derived from tests performed under the ambient temperature and supply voltage conditions summarized in Table 22: General operating conditions .

Table 60. I/O AC characteristics (1)(2)

Table 60. I/O AC characteristics (1)(2)

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Table 60. I/O AC characteristics (1)(2) (continued)

1. This value represents the I/O capability but the maximum system frequency is limited to 80 MHz.
2. The fall time is defined between 70% and 30% of the output waveform accordingly to I 2 C specification.

Figure 22. I/O AC characteristics definition (1)

1. Refer to Table 60: I/O AC characteristics .

Stresses above the absolute maximum ratings listed in Table 19: Voltage characteristics , Table 20: Current characteristics and Table 21: Thermal characteristics may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these conditions is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.

Table 19. Voltage characteristics (1)

1. To sustain a voltage higher than 4 V the internal pull-up/pull-down resistors must be disabled.

2. Include VREF- pin.

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Table 20. Current characteristics

1. A negative injection is induced by V IN < V SS . I INJ(PIN) must never be exceeded. Refer also to Table 19: Voltage characteristics for the minimum allowed input voltage values.

2. When several inputs are submitted to a current injection, the maximum ∑ |I INJ(PIN) | is the absolute sum of the negative injected currents (instantaneous values).

In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK ® packages, depending on their level of environmental compliance. ECOPACK ® specifications, grade definitions and product status are available at: www.st.com . ECOPACK ® is an ST trademark.