3µA/MHz Ambiq Apollo 4 MCU Targets Battery-powered IoT Devices with Voice Processing

Apollo 4 AMA4B2KK-KBRAmbiq Micro is using sub-threshold voltages under 0.5V to offer ultra-low-power Arm microcontrollers. In 2015, the company launch the Apollo Cortex-M4F MCU with 30µA/MHz power consumption in active mode, which was followed in 2016 by Apollo 2 in consuming just 10µA/MHz, and Apollo 3 (Blue)  dropped power consumption to as low as 6µA/MHz against using a Cortex-M4F @ 48 MHz in active mode.

The fourth generation of ultra-low-power Apollo microcontroller has now been announced with Apollo 4 and Apollo 4 Blue microcontrollers – the latter adding Bluetooth – halving the power consumption of Apollo 3 at just 3µA/MHz, or ten times less than the original ultra-low-power MCU from the company.

Apollo 4 Blue
Apollo 4 Blue Block Diagram

Apollo 4 (Blue) specifications and key features:

  • MCU Core – Arm Cortex-M4F core up to 192 MHz (TurboSPOT) with FPU, Memory Protection Unit (MPU), and Secure Boot
  • GPU – 2D/2.5D graphics accelerator with full alpha blending, texture and frame buffer compression
  • Ultra-Low Power Memory
    • Up to 2MB of non-volatile MRAM for code/data
    • Up to 1.8MB of low power RAM for code/data
  • Display I/F – 2-lane MIPI DSI 1.2 up to 500 Mbps, up to 640 x 480 resolution with 4-layers with alpha blending, frame buffer decompression
  • Audio
    • 1x stereo low power Analog microphone
    • 4x stereo Digital microphones
    • 2x full-duplex I2S ports with ASRC
  • Wireless Connectivity (Apollo 4 Blue only)
    • Bluetooth Low Energy 5 up to 2 Mbps, extended advertising packets, AOA/AOD for direction finding
    • Tx – 4 mA @ 0 dBm, Rx 4 mA
    • Tx – -20 dBm to +10 dBm output power
    • Rx Sensitivity – -97 dBm at 1 Mbps, -94 dBm at 2 Mbps
  • Ultra-Low Power Interface for On- and Off-Chip Sensors
    • 12-bit ADC, 11 selectable input channels
    • Up to 2.8 MS/s sampling rate
    • Temperature sensor with +/-3°C accuracy
  • Ultra-Low Power Flexible Serial Peripherals
    • 3x 2/4/8-bit SPI master interfaces
    • Up to 8x I2C/SPI masters for peripheral communication
    • 1x SPI slave for host communications
    • 4x UART modules with flow control
    • 1x USB 2.0 HS/FS device controller
    • 1x SDIO (SD3.0)/1x eMMC (v4.51)
  • Clock Sources – 16-52 MHz and 32.768 kHz Crystal (XTAL) oscillators; 1 kHz LFRC oscillator; 2x HFRC oscillator – 192/384 MHz
  • Ultra-Low Supply Current
    • 3 μA/MHz executing from MRAM (with cache)
    • 3 μA/MHz executing from SRAM
    • 1.5 μA low power sleep mode with RTC and 8KB SRAM retention
  • Operating Voltage – 1.71-2.2 V; SIMO buck; Multiple I/O voltages supported
  • Package Options
    • Apollo 4
      • 5 x 5 mm, 146-pin BGA with 105 GPIO
      • 3.9 x 3.9 mm, 121-pin WLCSP with 82 GPIO
    • Apollo 4 Blue – 4.7 mm x 4.7 mm, 131-pin SIP BGA
  • Temperature Range –40°C to 85°C
  • Process – TSMC 22nm ULL

Apollo 4 and Apollo 4 Blue are basically identical except for the latter adding Bluetooth 5 LE, and losing one I2C interface in the process. Packages are also different.

Applications listed by the company include smartwatches, wireless sensors and IoT, activity/monitors, motion and tracking devices, alarms and security systems, far-field voice remotes, consumer medical devices, predictive maintenance, and the smart home. The press release highlights Apollo 4 is especially well-suited to battery-powered smart IoT devices with always-on voice processing.

Apollo 4 Blue Development Board
Apollo 4 Development Board

The company offers a development board for the new Apollo 4 microcontrollers with I/O headers, buttons, and USB-C port. There’s no public documentation for the board that I could find, however.

Visit the product page for further information.

Share this:

Support CNX Software! Donate via cryptocurrencies or become a Patron on Patreon

ROCK Pi 4C Plus
Notify of
The comment form collects your name, email and content to allow us keep track of the comments placed on the website. Please read and accept our website Terms and Privacy Policy to post a comment.
Weller PCB manufacturer