Adesto Releases New Low-Power Flash Memory Devices Targeted at Wearable Applications and the IoT

March 03, 2019 by Gary Elinoff

This week, Adesto Technologies introduced its new FusionHD non-volatile memories (NVMs).

This week, Adesto Technologies introduces new non-volatile memories (NVMs) requiring up to 70% less power than standard flash memory devices.

The name of the electronics game today is to do more with less electrical power. IoT nodes are often difficult to access, so node devices may have to last years on the same battery charge, and the power available to wearables is orders of magnitude below what even a smartphone can muster.

Announced this week, Adesto's FusionHD family NVI’s designed specifically for those challenges.


Image from Adesto


As described by Paul Hill, Adesto’s senior marketing director. “Fusion quickly became our fastest-growing NVM family, and we expect FusionHD to achieve even greater success. The product adds powerful new features to address evolving market needs, and provides significant advantages across a wide range of demanding applications.”

Small Page Erase and Write Architecture

The FusionHD family devices feature a small page erase and write architecture. This formulation makes it possible to write small amounts of data without having to reprogram an entire page. It also enhances the speed of operation, saves power and, with fewer read/write operations overall, increases the life expectancy of the device.

This feature, not commonly found in standard flash devices, also makes it possible for large data packets to be accessed using fewer CPU clock cycles. This reduces not only processing time, but also saves battery power.  

Additionally, there is an internal read/write SRAM buffer that also serves to reduce the number of times that the flash array needs to be accessed. This further serves to extend service life, reduce power consumption and increase speed.

A Smart Peripheral

The intelligent host interface brings the FusionHD family into the realm of smart peripherals. The device’s read/modify/write operation facility not only makes software driver development easier but also frees the CPU to focus on other tasks.

The Active IRQ allows the device to signal the MCU when an operation is completed, serving not only to free the MCU but to also save on the overall system-wide power used in a given operation.

Security features include a programmable security register useable for system-level key storage and a unique device identification.

Members of the FusionHD NVM Family

All units are Serial Peripheral Interface (SPI) devices, which mean that they receive data serially. They are divided into dual and quad SPI inputs. The datasheets for the family are found here.

The user will note that they are divided into 1.8-volt and 3.0-volt versions, each with multiple dual and quad versions. The memory density for the FusionHD NVM family ranges from 256Kbit to 128Mbit.

The AT25SF641 is one example. It is a 64Mbit device, 3.0V device; in an 8-pad DFN package, its dimensions are 6 x 5 x 0.6 mm.

Power dissipation for this unit is:

  • 2µA Deep Power-Down Current (Typical)
  • 10µA Standby current (Typical)
  • 5mA Active Read Current (Typical)


Block diagram for the AT25SF641. Image source Adesto

Protocols Supported

  • Serial Flash Reset Signaling Protocol (JESD252)
  • The latest version of the SFDP standard (JESD216C)

The Competition

Low-power flash is an extremely competitive arena. There are many choices with many parameter trade-offs, so designers will have to do their homework. Here’s where to start:

  • Maconix MX25R: This family of devices features memory densities ranging from 512Kbit to 64Mbit. Deep down current is < 0.5uA, active current is 4mA or less, and operating voltages ranging from 1.65V to 3.6V are accommodated.
  • smMEM-AT45DB641 is a serial flash memory device from SensorMaestros that draws 400 nA in ultra-deep power down mode. The 64 Mbit device works with a power supply range of 1.7V to 3.6V.


The smMEM-AT45DB641. Image used courtesy of SensorMaestros



What do you look for in a flash memory device? Do you have experience with Adesto products? Share your experiences in the comments below.