AT21CS01 from Atmel is a two pin serial EEPROM. Astonishingly, it does not have a Vcc or power supply pin characteristic of any IC and does not require an external power source to work. This amazing memory IC operates with only a data pin and a ground pin. The memory in the IC is organized as 128×8 bits, that is, a total of 1-kbits.
The single-wire device, AT21CS01, operates with only an SI/O and GND pin. The SI/O signal functions as a combination of data and power line. That means, apart from moving data in and out of the IC, the SI/O pin also provides power to the device. During high time of the protocol sequence, the IC’s parasitic power scheme provides the IC with power.
Each AT21CS01 is factory programmed to include a unique serial number of 64-bits. The SI/O line can be accessed directly from outside the application, because the device complies with the IEC 61000-4-2 ESD tolerance. This memory IC comes in 4-ball WLCSP, 8-lead SOIC and 3-lead SOT23 packages. Market availability is slated for the fourth quarter of 2015.
Possible applications for AT21CS01 include ink and toner print cartridge identification, storing data for analog sensor calibration and management of after-market consumables. There are several advantages in using AT21CS01.
Manufacturers claim AT21CS01 consumes 33% lower power in its active mode when compared to devices offered by the competition. For instance, at 25°C, the typical write current for an AT21CS01/11 is 200 µA, the typical read current measures about 80 µA, and a typical standby current of 700 nA. Each memory location can endure 1 million write cycles.
With such features, the AT21CS01 is eminently suitable as identification markers for cables, batteries, consumables, wearables and IoT. To support different voltage requirements, the AT21CS01 comes in two variants. AT25C501 is suitable for applications operating in the range of 1.7 to 3.6V. However, when operating with Li-Ion or polymer batteries, applications require higher voltage ranges, such as 2.7 to 4.5V, for which, the AT21C511 is suitable.
With its ultra-low active and standby currents, the AT25C501 beats the competition by consuming at least one third less power. The single-wire interface follows the I2C communication protocol. This IEC 61000-4-2 Level 4 ESD compliant device can withstand discharges of +8KV in contact and +15KV in air.
The innovative memory is organized into for zones of 256-bits each, with a security register additional to the 1 Kb memory space. Each EEPROM has a 64-bit serial number programmed at the factory and includes 16-bytes extra for user programmability. That means the user can improve on the uniqueness of the serial number on each device.
The advantages of using AT25C501 are many. The designer needs only one pin from the ASIC/MPU/ASSP/MCU. Because of its smaller footprint, layout is simple and the consumed PCB area reduces. That makes it easy to integrate identification capabilities in cables and or consumables. Its lower energy consumption is a boon for instruments working on batteries. The high-speed mode of AT25C501 even in low power applications results in high performance.
