25AA020A/W16K

In this article, we will explore the application field and working principle of 25AA020A/W16K, a low-pin-count serial EEPROM with onboard protect circuitry developed by Microchip Technology. This 2Kb of nonvolatile memory is primarily used in industrial, medical and automotive applications, particularly portable electronics such as medical implants, where its nonvolatile nature and size make it an ideal choice. We will also discuss the elemental constituents of the 25AA020A/W16K, including its architecture, package and pinout.

Architecture

The 25AA020A/W16K is a serial EEPROM organized as 2K bits of memory. It has a selectable read and write times as fast 250ns. It features onboard protect circuitry, allowing it to operate in harsh industrial, medical and automotive conditions. It runs from a 1.8V to 5.5V voltage range and has a wide operating temperature range.

Package and Pinout Configuration

This memory is packaged in a small 8-pin SOIC package and is pin compatible with any other 8-pin SOIC package. It contains four control/data pins (SCLK, SO, SI, CS), one reset pin (RST), two power pins (VCC, VSS), and one output enable pin (OE). The chip can be programmed and interfaced using standard SPI protocol or using the Microchip “memory-load” protocol. The chip supports single-buffer, multiple-master IO operations, allowing a single chip to interface with multiple systems.

Read/Write Operations

Any operation on the 25AA020A/W16K begins with asserting the CS pin. When this pin is held low, the chip is activated and will respond to commands on the SCLK, SO, and SI pins. These pins are then used to program the chip or to read/write data to it. A write operation on the 25AA020A/W16K is straightforward. To begin, the chip’s CS pin must be held low. The write command is then written on the SCLK, SO, and SI pins. After these steps are complete, the data must then be written to the chip and the CS pin must be kept low until the entire operation is complete. After the write is complete, the chip can then be deactivated by de-asserting the CS pin.

A read operation on the 25AA020A/W16K is similar to the write operation. The CS pin must be held low to activate the chip and the read command is then written to the SCLK, SO, and SI pins. After the command is written, the chip will return the data requested on the SI pin. After the data is retrieved, the CS pin must be kept low until the entire operation is complete, and then the chip can be deactivated by de-asserting it.

Conclusion

The 25AA020A/W16K is a powerful and reliable miniaturized serial EEPROM. It has a selectable read and write times as fast 250ns and onboard protect circuitry, allowing it to operate in harsh industrial, medical and automotive conditions. It is programmed with the standard SPI protocol and it supports single-buffer, multiple-master IO operations. All in all, the 25AA020A/W16K is a great choice for applications in portable electronics such as medical implants.