Non volatile serial EEPROM’s are a key component of many embedded designs. This 20 minute seminar is an introduction to serial EEPROM technology as well as an introduction to Microchip’s product line. Here are some questions that we will answer during this presentation. Are you curious about the advantages of Serial EEPROMs?

We will talk about the features that make them so popular. If you ever have to decide which EEPROM bus is best for your application. We will compare the features of the major protocols. you wonder about small or thin package options. One advantage of EEPROMs is their small packaging. You wonder what design tools are available. We will talk about Microchip’s development tools and software development models.

Most serial EEPROMs use between 2 and 6 microcontroller pins. Are you pin limited and looking for a way to save micro I/Os? we will talk about Microchip‘s new single I/O EEPROM prompts. Now let’s look at our agenda.

We will start off with a brief overview of Microchip’s history of providing serial EEPROM products. Then we will look at some specific features common to all serial EEPROMs. Then we will compare and contrast 3 serial bus options. I 2C, microwire and SPI. And I will introduce a fourth option, Microchip’s new UNI/O family of single I/O EEPROMs After that we will check out our product road map and packaging options. Finally, we will look at a couple of tools and close with some ways you can get more information. This overview seminar is a quick look at some major features of serial EEPROMs. If you have more specific questions, we have a series of more detailed web seminars on many of these topics. I will go over the list of these other webinars, at the end of this one.

Even though Microchip is now primarily known as a micro controller company, we have been manufacturing non volatile memories for over 20 years. Today we continue this tradition with a complete range of serial EEPROM products. Microchip is also known for having outstanding delivery performance partly because of the company’s world class manufacturing capabilities. Quality is a key component of Microchip’s culture. Both of Microchip’s fabs as well as our assembly test facility meet the requirements of ISO/TS - 6949. This is a strict quality system that covers both design and manufacturing. Most of our packaging is done at our own assembly site in Thailand with the balance done at approved sub contractors. This control over our manufacturing allows us to achieve our excellent quality and delivery performance. Endurance is a key part of Microchip EEPROM products. We consider our industry leading endurance to be a strong measure of our overall quality. We also have a long history of innovation in our EEPROM product line. We have been the first to market with new features including low voltage operation, small packaging, faster speeds and application specific devices. Before we get into the differences among the EEPROM buses, let’s talk about some features and advantages that are common to all products regardless of the bus.

First serial EEPROMs have a low pin count. Typically, 8 pins and are available in very small packages. There are also 5 and 6 pin options. And we have recently introduced 3 pin EEPROMs.

Second, EEPROMs can both write and read a byte at a time. This is in contrast to flash technologies that are typically limited to sector operations. EEPROMs are available in a wide temperature and voltage range. Most Microchip EEPROMs are available in 1.8 volt options which is excellent for battery applications. They also work up to 5 volts and automotive grade temperatures of 125 degrees C.

EEPROMs also have very low power requirements with virtually all Microchip devices having a typical stand by current of well under .1 micro amps.

EEPROMs are also very cost effective since they are small devices in small packages.

Finally Microchip’s EEPROM products are known for their extremely high endurance. We will talk more about that on the next slide.

Endurance is defined as the number of times that one memory location or bit can be erased and rewritten before that location fails or no longer holds the correct information. This is a pretty tight definition. When one bit on a memory device fails, the entire device is defined to have failed. Serial EEPROMs are excellent for applications requiring many data changes. Most of our EEPROM products are specified to one million arrays rate cycles which is much more than most other non volatile memory technologies. This data sheet value of one million cycles is based on specific conditions for 25 degrees C and 5 volts. That’s because endurance degrades with increasing temperature and to a lesser extent with increase in voltage. So to accurately predict endurance in an application, it’s important to consider the actual operating conditions. That’s why we developed our total endurance software. This modeling tool allows the user to enter his operating conditions to create a model at the expected endurance in a specific application.

Two components give Microchip EEPROMs their excellent endurance. First our products are built using Microchip’s PEEC or PMOSS Electrically Erasable Cell process technology. This cell was developed specifically to give our products high endurance and reliability.

Second, every bit of every device is tested three times in our triple test flow process. This combination of an excellent cell structure and outstanding testing gives Microchip its industry leading endurance. We have talked about the major features of all serial EEPROM products. Now let’s take a look at the three buses and some of the differences among them.

Serial EEPROMs have historically come in three bus types, I2C, microwire and SPI. This table shows us some specific features of each bus. I2C developed by Phillips is an abbreviation for inter integrated circuit. Microwire was developed by National Semiconductor. SPI, an abbreviation for serial peripheral interface, was developed by Motorola. You will often hear I2C devices referred to as two wires, since there are typically two signal connections between the microcontroller and the memory device. Similarly, microwire devices are referred to as three wires. Each bus has certain data security features. I2C devices have a right protect pin that can prevent rights to the array. Microwire makes use of right enable and disable software commands. SPI also uses these software commands as well as a status register to protect the device. It also has hardware options that can protect portions of the array.

Let’s pay special attention to the last parameter. The number of signal lines between the EEPROM and the micro controller. I2C devices only have 2 signal lines to the micro. A clock signal and one data signal that carries both incoming and outgoing data. Microwire and SPI devices both require 4 I/Os, independent data in and data out lines as well as a chip select and a clock. So an advantage of I2C is that it only uses two I/O ports on the micro controller. But what if you would like to connect an external EEPROM to a micro using only one I/O pin. Microchip has developed its UNI/O protocol which does just that. Let’s talk more about the UNI/O bus and UNI/O EEPROMs on the next slide.

Watch or read:
Serial EEPROM Overview Part 2 of 2
UNI/O technology saves pins on low pin count microcontrollers