 Hello, and thank you for joining me in this webinar. My name is John Tran, and I am SD application engineer supporting RFID and NFC products. Today, we'll learn about SD-NFC product portfolio and what it can do to help you with adding NFC technology into your existing or future products. We will focus mainly on the application approach with modulation using our NFC Dynamic Tag IC. What is NFC? NFC stands for Near Field Communication. It is a wireless technology that utilizes magnetic instead of electromagnetic field. While this limits the range, which is around 1 meter for ISO 15693, and the range is a function of the reader field strain, so in most of the mobile phone on the market today, NFC range is around 4 to 5 centimeters. NFC inductive nature allow the unpowered devices or products to have contactless configuration at assembly line. Mobile payment is another popular use of this technology, and close proximity improves security. In many cases, NFC complements all the wireless technology, such as Wi-Fi and Bluetooth. It allows seamless pairing and provisioning. The SD-25 product families include NFC tag ICs, which can be used in ticketing, gaming, or medical. These chips can be integrated into antenna inlays with adhesive backing. SD only makes the silicon, so the inlays would have to be done by a third party. The dynamic tag ICs, on the other hand, have I2C interface, which allows hard-wide connectivity to microcontrollers or application processors. Such features enables zero-power wireless configuration at the assembly line. NFC dynamic tags are packaged components, so they can be soldered onto PCBs. Our SD-25R product families serve its application, such as point-of-sale terminals, physical access control, and reader and tag embedded solutions. Parks, like electronic toothbrush, is an example of reader and tag system, where the disposable end is identified and configured wirelessly. Here is a more complete view of our SD-25NFC portfolio. As you can see, SD is a one-stop shop for tags and reader. When you look at a tag IC, you see that we produce the SD-25TA, the SD-25TB, and SD-25TV. The TA is ISO 14443A, tag type 4, and the SD-25TB is the ISO 15693, tag type 5. The TB is not NFC-formed compliant and is used mostly for mass transit. Then we also have the dynamic tag. These are tags that have both RF interface and I2C interface. The M24SR, the M25R, and SD-25DV I2C all have I2C interfaces. The SD-25DV PWM does not have an I2C interface, but it's considered dynamic tag IC because the PWM signal is changeable. The M24R is an older ISO 15693 dynamic tag, and it's superseded by the SD-25DV I2C. For the NFC reader or transceivers, we start with the SD-25R95. This is an entry-level low-power NFC reader. Then we have the 3911B with automatic antenna tuning capability and higher power output. In some variants, like the 3914 or 3915, we have automotive temperatures. We also have the 3916, the 3917, and these readers can go up to 1.7 watt. Finally, we also have the UHF reader, these for the 900MHz band, long-range RFID. Now let's turn our attention to today's feature device, the SD-25DV PWM. As I have mentioned earlier, the dynamic tag IC differs from static tag in the ability to change characteristics via NFC technology. From our I2C base device, the SD-25DV I2C, the dynamic nature is centric to the changing memory content. At times, you could use it as an NFC bridge. For the SD-25DV PWM, it is the analog output in the form of PWM signals. The PWM output can have up to 15-bit resolution, which is equivalent to 62.5 nanosecond resolution step. In addition to this capability, the SD-25DV PWM device comes with factory-encoded visual signature and special memory protection scheme using 32-bit or 64-bit passwords. When operating in PWM mode, the device requires a voltage supply that can be between 1.8 volt and 5.5 volt. So we have seen earlier that the SD-25DV PWM device complies to NFC forum tag type 5 ISO 15693. To communicate, it meets an antenna with inductance that will work with the 28.5 picofarad chip capacitors to produce a resonant frequency around 13.56 megahertz. It is also important to note that the same antenna can work with SDR dynamic tag ICs, such as the M24SR and M24LR. Please review the application note 3249 if you need additional information regarding internal or chip's capacitance and how that is critical in antenna tuning. Due to relatively small memory size, there's no support for extended RF commands and there is no fast command. At the protocol level of ISO 15693, the SD-25DV PWM utilizes the 13.56 megahertz carrier frequency. Standard ISO 15693 dictates that reader frequency modulation can be set at 10% or 100% ASC, which stands for Amplitude Chip Keying. For the tag load modulation, it uses Manchester coding with single dual subcarrier. The NFC forum tag type 5. However, requires 100% ASC modulation single carrier at 26 k-bit per second as a base. So here's the list of all the standard commands and four custom commands with support PWM configuration and memory protection. The highly used standard commands are inventory where you can get the chip UID, read and write single block. Lock block command allows the user to permanently lock a block of memory. Select and stay quiet command allow the reader to access multiple tags in the RF field. Let's look over the technical specification of the PWM outputs. There are two versions, one port and two ports. The PWM frequency is adjustable from 489 hertz to 31.25 kilohertz. The signal duty cycle can also be changed from 0 to 100%. There is a 15-bit register which is dedicated for PWM frequency output. At full 15-bit, it is amount to a period of 489 hertz, while full 9-bit is used when the frequency gets up to 31.25 kilohertz. The PWM output is bush cold, and it can sing a source up to 4 milliamps. The PWM start of time is three millisecond or less. As you can see here, the device, both devices, the one PWM output version and two PWM output versions, are pin-comparables. Each device can be identified by reading the IC reference registers, 38-hacks for one port and 39-hacks for two ports. The two K-bit or 256-bytes user memory can be configured as one area or two areas. If the memory is split into two areas, each area can only be protected by a 32-bit password. Otherwise, a single area can be protected by 64-bit passwords. Splitting the memory into two areas allow one area to store publicly accessible information like URL and warranty data. The second area is reserved to store specific data that is pertain to usage and error codes. Other protected memory locations are for PWM controls and system EE prom memory. Each can be protected by a 32-bit password. Finally, there are dedicated locations for the 64-bit UID and digital signature. The PWM signal register is 32-bit wide. The first 15-bit is dedicated for the signal pulse width. Then the period will take 15-bit. Finally, the last bit is being used to enable and disable the PWM. When the enable bit is programmed with zero, the output will be disabled, and its state will be high V. The value for the period could range between 5 and 12 and 32,767. This corresponds to frequency of 489 hertz and 31.25 kilohertz. The 32-bit pulse width can be between 0 and 32,767. So by changing these 15-bit values, the period and the pulse width, you effectively change the PWM frequency and duty cycle. Here's what the PWM waveform looks like at different duty cycle. Notice that the period T for a given signal can be changed from 2 millisecond to 32 microsecond. The formula shows that duty cycle is simply a percentage of pulse width with respect to the period of the safe node. Notice that when the duty cycle is zero, the output is equivalent to logical zero. And when the duty cycle is 100%, the output is logical one. Another feature of the SE25 DV PWM device is its ability to change the output drive level. There is a resistor inside the SE25 DV, which makes this possible. By changing the PWM output drive level, you can choose to increase and improve output impedance, or you can reduce commutation noise and the power consumption as seen in the table here. So here are two examples using the same R load of 10 kiloohms in 3.3 volts as VCC. You can see that by changing the output drive from 4 million to 1 million, a change in voltage offset can be achieved. And there are applications such as lighting where changing the offset can be very useful. We have seen from the specification that the SE25 DV PWM device contains a digital signature. What is true SE25 digital signature? It is SE solution for product authenticity verification. It is like the holographic sticker that you have seen in the past on different type of software products back in the day when all these were deployed via CD-ROMs. The interesting about adding digital signatures to an SE tag is that it can be used like those holographic stickers. And you can also have additional information like URL and email addresses just in case the customer wants to get more information. So by combining NFC and digital signature, we create a mean to protect the brand and improve user experience. To understand how true SD25 works, let's talk about Diffie-Helman KX Change. This method was first invented so that cryptographic key, which is used for data encryption, can be exchanged securely over a public channel like the internet. The beauty of this method is that it works between two people or parties that have no prior knowledge of each other. In this diagram, Alice and Bob agree on a public key algorithm. Bob sends Alice his public key. Alice encrypts her message with Bob's public key and sends it to Bob. Bob decrypts Alice's message with his private key. The message can be data encryption key, which allows Alice and Bob to communicate securely. In the real world, encrypting an actual message with a private key is very inefficient. Sometimes the message or document can be quite large. Instead, we use the document's hash. The hash of a document is its fingerprint. In the context of the true SD25, the message is the UID or the chip unique identifier, which is quite small. SD encrypts the hash of the UID with our private key. The encrypted hash becomes SD digital signature. SD sends the signature to you as it's stored in the SD25 device. You decrypt the hash with SD public key, thereby verifying the signature. The one-way cryptographic hash is used to make sure that the UID was not tampered with. This is a block diagram of the entire process. From the left, the UID and SD private key are fed into the cryptographic algorithm. The result is a digital signature. SD also produces a digital certificate. A digital certificate, also known as a public key certificate, is used to cryptographic the link ownership of a public key with the entity that owns it. Digital certificates are for sharing public keys to be used for encryption and authentication. Digital certificates include the public key being certified, identifying information about the entity that owns the public key, metadata relating to the digital certificate, and a digital signature of the public key created by the issue of the certificate. During the verification steps, the UID and digital signatures are fed into an algorithm to determine if the product is genuine or not. In today's world, more things are being connected to the cloud. True SD25 methodology takes advantage of this reality. The methodology is comprised of three major steps. The digital signature encoding is then secured at the site. As SD is a major manufacturer of bank grade smart card ICs, we employ a similar metric in the industrialization process and tools. We use SSM, or hardware secure module, that is FIPS 140-2 compliant. The verification step is done at the product level when it's being deployed. As a customer, you will need to sign an NDA to get dedicated application note and example source codes. These items are not available publicly on sd.com. Public key and certificates are not available publicly as well. This step is necessary to implementation of the solution. During the encoding step, we use FIPS 140-2 compliant hardware security modules and SD private key to create the digital signature out of the UID base. At EWS, or electronic wafer sorting, we program the content into a die. When you receive the SD25 DVPWM device, you will find first the UID and then the digital signature as read only memory locations above the user memory. During the verification process, a phone equipped with an app can access a cloud-based application to verify the signature. If you are designing an embedded reader and tag solution, the firmware of the microcontroller application processor will have the algorithm to perform that verification process. The concept of cloud management goes beyond the execution of the algorithm as a web application. The cloud itself can store all the UID of that particular product. So if two or more copies are seen, the system can take steps to mitigate the problems. As a customer, it is important that you work closely with SD to implement true SD25. Once NDA is signed, application notes are available for the SD25 DVPWM devices. Remember that standard datasheet does not include information relating to the verification of the digital signatures. Similarly, we have special apps under NDA for Android and iOS mobile phone that are available so that you can demonstrate digital verification. Also, there are source code samples available for SCM32. And of course, since they are all C code, can be implemented on other type of microcontrollers as well. In terms of temperature, the SD25 DVPWM device can operate up to 105 degrees Celsius. However, if the RF interface is active, the maximum operating temperature is only 85 degrees Celsius. The SD25 DVPWM device complies to ISO 15693 standard. And it is certified as NFC forum type 5 tag. However, it is important to note that the device does not come pre-formatted. This means that a step of writing the CC file information is needed before writing any NDEF message. Please refer to application note 5151 for more information regarding NDEF. You can start evaluating the SD25 DVPWM device by procuring this evaluation board. It comes with a 22x38 millimeter antenna, which can give a RF range of around 3 to 4 centimeters, if correctly used with an NFC-enabled phone. Powered by a micro USB port, the LED range illustrates change in duty cycles. It has four output pins so that PWM6 node can be fed out externally. Use the schematic of the evaluation board. As you can see, the 5 volt coming in from the USB port powers the board. An analog integrator converts the PWM output to voltages, which then go to a comparator to light up different segments of the LED. This is done to visually illustrate the duty cycle of the PWM output. The four pins connector can also be used so that you can connect PWM signal along with the voltage out to control all the boards. To work with the board, there are two solutions. First, it is the PC software, the SD25 PC NFC for reader control. This software, as you can see, can be downloaded from st.com under this hyperlink. It can support multiple boards evaluation reader boards from ST, boards such as the SD25R95HF demo board, the SD25R3911B disco board. This also can work with FEDG readers, such as the CPR30LR1002 and the MR102. These refer to user manual 2444, available on st.com, for further information. Perhaps the easiest approach will be the use of your phone because very often you might not need anything except for the board itself and a micro USB cable to connect to a voltage source. The Android app can be downloaded or installed from Google Play Store. As you can see the screenshot, it allows you to graphically control the output of the PWM. You can also use the iOS app on Apple App Store. Be aware that you need an iPhone 8 or higher that is installed with the latest version of iOS. And I believe that is anything above iOS 12 should do the work. The visual interface is slightly different than the Android. But it more or less allows you to execute the features of the PWM output. For ordering, the SD25DV PWM comes in standard S08 and TSOP 8 pin packages. These are the part number if you need to order the one that has one PWM output and the one that has two PWM outputs. And the part number for the evaluation board is SD25DV PWM ESET. So we have been discussing about all the features of the SD25DV PWM. We talk about the 2K bit memory size, digital signatures, passwords. We also talk about PWM output and all the RF protocol support. So you might have wondered, what are we going to use this device for? What can it do to improve what I have today? Smart industry and smart city employs LED for lighting. We are starting to phase out our incandescent bulbs with warm LED and fluorescent bulbs with daylight LED. These steps are necessary to reduce our carbon footprint and chemicals that we introduce into the environment. LED lighting also allows color temperature, which is not possible with all the other lighting technology. But all that saving and capability does come at a cost. The difficult in LED lighting is LED drivers adjustment. Traditionally, jumpers and resistors are used to configure LED drivers at the manufacturing line. The manual process requires human labor. It is expensive and error-prone. Sometimes this process is done just before the light is being installed. So we need a flexibility in configuration. We need a methodology where we can do it wirelessly. This is where NFC comes in. A phone or a dedicated NFC reader can be used to set the temperature of the LED driver. Sometimes this process can be done with the driver being inside a box if the RF reader is powerful enough. Here's a more detailed view of what is happening inside an LED driver. In the high-end segment of LED driver, microcontrollers can be found to generate the necessary PWM signals. The connector and resistor can be replaced by the NFC dynamic tag IC, like the SC25DVI2C. In the fact that the labor-intensive process of changing resistor and dip switch can be replaced by programming, the NFC is a significant cost-saving. Now, if you shift that to a low-end segment where the microcontroller is not needed, the SC25DVI PWM can truly bring simplicity to life. Here, the PWM output can go to a RC and amplifier, and that goes directly to the LED driver. Skylander and Disney Infinity were very popular game platforms a few years ago. It is a gaming platform that incorporates reader and tag solutions. There are usually three reader antennas, which multiplex three pads where figurines can be placed. There is an RFID tag in each figure. The idea involved these characters that could store game data and that game pieces can carry around and play on friends' gaming unit. It uses a regular RFID tag, and if we can use the SC25DVI PWM device, they along with off antenna energy harvest circuit, like the one you see here, PWM output can drive by color LED so that different color can show mode of game pieces. Wouldn't that be cool? Just in case you wonder, I include the schematic of an off antenna energy harvesting circuit. The general idea is that we will rectify an AC voltage across AC0 and AC1 input of the SC25DVI PWM device. The circuit shows a simple halfway rectifier. You can also implement a full wave rectifier if you wish. The current limiting resistor leaves some energy left for the tag. Otherwise, you wish starving the tag as a circuit would pull as much current as possible from the coil. The resulting voltage would light the LED and also supply the PWM section of the SC25DVI device. I do want you to be aware that there's a limit to what you can harvest NFC power. The certainly range of distance between tag reader and antenna can have huge difference. Antenna size is also critical. Small tag antenna reduces power delivery. Reader RFU strength is also another important factor. Besides the ability to add lighting, audio generation is another possibility. Inside the gaming platform, you could possibly use a high-power NFC reader like the SC25R3911B so that maximum energy harvesting can be utilized to power all the components. The PWM output can directly drive a piezo transducer to produce different tones. However, if speech synthesis is desired, a low-pass filter and dag might be used. The sound is pretty awesome, right? Beyond the application of light and sound, the SC25DVI PWM can be used to enable power modules and batteries. Looking at this schematic above, the SC25DVI PWM output is connected to a FET switch. Changing the duty cycle from 0 to 100% duty cycle via the short cell or open the FET switch and thus enabling device to use this power module. Lithium and lipo batteries have been found in so many devices we use today. Their popularity and cost lead to a growing issue of thefts. Another important issue is quality assurance. Using a clone battery can have serious fire safety consequences. Embedded, the SC25DVI PWM into the battery or power module would allow the code at the checkout to enable the battery after the cell has been completed. You can also do this over the phone if you buy these devices online. I have nothing against Bluetooth and Wi-Fi enabled locks, but they sure are very popular today. However, there's something more secure about an NFC-enabled lock. One thing for sure is not feasible for someone to remotely hack it. There is different level of NFC-enabled lock, of course. At the highest level, a read and tag solution is implemented which allows better security and capability. In such an application, the reader would be embedded into the door itself. And you would open with a card-emulated phone or just a simple card. However, the SC25DVI PWM can do the task for less demanding locking application, an application where you don't really need a reader inside the lock. You can simply put the SC25DVI inside the lock with some circuitry to allow it to move a servo motor, DC motor, or some kind of linear solenoid. And in some cases, if the power footprint is small enough, the lock in the door might not need battery to operate. It can simply harness the power from the reader. The SC25DVI PWM device can be used to change speed of tiny DC motors to produce different vibrations. That can drive small toys in medical devices. The toy you see here moves when the bristle starts to vibrate. PWM frequency can change to produce different level of vibrations. The simplicity is controlling using NFC technology without any knobs and switches. I'd like to thank you again for being here. I hope that you find this webinar interesting and that you will be able to use the SC25DVI PWM in your existing and future applications.