UCODE I2C Reference Design

[jon_ledwith]

I am looking for a reference design for the UCODE I2C device SL3S4011FHK. I have designed it into a product from the system level but now need to have proper schematic implementation. The areas of concern are the power connections and the I2C interface. The antenna/antenna connections are self explanatory based on the antenna reference design/ App note AN11180. 

Is there anyone that has used this device in a design? (silly question)

Do I need a diode from my system power to VDD such that the device will not power my circuitry when being interrogated?

What kind of filtering is recommended on VDD?

Any help would be welcome!

Thanks.

[HarleyShen]

Ucode I2C

What is the package of this chip?

1, 1 PIN PIN package is special shape, but do not give the specific size.Is it the same size as other pins?

2. The size of the metal cooling pads in the middle area is not available.

[Kan_Li]

Hi Jon,

I am sorry, but I don't understand "Do I need a diode from my system power to VDD such that the device will not power my circuitry when being interrogated?" Is it possible to review your schematics or a block diagram related with it?

Thanks for your patience!

Have a great day,
Kan

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[jon_ledwith]

Kan,

Thank you in advance for your effort. I am providing system level design activities for a project. I have delegated schematic capture and layout. The schematic came back to me with some components I did not believe were necessary. 

The designer was concerned that using an RFID interrogator would create power on the VDD pin of U16. I am familiar with the M24LR64E devices that can power external circuitry, but that device has both a separate Vout pin for the rectified RF and the datasheet explicitly states there is an internal circuit (regulator) that blocks the rectified RF generated signal from feeding the VDD pin. I have instructed the designer to  be able to strap over the diode and I2C level shifter as can be seen in the above updated schematic.

Since the device can be interrogator powered for reading and writing the device (no need for power to be applied to VDD), if there was a reference circuit published for this device or explicit wording in the datasheet regarding the device behaviors, there would be little question as to how to properly treat VDD.

The question about filtering on VDD was a question from me regarding decoupling, RF bead, etc. that should be on VDD of the device.

Jon 

[Kan_Li]

Hi Jon,

I am sorry, but are we talking about M24LR64E? I was thinking this issue was related with SL3S4011FHK, which has no VOUT pin, and its VDD pin is for the I2C interface. Please refer to the following for details.

Have a great day,
Kan

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[jon_ledwith]

Kan,

We are talking about UCODE I2C device. I brought up the other device as something I was familiar with. I am not certain my question has been answered. I understand a supply needs to be connected to VDD. I have asked repeatedly if there are any specific filtering requirements for VDD.

I have another specific question:

 - I have observed the reference antenna designs in AN11180 for slot antennas for the device.

Can the GND pin on the device be connected to the ground plane that is used for the antenna?

Thanks,

Jon

[Kan_Li]

Hi Jon,

I don't understand "ground plane that is used for the antenna", is it possible to give any example or something like that?

Thanks for your patience!

Have a great day,
Kan

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[jon_ledwith]

Kan,

I am including a snip from AN11180.pdf. It is an NXP document. 

Please read 6.1 Antenna Geometry. The YELLOW is the PCB ground plane that also acts as the antenna for the UCODE I2C device.

Assume that I am connecting the 4 pads (VDD, SDA, SCL, GND) to devices on the yellow PCB.

Can I connect the UCODE I2C GND line (one of the four pads inside the antenna slot) to the PCB ground plane such that a device (microcontroller) using the ground plane for it's ground can communicate with the UCODE I2C device via I2C?

Thanks,

Jon

[Kan_Li]

Hi Jon,

From my understanding, UCODE I2C GND line is connected with the GND of the host controller.

Have a great day,
Kan

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