I am using the SI3402-B chip to use POE（isolate）.

But it does not work when loading exceed 5V/1.3A.

When I remove the tvs diode of the Transformer primary，it can work at 5V/3A, what is the reason of this phenomenon？

I can not understand the calculation in AN901 on page 22 equation 65/65. If i put in the values R5 = 48.1x10^3, n = 3, C = 16uF and Rload = 5V/1A i get an fc of 129kH and not 12kHz. Am I assuming the wrong values? 

Hello,

 

We have an isolated PoE PD test board with an Si3402-B on board, using a Coilcraft FA2732 transformer to create an isolated +12V at the output.

Class detection works fine, but when starting the PSE, the output ramps to approx. 8V and then it aborts; the PSE reports OVL.

Do you see any obvious issue in the enclosed schematics? Can the opto-coupler have a significant influence on the boot-up process?

 

Thanks for your help.

Hello,

We are testing a DC-DC converter and the gate driver is Si8233BD. A 50kHz, 3.3V PWM is generated from the TI28377S launchpad (DSP) and is given to the driver IC (VIA, VIB). We are getting the VOA output pulses, but the VOB is always clamped to high. Please find the attached schematics. Could you please help us to resolve the issue.

 

Thanks

What is the difference between Si8655BA-B-IU and Si8655BA-C-IU 

If it's in the datasheet , I really can't see it.

Extra credit:  Why is the small-pitch package called a "QSOP?"  I expected pins on four sides.

There is some interference/pulse in IIC line, it is about 1.6V. which may be recognized as high and be outputted in the other side. How to improve this?

For Si8400,  In some systems, there is oscillating at the first logic low. this will cause communication error. After disabling the accelerate function of IIC accelerator, this issue can be solved. See attached "A" waveform. Could you please give some hint to solve this issue according to the existing waveform?

I am using a SiLabs 864x digital isolator ( with no enable pins and no pre-determined output levels). Both sides are powered with 3.3V/GND, but the supplies are separate. When the 3.3V supply is off, my digital inputs can still be active. Since the supply is off on both sides, as expected, my input signals do not propagate. However, I am measuring voltage at the supply pin on the input side. This appears to be back-fed from the input signals.

Given that some input signals are at logic high before powering up the input and output supply voltages to 3.3V, intermittently I have seen failures in propagating the inputs to the outputs. That is, after powering both sides to 3.3V, an input may be at a logic high, but the corresponding output pin is stuck at a logic low.

These devices have a lockout feature for supply voltages below a given  threshold, but it appears that the lockout continues even though the voltages are above the threshold. The only reliable way to resume normal communication is to force the inputs (disconnect) to a logic zero and then cycle the input side supply voltage (off and back to on). Followed by re-connecting a cable that feeds the inputs.

My questions are: Is it required that all inputs are at a logic zero prior to supplying power to the input side? If this is true, would a  tristate condition work as well? Is there a reason why the outputs would not follow the inputs when both supplies are powered?

 

Hello,

what are the meaning of the curve "Safety Limiting Current"?

Is there a application note available how to handle this curve?

Thanks

Hi,

I know that Si8600AD-B-IS is an I2C isolator. But I am not finding any bi-directional isolators. So can I use this one for GPIO Isolation?

Hello:

Now, I meet a question. when Si8273GB is used, its output voltage is 2.47V. why? I want to get 6V. I want to know if the Si8273  get 6V output voltage.

thank you.

Hi

when i used si827x to driving GaN device, the driving waveform shows that source ability does not meet the IOH spec. at 0ns ~ 5ns.

I hope siliconlab can provide the transient ability curve. That will be great if can provide Spice model (only the driving part).

Thank you.

 

 

As per truth table in datasheet Si827x(Page No:12),The state of Voa and Vob are mentioned in the condition of VDDA and VDDB powered.

If VDDA and VDDB are unpowered during start up,what would be the state of Voa and Vob?

 

Hi Silabs,

I am using SI8602AC-B in our design for isolating I2C signals.

SCL is unidirectional and SDA is bidirectional.

Design flow is like ADC-> SI8602AC -> MCU(ATSAME54)

ADC supply voltage is 5V and MCU is 3.3V

1. Does SI8602 can act as a voltage level translator that convert 5V I2C to 3.3V I2C?

2. Can BVDD and AVDD be different?

Attached snippet of my SCH.

 

Please respond... Thanks