TPS3824: TPS3824-33: WDI & /RESET

Steven He92

Part Number: TPS3824
Other Parts Discussed in Thread: TPS3820

Dear Sir,

I use TPS3824-33, I just test IC's performance so WDI didn't connect to MCU.

1. Please you kindly help check Fig-1/2/3 waveform correct?

2. The datasheet have mention: " If the WDI pin detects that it is in a high-impedance state the TPS3820/3/4/8 will generate its own WDI pulse to ensure that RESET does not assert."

but I saw Fig-1, WDI(floating) didn't have generate a pulse.

Thanks!

Steven

over 6 years ago

0 Michael_DeSando over 6 years ago

TI__Genius 12630 points

Steven,

Did you attach images? What figures are you referring too? I don't see any figures attached.

-Michael

0 Steven He92 over 6 years ago in reply to Michael_DeSando

Expert 2125 points

Dear Sir,

Please refer attached file.

3443.Test waveform.docx

0 Steven He92 over 6 years ago in reply to Steven He92

Expert 2125 points

Dear Ser,

The attached file waveform is correct ?

Thanks!

Steven

0 Michael_DeSando over 6 years ago in reply to Steven He92

TI__Genius 12630 points

Steven,

My apologies, my response never sent!

Figure 1 is correct. If WDI is left floating (high impedance) the device generates its own WDI signal internally so the RESET never triggers which is what Fig 1 shows. Correct.

Figure 2: (20k to VDD) this is not a correct configuration. It is not recommended to connect WDI to vdd.

Figure 2: (2k to GND) this is also correct. This requires an external input signal to prevent the RESET output from triggering within the specified Watchdog window (1.6 seconds). Because there is no signal (signal needs to reach at least 0.7xVDD), the RESET continuously triggers. This is correct.

-Michael

Power management

Power management forum

TPS3824: TPS3824-33: WDI & /RESET