LM3881: What is the formula to calculate the TADJ ??

Adwait Deshpande

Part Number: LM3881

Tool/software:

Hello,

I wanted to have 50us Time Delay between the Each FLAG A , FLAG B, FLAG C.

In the Datasheet no formula is mentioned to calculate TADJ Time Delay. The CADJ capacitor value is mentioned 10nF to have 1.2mS delay.

Can you please suggest the correct formula ??

OR Validate the Below mentioned formula calculate TADJ : TADJ(μs)=120×CADJ(nF)

0 yihe 9 months ago

The timing capacitor-clock period relationship is typically 120us/nF.

so 10nF will get your 1.2ms per clock. as shown in the data sheet, for each delay takes a 9 or 8 clock cycle.

the minimum Cadj for LM3881 is 200pF, which give you 24us per clock cycle.

50us is not something this devices can support.

Regards

Yihe

0 Adwait Deshpande 9 months ago in reply to yihe

Yihe, Thank you for your prompt response.

Could you please suggest any power sequencer ic. which will provide me the Delay of 50us between the FLAG A, FLAG B & FLAG C.

0 yihe 9 months ago in reply to Adwait Deshpande

I do not think that we have devices to support 50us delay unfortunately.

Regards

Yihe

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