UC1845A: RT range for UC1845A

Kazuhiko Hirano

Part Number: UC1845A
Other Parts Discussed in Thread: UC1845

Tool/software:

Hello,

The datasheet Figure 6-5 shows Maximum Duty Cycle vs Timing Resistance. It shows the maximum duty cycle varies 20% to 100% depending Rt values. However, the maximum duty cycle of UC1845A　 is 50%. So this means that Rt must be from 0.5Kohms to around 0.9Kohms at UC1845A?

Best regards,

K.Hirano

3 months ago

0 Hong Huang 3 months ago

TI__Guru 73495 points

Hi,

That figure is for Dmax = 100%. UC1845 Dmax = 50%, so that figure needs to be cut half.

0 Kazuhiko Hirano 3 months ago in reply to Hong Huang

TI__Genius 15008 points

Hong,

Do you mean Dmax is 50% with RT=100Kohms at UC1845A?

Best regards,

K.Hirano

0 Hong Huang 3 months ago in reply to Kazuhiko Hirano

TI__Guru 73495 points

Hi,

I mean from the fig 6-5, after you get a Dmax, you need to make it half for UC1845A.

So for RT = 100k, the fig shows Dmax = 100%, then for UC1845A, Dmax = 100%/2 = 50%.

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UC1845A: RT range for UC1845A