LP38693: Output tolerances

Hi Ryan

-0,8 to 0.2% deviation added on top of the 2%?, however that doesn't bring it to the +-4% shown for the full operating range:
3.2 V ≤ VIN ≤ 10 V, 100 μA < IL < 0.5 A Full operating temperature range.

Anyhow given our usage, would it be app.: 1.25V -2,2% (0deg )/ +2,15% (55deg) as min/max?

Hi Steen,

Correct, our typical device will not reach the 4% min/max limits even over the full temperature range. Rather our typical unit will directly fall on the curve in Figure 7. Please note that since Vref is typically 1.25 V and this is our typical Vadj at 25 C as well, the typical characteristics curve shows 0% deviation at 25 C.

As you state the min/max limits at 25 C are 2%. This shows that there can be 2% variation before accounting for temperature. Since the full temperature range increases to 4%, we know that the temperature variation is also 2%.

Figure 7 shows that the typical unit will have 0.2% deviation over your abbreviated temperature range and 0.8% deviation over the full temperature range. If we use a ratio we can estimate what the abbreviated temperature variation might be:

(x (temp contribution) / 0.2% (typ)) = (2% (temp contribution)/ 0.8% (typ))
x (temp contribution = 0.5%

Since we know that we would have 2% additional variation without temperature this would yield an estimated min/max of 2.5% over the abbreviated temperature range.

You may want to consider one of our newer LDO families such as TPS7A90 which is a 1% part over the full temperature range.

Very Respectfully,
Ryan