A product where we used the UA730CD, as shown in figure 4 of the datasheet "Figure 4. Positive-Voltage Regulator (External npn Pass Transistor)".
The UA730CD is configured so that we get 19V nominal. Before the product is sent out it gets tested and the voltage tolerance is within the a +/-1V from 19V nominal. However, after a few years of use, we have had a need to upgrade the product, we see that the output voltage from the linear regulator has increased by to 20.22V and upon further testing we found that the Vref voltage is measuring 7.62V which is above the MAX specified in the datasheet.
with the resistor values we have in the circuit for R1 and R2, it makes perfect sense why we are measuring 20.22V, because of the Vref voltage is 7.62, however we do not know why this reference voltage would increase to this value.
Could someone at TI have an explanation on what is happening and what should we do in order to get this issue resolved? A change in the footprint of the device (SO-14) is not desired as it would require a complete PCB redesign.
For your information, the values for R1, R2 in the figure 4 circuit are .
| R1 | 16560.4 |
| R2 | 10000 |
