Original question:
1) Page 11, section 5
- typo : should be Vadptr_on instead of Vadptr_off
- the calculation result of Rapd1+Rapd2 is incorrect: should be 69.23+3.01=72.24 and not 72.81
2) Page 11, section 6 - what is the Vapdh ?
According to datasheet, Vapdh=0.095V (page 10), but here it is assumed that Vapdh=0.3V
Hey Israel,
1. In both the datasheet and the EVM User's Guide, there is no reference to the calculation of the adapter voltage divider on page 11. Can you be more specific on what you are asking?
For the EVM, we use a 48V adapter. The APD threshold is 1.5V, so the divider with R10 and R11 with a 48V input yield a 2.3V threshold, so it APD will be turned on. We designed it to turn on at 35V: 35* (4.42k/(4.42k+100k)) = 1.48V, which falls within the range of the APD turn on. We have to use nominal values and that was close enough for me.
You are welcome to order an EVM and try using an 48V adapter.
2. Vapdh: The APD voltage threshold hysteresis.
V = Voltage
APD = APD pin threshold
H = hysteresis
Can you specify, or show a picture, where it is assumed and used as 0.3V?
If this post answers your question, please indicate so by marking this thread as resolved. Thank you.
Regards,
Michael P.
Applications Engineer
Texas Instruments
