I would like to populate coin cell (not rechargeable) for Real Time Clock on my board which I am designing with i.MX6Q. First I thought single 3.0V coin cell was enough for i.MX6Q. But I can not solve the problem of recharging protection.
-VDD_SNVS_IN is required from 2.8 - 3.3V (i.MX6Q datasheet)
-Coin cell voltage (e.g. CR2032) is normally 3.0V.
-Coin cell needs recharge protection. In UL standard, a low leakage diode is recommended as the protection device. The following picture is copied from Panasonic website.
When I put protection diode between coin cell and i.MX6Q, the voltage at VDD_SNVS_IN drops approx. 0.3-0.6V because of V(Forward), so the voltage made by single coin cell does not meet 2.8V.( >3.0V-0.3V)
Does i.MX6Q only intend to use with rechargeable coin cell which may not need a protection diode?
I would really appreciate it if you could give me an advice.