Digilent Genesys ZU Reference Manual page 41

Table 10.3.1: Fan jumper positions
Jumper JP2 "AUTO FAN"
Set
Not set
10.4. Coin battery
A Seiko TS621E lithium rechargeable battery provides power to the MPSoC Battery Power Domain (BPD)
through the VCC_PSBATT pin. It is connected in parallel with a 100 uF capacitor. The BPD includes the
real‐time clock with a dedicated crystal oscillator and a RAM available for storing a secure configuration
key. The capacitor alone can provide power for approx. 15 minutes after main power is turned off. The
battery will provide power after that.
The nominal voltage of the TS621E is 1.5 V and has a nominal capacity of 1.3 mAh. The Zynq UltraScale+
MPSoC Data Sheet: DC and AC Switching Characteristics (ds925) lists the maximum ICC_PSBATT at 3.65
uA. Some leakage current exists through the charging diode, a maximum of 100 nA. Therefore, the
capacity of the fully‐charged battery is enough for a minimum of: 1.3 mAh * 1000 uA / 1 mA / 3.75 uA =
347 hours = 14 days without main power. Whenever main power is turned on the battery will be re‐
charged.
The battery is removable and can be replaced only by a 1.5 V, 6.8 mm rechargeable lithium coin battery.
Do not use non‐rechargeable batteries!
However, those prepared to void their warranty can physically remove the charging circuit by de‐
soldering D13 or R400. In this case any battery, even a non‐rechargeable one, that meets MPSoC voltage
specs can be used.
https://reference.digilentinc.com/reference/programmable‐logic/genesys‐zu/reference‐manual/2‐28‐20
Fan Speed
Automatic
Full