ZCU104 Board User Guide 22
UG1267 (v1.1) October 9, 2018 www.xilinx.com
Chapter 3: Board Component Descriptions
Encryption Key Battery Backup Circuit
The XCZU7EV MPSoC U1 implements bit stream encryption key technology. The ZCU104
board provides the encryption key backup battery circuit shown in Figure 3-2.
The Seiko TS518FE rechargeable 1.5V lithium button-type battery B1 is soldered to the
board with the positive output connected to the XCZU7EV MPSoC U1 V
CC_PSBATT
pin Y23.
The battery supply current I
BATT
specification is 150 nA maximum when board power is off.
B1 is charged from the UTIL_1V8 1.8V rail through a series diode with a typical forward
voltage drop of 0.38V and 4.7 ΩK current limit resistor. The nominal charging voltage is
1.42V.
X-Ref Target - Figure 3-2
Figure 3-2: Encryption Key Backup Circuit