ZCU104 Board User Guide
22
UG1267 (v1.1) October 9, 2018
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
.
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
Ω
K current limit resistor. The nominal charging voltage is
1.42V.
X-Ref Target - Figure 3-2
Figure 3-2:
Encryption Key Backup Circuit
X20247-013018