Xilinx ZCU106 User Manual page 27

Encryption Key Battery Backup Circuit
The XCZU7EV MPSoC U1 implements bit stream encryption key technology. The ZCU106
board provides the encryption key backup battery circuit shown in
X-Ref Target - 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
The battery supply current I
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.
On MPSoC devices, the encryption key battery is also used for the battery-backed RAM and
the real-time clock (RTC) supply voltage. See Zynq UltraScale+ MPSoC Data Sheet: DC and
AC Switching Characteristics (DS925)
ZCU106 Board User Guide
UG1244 (v1.0) March 28, 2018
To MPSoC U1 Pin Y23
(VCC_PSBATT)
Figure 3-2: Encryption Key Backup Circuit
specification is 150 nA maximum when board power is off.
BATT
[Ref
www.xilinx.com
Chapter 3: Board Component Descriptions
11].
Figure 3-2.
X19003-083017
pin Y23.
CC_PSBATT
27
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