Xilinx VCU110 User Manual page 14

Encryption Key Backup Circuit
The XCVU190 FPGA U1 implements bitstream encryption key technology. The VCU110
board provides the encryption key backup battery circuit shown in
TS518FE rechargeable 1.5V lithium button-type battery B1 is soldered to the board with the
positive output connected to the XCVU190 FPGA U1 V
current I specification is 150 nA maximum when board power is off. B1 is charged from
BATT
the SYS_1V8 1.8V rail through a series diode with a typical forward voltage drop of 0.38V
and a 4.7 kΩ current limiting resistor. The nominal charging voltage is 1.42V.
Figure 1-4 shows the encryption key battery backup circuit.
X-Ref Target - Figure 1-4
VCU110 Evaluation Board
UG1073 (v1.2) March 26, 2016
FPGA_VBATT
To U1 pin AN13
Figure 1-4: Encryption Key Backup Circuit
www.xilinx.com
Chapter 1: VCU110 Evaluation Board Features
Figure
pin AN13. The battery supply
CCBATT
SYS_1V8
1
D15
200 mW
3
40V
BAS40-04
2
R115
1
4.70k
1/16W
2
1%
1
TS518FE_FL35E
2
B1
BAT_TS518FE_FL35E
GND
1-4. The Seiko
14
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