Xilinx ZC702 User Manual

ZC702 Board User Guide www.xilinx.com 17
UG850 (v1.7) March 27, 2019
Feature Descriptions
Encryption Key Backup Circuit
The XC7Z020 SoC U1 implements bitstream encryption key technology. The ZC702 board
provides the encryption key backup battery circuit shown in Figure 1-5.
The Seiko TS518FE rechargeable 1.5V lithium button-type battery B1 is soldered to the
board with the positive output connected to the XC7Z020 SoC U1 VCCBATT pin G9. The
battery supply current IBATT specification is 150 nA maximum when board power is off. B1
is charged from the VCCAUX 1.8V rail through a series diode with a typical forward voltage
drop of 0.38V and 4.7 K
Ω current limit resistor. The nominal charging voltage is 1.42V.
X-Ref Target - Figure 1-5
Figure 1-5: Encryption Key Backup Circuit
UG850_c1_05_0632719
GND
2
1
B1
Lithium Battery
Seiko
TS518SE_FL35E
1.5V
2
1
3
BAS40-04
D8
40V
200 mW
NC
FPGA_VBATT
+
VCCAUX
R2
4.70K 1%
1/16Ω
To SoC
U1 Pin G9
(VCCBATT)
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Xilinx ZC702 Specifications

General

Brand	Xilinx
Model	ZC702
Category	Motherboard
Language	English