Datasheet

Zybo Z7 Board Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 10 of 30
The recommended power source is an external power supply (such as a wall-wart) with a barrel jack connector
(also known as a coaxial power connector). The supply must use a center-positive 2.1mm internal-diameter plug
and deliver between 4.5V to 5.5V DC. It should also be able to output at least 2.5 A (12.5 Watts) in order to
support power-hungry Zynq projects and external peripherals. To use an external supply with a barrel jack, plug it
into the power jack (J17), set jumper JP6 to “WALL”, and then set SW4 to “ON”. Suitable supplies can be purchased
from the Digilent website or Digilent distributors, as well as popular electronics vendors.
An external power source, such as a battery pack, that does not have a suitable barrel jack connector can still be
used by wiring it’s positive terminal to the center pin of JP6 and the negative terminal to the pin labeled J16 next
to JP6. The external supply must still meet the same voltage and current requirements as a supply attached to the
barrel jack.
It is also possible to power the Zybo Z7 from the USB programming port (J12), however the Zybo Z7 often requires
more current than the 0.5 A of current that is allowed by a USB 2.0 device. If this limit is exceeded, many USB hosts
will begin to droop the voltage briefly until the Zybo Z7 resets, dropping current consumption into acceptable
ranges. To help prevent this, a USB host port should be chosen that can support higher current (often referred to
as a “fast charging USB port” or similar by laptop/PC vendors). Many USB battery packs and wall supplies will also
support higher current draws. Even when attached to a host capable of providing more current, the Zybo Z7 will
limit itself to .75 A, and will reset if this current is reached. If you experience your project resetting (indicated by a
brief flicker on the PGOOD LED and the DONE LED turning off) while powered from a high current USB port, you
will either need to lower the power consumption of your project or use an external power source.
For reference, we found that the out of box demo loaded on the Zybo Z7 at the factory consumes about 0.5 A from
the input power source. More demanding applications, including any that drive multiple peripheral boards or other
USB devices, will likely draw more.
The Zybo Z7 has over-voltage protection up to 20 V on all power inputs that will kick in when a voltage of greater
than 5.7 V is detected on the selected input. It will also limit current draw to .75 A when powered from USB and 4
A when powered from an external source. This protection is implemented using a Texas Instruments TPS25940
eFuse, please refer to its datasheet for further specifications.
Table 1.1.1 provides an overview of the power input specifications for the Zybo Z7.
Connector Type
JP6
Configuration
Connector
Label
Schematic net
name
Min/Rec/Max
Voltage (V)
Current Limit
(A)
Barrel jack
WALL
J17
VJACK
4.5/5/5.5
4.0
Battery/Other
BAT
JP6, J16
VU5V0
4.5/5/5.5
4.0
USB
USB
J12
VBUS
See USB
specification
0.75
Table 1.1.1. Zybo Z7 Power Input Specifications.
1.2 Power Specifications
Table 1.2.1 describes the characteristics the Zybo Z7's on-board power rails. It can be used to estimate power
consumption for a project, or determine how much current attached peripherals can draw before being limited.