Data Sheet
Cmod A7 Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 3 of 10
Net
name
Upstream
net name
Power IC
Type
Power
IC
Label
Min/Typ/Max
Voltage
Max.
Current
Major Devices
and Connectors
VCC1V0
VU
Switching
PS
IC10
0.95V/1.00V/1.05V
1.2A
FPGA Core and
Block RAM
VCC1V8
VU
Switching
PS
IC10
1.71V/1.80V/1.89V
0.6A
FPGA AUX
and ADC, USB
Core
VCC3V3
VU
Switching
PS
IC10
3.135V/3.30V/3.465V
0.6A
SRAM, USB
Controller,
PMOD, LEDS,
Buttons, FPGA
USER I/O
Table 1.1. Power Rail Characteristics.
1.1 Power Input Options
It is possible to power the Cmod A7 from either USB or from an external power supply attached to pins 24 and 25
of the DIP connector, labeled “VU” and “GND”, respectively. The required characteristics of a power source
attached to either of these two options is outlined in Table 1.1.1.
Connector Type
Connector Label
Schematic net name
Min/Rec/Max Voltage
USB
J3
USB5V0
4.5/5/5.5
DIP
J1 (Pin 24)
VU
3.32/5/5.5
Table 1.1.1. Power source options.
The minimum external voltage that can be applied to VU depends on the amount of current drawn from the
VCC3V3 rail via the Pmod header. With 0mA drawn from the Pmod header, the minimum external voltage is 3.32V.
With 100mA drawn from the Pmod header, the minimum external voltage is 3.38V. With 250mA drawn from the
Pmod header, the minimum external voltage is 3.48V.
When the Cmod A7 is being powered by the USB connector, the voltage from the USB device is driven onto the VU
pin. This allows users to power an external circuit from the USB host in addition to the Cmod A7. The VU pin is
driven via a schottky diode, so a small voltage drop will occur, but it should be assumed the voltage present on VU
will be close to 5V.
Warning: When a USB host is attached to the Micro-USB connector, the VU pin on the DIP connector (pin 24) is
driven to the voltage being provided by the USB host (typically between 4.5V-5.5V). If you have a power source
attached to the VU pin, you must disconnect it before attaching a USB host, or risk damaging it. This can be
particularly dangerous if the power source is a battery.