User guide

Atlys Reference Manual
Doc: 502-178 page 7 of 19
Power Supplies
The Atlys board requires an external 5VDC, 4A+ power source with a coax center-positive 2.1mm
internal-diameter plug (a suitable supply is provided as a part of the Atlys kit). Voltage regulator
circuits from Linear Technology create the required 3.3V, 2.5V, 1.8V, 1.0V, and 0.9V supplies from
the main 5V supply. The table below provides additional information (typical currents depend strongly
on FGPA configuration and the values provided are typical of medium size/speed designs).
The four main voltage rails on the Atlys board use Linear Technology LTC2481 Delta-Sigma 16-bit
ADC's to continuously measure supply current. Accurate to within 1%, these measured values can be
viewed on a PC using the power meter that is a part of the Adept software.
Power
Jack
Battery
Connector
Power Select
Jumper JP13
VU
1.8V
1.2V
2.5V
3.3V
IC16
IC15
IC16
IC15
EN
Power
Switch
Vswt
IC17
EN
0.9V
.01Ω
LTC2481
To Digilent
Adept USB
I2C Bus
IC14
To Expansion
Connectors,
HDMI, USB
PG
PG
PG
PG
EN
EN
EN
Power On
LED (LD15)
LT3501
3A Regulator
LTC3546
1A Regulator
LT3501
3A Regulator
LTC3546
3A Regulator
ON
OFF
LTC3413
DDR Term. Reg.
Load Switch
J11
.01Ω
LTC2481
.01Ω
LTC2481
.01Ω
LTC2481
Atlys Power Supplies
Supply
Circuits Device
Amps (max/typ)
3.3V FPGA I/O, Video, USB ports, Clocks, ROM, Audio IC16: LT3501 3A / 900mA
2.5V FPGA Aux, VHDC, Ethernet PHY I/O, GPIO IC15: LTC3546 1A / 400mA
1.2V FPGA Core, Ethernet PHY core IC15: LTC3546 3A / 0.8 – 1.8A
1.8V DDR & FPGA DDR I/O IC16: LT3501 3A / 0.5 -- 1.2A
0.9V DDR Termination Voltage (V
TT
) IC14: LTC3413 3A / 900mA