Information

Nexys4 DDR™ FPGA Board Reference Manual

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least 1A of current (i.e., at least 5W of power). Many suitable supplies can be purchased from Digilent, through

Digi-Key, or other catalog vendors.

An external battery pack can be used by connecting the battery’s positive terminal to the center pin of JP3 and the

negative terminal to the pin labeled J12, directly below JP3. Since the main regulator on the Nexys4 DDR cannot

accommodate input voltages over 5.5VDC, an external battery pack must be limited to 5.5VDC. The minimum

voltage of the battery pack depends on the application: if the USB Host function (J5) is used, at least 4.6V needs to

be provided. In other cases, the minimum voltage is 3.6V.

Voltage regulator circuits from Analog Devices create the required 3.3V, 1.8V, and 1.0V supplies from the main

power input. Table 1 provides additional information. Typical currents depend strongly on FPGA configuration and

the values provided are typical of medium size/speed designs.

Supply

Circuits

Device

Current (max/typical)

3.3V

FPGA I/O, USB ports, Clocks,

RAM I/O, Ethernet, SD slot,

Sensors, Flash

IC17: ADP2118

3A/0.1 to 1.5A

1.0V

FPGA Core

IC22: ADP2118

3A/ 0.2 to 1.3A

1.8V

DDR2, FPGA Auxiliary and

RAM

IC23: ADP2138

0.8A/ 0.5A

Table 1. Nexys4 DDR power supplies.

2.1 Power protection

The Nexys4 DDR features overcurrent and overvoltage protection on the input power rail. A 3.5A fuse (R287) and a

5V Zener diode (D16) provide a non-resettable protection for other on-board integrated circuits, as displayed in

Figure 2. Applying power outside of the specs outlined in this document is not covered by warranty. If this

happens, either or both might get permanently damaged. The damaged parts are not user-replaceable.

3 FPGA Configuration

After power-on, the Artix-7 FPGA must be configured (or programmed) before it can perform any functions. You

can configure the FPGA in one of four ways:

1. A PC can use the Digilent USB-JTAG circuitry (portJ6, labeled “PROG”) to program the FPGA any time the

power is on.

2. A file stored in the nonvolatile serial (SPI) flash device can be transferred to the FPGA using the SPI port.

3. A programming file can be transferred to the FPGA from a micro SD card.

4. A programming file can be transferred from a USB memory stick attached to the USB HID port.