BRK8370 Breakout Board

Unlike our integration modules, breakout boards are not intended for production integration. We reserve the right to change dimensions and functionality of this board at any time and may not necessarily have the previous version available for purchase.

Powering the BRK8370

The BRK8370 requires a clean, filtered, DC supply within the range of 6 V to 18 V. This supply may be delivered in one of two ways:

  1. 6-pin Mini-Fin connector – Pins 1, 2, and 3 are tied to the input supply net +VDCIN. Pins 4, 5, and 6 are tied to ground. The total maximum current allowed over this connector is 8 A. The part number is Molex 0455580003. The mating plug part number is Molex 0455590002. Several options for crimping pins are available, including Molex 0039000038. While it is possible to provide power using a commercial PC power supply with compatible pinout, it is recommended to create a custom cable harness for use with an appropriate bench supply.
  2. DC barrel jack  –  The jack is part number PJ-102AH from CUI, Inc.  It is a standard “canon-style” 2.1mm / 5.5mm jack.  The outer ring is connected to DGND.  The center pin is connected to +VDCIN.

Please refer to Powering the XEM8370 for information on the XEM8370 power systems.

Regulators on the BRK8370 provide 3.3V and 5V power for the onboard SYZYGY and QSFP+ ports.

Power RailSupply CapacityUses

LED Indicators

The BRK8370 includes three LED indicators for power status. The XEM8370_PGOOD and BRK8370_PGOOD signals are also broken out to test points. These are 3.3V, good when high signals.

VDCIN PWR (D1)+VDCIN present
XEM8370 PGOOD (D2)All XEM8370 on-board power supplies active and within expected range
(Does not include VIOx supplies)
BRK8370 PGOOD (D3)All BRK8370 on-board power supplies active and within expected range


The XEM8370 may optionally read peripheral information and configuration data from a small EEPROM on the peripheral. If available, the EEPROM can be used to automatically set the voltages for the three programmable voltage regulators on the XEM8370. An EEPROM is installed on the BRK8370 but is not loaded with any configuration by default.

See the Expansion Connectors page Peripheral Personality EEPROM section for more information.

Peripherals and Connectors

The XEM8370 Pin List has full connection information in the “BRK8370” columns. Additionally, please refer to the schematics and layout available on the Pins downloads page for detailed connection diagrams.


For information on the SYZYGY ports see the BRK8370 SYZYGY Ports page.

QSFP+ Transceiver Sockets

The BRK8370 has four QSFP+ cages installed. Full QSFP transceiver connection pinout and control signal I/O connections are listed on the XEM8370 Pin List.

QSFP1J8GTY 130Bank 68
QSFP2J9GTY 129Bank 68 and 69
QSFP3J30GTH 228Bank 69
QSFP4J31GTH 227Bank 68 and 69

QSFP transceivers are not included. The following 10Gtek part is one example option.

10GtekAMQ10-SR4-M140GBASE-SR4 QSFP+ Transceiver for MMF, 100M$39.00 / each

2mm I/O Headers

The rest of the unused I/O are broken out into 3 banks of 2mm headers. Each header bank also has a row of ground pins. The headers pins are unpopulated by default.

The I/O voltage level of different banks can be controlled with the adjustable voltage regulators on the XEM8370. See the Device Settings page for more details.

For full I/O connection details see the XEM8370 Pin List.

Header DesignatorPin CountConnected BanksOther
MC440 I/O68 and 69
MC538 I/O64, 68 and 69VCCO_64_66 and VCCO_67_68_69
MC648 I/O88 and 89VCCO_88_89


The BRK8370 has a built in USB JTAG adapter. Connect to the USB-C connector J11 for Xilinx tools compatible access to the XEM8370’s JTAG interface.

The JTAG connections are also wired to a dedicated 2mm header J5 that is compatible with the Xilinx JTAG cable. The JTAG interface presented is at a 1.8V signaling voltage. This header is not populated by default. This footprint is compatible with the Molex part 87831-1420.

1GND2+1.8V (Vref)

Clock Oscillator

There are two clock oscillators onboard the BRK8370. These supply 156.25Mhz clocks to both the GTY and GTH banks, which supports a wide variety of Ethernet protocol options to use with the QSFP ports.

Additionally there are two open 3.2 x 2.5mm 6 pin LVDS oscillator footprints available on the BRK8370 to allow for additional clock frequencies to be added if required. These footprints are compatible with oscillators like the SIT9120AI-2B3-XXE156.250000.

MGT 129 REFCLK0U4156.25 MhzMC1 26 / 28R29 / R30
MGT 226 REFCLK0U10156.25 MHzMC2 66 / 68V6 / V5
MGT 225 REFCLK0U6MC2 65 / 67AB6 / AB5Not Placed
MGT 228 REFCLK0U7MC2 46 / 48K6 / K5Not Placed

MGT External Refclock Inputs

Two external refclock inputs are available on the BRK8370. These allow for a 3.3V LVCMOS external clock to be connected to the provided U.FL connector. The clock will be converted to LVDS on board and fed into the associated XEM8370 refclock. Details on these connections are listed in the table below.

MGT 130 REFCLK0J10MC1 25 / 27L29 / L30
MGT 227 REFCLK0J12MC2 45 / 47P6 / P5

Power Enable Switch

The XEM8370 has a pin on the expansion connector that can control the main power to the board. When this pin is not connected, the board will power on normally. If the pin tied to ground, the VDCIN protection circuit will remain disabled and keep the board powered off. The XEM8370 POWER ENABLE switch on the BRK8370 allows you to pull this pin to ground if desired.

Additionally this PWR_EN signal is brought out to a test point next to the switch.

Note that disabling power with this switch does not remove the power input connection to the expansion connectors. Do not mount or unmount the XEM8370 without completely removing power from the BRK8370 first.


The FPGA’s ADC related pins are brought out to test points on the BRK8370. See the Expansion Connectors page for more information.

XEM8370 Mounting

The XEM8370 is not hot pluggable. Disconnect all power before mounting or unmounting the XEM8370.

The XEM8370 uses multiple high pin count expansion connectors. Care must be taken when mounting and unmounting from the BRK8370. See the Jack Screw Instructions page for the proper mounting procedure.

Schematic and Design Files

The BRK8370 schematics and design files are available in the Downloads section of the Pins website.

Mechanical Drawing

3D Models are available in SolidWorks, STEP, EASM and IGES formats.