User Guide

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Hardware Guide

The AD-FMCXMWBR1-EBZ is a board that provides connectivity between X-MW blocks and research and development tools. X-Microwave modules provide solutions for prototyping RF and microwave circuits faster, easier and at a lower cost. They offer a broad selection of ADI parts as drop-in X-MW blocks in different configurations and optimized for different frequencies. Using this system it is possible to create RF and Microwave designs that incorporate X-MW building blocks and are controlled either with the X-MW controller or with an FPGA device.

Kit Contents

AD-FMCXMWBR1-EBZ Kit |
AD-FMCBRIDGE1A	FMC Card with level translators and power supplies; BR-066232 RevB
AD-FMCBRIDGE1B	Prototyping board with access to all signals of interest; BR-066233
Ribbon cable	For signal rails
Custom cable	For power rails

The FMC X-Microwave Bridge Kit contains both the FMC X-Microwave Bridge Board and the FMC X-Microwave Protoplate Board.

The boards are connected using a ribbon cable for the signal rails and another cable for the power rails.

Specifications

Key Features
User interfaces	FMC standard connector for connection to FMC development kit (from Xilinx or Intel)
	RaspberryPi 40pin header for connection to X-MW controller
Voltage translation	Control of modules with different voltage requirements while allowing compatibility between ICs
Power Supplies	Access to power supplies available in the FMC
	Create new power rails suitable to power LDOs and create bias voltages in the prototyping area
Connectivity	Provide a bridge between X-MW protoplate and an FMC development kit

Connectivity and User Interface

• FMC standard connector (FMC+ compatible)

• Raspberry Pi standard 40 pin connector

• Connector headers for the cables that connect the adapter PCB and the interface PCB

Because it is intended to be compatible with various development boards, the FMC bridge cannot be built as a single board. The proposed solution is inspired from the design of the X-MW protoplate. An interface PCB, attached to the prototyping plate, will be connected to an FMC card with some ribbon cables for power and signals. There are two controlling modes for the AD-FMCXMWBR1-EBZ: with an FMC compatible device or a Raspberry Pi compatible device (such as the X-MW controller). The FMC bridge will direct from the development board to the protoplate two SPI buses, two I2C buses and 8 GPIO pins.

In the image below are presented the signals on the FMC connector used in this design (with italic fonts).

In the X-MW controller mode the protoplate has access to one SPI bus, one I2C bus and many GPIO pins. Connector P10 is compatible with the X-Microwave controller or a RaspberryPi. It can be connected with a ribbon cable and has the pinout as presented below. In the same figure you can see the correspondence between the input pins of the FMC Bridge and the original X-MW protoplate interface board.

To connect wires on the protoplate you can solder them directly on the holes or use any male pin header with at least 0.230” (5.84mm) mating contact length and 0.320” (8.13mm) post contact length and 0.100” (2.54mm) pitch.

Power

Input Power

By default the AD-FMCXMWBR1-EBZ is supplied by the 12P0V pin on the FMC connector. By the FMC standard this pin provides power from the carrier to the mezzanine card with maximum 1A and maximum 1000 uF capacitive load. Because in max load all the circuits on the board need more than 1A there is an alternative supply method. For applications that require higher load currents, AD-FMCXMWBR1-EBZ can be supplied externally from a power supply with the following specifications:

• Input: 100-240V, 50-60 Hz

• Output: 12V 5.0A (minimum)

• Rectangular 6 position output connector compatible with Molex 0039301060 connector

The power path selection is achieved using the LTC4418 dual channel prioritized powerpath controller. It connects one of the two power supplies to a common output, based on priority and validity. The higher priority supply defined in this case is the external supply.

The channels of LTC4418 have overvoltage and undervoltage thresholds defined, so the supply is considered valid when the voltage is within the OV UV window for at least the configured validation time. If the external supply and the FMC 12V supplies are valid, LEDs DS1 and DS2 will be on, accordingly. The validity thresholds of the input supplies are listed in the table below:

Input power supply validity
	External supply	FMC 12V0
Channel	1 (prioritized)	2
UV threshold	10 V	10 V
OV threshold	13 V	13 V
Hysteresis	250mV	250mV
Inrush limit	4 A	4 A
Validation delay	16 ms	16 ms
Vout droop max	2 V	2 V

Important

If connected, the external supply will be prioritized. Both supplies can be connected and valid at the same time.

Output Power

The AD-FMCXMWBR1-EBZ gives user access to the power supply pins of the FMC connector and creates new power supply rails as follows:

• Direct from FMC:

  • +12V (1A)

  • +3.3V (3A)

  • +VADJ 0-3.3V (4A)

• New power rails (supplied with an external source):

  • +6V (1A)

  • +4V (1A)

  • 18V (50mA)

  • +3V3 (1A)

  • 2x (1.2-12V) Pot adjustable

  • 1x (-6V-0V) Pot adjustable

The user will have access on the FMC bridge to the power rails coming directly from the FPGA through the FMC connector. These supplies can be used, along with the power rails created on the FMC bridge (P11). The supply chain should provide some common voltage values suitable for the X-MW modules. Many of these modules have already integrated LDOs at the input so the voltage rails should provide enough headroom for the voltage so it does not drop under the desired value. If there are variable bias voltages needed in the prototype circuit, the FMC bridge will provide three potentiometer adjustable power supplies with a wide range of values.

Digital Communication

The X-MW blocks communicate with the controller through digital communication protocols. The paths for communication include:

• 2x SPI rails with CLK, CIPO, COPI and CS0-7 signals

• 2x I2C rails with SDA, SCL signals

• GPIO0-7

All the above signals can be accessed on the P9 pin header. Using a ribbon cable, the signals are connected to the Protoplate interface board, where all the corresponding pads are labelled.

Level Translation

To be able to use different FPGAs with modules that have different voltage requirements there is necessary to use some level translation ICs. The voltage level translation between the driver device and the receiver devices must be bidirectional and compatible with the common voltage levels of the FPGAs (1.8V, 3.3V). If the two levels do not suit the needs of the user, the 1.8V corresponding pins can be disconnected from the LDO output that generates it (by desoldering R133) and use P12 as input for the new voltage rail. Each communication protocol can be independently level translated, and the feature is implemented as follows:

	Level translator IC		Supply voltage
SPI (CLK, COPI)	74AVC4T774GUX	4 inputs, with direction pin each	0.8V - 3.6V
SPI (CIPO)	74LVC1T45GS	1 input, 1 direction pin	1.2V - 3.6V
SPI (CS)	74AVCH8T245PW	8 inputs, common direction pin	0.8V - 3.6V
I2C	NTS0302JKZ	2 inputs	0.95V - 3.6V
GPIO	74AVC4T774GUX	4 inputs, with direction pin each	0.8V - 3.6V

GPIO direction pins are programmable from the FPGA. They are set by default to be 6 output pins and 2 input pins, but the user has the option to configure them as needed either through software or by desoldering the pull-up resistor (VADJ) and soldering it into pulldown (GND) position (footprint is available on the PCB).

Compatibility and Reconfigurability

The FMC bridge is mainly intended to be used with an FMC compatible development board which will be able to control the modules as well as the level translation ICs. Because these development boards have a higher processing capability we are able to provide paths for two sets of each communication protocol (SPI, I2C) to the protoplate. The direction of the level shifters is also controlled by the FPGA by default. The system was designed in such a way that one SPI bus, one I2C bus and 8 GPIO pins can be used in both control modes (not simultaneously).

Schematics and CAD Files

All the products described on this page include ESD (electrostatic discharge) sensitive devices. Electrostatic charges as high as 4000V readily accumulate on the human body or test equipment and can discharge without detection. Although the boards feature ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. This includes removing static charge on external equipment, cables, or antennas before connecting to the device.