AD5766-SDZ HDL project#

Overview#

The AD5766/ AD5767 are 16-channel, 16-/12-bit, voltage output Digital-to-Analog Converters (DAC). The DAC generates output voltage ranges from an external 2.5 V reference. Depending on the span selected, the mid-point of the output span can be adjusted allowing for a minimum output voltage as low as −20 V or a maximum output voltage of up to +14 V.

The AD5766/ AD5767 have integrated output buffers which can sink or source up to 20 mA. This makes the AD5766/AD5767 suitable for Indium Phosphide Mach Zehnder Modulator (InP-MZM) biasing applications.

The part incorporates a power-on reset circuit that ensures that the DAC outputs power up to 0V and remain at this level until the output range of the DAC is configured. The outputs of all DACs are updated through register configuration, with the added functionality of user-selectable DAC channels to be simultaneously updated.

The AD5766/ AD5767 require four power supplies. AVCC is the analog supply for the low voltage DAC circuitry. AVDD and AVSS are the positive and negative high voltage power supplies for the output amplifiers. A VLOGIC supply pin is provided to set the logic levels for the digital interface pins. The AD5766/ AD5767 utilize a versatile 4-wire serial interface that operates at clock rates of up to 50 MHz for write mode and up to 10MHz for readback and daisy-chain mode, and is compatible with SPIR, QSPI., MICROWIRE. and DSP interface standards.

The AD5766/ AD5767 are available in a 4mm x 4mm WLCSP package and operates at the range of -40C to +105C.

Applications:

Mach Zehnder Modulator Bias Control
Analog Output Modules
Process Control

Supported boards#

EVAL-AD5766

Supported devices#

Supported carriers#

ZedBoard on FMC slot
SDP-I-FMC

Block design#

Block diagram#

The data path and clock domains are depicted in the below diagram:

Jumper setup#

Jumper/Solder link	Default Position	Description
LK1,LK2,LK3	A	Supplied by the 3.3 V supply (J12)
LK4,LK5	B	Supplied by the ADP5071 power solution
LK6	B	Positive and negative output rails power up simultaneously when EN2 is high
LK7	A	Selects the ADR4525 2.5 V reference
LK8	B	Supplied by the 3.3 V supply (J12)
LK9	A	1.2 MHz switching frequency (default)
LK10	A	Slowest slew rate (best noise performance)
LK11,LK12	Removed	Insert link to bypass the LC filter on the ADP5071 positive output
SW1	Pos-2	ADP5070_VPOS = +8V, ADP5070_VNEG = -22V

CPU/Memory interconnects addresses#

The addresses are dependent on the architecture of the FPGA, having an offset added to the base address from HDL (see more at HDL Architecture).

Instance	Address
spi/axi	0x44A0_0000
spi/axi_ad5766	0x44A1_0000
axi_ad5766_dac_dma	0x44A2_0000

I2C connections#

I2C type	I2C manager instance	Alias	Address	I2C subordinate
PL	iic_fmc	axi_iic_fmc	0x4162_0000	—
PL	iic_main	axi_iic_main	0x4160_0000	—

SPI connections#

SPI type	SPI manager instance	SPI subordinate	CS
PL	axi_spi_engine	ad5766	0

GPIOs#

The Software GPIO number is calculated as follows:

Zynq-7000: if PS7 is used, then offset is 54

GPIO signal	Direction	HDL GPIO EMIO	Software GPIO
	(from FPGA view)		Zynq-7000
reset	INOUT	32	86

Interrupts#

Below are the Programmable Logic interrupts used in this project.

Instance name	HDL	Linux Zynq	Actual Zynq
axi_ad5766_dac_dma	13	57	89
spi	12	56	88

Building the HDL project#

The design is built upon ADI’s generic HDL reference design framework. ADI does not distribute the bit/elf files of these projects so they must be built from the sources available here. To get the source you must clone the HDL repository, and then build the project as follows:

Linux/Cygwin/WSL

user@analog:~$ cd hdl/projects/ad5766_sdz/zed
user@analog:~/hdl/projects/ad5766_sdz/zed$ make

A more comprehensive build guide can be found in the Build an HDL project user guide.

Resources#

HDL related#

ad5766_sdz HDL project source code

IP name	Source code link	Documentation link
AXI_AD5766	library/axi_ad5766	—
AXI_CLKGEN	library/axi_dmac	[Wiki]
AXI_DMAC	library/axi_dmac	here
AXI_HDMI_TX	library/axi_hdmi_tx	[Wiki]
AXI_I2S_ADI	library/axi_i2s_adi	—
AXI_SPDIF_TX	library/axi_spdif_tx	—
AXI_SYSID	library/axi_sysid	[Wiki]
AXI_SPI_ENGINE	library/spi_engine/axi_spi_engine	here
SPI_ENGINE_EXECUTION	library/spi_engine/spi_engine_execution	here
SPI_ENGINE_INTERCONNECT	library/spi_engine/spi_engine_interconnect	here
SYSID_ROM	library/sysid_rom	[Wiki]
UTIL_I2C-MIXER	library/util_i2c_mixer	—

SPI Engine Framework documentation

More information#

ADI HDL User guide

Support#

Analog Devices, Inc. will provide limited online support for anyone using the reference design with ADI components via the EngineerZone FPGA reference designs forum.

For questions regarding the ADI Linux device drivers, device trees, etc. from our Linux GitHub repository, the team will offer support on the EngineerZone Linux software drivers forum.

For questions concerning the ADI No-OS drivers, from our No-OS GitHub repository, the team will offer support on the EngineerZone microcontroller No-OS drivers forum.

It should be noted, that the older the tools’ versions and release branches are, the lower the chances to receive support from ADI engineers.