EVAL-ADA4356EBZ

Overview

Software enablement for EVAL-ADA4356EBZ consists of:

• HDL for ZedBoard

• PyADI-IIO API

• GUI option: Analysis, Control, Evaluation (ACE) software, IIO Oscilloscope

Note

Although the GitHub URLs and filenames refer to ADA4355, the software is for ADA4356 as well.

Digital Interface

The EVAL-ADA4356EBZ’s HDL firmware has been developed around the ZedBoard. The embedded Linux stack is based on the IIO (Industrial I/O) architecture, enabling the host PC to communicate with the EVAL-ADA4356EBZ through the ZedBoard with tools such as ACE, Python (through the pyadi-iio package), or MATLAB (with the precision toolbox). Generic, non-specific IIO tools such as IIO Oscilloscope, Scopy, and IIO command line tools can also be used to evaluate the EVAL-ADA4356EBZ’s basic functionality.

The EVAL-ADA4356EBZ interfaces with the ZedBoard through its FMC connector (P3) to configure the ADA4356’s ADC through the 4-wire SPI in LVDS mode. The table below shows the LVDS connections.

Table 1 LVDS Connections

EVB Signal	DUT Pin	FMC Pin	FMC Name	ZedBoard Name
DCOP	D14	H4	CLK0-M2C_P	FMC_CLK0_P
DCON	D13	H5	CLK0-M2C_N	FMC_CLK0_N
FCOP	C14	G6	LA00_CC_P	FMC_LA00_CC_P
FCON	C13	G7	LA00_CC_N	FMC_LA00_CC_N
D1AP	B14	H10	LA04_P	FMC_LA04_P
D1AN	B13	H11	LA04_N	FMC_LA04_N
D0AP	A14	G9	LA03_P	FMC_LA03_P
D0AN	A13	G10	LA03_N	FMC_LA03_N

PyADI-IIO API

The pyadi-iio python package is composed of drivers that allow users to control and evaluate software-enabled ADI parts through python scripts. A driver for ADA4356 has been created.

The key drivers used in controlling the EVAL-ADA4356EBZ are:

• ADA4356: Interacts with the board’s main IC, the ADA4356 uModule. Reads the device’s output.

• AD7291: Controls the AD7291 ADC, used in the board’s self-debug circuit.

• one-bit-adc-dac: Reads and writes the gain and frequency settings for the ADA4356.

Refer to the Driver Guide section below for key installations and proper driver usage.

Analysis, Control, Evaluation (ACE) Software

The EVAL-ADA4356EBZ hardware can be controlled and configured through the ACE Software. ADI’s “Analysis, Control, Evaluation” (ACE) is a desktop software application that allows the evaluation and control of multiple evaluation systems from across the Analog Devices product portfolio.

The controller board supported by ACE for the evaluation of EVAL-ADA4356EBZ is the ZedBoard.

Note

For ACE installation and documentation instructions, refer to the ACE user guide. Once ACE is installed, open the ACE application and search for the EVAL-ADA4356EBZ board plugin in ACE’s plugin manager, then install or update.

Controlling the EVAL-ADA4356EBZ

Using ACE

The plugin for the EVAL-ADA4356EBZ is available in ACE. The ACE plugin allows the EVAL-ADA4356EBZ’s gain and frequency settings to be configured, board supplies to be measured, and the resulting output waveform to be observed.

To control the EVAL-ADA4356EBZ through ACE, the host PC must first be physically connected to the FPGA using an ethernet cable. The following steps must then be followed:

1. Open ACE. Within the software, navigate to plugin manager. The plugin manager is where all the available plugins for ADI boards can be found and installed.

2. In the plugin manager, select the Available Packages dropdown. This checks for plugins that are available for installation; plugins already installed will not be found under this selection and will be under Installed Plugins instead.

3. Tick the checkbox for Boards, search for ADA4356, then install.

4. Once installation is complete, restart ACE. Upon rebooting ACE, the evaluation board hardware should be detected, as seen in the screenshot below.

Figure 1 ACE Start Page

Using IIO Oscilloscope

ADI’s IIO Oscilloscope can be downloaded from the IIO Oscilloscope releases page. Install this on the host PC.

1. Start IIO Oscilloscope.

   Note

   It may take a little time for the window to appear after it is launched; do not click multiple times.

   • Most of the time, IIO Oscilloscope will scan for and discover ADA4355/4356 on its own when it is first opened and show it as ready to connect. If ada4355 shows up under IIO Devices, the system is ready to connect. Click the Connect button in the lower right hand corner to proceed.

   • If IIO Oscilloscope has not found the ADA4355/4356 yet, select Manual and type in ip:analog.local and click Connect. The password is analog (all lowercase).

2. When the Capture window opens, check the voltage0 checkbox under ada4355 to select the plot channel.

3. Change the default number of samples to something higher than 400, for example 8192 (= 2¹³).

4. Click the Enable All button. Once the voltage0 channel has been selected, the orange caution symbols will turn to arrow symbols. To begin reading data, click the gray arrow to Run. This should display the data being gathered by ADA4356 in the plot screen.

5. To stop data collection, click the red circle where the Run arrow used to be.

Using Python (via pyadi-iio package)

Installing the Assets for Python Programming

In preparation for using the PyADI-IIO package, the following resources must be downloaded and installed.

Python 3.x, libiio, pyadi-iio

Follow these steps to install Python:

1. Download a preferred version of Python (should be version 3.8 or higher).

2. Right click on the downloaded .exe file and select Run as Admin. This should open the Python dialog box.

3. If this is the only Python version to be installed on the device, tick the Add Python 3.x to PATH checkbox.

4. Select Customize installation.

5. In Optional Features, proceed with all features checked and click Next.

6. In Advanced Options, make sure the Install for all Users checkbox is ticked.

7. Click Install and wait for completion.

Running pip as Admin:

1. On your Windows start menu, search for cmd. This will show Command Prompt; right click on it and select Run as Admin.

2. In the command prompt, update the pip package:

   py -m pip install --upgrade pip
   

   If multiple Python versions are installed, specifically target your preferred version by adding -3.x (replace x with actual version number) after py.

3. Wait for successful installation. You now have an updated global instance of pip.

Driver Guide

Note

For this guide, variables with my_ prefix refer to user-defined values.

ADA4356 Driver

The ADA4356 PyADI driver can be used through the following commands:

• adi.ada4355(uri=my_uri) — Establishes connection to the on-board ADA4356. Requires a unique resource identifier (URI) attribute. Using the EVAL-ADA4356EBZ mounted on a ZedBoard, this URI should be ip:analog.local. This command can be assigned to a variable for easier initialization of other attributes.

• adi.ada4355(uri=my_uri).rx_buffer_size = my_buffer_size — Initializes the number of data points to be captured and stored.

• adi.ada4355(uri=my_uri).rx_enabled_channels = [0] — Initializes which channels are enabled. Since ADA4356 only has a single channel, this is set to 0.

• adi.ada4355(uri=my_uri).ada4355_register_write(0x0D, 0x00) — Directly accesses a register of ADA4356. 0x0D accesses the Test Mode, and 0x00 sets the Test Mode to OFF; this ensures that the ADA4356 is not initialized in test mode (which outputs example test data rather than actual data).

• adi.ada4355(uri=my_uri).rx() — Captures the data received by the ADA4356’s internal ADC. The data is in its “codes” form. To convert to voltage, multiply by 0.00012207, or use adi.ada4355(uri=my_uri).rx_scale.

• adi.ada4355(uri=my_uri).rx_destroy_buffer() — Destroys the buffer, thereby also erasing its contents. It is preferred to destroy the buffer and create a new one to capture another set of data to free up memory.

Example code:

import adi

my_uri = "ip:analog.local"
my_buffer_size = 4096

# Assign to variable for easier initialization
my_4356 = adi.ada4355(uri=my_uri)
my_4356.rx_buffer_size = my_buffer_size
my_4356.rx_enabled_channels = [0]
my_4356.ada4355_register_write(0x0D, 0x00)

data = my_4356.rx() * my_4356.rx_scale
# or: my_4356.rx() * 0.00012207

my_4356.rx_destroy_buffer()

AD7291 Driver

• adi.ad7291(uri=my_uri) — Establishes connection to the on-board AD7291. Requires a URI attribute. Using the EVAL-ADA4356EBZ mounted on a ZedBoard, this URI should be ip:analog.local.

• adi.ad7291(uri=my_uri).temp0() — Returns the temperature reading of the AD7291 in Celsius. To access raw readings, use .temp0.raw. To access scale value, use .temp0.scale.

• adi.ad7291(uri=my_uri).voltageX() — Returns the voltage output of each channel in millivolts. Replace X with the channel number minus 1 (Channel 1 is voltage0, Channel 2 is voltage1, etc.). To access raw readings, use .voltageX.raw. To access scale value, use .voltageX.scale.

The corresponding channel assignments are:

Parameter	Channel Assigned
3.3V LDO	voltage0
2.5V LDO	voltage1
1.8V LDO	voltage2
1.65V Sense	voltage3

Example code:

import adi

my_7291 = adi.ad7291(uri=my_uri)
print(my_7291.temp0())
print(my_7291.voltage0())
print(my_7291.voltage1())
print(my_7291.voltage2())
print(my_7291.voltage3())
print(my_7291.voltage4())

one-bit-adc-dac Driver

The one-bit-adc-dac can both read and write the logic for setting the gain and frequency. This driver can be used through the following commands:

• adi.one_bit_adc_dac(uri=my_uri) — Establishes connection to ADA4356’s digital gain and frequency control. Requires a URI attribute set to ip:analog.local.

• adi.one_bit_adc_dac(uri=my_uri).<channel name> — Reads the value set on the selected channel’s parameter; its value is either 0 (LOW) or 1 (HIGH).

The one-bit-adc-dac has a total of 8 logic channels, but only 4 channels are used to set the ADA4356:

Parameter Name	Channel Assigned	Channel Name	Used in ADA4356?
GSEL0	voltage0	gpio_gsel0	Yes
GSEL1	voltage1	gpio_gsel1	Yes
GSEL2	voltage2	gpio_gsel2	Yes
FSEL0	voltage3	gpio_fsel0	Yes
GSEL3	voltage4	gpio_gsel3	No
FSEL1	voltage5	gpio_fsel1	No

To set or change the value of each parameter, run adi.one_bit_adc_dac(uri=my_uri).<channel name> = my_set, where my_set is equal to either 0 (LOW) or 1 (HIGH).

Gain and Frequency Settings Truth Table

Setting	GSEL0	GSEL1	GSEL2	FSEL0
133 kOhm	0	0	X	X
11 kOhm	0	1	X	X
4.54 kOhm	1	0	X	X
Current Divider Disabled	X	X	0	X
Current Divider Enabled	X	X	1	X
LPF Bandwidth = 100 MHz	X	X	X	0
LPF Bandwidth = 1 MHz	X	X	X	1

Note: “X” means “Don’t Care”

Current-to-Bits Operation

The EVAL-ADA4356EBZ provides two methods for generating an input current for the ADA4356:

• On-board Buffered Howland Current Source (BHCS) driven by an external voltage source.

• Avalanche Photodiode (APD) connection via a 3-pin socket.

Both inputs route through a programmable current divider, which can be enabled to extend the measurable range by attenuating higher input currents.

Input selection is controlled by populating a single 0 Ohm (0603) resistor as summarized below:

Populated Resistor	Selected Input	Input Type	Path
R7	APD	Current	APD1 -> ADA4356
R17	APD	Current	APD1 -> Current Divider -> ADA4356
R8	Buffered Howland Current Source (BHCS)	Voltage	J1 -> BHCS -> Current Divider -> ADA4356

By default, R8 is populated, enabling the BHCS signal path. In this configuration, the signal chain operates as follows:

VIN (J1) -> Buffered Howland Current Source (BHCS) -> Optional Current Divider -> ADA4356 Input

An external voltage applied at J1 is converted to proportional current by the BHCS, optionally attenuated by the current divider, converted to voltage by the ADA4356’s programmable gain transimpedance amplifier (PGTIA), and finally digitized by the ADA4356’s ADC.

Voltage-to-Current Conversion via BHCS

The Buffered Howland Current Source converts the applied input voltage into a current according to:

I_BHCS = V_IN / (5 x R_S)

Where:

• V_IN is the voltage applied at connector J1.

• R_S is the selected BHCS range resistor (R14, R18, or R19). The factor of 5 arises from the internal resistor ratios of the BHCS topology.

The resulting current is sourced or sunk into the subsequent signal chain.

Input Current Range Extension via Current Divider

The input current divider can be enabled to extend the input current range by attenuating the signal current before it reaches the ADA4356’s input. This feature is optional and is controlled by the GSEL2 pin (divider enabled when GSEL2 = 1; disabled when GSEL2 = 0).

The divider is implemented using the ADG772 (U4) analog switch in series with R22 = 604 Ohm. When the divider is enabled, the effective division ratio is primarily determined by the ON resistance of the ADG772 (R_ON) and R22.

The ADG772 R_ON is typically 3.8 Ohm, and may vary due to:

• Part-to-part variation

• Temperature

• Supply voltage

• Bias conditions

This variability introduces an added gain error term when the divider is enabled.

When the divider is enabled (GSEL2 = 1), the input current is divided as:

I_{SIG_IN} = I_{BHCS_OUT} x R_ON / (R_ON + R22)

Using typical values R_ON = 3.8 Ohm and R22 = 604 Ohm:

I_{SIG_IN} = I_{BHCS_OUT} x 3.8 / (3.8 + 604) = I_{BHCS_OUT} / 160

Where:

• I_{BHCS_OUT} is the BHCS output current.

• I_{SIG_IN} is the input current presented to the ADA4356.

When the divider is disabled (GSEL2 = 0):

I_{SIG_IN} = I_{BHCS_OUT}

ADA4356 Internal Signal Chain

The ADA4356 includes the following internal functional blocks:

• Programmable gain transimpedance amplifier (PGTIA)

• Fully differential amplifier (FDA)

• Low-pass filter

• 14-bit, 125 MSPS ADC

Programmable Gain Transimpedance Amplifier (PGTIA)

The PGTIA converts the input current into a voltage and is internally referenced to V_{TIA_REF} = 1.65 V.

The PGTIA output voltage is:

V_{TIA_OUT} = V_{TIA_REF} - I_{SIG_IN} x R

Where:

• V_{TIA_REF} is the internal 1.65 V TIA reference.

• R is the selected transimpedance gain.

• V_{TIA_OUT} is the output voltage of the TIA.

For example, if 11 kOhm transimpedance gain is selected and I_{SIG_IN} = 80 uA, the output of TIA will be:

V_{TIA_OUT} = 1.65 V - 80 uA x 11 kOhm = 0.77 V

Fully Differential Amplifier (FDA)

The PGTIA output feeds into a Fully Differential Amplifier (FDA), whose inverting input is biased to:

V_{FDA_REF} = 0.825 V

The FDA output is given by:

V_{FDA_OUT} = V_{TIA_OUT} - V_{FDA_REF}

Substituting the TIA relationship:

V_{FDA_OUT} = (V_{TIA_REF} - I_{SIG_IN} x R) - 0.825 V

With V_{TIA_REF} = 1.65 V, this simplifies to:

V_{FDA_OUT} = 0.825 V - (I_{SIG_IN} x R)

This indicates that the FDA output voltage decreases linearly with increasing input current.

14-bit, 125 MSPS ADC Transfer Function

The FDA output drives a 14-bit ADC with an input range of approximately +/- 1 V (2 V peak-to-peak). The ADC output code can be modeled as:

ADC code = 2¹⁴ x V_{FDA_OUT} / V_{ADC_REF}

With V_{ADC_REF} = 2 V_PP, this reduces to:

ADC code = 2¹³ x V_{FDA_OUT}

Substituting the FDA expression derived above:

ADC code = 2¹³ x [0.825 V - (I_{SIG_IN} x R)]

Note that for I_{SIG_IN} = 0, the ADC code will be:

ADC code = 2¹³ x 0.825 V = 6758

This decreases as current into the ADA4356 increases.

Known Hardware Errata

Rev. A, 10/2025 Release

• The onboard current sense based on LT6105 is not wired correctly and cannot measure the supply current of the overall 3.3 V supply as originally intended. Please disregard the output of this current sense circuit and its readings in the self-debug ADC output.

Downloads

Download

Boot Files:

4356 Boot Files (Aug 13, 2025) — Based on July 14 version, but fixes Trig In - Trig Out loopback.

4356 Boot Files (July 14, 2025) — First version to support EVAL-ADA4356 with corrected FMC connection for frame clock. Includes support for onboard self-debug ADC. Has bug in Trig In - Trig Out loopback.

ADA4355 Boot Files for ADA4356 on EVAL-ADA4355 Board (March 12)

Warning

These boot file versions are preliminary, use them at your own risk. The official boot files will be released in Kuiper Linux.