EVAL-AD7490-ARDZ

Arduino Compatible Evaluation Board for AD7490

Overview

The EVAL-AD7490-ARDZ is an Arduino compatible evaluation board for evaluating all features of AD7490. The AD7490 is a 12-bit, 16-channel, high speed, low power, successive approximation (SAR) ADC that operates from a single 2.7 V to 5.25 V power supply and features throughput rates of up to 1 MSPS. The evaluation board can be controlled via the SDP-K1 (EVAL-SDP-CK1Z) board which enables control and data capture via the PC’s USB port. The EVAL-AD7490-ARDZ can be powered directly from USB via the SDP-K1 controller board, or via an external 5 V supply. To facilitate the low noise voltage supply requirements and standalone operation, the EVAL-AD7490-ARDZ features the following components on board:

• MAX17291: Low I:sub:Q Current DC-DC Boost Converter

• ADP7118: 200mA Low Noise CMOS LDO

• ADR3625: Precision Micropower Voltage Reference

• MAX44260: 1-channel 15MHz Low-Offset Low-Power Rail-to-Rail Op-Amp

• MAX44263: 2-channel 15MHz Low-Offset Low-Power Rail-to-Rail Op-Amp

• ADA4807-1: 1-channel 180 MHz Low Noise Rail-to-Rail Op-Amp

• LTC3265: Low Noise Dual Supply with Boost and Inverting Charge Pumps (provision only)

Figure 1 EVAL-AD7490-ARDZ Evaluation Board Top View

Figure 2 EVAL-AD7490-ARDZ Evaluation Board Angle View

Features

• Fully featured evaluation board for AD7490

• PC-based control when used with the SDP-K1 controller board (EVAL-SDP-CK1Z)

• Arduino UNO–compatible form factor and pin configuration

• Supports standalone operation

• Accepts 0 V to 5 V unipolar input signals on all ADC channels

• Supports −2.5 V to +2.5 V bipolar input on VIN15 channel

• Supports input signal frequencies from 0 to 500kHz

• Includes drivers for embedded firmware and software development

• Compatible with ACE software plugin for control and data analysis (time and frequency domains)

Applications

• Multichannel system monitoring

• Battery-powered equipment

• Power line monitoring

• Data acquisition, instrumentation, and process control

Package Contents

• EVAL-AD7490-ARDZ Evaluation Board

Additional Equipment Needed

• EVAL-SDP-CK1Z controller board (must be ordered separately and includes a USB-A to USB-C cable)

• Signal generator

• PC running Windows 10/11 with ACE software installed

• External DC power supplies

Block Diagram

Figure 3 EVAL-AD7490-ARDZ Functional Block Diagram

Hardware Description

The EVAL-AD7490-ARDZ is an Arduino form factor evaluation board for AD7490 featuring essential on-board circuitry to support both full feature and standalone operation. It can accept unipolar input signals between 0 V to 5 V on all channels (VIN0 to VIN15) and can also be configured to accept bipolar input signals between -2.5 V to +2.5 V on channel VIN15. For more information on AD7490, please refer to the device datasheet.

Power Supply Section

The board can be powered either by an external 5 V DC source or through the SDP-K1 controller via the Arduino header. The 5 V input is boosted to ~6 V using the MAX17291 and then regulated by the ADP7118-5.0 LDO to provide a stable on-board 5 V rail. This regulated supply powers critical components, including the AD7490 VDD, analog front-end circuitry, DC bias generator, and ADC reference.

An optional LTC3265 charge pump (not populated by default) can generate ±5.25 V supplies for bipolar input signals on VIN15. These rails may alternatively be provided externally via test points. The ±5.25 V supply enables level shifting of bipolar inputs to a 0–5 V range.

The AD7490 VDRIVE pin powers the SPI interface and can be sourced from the SDP-K1’s 3.3 V or IOREF rail. The board also supports configuration via jumpers and test points to allow external supplies to bypass the on-board 5 V regulator and 2.5 V reference. Refer to Tables 2 and 3 for details.

ADC Reference Voltage

The on-board 2.5 V reference is generated by the ADR3625 and buffered by the MAX44260 to drive the AD7490 REFIN pin and the DC bias circuit. This rail can be bypassed to accept an external low-noise 2.5 V source. Refer to Tables 2 and 3 for configuration details.

Analog Front-End (AFE) Circuitry

The analog front end comprises eight dual-channel MAX44263 buffers and sixteen identical RC low-pass filters that condition inputs prior to the AD7490. All channels support 0–5 V unipolar signals, with filter cutoff set to ~505 kHz. Refer to Table 2 for ADC channel input test points.

DC Bias Generator

The DC bias generator uses an ADA4807-1 configured as a difference amplifier to shift bipolar inputs to a unipolar range for the AD7490 VIN15 channel, producing an inverted AC component. It requires ±5.25 V rails supplied externally or via the optional LTC3265. This function is available only on VIN15. Refer to Tables 2 and 3 for configuration details.

SPI Interface

The AD7490 supports multi-channel data acquisition via its SPI interface, with signals routed to the Arduino header using standard pin assignments. An on-board 12-pin PMOD connector provides access to the same SPI lines for flexible controller interfacing. Refer to the image and Table 1 below for pin details.

Table 1 Pinout for PMOD SPI Interface

Pin Number	Pin Description
1	No Connection
2	SPI Chip Select (CS)
3	No Connection
4	SPI MOSI
5	No Connection
6	SPI MISO
7	No Connection
8	SPI SCK
9	GND
10	GND
11	IOREF/MCU_VDD
12	IOREF/MCU_VDD

Figure 4 PMOD SPI Interface

Test Points and Jumper Locations

Table 2 and table 3 summarizes the test points and jumper locations on the board with detailed description for each.

Table 2 EVAL-AD7490-ARDZ Test Points

Test Point	Test Point Name	Description
TP1	5V0_IN	Input voltage rail
TP2	GND	GND
TP3	BST	Boost converter output
TP4 & TP5	EXT_LDO	External 5.0 V LDO input (TP4 is positive, TP5 is negative)
TP6	5V0	5.0 V LDO rail
TP7 & TP8	EXT_REF	External 2.5 V reference (TP7 is positive, TP8 is negative)
TP9	2V5	2.5 V reference rail
TP10	+5V25	+5.25 V rail
TP11	-5V25	-5.25 V rail
TP12	VCC_EXT	External +5.25 V input
TP13	GND	GND
TP14	VEE_EXT	External -5.25 V input
TP15	2V5_BUF	Buffered 2.5 V reference
TP52	VDD	Voltage at VDD pin of ADC
TP54	VDRIVE	Voltage at VDRIVE pin of ADC
TP17 & TP58	VIN0	ADC Input on Channel 0 (TP17 is the signal input, TP58 is GND)
TP16 & TP57	VIN1	ADC Input on Channel 1 (TP16 is the signal input, TP57 is GND)
TP22 & TP60	VIN2	ADC Input on Channel 2 (TP22 is the signal input, TP60 is GND)
TP36 & TP67	VIN3	ADC Input on Channel 3 (TP36 is the signal input, TP67 is GND)
TP23 & TP61	VIN4	ADC Input on Channel 4 (TP23 is the signal input, TP61 is GND)
TP37 & TP68	VIN5	ADC Input on Channel 5 (TP37 is the signal input, TP68 is GND)
TP24 & TP62	VIN6	ADC Input on Channel 6 (TP24 is the signal input, TP62 is GND)
TP38 & TP46	VIN7	ADC Input on Channel 7 (TP38 is the signal input, TP46 is GND)
TP25 & TP63	VIN8	ADC Input on Channel 8 (TP25 is the signal input, TP63 is GND)
TP39 & TP70	VIN9	ADC Input on Channel 9 (TP39 is the signal input, TP70 is GND)
TP26 & TP64	VIN10	ADC Input on Channel 10 (TP26 is the signal input, TP64 is GND)
TP40 & TP48	VIN11	ADC Input on Channel 11 (TP40 is the signal input, TP48 is GND)
TP27 & TP65	VIN12	ADC Input on Channel 12 (TP27 is the signal input, TP65 is GND)
TP41 & TP72	VIN13	ADC Input on Channel 13 (TP41 is the signal input, TP72 is GND)
TP28 & TP66	VIN14	ADC Input on Channel 14 (TP28 is the signal input, TP66 is GND)
TP19 & TP73	VIN15-Unipolar	ADC Input on Channel 15 - UNIPOLAR (TP19 is the signal input, TP73 is GND)
TP16 & TP59	VIN15-Bipolar	ADC Input on Channel 15 - BIPOLAR (TP16 is the signal input, TP59 is GND)

Figure 5 EVAL-AD7490-ARDZ Test Points

Table 3 EVAL-AD7490-ARDZ Jumper Configurations and External SMB Connectors

Jumper	Default Connection	Description
J1	[2-3]	Input Voltage Selector: Selects 5.0 V source from either external input (P1) or the Arduino header; defaults to Arduino 5.0 V rail.
J2	[2-3]	Regulated 5.0V Rail Selector: Selects the regulated 5.0V source from either external (TP4 & TP5) or the on-board 5.0V LDO; defaults to the on-board 5.0V LDO
J3	[1-2]	Reference Input Voltage Selector: Selects the input voltage source for the 2.5V reference from either the regulated 5.0V LDO or the 5.0V rail (5V_SYS); defaults to the regulated 5.0V LDO
J4	[2-3]	Reference Voltage Selector: Selects the 2.5V ADC reference from either external (TP7 & TP8) or the on-board reference; defaults to the on-board reference.
J5	[2-3]	VCC Voltage Selector for Bipolar Signal Input: Selects the +5.25V (VCC) source from either external (TP12) or internally generated by LTC3265 charge pump; defaults to external since LTC3265 is not populated
J6	[2-3]	VEE Voltage Selector for Bipolar Signal Input: Selects the -5.25V (VEE) source from either external (TP14) or internally generated by LTC3265 charge pump; defaults to external since LTC3265 is not populated
J7	-	External SMB Connector for VIN0
J8	-	External SMB Connector for VIN1
J9	[2-3]	VIN15 Input Signal Selector: Selects the input signal routed to VIN15 from either unipolar or bipolar; defaults to bipolar input
J10	[1-2]	VDD Input Selector: Selects the supply input for ADC’s VDD pin from either the input 5.0V rail (5V_SYS) or the on-board 5.0V LDO; defaults to the on-board 5.0V LDO
J11	[1-2]	VDRIVE Input Selector: Selects the supply input for ADC’s VDRIVE pin from either the Arduino 3.3V rail or IOREF; defaults to Arduino IOREF.

Figure 6 EVAL-AD7490-ARDZ Jumper Locations

Board Specifications

Parameter	Minimum	Typical	Maximum	Unit	Remarks
External Input Supply	1.8	5.0	5.5	V	Connects to P1
Bipolar Input Voltage Range	-2.5	-	+2.5	V	VIN15 only
Unipolar Input Voltage Range	0	-	5.0	V	All ADC input channels (VIN0 - VIN15)
Input Signal Frequency	-	-	500	kHz	All ADC input channels (VIN0 - VIN15)
ADC Sampling Rate	-	1	-	Msps	-
SNR	65	-	-	dB	50kHz sine wave input, -0.5 dBFS fundamental power, 950kHz sampling rate
THD	-	-	-65	dB	50kHz sine wave input, -0.5 dBFS fundamental power, 950kHz sampling rate
SINAD	64	-	-	dB	50kHz sine wave input, -0.5 dBFS fundamental power, 950kHz sampling rate
ENOB	10.2	-	-	bits	50kHz sine wave input, -0.5 dBFS fundamental power, 950kHz sampling rate
SFDR	68	-	-	dB	50kHz sine wave input, -0.5 dBFS fundamental power, 950kHz sampling rate

Hardware Setup

The evaluation board caters to a combination of setup configurations depending on the user application. These are determined by the input supply options and the type of input signals (unipolar or bipolar) being evaluated.

Evaluating Unipolar Test Signals

By default, the EVAL-AD7490-ARDZ accepts unipolar signals on VIN0–VIN14. To enable unipolar input on VIN15, short pins 1 and 2 of J9, then connect the input signal to the designated test point as shown below:

Figure 7 Setup for Evaluating Unipolar Signals

Evaluating Bipolar Test Signals

Bipolar signals are supported only on VIN15. To enable this, short pins 2 and 3 of J9 and connect the input to the VIN15 (Bipolar) test point (see Figure 4). A 2-channel isolated DC supply configured for ±5.25 V is required: connect the midpoint to GND, +5.25 V to VCC, and −5.25 V to VEE, as shown below.

Figure 8 Setup for Evaluating Bipolar Signals

Using External 5.0 V Supply

An external 5.0V supply can be used to power the board separate from the controller. This can be configured by connecting the external 5.0V supply to P1 and shorting pins 1 & 2 of J1 as shown below:

Figure 9 Setup for using External 5.0 V Supply

Example Setup - Evaluating Bipolar and Unipolar Signals

This section describes the hardware setup for evaluating both unipolar and bipolar types of signals without using an external 5.0V supply. This enables evaluation of unipolar signals on VIN0-VIN14 and assigning VIN15 as the dedicated input for bipolar signals. This setup requires the following equipment and/or materials:

• 1x EVAL-AD7490-ARDZ

• 1x EVAL-SDP-CK1Z (SDP-K1 controller board)

• 1x Signal Generator

• 1x 2-channel isolated DC power supply

• PC/Laptop running Windows 10/11

• 1x BNC to Test Clip cable

• 1x USB (type-A to type-C or type-C to type-C) power and data cable

• Banana Jacks, Plugs, and extra Test Clip cables

Setup Procedure

1. Configure the EVAL-AD7490-ARDZ board to use the 5.0 V supply provided by the Arduino header by shorting pins 2 and 3 of J1.

2. Configure the EVAL-AD7490-ARDZ board to accept bipolar signals on VIN15 by shorting pins 2 and 3 of J9.

3. Locate the P14 (VIO_ADJUST) jumper on the SDP-K1 controller board and set it to 3.3 V.

4. Mount the EVAL-AD7490-ARDZ board to the SDP-K1 controller board.

5. Set the output voltage of each channel of the 2-channel isolated DC supply to 5.25 V, and the OCP limit to at least 100 mA. Do not turn on the channels of the power supply at this point.

6. Connect the 2 channels of the isolated DC supply in series. Connect their midpoint to GND, +5.25 V to VCC, and −5.25 V to VEE test point of the EVAL-AD7490-ARDZ board.

7. Connect the USB-C port of the SDP-K1 controller board to the PC via USB cable. The two LEDs (DS1 and DS2) on the eval board should light up shortly after.

8. Turn on the two channels of the isolated DC supply to enable the DC bias circuitry on VIN15.

9. Configure the output of the signal generator to generate ADC test signals from 0 up to 500kHz:

   • Unipolar test signals - Connect the output of the signal generator to any channel from VIN0 - VIN14. Make sure that the signal level does not exceed the specified range of 0 - 5 V.

   • Bipolar test signals - Connect the output of the signal generator to VIN15. Make sure that the signal level does not exceed the specified range of -2.5 V to +2.5 V.

Figure 10 Setup for Evaluating Unipolar and Bipolar Signals, Internal 5.0 V Supply

Once configured, proceed to the Software Setup section to download and install the complementary evaluation software for EVAL-AD7490-ARDZ using ACE.

Software Setup

The EVAL-AD7490-ARDZ is supported by ADI’s Analysis | Control | Evaluation (ACE) software for control, data capture, and data analysis. This section provides the step-by-step procedure for the required prerequisites prior to evaluation using ACE.

Installing ACE Software

1. Download and install ADI’s ACE software through this link: Analysis | Control | Evaluation (ACE).

2. After installation, check if the Plug-in Manager prompts for any essential updates.

   

3. Click on the Plug-in Manager tab on the left panel to update essential plug-ins.

   

4. Click on Available Updates, and check all plug-in types (Boards, Chips, Support, Hardware, Essential Only). This will display all essential plug-in types that need to be updated.

5. Once all essential plug-ins are listed, click the Update All button at the bottom, wait for the update process to finish and then, restart ACE.

   

Installing ACE Plugin Support for EVAL-AD7490-ARDZ

In order for ACE to properly detect and capture data from the hardware setup, the board plug-in for AD7490 should be installed in ACE. To install:

1. Click on the Plug-in Manager on the left panel.

2. Click on Available Packages and then, click on the Boards and Chips checkbox.

3. Type “AD7490” on the search entry. The corresponding plug-ins for AD7490 should appear as listed similar to the image below:

   

4. Select both plugins by clicking on each entry while holding the CTRL key.

5. Click on the Install Selected button at the bottom and then, Restart ACE.

Uploading the tinyIIOd firmware to SDP-K1

Given that the SDP-K1 controller board is sourced separately, it does not come preloaded with the tinyIIOd firmware that can communicate to the ACE software and plug-ins. To install the appropriate firmware, ACE’s internal SDP-K1 Recovery Tool will be utilized.

1. Launch the ACE software and under the Tools tab on the left panel, click on the SDP-K1 Recovery Tool.

   

2. The SDP-K1 Recovery Tool view should pop-up from the right panel. Click on the Search button to detect the SDP-K1 board attached to the PC.

3. Click on the device ID of the detected SDP-K1 board and click on the Standard Firmware option.

4. Lastly, click the Flash Firmware button and wait for the firmware upload to finish.

   

   Note

   After successful upload of the default firmware, ACE will be able to automatically detect the mounted evaluation board, and a pop-up should appear prompting to upload the dedicated evaluation firmware.

5. Click the OK button on the pop-up window and wait for the firmware upload to finish.

   

6. Once the evaluation firmware has been uploaded, ACE should now be able to detect the evaluation board and display the correct hardware name in the Attached Hardware panel.

   

   Note

   After successful completion of the previous steps, the setup is now ready for evaluation using ACE.

7. Once ACE has detected the hardware setup, double click on the plugin icon in the Attached Hardware panel to open the board view and refer to the built-in plugin documentation for AD7490 for details on evaluating ADC test signals using the EVAL-AD7490-ARDZ evaluation board.

Software Resources

• AD7490 No-OS Device Driver

• AD7490 PyADI-IIO Example Code (PyADI-IIO library support for Python development)

• ACE plug-in support for EVAL-AD7490-ARDZ via Analysis | Control | Evaluation (ACE)

Additional Resources

• AD7490 Product Page

• SDP-K1 Evaluation Board

Design and Integration Files

Download

EVAL-AD7490-ARDZ HW Design Files

• Schematic

• PCB Layout

• Bill of Materials

Help & Support

For questions and more information, please visit the EngineerZone Support Community or contact your local ADI representative.