ANALOG DEVICES UG-285 Service Manual

Evaluation Board User Guide

UG-285

One Technology Way •P.O. Box 9106 •Norwood, MA 02062-9106, U.S.A. •Tel: [phone] •Fax: [phone] •www.analog.com

Evaluating the AD5544 Current Output/Serial Input DAC

FEATURES

Full-featured evaluation board for the AD5544

Graphic user interface software for board control and data analysis

Connector to EVAL-SDP-CB1Z system demonstration platform board

Various power supply options

APPLICATIONS

Automatic test equipment

Instrumentation

Digitally controlled calibration

GENERAL DESCRIPTION

The AD5544 quad, 16-bit, current output, digital-to-analog converter (DAC) is designed to operate in a 2.7 V to 5.5 V supply range. But this voltage is limited up to 3.3 V due to EVAL-SDP-CB1Z restrictions.

The applied external reference input voltage (VREFx) determines the full-scale output current. Integrated feedback resistors (RFBx) provide temperature-tracking, full-scale voltage outputs when combined with an external I-to-V precision amplifier.

A double-buffered serial data interface offers high speed, 3-wire, SPIand microcontroller-compatible inputs using serial data in (SDI), chip select (CS), and clock (CLK) signals. In addition, a serial data out pin (SDO) allows for daisy-chaining when multiple packages are used. A common, level-sensitive, load DAC strobe (LDAC) input allows the simultaneous update of all DAC outputs from previously loaded input registers. Additionally, an internal power-on reset forces the output voltage to 0 at system turn on. An MSB pin allows system reset assertion (RS) to force all registers to zero code when MSB = 0 or to half-scale code when MSB = 1.

The AD5544 is packaged in a compact 28-lead SSOP.

The EVAL-AD5544/45SDZ board is used in conjunction with the EVAL-SDP-CB1Z system demonstration platform (SDP) board available from Analog Devices, Inc., which is purchased separately from the evaluation board. The USB-to-SPI communication to the AD5544 is completed using this Blackfin®-based demonstration board. The software offers a waveform generator.

EVAL-SDP-CB1Z

GPIO

USB

SPORT

FUNCTIONAL BLOCK DIAGRAM

			ADR01
		REFERENCE
			VREFx	IOUTA	AD8065
	LDAC
					I-TO-V	VOUTA
	RS	AD5544
	MSB
				IOUTD	AD8065
					I-TO-V
	CS	SCLK	SDIN	SDO		VOUTD
						09900-001

Figure 1.

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT	Rev. A | Page 1 of 12
WARNING AND LEGAL TERMS AND CONDITIONS.

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Evaluation Board User Guide

TABLE OF CONTENTS
Features ..............................................................................................	1
Applications.......................................................................................	1
General Description .........................................................................	1
Functional Block Diagram ..............................................................	1
Revision History ...............................................................................	2
Evaluation Board Software ..............................................................	3
Installing the Software .................................................................	3
REVISION HISTORY
5/12—Rev. 0 to Rev. A
Changes to General Description Section ......................................	1
Changes to Figure 2..........................................................................	3
Changes to Evaluation Board Schematics and Artwork Section...	5
5/11—Revision 0: Initial Version

Running the Software ...................................................................	3
Using the Evaluation Board Software .............................................	4
Example ..........................................................................................	4
Evaluation Board Schematics and Artwork...................................	5
Evaluation Board Layout..............................................................	8
Related Links......................................................................................	9

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Evaluation Board User Guide

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EVALUATION BOARD SOFTWARE

09900-002

Figure 2. Device Manager Showing the SDP Board Connected

INSTALLING THE SOFTWARE

The EVAL-AD5544/45SDZ evaluation kit includes the software and drivers on CD. To install the software, do the following:

1.Install the software before connecting the SDP board to the USB port of the PC.

2.Start the Windows® operating system and insert the EVALAD5544/45SDZ evaluation kit CD.

3.Download the EVAL-AD5544/45SDZ LabVIEW™ software. The correct driver, SDPDriversNET, for the SDP board should download automatically after LabVIEW is downloaded, supporting both 32and 64-bit systems. However, if the drivers do not download automatically, the driver executable file can also be found in the Program Files/Analog Devices folder. Follow the on-screen prompts to install it.

4.After installation of the software and drivers is complete, plug the EVAL-AD5544/45SDZ into the SDP board and the SDP board into the PC using the USB cable included in the box.

5.When the software detects the evaluation board, proceed through any dialog boxes that appear to finalize the installation (Found New Hardware Wizard/Install the Software Automatically and so on).

RUNNING THE SOFTWARE

To run the evaluation board program, do the following:

1.Click Start/All Programs/Analog Devices/EVALAD5544/45SDZ.

2.If the SDP board is not connected to the USB port when the software is launched, a connectivity error displays (see Figure 3). Simply connect the evaluation board to the USB port of the PC, wait a few seconds, click Rescan, and follow the instructions.

09900-003

Figure 3.

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USING THE EVALUATION BOARD SOFTWARE

Once the software is launched, the main window pops up (see Figure 4).

09900-004

Figure 4. Main Window

The first step is to select the device to use that is connected to the SDP board, in this case the AD5544, and click OK.

After selecting the device, the AD5544 evaluation software window appears (see Figure 5) to start writing to the device.

09900-005

Figure 5. AD5544 Evaluation Software Window

Evaluation Board User Guide

The desired 16-bit data loads and updates one of the four DACs that you selected within the AD5544 part.

There are two modes for loading the data. Synchronous mode enables you to program each channel separately and update them simultaneously. Program LDAC high, load the channels, and finally pull LDAC low. Asynch-ronous mode enables you to load and update each channel separately (the LDAC button is ignored in this case).

The reset button, RS, updates all channel outputs to zero scale or midscale when MSB is pulled low or high.

EXAMPLE

With LDAC and RS tied high for asynchronous loading mode, specify quarter scale (0x4000, 16384d) in the Input Data box and click Load and Update DAC A. The expected output obtained is

VOUT = −VREF ×65D,536 = −10×1665,,384536 = −2.5 V

When you change the loading synchronism mode to synchronous and write the value 0xC000 (49152d), you see no change in the output until LDAC is tied low. The expected output for this case is

VOUT = −VREF ×65,536D = −10×65,53649,152 = −7.5 V

Rev. A | Page 4 of 12