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Evaluation Board for the AD7294 12-Bit, Multichannel,

ADC, DACs, Temperature Sensors, and Current Sensors

EVAL-AD7294

Rev. 0

Evaluation boards are only intended for device evaluation and not for production purposes.

Evaluation boards are supplied “as is” and without warranties of any kind, express, implied, or

statutory including, but not limited to, any implied warranty of merchantability or fitness for a

particular purpose. No license is granted by implication or otherwise under any patents or other

intellectual property by application or use of evaluation boards. Information furnished by Analog

Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog

Devices for its use, nor for any infringements of patents or other rights of third parties that may result

from its use. Analog Devices reserves the right to change devices or specifications at any time

without notice. Trademarks and registered trademarks are the property of their respective owners.

Evaluation boards are not authorized to be used in life support devices or systems.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

FEATURES

Full featured evaluation board for AD7294

Graphical user interface software with USB control

Can be powered entirely from the USB port or using an

external power source

Various link options

APPLICATIONS

Cellular base stations (GSM, EDGE, UMTS, CDMA)

Point-to-multipoint and other RF transmission systems

12 V, 24 V, 48 V automotive applications

Industrial control

GENERAL DESCRIPTION

This data sheet describes the evaluation board for the AD7294,

which is a 12-bit monitoring and control device with multichannel

ADC, DACs, temperature sensors, and current sensors. The

AD7294 is a highly integrated solution that offers all the func-

tionality necessary for precise control of the power amplifier in

cellular base station applications.

The AD7294 includes low voltage (±200 mV) analog input

sense amplifiers for current monitoring across shunt resistors,

temperature sense inputs, and four uncommitted analog input

channels multiplexed into a successive approximation (SAR)

analog-to-digital converter (ADC) with a 3 s conversion time.

A high accuracy internal reference is provided to drive both the

digital-to-analog converter (DAC) and the ADC. Four 12-bit

DACs provide the outputs for voltage control. The AD7294 also

includes limit registers for alarm functions.

The part is designed on the Analog Devices, Inc., high voltage

diffused metal-oxide semiconductor (DMOS) process for high

voltage compliance—59.4 V on the current sense inputs, and up to

a 15 V for the DAC output voltage. Full details about the AD7294

are available in the AD7294 data sheet, which is available from

Analog Devices and should be consulted in conjunction with

this data sheet when using this evaluation board.

Configuration of the various link options is explained in the

Evaluation Board Hardware section. Interfacing to the AD7294

is through a USB microcontroller, which generates the I

C signals.

External sockets are provided for several input and output signals.

The EVAL-AD7294 is supplied with software to enable communi-

cation between the user and the device. Other on-board components

include an EEPROM, a Cypress USB microcontroller, and a

voltage regulator.

FUNCTIONAL BLOCK DIAGRAM

07922-001

LIMIT

REGISTERS

MUX

CONTROL LOGIC

C INTERFACE

PROTOCOL

TEMP

SENSOR

HIGH SIDE

CURRENT

SENSE

HIGH SIDE

CURRENT

SENSE

REF

OUT

REF

DAC

T1 T2

TO LOAD

RS1(+) RS2(+) RS2(–)RS1(–)

D1+

D2+

D1–

D2–

(1 TO 6)

AGND

(1 TO 7)

DAC OUT

GND AB/CD

AD7294

REF

OUT

REF

ADC

(1 TO 2)

ALERT/BUSYDCAP

REF

10.41

SENSE

OVERRANGE

SENSE

OVERRANGE

SENSE

12-BIT

ADC

DAC OUTV+

AB/CD

DGND (1 TO 2)

12-BIT

DAC

100kΩ 200kΩ

12-BIT

DAC

100kΩ 200kΩ

12-BIT

DAC

100kΩ 200kΩ

12-BIT

DAC

100kΩ 200kΩ

OFFSET IN A

OUT

OFFSET IN B

OUT

OFFSET IN C

OUT

OFFSET IN D

OUT

2.5V

REF

AS0AS1AS2SCLSDA

Figure 1. Typical Configuration for AD7294 in Cellular Base Station RF Lateral-Diffused Metal-Oxide Semiconductor (LDMOS) Power Amplifier Control

Summary of content (24 pages)

PAGE 1
Evaluation Board for the AD7294 12-Bit, Multichannel, ADC, DACs, Temperature Sensors, and Current Sensors EVAL-AD7294 temperature sense inputs, and four uncommitted analog input channels multiplexed into a successive approximation (SAR) analog-to-digital converter (ADC) with a 3 μs conversion time. A high accuracy internal reference is provided to drive both the digital-to-analog converter (DAC) and the ADC. Four 12-bit DACs provide the outputs for voltage control.
PAGE 2
EVAL-AD7294 TABLE OF CONTENTS Features .............................................................................................. 1 Main Window ............................................................................. 10 Applications ....................................................................................... 1 Configuration Window ............................................................. 10 General Description ......................................................................
PAGE 3
EVAL-AD7294 EVALUATION BOARD HARDWARE K10 and K11 can be, but do not have to be, inserted as previously described. POWER SUPPLIES There are two options available for powering the AD7294 evaluation board: • • Using the USB port of a computer Using an external power supply The default option for powering the board is to use the USB port.
PAGE 4
EVAL-AD7294 LINKS The link options on the evaluation board should be set for the required functionality prior to using the board. There are 20 link options, the functions of which are outlined in Table 1. By default, power to the board is supplied through the USB port. Table 1. Link Function Descriptions Link No. K1 K2 K3 K4 K5 K6 K7 K8 K9 K10 K11 K12 K13 K14 Function This link option selects the source of the VIN0 analog input to the AD7294.
PAGE 5
EVAL-AD7294 Link No. K15 Function This link option selects whether the VOUT A signal is filtered prior to being supplied to the VOUT A SMB. K16 K15 in Position A: the VOUT A signal is filtered by a 100 kΩ resistor and a capacitor. This link option should be used in conjunction with K16 in Position A to provide the output signal to the VOUT A SMB. K15 in Position B: the VOUT A signal from the AD7294 is connected directly to K16.
PAGE 6
EVAL-AD7294 SOCKETS CONNECTORS There are 22 SMB input/output sockets relevant to the operation of the AD7294 on this evaluation board. All of these sockets are used for applying an externally generated signal to the evaluation board or for accessing an output signal from the AD7294.
PAGE 7
EVAL-AD7294 GETTING STARTED SUMMARY OF THE SETUP SEQUENCE 1. 2. 3. 4. Install the AD7294 graphical user interface software, which accompanies the evaluation board. Do not connect the USB cable from the AD7294 evaluation board to the computer USB hub at this stage. See the Installing the Software section for more information. Connect the USB port from the computer to the evaluation board, and run the USB installation wizard. See the Connecting the USB Cable section for more information.
PAGE 8
EVAL-AD7294 6. 5. 6. A warning message appears (see Figure 9), indicating that the new hardware you are installing (AD7294 evaluation kit) has not passed the Windows logo testing to verify compatibility with Windows XP. This error appears because this is an evaluation setup installation and is not meant to be used in a production environment. Click Continue Anyway, and then click Finish. 07922-006 7.
PAGE 9
EVAL-AD7294 When using an external power supply, VERIFYING THE LINKS AND POWERING UP THE EVALUATION BOARD 1. Care should be taken before applying power and signals to the evaluation board. It is necessary to ensure that all links are positioned correctly for the chosen operating mode. Table 2 shows the position in which all the links are set when the evaluation board is packaged. There are two different modes in which to operate the evaluation board.
PAGE 10
EVAL-AD7294 USING THE SOFTWARE MAIN WINDOW 07922-013 After following the procedures in the Getting Started section, the main window, shown in Figure 11, appears upon starting the evaluation software program. Use the drop-down menus in this window to navigate through the various operational functions of the AD7294 evaluation board. Figure 13. ADC Menu of the Main Window DAC Menu The DAC menu allows you to load values to any of the four DAC channels.
PAGE 11
EVAL-AD7294 DEVICE ADDRESS INFORMATION WINDOW The Register Map window is a useful tool that allows reading any register that can be accessed by the address pointer register. For more information, see the AD7294 data sheet. Each data register, whether 8 bits or 16 bits, is accessed by the software, and then the contents are displayed in this window. The window provides details about the function or mode represented by each bit, as shown in Figure 16.
PAGE 12
EVAL-AD7294 READ CHANNEL WINDOW To read the converted analog signals from the 9-channel ADC, select Read Channel in the ADC menu of the main window. The Read Channel window appears, allowing you to select which channel to access by clicking one of the nine tabs at the top of the window. There are two methods of reading the converted data. Clicking Read Single Value adds one value at a time to a list, whereas clicking Start Scope results in the values being stored in an array to draw the scope plot.
PAGE 13
EVAL-AD7294 limit up to 4095 in the Hysteresis Value box in the Limits tab (see Figure 19). The Vref tab (see Figure 21) allows you to select an external reference for the ADC, with two decimals of accuracy. 07922-020 If the hysteresis register is filled with all 1s, the part operates in minimum/maximum mode. The DATAHIGH register stores the maximum conversion result, and the DATALOW register stores the minimum conversion result.
PAGE 14
EVAL-AD7294 ALERT MANAGER WINDOW The Alert Manager window analyzes the alert register to check for any alert events. An alert is signaled on a specific channel when the input analog signal becomes greater than or less than the specified limits. The software changes the marker from the color gray to the color red to convey an alert (see Figure 23). Due to timing constraints inherent in the software and Windows, an alert can be checked every 100 ms to 2000 ms.
PAGE 15
EVAL-AD7294 EXTERNAL TEMPERATURE SENSOR OFFSET CALIBRATION WINDOW The External Temperature Sensor Offset Calibration window is used to calibrate the temperature, correcting errors attributable to noise that may be coupled onto the Dx+ and Dx− lines of the remote temperature sensors. Both TSENSE1 and TSENSE2 can be offset using the gauges shown in Figure 25. The gauges can be adjusted from between −32°C and +31.
PAGE 16
EVAL-AD7294 LOAD DAC WINDOW The DAC tab in the main window contains only one option, Load DAC Channel. The Load DAC window allows you to select any of the four DAC outputs and then load a value, using the gauge on the left side of the window (see Figure 26). All four DACs can be loaded simultaneously. Note that the DAC output is twice the reference voltage when no offset is applied. VOUT = 3VOFFSET − 5 + VDAC Figure 27 shows an external voltage of 2.0 V being applied to DAC1.
PAGE 17
EVAL-AD7294 FREQUENTLY ASKED QUESTIONS How Can I Confirm that the Hardware Has Been Correctly Installed in my Computer? Right-click My Computer and left-click Properties. On the Hardware tab, click Device Manager (see Figure 28). 07922-029 EXPAND ROOT DIRECTORY Figure 29. Universal Serial Bus Controllers Root Directory, with Correctly Installed Hardware 07922-028 During the Installation, the Message in Figure 30 Appears. When I Click Finish, the Message in Figure 31 Appears.
PAGE 18
EVAL-AD7294 evaluation board and wait for approximately 30 sec before plugging it in again. 1. EXPAND THIS DIRECTORY 2. RIGHT-CLICK ON THIS DEVICE 07922-032 CORRECTLY INSTALLED Proceed through the installation wizard a second time. A correct installation is indicated by the expanded root directory shown in Figure 33.
PAGE 19
EVAL-AD7294 LAYOUT AND CONFIGURATION GUIDELINES POWER SUPPLY DECOUPLING AND GROUNDING When accuracy is important in a circuit, carefully consider the power supply and ground return layout on the board. The printed circuit board containing the AD7294 should have separate analog and digital sections, each having its own area of the board. If the AD7294 is in a system where other devices require an AGND-to-DGND connection, the connection should be made at one point only.
PAGE 20
EVAL-AD7294 EVALUATION BOARD SCHEMATIC AND ARTWORK 07922-034 Figure 34. Evaluation Board Schematic Rev.
PAGE 21
07922-035 EVAL-AD7294 Figure 35. Evaluation Board Schematic, Auxiliary Blocks Rev.
PAGE 22
EVAL-AD7294 4950mil 07922-036 3100mil 07922-037 Figure 36. Evaluation Board Layout, Component Side View Figure 37. Evaluation Board Layout, Silkscreen View Rev.
PAGE 23
07922-038 EVAL-AD7294 Figure 38. Evaluation Board Layout, Solder Side View Rev.
PAGE 24
EVAL-AD7294 ORDERING INFORMATION BILL OF MATERIALS Table 5.