a
Evaluation Board for 32 Channel,
Infinite Sample-and-Hold
EVAL-AD5532EB
FEATURES
Full-Featured Evaluation Board for the AD5532/AD5533
On-Board 3V Reference
Various Link and Switch Options
PC Software for Control af AD5532/AD5533
Socketed AD5532/AD5533 for Easy Replacement
INTRODUCTION
This Technical Note describes the evaluation board for the
AD5532 and AD5533. These devices combine a 32 channel
voltage translation function with an infinite output hold
capability. An analog input voltage on the common input pin,
Vin, is sampled and its digital representation transferred to a
chosen DAC register. The output of this DAC is then
updated to reflect the new contents of the DAC register.
Channel selection is accomplished via the parallel address
inputs A0-A5 or via the serial input port. The AD5532 is
operated with AVcc= +5V+/-5%, DVcc= 2.5V to 5.25V,
Vss= -4.75V to -16.5V, Vdd= 10V to 16V and requires a
stable +3V reference on the REF_IN pin as well as an offset
voltage on OFFS_IN. These devices are available in a 74lead LFBGA package. Full datails are available in the
AD5532 and AD5533 datasheets from Analog Devices and
should be consulted in conjunction with this Technical Note
when using the Evaluation Board.
On-board components include an AD780 which is a pin
programmable +3V ultra high precision bandgap reference
and an AD5541 which is a 16-bit DAC that can be used to
provide an analog input voltage to the AD5532/AD5533.
There are various link and switch options which are explained in detail on page 2.
Interfacing to this board from a PC is through a 36-way
Centronics connector. This 36-way connector is compatible
with most printer cables and is usually connected to the
parallel printer port on a standard PC via a standard printer
cable.
OPERATING THE AD5532 EVALUATION BOARD
Power Supplies
The following external supplies must be provided: +5V
between the DVCC and DGND inputs which supplies the
DVCC pins on the AD5532. +5V between the AVCC and the
AGND inputs to supply the AD780, the AD5541, the AD820
and the AVCC pins on the AD5532. -15V to the VSS input
to supply the AD5532 AVSS pins. +15V to the VDD input
to supply the AD5532 AVDD pins.
Each supply is decoupled to the relevant ground plane with
a 47uF and a 0.1uF capacitor pair as it enters the board. Each
device supply pin is again decoupled with a 10uF and a 0.1uF
capacitor pair to the relevant ground plane.
There are 2 ground planes on the board, AGND and DGND.
These are connected together at one location close to the
AD5532. It is recommended not to connect these anywhere
else to avoid ground loop problems.
FUNCTIONAL BLOCK DIAGRAM
Power Supply Inputs
V0
3V
Reference
V0
AD5532/33
32-Channel
DAC/SHA
External
Ain
Ain
V31
Parallel Interface
14 pin Header
Seri al Inte rfa ce
36 p in C o nn ec to r
V31
DAC
REV. 0 04/00
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
EVAL-AD5532EB
LINK AND SWITCH OPTIONS
There are 2 link options and 3 switches which must be set for the required operating setup before using the evaluation board.
The functions of these link options and switches are outlined below.
Table I. Link and Switch Functions.
Link No.
Function.
LK1
This link option allows the user to select whether the AD5532 serial or parallel interface will be used.
When this link is in position "A" the SER/PAR pin is tied high thus selecting the serial interface.
When this link is in position "B" the SER/PAR pin is tied low thus selecting the parallel interface.
LK2
This link option is unused.
Switch No.
Function.
S1
This switch selects
clearly labelled on
When the slider is
When the slider is
S2
This switch selects the source of the offset voltage that must be applied to the AD5532 OFFS_IN pin. It has
2 settings each clearly labelled on the board, namely OFFS_OUT and SK1.
When the slider is moved to the OFFS_OUT position, the AD5532 OFFS_OUT pin provides the offset
voltage.
When the slider is moved to the SK1 position, the offset voltage must be provided via the exteral SMB socket,
SK1
S3
This switch selects the source of the analog input voltage that must be applied to the AD5532 VIN pin. It
has 2 settings each clearly labelled on the board, namely DAC and SK3.
When the slider is moved to the DAC position, the AD5541 sets up the analog input voltage under the control
of the evaluation software provided in the evaluation kit.
When the slider is moved to the SK3 position, the analog input voltage must be provided via the exteral SMB
socket, SK3
the source of the reference voltage for the AD5532 REFIN pin. It has 2 settings each
the board, namely REFOUTand AD780.
moved to the REFOUT position, the AD5532 REFOUT pin provides the 3V reference.
moved to the AD780 position, the AD780 reference provides the 3V reference.
SET-UP CONDITIONS
Care should be taken before applying power and signals to the evaluation board to ensure that all link/switch positions are
set as per the required operating mode. Table II shows the position in which all the links are set when the evaluation board
is sent out.
Table II. Initial Link and Switch Positions
Link No.
Position
Function.
LK1
A
Serial interface selected.
LK2
-
Not used.
S1
AD780
AD780 provides 3V reference.
S2
OFFS_OUT
The AD5532 OFFS_OUT pin provides the offset voltage which is connected to
the AD5532 OFFS_IN pin.
S3
DAC
The analog input voltage is provided by the AD5541 DAC under the control of the
evaluation software.
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EVAL-AD5532EB
EVALUATION BOARD INTERFACING
Serial interfacing
The 36-pin centronics connector interfaces to the serial interface on the AD5532 and also interfaces to the serial interface on
the AD5541. The evaluation software provided with the evaluation kit will only work when the user is using the serial interface.
The pin-out description and function of the 36-pin serial interface connector, J2, is given in Table III.
Table III. 36-pin Serial Interface connector.
Pin No.
Name
Description.
2
DIN
Connects to both the AD5532 and AD5541 DIN pins. Serial data is loaded to either
of these devices via this pin.
3
SCLK
Connects to the serial clock pins on the AD5532 and the AD5541.
4
SYNC(SHA)
Connects to the SYNC pin on the AD5532.
5
CS(DAC)
Connects to the CS pin on the AD5541.
6
TRACK
Connects to the TRACK/RESET pin on the AD5532.
10
DOUT
Connects to the DOUT pin on the AD5532.
13
BUSY
Connects to the BUSY pin on the AD5532.
19-30
GND
Connects to the DGND plane on the board.
For further information on the functions and timing of these signals refer to the AD5532 and AD5533 Data Sheets.
Parallel interfacing
The parallel interface connections are made available for user expansion at the 14-pin parallel interface header, J1. The pinout description and function of this header is given in Table IV.
Table IV. 14-pin Parallel Interface connector.
Pin No.
Name
Description.
1
TRACK
Connects to the TRACK/RESET pin on the AD5532.
2
OFFS_SEL
Connects to the OFFS_SEL pin on the AD5532.
3
CAL
Connects to the CAL pin on the AD5532.
4
A5
Connects to the A5 pin on the AD5532.
5
A4
Connects to the A4 pin on the AD5532.
6
A3
Connects to the A3 pin on the AD5532.
7
-
unused
8
A2
Connects to the A2 pin on the AD5532.
9
A1
Connects to the A1 pin on the AD5532.
10
A0
Connects to the A0 pin on the AD5532.
11
WR
Connects to the WR pin on the AD5532.
12
CS
Connects to the CS pin on the AD5532.
13
BUSY
Connects to the BUSY pin on the AD5532.
14
GND
Connects to the DGND plane on the board.
For further information on the function and timing of these signals refer to the AD5532 Data Sheet.
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EVAL-AD5532EB
EVALUATION BOARD SOFTWARE
Software installation
Install the ad5532 software from the floppy disk onto your PC
by executing setup.exe. Ensure that the Centronics cable
connects the PC to the AD5532 eval board. Run ad5532.exe.
The main menu looks as follows:
Select Channel
Once the offset is acquired you can apply an input voltage on
any selected channel as follows:
• Select any channel and enter the required VIN value (0-3V)
at Analog Input Voltage. Press Return.
• Click on Update Selected Channel to acquire the input
voltage and measure the corresponding VOUT. Check that
VOUT = 3.52*VIN - 2.52*VOFFSET (AD5532-1/-3/-5, AD5533)
and VOUT = 7*VIN - 6*VOFFSET (AD5532-2)
Fig. 1: Main Menu.
1) SHA Mode
In SHA mode an analog input voltage is set up on VIN via the
AD5541 DAC and the serial interface. The corresponding
VOUT output can be measured at the selected channel.
Cal Mode
This mode allows all 32 channels to acquire V IN simultaneously and can be useful in calibration.
• Ensure that switch S3 is at the DAC position. This
connects V IN to the AD5541 output, putting V IN under
software control.
• Select Cal Mode and enter the required VIN value at Analog
Input Voltage. Press Return.
• Click on Update Selected Channel to acquire VIN.
• De-select Cal Mode for individual channel selection.
Offset Channel
Program the offset voltage control channel as follows:
• Ensure that switch S2 is at the OFFS_OUT position. This
connects OFFS_IN to OFFS_OUT.
• Ensure that switch S3 is at the DAC position. This
connects V IN to the AD5541 output, putting V IN under
software control.
• Select Offset Channel and enter the required offset value at
Analog Input Voltage. Press Return.
• Click on Update Selected Channel to acquire the offset.
• De-select the Offset Channel.
Track OFF/ON
For evaluation purposes Track is normally set OFF so that
the selected channel begins to acquire when it is addressed.
Fig. 2: SHA Mode.
2) DAC Mode
In DAC mode all or one of the 32 DAC registers are written
to via the serial interface.
Cal Mode
This mode allows all 32 DACs to be loaded with all zeros or
all ones for system calibration.
• Select Cal Mode and enter a hex value at DAC Word. The
maximum value is 3FFFh. Press Return.
• Click on Update Selected Channel to update all DACs.
• De-select Cal Mode for individual DAC selection.
Offset Channel
Use this to program the offset as follows:
• Ensure that switch S2 is at the OFFS_OUT position. This
connects OFFS_IN to OFFS_OUT.
• Select Offset Channel and enter the required offset value in
hex at DAC Word. Press Return.
• Click on Update Selected Channel to acquire the offset.
• De-select the Offset Channel.
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EVAL-AD5532EB
Select Channel
Once the offset is acquired you can write a value (in hex) to
any selected DAC register as follows:
• Select any channel and enter the required hex value (0000
to 3FFF) at DAC Word (Hex). Press Return.
• Click on Update Selected Channel.
• Measure the corresponding VOUT.
4) Calibrated/SHA Mode
This mode allows the user to determine the output range of
each channel for a particular offset value. Results can be saved
to a file and re-loaded in a later session.
Channel Calibration
Determine the endpoints (VIN = 0.1V and VIN = 2.98V) of any
channel as follows:
• Enter the value at the OFFS_IN pin at Offset In(V).
• Select any particular input channel.
• Click on Calibrate Channel.
• Measure VOUT at the selected channel and enter it's value for
VIN = 100mV.
• Measure VOUT at the selected channel and enter it's value for
VIN = 2.98V.
See the Usable Range for the selected channel.
Fig. 3: DAC Mode.
3) Acquire/Readback Mode
This mode allows the user to read back the data in a particular
DAC register via the serial interface.
Acquire & Readback
Use this function to acquire VIN and read back the corresponding DAC value as follows:
• Select any channel and enter the required VIN value (0-3V)
at Analog Input Voltage. Press Return.
• Click on Acquire & Readback to acquire VIN and read back
the DAC value in hex at DAC Code.
Readback
Use this function to readback a particular DAC as follows:
• Select any channel and press Return.
• Click on Readback Only to read back the DAC value in hex
at DAC Code.
Fig. 5: Calibrated SHA Mode.
Saving calibration results
Offset and Gain values for all channels can be saved to a file
by clicking on Save Coefficients. To automatically save all
coefficients click on Auto-save Coefficients. Use Load Coefficients to reload coefficients from a previous session.
Required O/P voltage
Enter a value at Required O/P Voltage to program a specific
value at VOUT for the selected channel.
Fig. 4: Acquire & Readback Mode.
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Fig. 6: Evaluation Board Circuit Diagram.
EVAL-AD5532EB
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EVAL-AD5532EB
Fig. 7: Eval-AD5532EB Evaluation Board.
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