Analog Devices AD5370 Evaluation Board EVAL-AD5370EBZ EVAL-AD5370EBZ Hoja De Datos

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Preliminary Technical Data 
EVAL-AD5370/2/3EB
 
Rev. Pr A| Page 3 of 12 
GENERAL DESCRIPTION  
FUNCTIONALITY OVERVIEW 
The evaluation board for the AD537x is designed to allow the 
user to fully evaluate all the functions and performance of the 
AD537x prior to designing it into a system. The evaluation 
board can be used in a stand-alone mode with the control 
signals being provided through the 20 pin header J3 or it can be 
connected to a PC using the USB cable supplied with the 
evaluation board kit. Software is provided which allows the user 
to program the various registers of the AD537x with ease. The 
software operation is described later in this document.  
POWER SUPPLIES 
The evaluation board requires a +5V supply for DV
CC
. The V
DD
 
and V
SS
 supplies can be any value within the power supply 
limits as specified in the AD537x data sheet. Power supply 
connections are made to the screw terminals of J2. The USB 
interface, if used, gets its power supply from the USB port of the 
PC. This power supply is not used by the AD537x or any of its 
associated circuitry. When connecting the power supply leads it 
is recommended that the supplies are turned off and that the 
ground leads are connected first. 
REFERENCE SELECTION 
The evaluation board includes two voltage references ICs, the 
ADR435 and ADR423 which are 5V and 3V references 
respectively. An SMB connector is provided to allow an external 
voltage to be connected for use as a reference. Link LK4 is used 
to select which reference source is used by the AD537x as 
shown in Table 1.  
Table 1. Reference Selection using LK4 
LK4 
Position 
Description 
The reference voltage is 3V (default) 
The reference voltage is 5V 
The voltage on the SMB, EXT_REF is used as the 
reference voltage 
 
By default the voltage reference pins of the AD537x, VREF0 and 
VREF1, both use the same reference, i.e. that selected by LK4. If 
it is required that the reference pins should use different voltage 
references this can be achieved by removing the 0Ω resistor 
associated with each VREF pin. The required reference can then 
be connected to the testpoint associated with the VREF pin. 
Table shows the 0Ω resistor and testpoint associated with each 
VREF pin. 
Table 2. 0Ω Resistor and Testpoints for VREF pins 
VREF Resistor 
Testpoint 
VREF0 R17 
T63 
VREF1 R18 
T64 
 
USING THE USB INTERFACE 
The software provided with the evaluation board kit allows the 
user to program the registers of the AD537x via the USB 
interface. It is important that the software supplied is installed 
on the PC before the board is connected. See the Using the USB 
Software section for more information. The USB circuitry gets 
its power from the USB port of the PC and will generate the 
required interface signals, 
RESET
,
 CLR,
 
SYNC, 
SCLK etc. to 
control the AD537x. To use the interface LK1, LK3 and LK8 
should be in place. The function of these links is described in 
Table 4.  
STAND-ALONE OPERATION 
The evaluation board can be used as a stand-alone device if 
required. This has the advantage that it lets the user to connect 
the interface pins of the AD537x to their own DSP or micro-
controller thus allowing them to write code to operate the 
AD537x as their application requires. To use the board in stand-
alone mode the connection to the USB interface must be 
removed. This is achieved by removing LK1, which will three-
state the connections to
 CLR, LDAC, SYNC, SCLK and DIN. 
LK3 
should be removed to isolate the RESET pin from the USB 
interface and the push-button. The interface signals required to 
control the AD537x can then be provided through the 20 pin 
header J3. The pinout of J3 is shown in Table 3
 
Table 3. J3 Header Pinout 
Pin Signal 
Pin 
Signal 
1 DIN  8 
LDAC 
2 NC 
10 
CLR 
3 SCLK  12 
BUSY 
4 NC 
14 
RESET 
5 NC 
16 
NC 
SYNC 
18 NC 
7,9,11,13, 
15,17,19,20 
DGND