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PmodDA3™ Reference Manual
Revised April 12, 2016
This manual applies to the PmodDA3 rev. B
DOC#: 502-241
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 1 of 2
Overview
The PmodDA3 is a 16-bit digital-to-analog converter (DAC) with an SMA connector for high resolution and low
noise analog output.
1 Functional Description
The PmodDA3 utilizes Analog Devices AD5541A to provide analog output with 16-bit resolution.
2 Interfacing with the Pmod
The PmodDA3 communicates with the host board via a SPI-like protocol. This interface is different than the
traditional SPI protocol in the fact that the pin normally designated to the host receiving data (MISO), is now used
for a Load DAC (LDAC) function so that the output of the DAC can be updated immediately once the module is
loaded with the incoming 16 bits of data.
To send data to the Pmod, users must drive the Chip Select (CS) line to a logic level low voltage and then send the
16 clock pulses and 16 bits of data in SPI Mode 0; that is, placing the most significant bit (MSB) of data on the data
line right after the Serial Clock line (SCLK) has been brought to a logic level low voltage.
When all of the data has been latched into, i.e. prepared for, the internal serial input register, bringing the CS line
back to a logic level high voltage will transfer all of the data from the shift register to the serial input register if
The PmodDA3.
Features include:
PmodDA3™ Reference Manual
Copyright Digilent, Inc. All rights reserved.
Other product and company names mentioned may be trademarks of their respective owners.
Page 2 of 2
LDAC is at a high voltage state. Pulsing the LDAC pin low and then high will asynchronously transfer all of the data
into the DAC register, resulting in the appropriate analog voltage on the SMA connector. Alternatively, users may
hold the LDAC pin at a logic level low voltage when bringing the CS pin high to directly transfer the data from the
shift register to the DAC register.
Pin
Signal
Description
1
~CS
Chip Select
2
DIN
Data Input
3
~LDAC
LOAD DAC
4
SCLK
Serial Clock
5
GND
Power Supply Ground
6
VCC
Power Supply (3.3V/5V)
Table 1. Pinout description table.
Any external power applied to the PmodDA3 must be within 2.7V and 5.5V; however, it is recommended that the
Pmod is operated at 3.3V.
3 Physical Dimensions
The pins on the pin header are spaced 100 mil apart. The PCB is 1.2 inches long on the sides parallel to the pins on
the pin header and 0.8 inches long on the sides perpendicular to the pin header.