AN-759 Datasheet, PDF (1/4 Pages) Analog Devices – Expanding the Number of DAC Outputs on the ADuC8xx and ADuC702x Families

AN-759
APPLICATION NOTE
One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106 • Tel: [phone] • Fax: [phone] • www.analog.com
Expanding the Number of DAC Outputs on the ADuC8xx and ADuC702x Families
by Aude Richard
INTRODUCTION
The MicroConverter^® family of products from Analog
Devices incorporates both single and multiple voltage
output DACs.
In certain applications additional analog output channels
may be required. Therefore, the MicroConverter must
be interfaced to a discrete external multichannel DAC.
Interfacing the MicroConverter to Analog Devices’ family
of small footprint, SPI^® -compatible, multichannel DACs
is an extremely easy way to expand the voltage output
channels available in your system.
This application note describes how to interface the
ADuC814 or the ADuC7020 to the AD5304/AD5314/
AD5324 (AD53x4) quad voltage output 8 - /10 - /12-bit
DACs using a simple 3-wire SPI-compatible interface.
AD53x4
The AD53x4 (Figure 1) is a quad 8 -/10 -/12-bit buffered
voltage output DAC in a 10 -lead micro SOIC package
that operates from a single 2.5 V to 5.5 V supply con-
suming 500 A at 3 V. Its on - chip output amplifiers
allow rail-to-rail output swing to be achieved with a
slew rate of 0.7 V/s. A 3-wire serial interface is used
that operates at clock rates up to 30 MHz and is compat-
ible with standard SPI interface standards. For more
details, refer to the AD5304 data sheet.
SCLK
SYNC
DIN
LDAC
V_DD
REFIN
INPUT
REGISTER
DAC
REGISTER
STRING _BUFFER
DAC A
INTERFACE
LOGIC
INPUT
REGISTER
DAC
REGISTER
STRING _BUFFER
DAC B
INPUT
REGISTER
DAC
REGISTER
STRING
DAC C
BUFFER
INPUT
REGISTER
DAC
REGISTER
STRING
DAC D
BUFFER
POWER-DOWN
POWER-ON
RESET
AD5304/AD5314/AD5324
LOGIC
GND
Figure 1. AD53x4 Functional Block Diagram
V_OUTA
V_OUTB
V_OUTC
V_OUTD
REV. 0