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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.
a
AD9835
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1998
50 MHz CMOS
Complete DDS
FUNCTIONAL BLOCK DIAGRAM
IOUT
COMP
REFINFS ADJUSTREFOUTAGNDAVDDDGNDDVDD
MCLK
PSEL0 PSEL1
12
S
AD9835
ON-BOARD
REFERENCE
10-BIT
DAC
PHASE0 REG
PHASE1 REG
PHASE2 REG
PHASE3 REG
FULL-SCALE
CONTROL
COS
ROM
PHASE
ACCUMULATOR
(32 BIT)
MUX
FREQ0 REG
FREQ1 REG
MUX
16-BIT DATA REGISTER
SYNC
FSELECT
FSELECT
BIT
SELSRC
SYNC
8 LSBs8 MSBs
DECODE LOGIC
FSYNC SCLK SDATA
SERIAL REGISTER
CONTROL REGISTER
FSELECT/PSEL REGISTER
DEFER REGISTER
SYNC
SYNC
SELSRC
PSEL0
BIT
PSEL1
BIT
FEATURES
5 V Power Supply
50 MHz Speed
On-Chip COS Look-Up Table
On-Chip 10-Bit DAC
Serial Loading
Power-Down Option
200 mW Power Consumption
16-Lead TSSOP
APPLICATIONS
DDS Tuning
Digital Demodulation
GENERAL DESCRIPTION
The AD9835 is a numerically controlled oscillator employing
a phase accumulator, a COS Look-Up Table and a 10-bit
D/A converter integrated on a single CMOS chip. Modulation
capabilities are provided for phase modulation and frequency
modulation.
Clock rates up to 50 MHz are supported. Frequency accuracy
can be controlled to one part in 4 billion. Modulation is ef-
fected by loading registers through the serial interface. A
power-down bit allows the user to power down the AD9835 when
it is not in use, the power consumption being reduced to 1.75 mW.
The part is available in a 16-lead TSSOP package.