Datasheet

AD9958 Data Sheet
Rev. B | Page 2 of 45
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
General Description ......................................................................... 4
Specifications ..................................................................................... 5
Absolute Maximum Ratings ............................................................ 9
ESD Caution .................................................................................. 9
Pin Configuration and Function Descriptions ........................... 10
Typical Performance Characteristics ........................................... 12
Application Circuits ....................................................................... 15
Equivalent Input and Output Circuits ......................................... 18
Theory of Operation ...................................................................... 19
DDS Core ..................................................................................... 19
Digital-to-Analog Converter .................................................... 19
Modes of Operation ....................................................................... 20
Channel Constraint Guidelines ................................................ 20
Power Supplies ............................................................................ 20
Single-Tone Mode ...................................................................... 20
Reference Clock Modes ............................................................. 21
Scalable DAC Reference Current Control Mode ................... 22
Power-Down Functions ............................................................. 22
Modulation Mode ....................................................................... 22
Modulation Using SDIO_x Pins for RU/RD........................... 25
Linear Sweep Mode .................................................................... 26
Linear Sweep No-Dwell Mode ................................................. 27
Sweep and Phase Accumulator Clearing Functions .............. 28
Output Amplitude Control Mode ............................................ 29
Synchronizing Multiple AD9958 Devices ................................... 30
Automatic Mode Synchronization ........................................... 30
Manual Software Mode Synchronization ................................ 30
Manual Hardware Mode Synchronization .............................. 30
I/O_UPDATE, SYNC_CLK, and System Clock
Relationships ............................................................................... 31
Serial I/O Port ................................................................................. 32
Overview ..................................................................................... 32
Instruction Byte Description .................................................... 33
Serial I/O Port Pin Description ................................................ 33
Serial I/O Port Function Description ...................................... 33
MSB/LSB Transfer Description ................................................ 33
Serial I/O Modes of Operation ................................................. 34
Register Maps and Bit Descriptions ............................................. 37
Register Maps .............................................................................. 37
Descriptions for Control Registers .......................................... 40
Descriptions for Channel Registers ......................................... 42
Outline Dimensions ....................................................................... 45
Ordering Guide .......................................................................... 45
REVISION HISTORY
4/13—Rev. A to Rev. B
Changes to Linear Sweep Mode Section and Setting the Slope of
the Linear Sweep ............................................................................. 25
Changes to Figure 38 and Figure 39 Captions ............................ 27
Changes to Ramp Rate Timer Section ......................................... 28
Updated Outline Dimensions ....................................................... 44
7/08—Rev. 0 to Rev. A
Changes to Features .......................................................................... 1
Inserted Figure 1; Renumbered Sequentially ................................ 1
Changes to Input Level Parameter in Table 1 ............................... 4
Added Profile Pin Toggle Rate Parameter in Table 1 ................... 6
Changes to Layout ............................................................................ 8
Changes to Table 3 ............................................................................ 9
Added Equivalent Input and Output Circuits Section .............. 17
Changes to Reference Clock Input Circuitry Section ................ 20
Change to Figure 35 ....................................................................... 21
Changes to Setting the Slope of the Linear Sweep Section ....... 25
Changes to Figure 37...................................................................... 26
Changes to Figure 38 and Figure 39 ............................................ 27
Changes to Figure 40...................................................................... 30
Added Table 25; Renumbered Sequentially ................................ 31
Changes to Figure 41...................................................................... 31
Changes to Figure 42, Serial Data I/O (SDIO_0, SDIO_1,
SDIO_3) Section, and Added Example Instruction Byte
Sect ion .............................................................................................. 32
Added Table 27 ............................................................................... 33
Changes to Figure 46, Figure 47, Figure 48, and Figure 49 ...... 35
Changes to Register Maps and Bit Descriptions Section and
Added Endnote 2 to Table 28 ........................................................ 36
Added Endnote 1 to Table 30 ........................................................ 38
Added Exposed Pad Notation to Outline Dimensions ............. 44
9/05—Revision 0: Initial Version