AD9854AST datasheet(4/52 Pages) AD

4 / 52 page

AD9854

Rev. E | Page 4 of 52

GENERAL DESCRIPTION

The AD9854 digital synthesizer is a highly integrated device

that uses advanced DDS technology, coupled with two internal

high speed, high performance quadrature DACs to form a digitally

programmable I and Q synthesizer function. When referenced

to an accurate clock source, the AD9854 generates highly stable,

frequency-phase, amplitude-programmable sine and cosine

outputs that can be used as an agile LO in communications, radar,

and many other applications. The innovative high speed DDS core

of the AD9854 provides 48-bit frequency resolution (1 μHz tuning

resolution with 300 MHz SYSCLK). Maintaining 17 bits ensures

excellent SFDR.

The circuit architecture of the AD9854 allows the generation of

simultaneous quadrature output signals at frequencies up to

150 MHz, which can be digitally tuned at a rate of up to

100 million new frequencies per second. The sine wave output

(externally filtered) can be converted to a square wave by the

internal comparator for agile clock generator applications.

The device provides two 14-bit phase registers and a single pin

for BPSK operation.

For higher-order PSK operation, the I/O interface can be used

for phase changes. The 12-bit I and Q DACs, coupled with the

innovative DDS architecture, provide excellent wideband and

narrow-band output SFDR. The Q DAC can also be configured

as a user-programmable control DAC if the quadrature function

is not desired. When configured with the comparator, the 12-bit

control DAC facilitates static duty cycle control in high speed

clock generator applications.

Two 12-bit digital multipliers permit programmable amplitude

modulation, on/off output shaped keying, and precise amplitude

control of the quadrature output. Chirp functionality is also

included to facilitate wide bandwidth frequency sweeping

applications. The programmable 4× to 20× REFCLK multiplier

circuit of the AD9854 internally generates the 300 MHz system

clock from an external lower frequency reference clock. This

saves the user the expense and difficulty of implementing a

300 MHz system clock source.

Direct 300 MHz clocking is also accommodated with either single-

ended or differential inputs. Single-pin conventional FSK and

the enhanced spectral qualities of ramped FSK are supported.

The AD9854 uses advanced 0.35 μm CMOS technology to

provide a high level of functionality on a single 3.3 V supply.

The AD9854 is pin-for-pin compatible with the AD9852 single-

tone synthesizer. It is specified to operate over the extended

industrial temperature range of −40°C to +85°C.

AD9854AST Datasheet(PDF) 4 Page - Analog Devices

AD9854AST Datasheet(HTML) 4 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

Datasheet Download

Link URL