Analog Devices AD9912 User Manual

1 GSPS Direct Digital

AD9912

FDBK_IN

DAC_OUT

AD9912

S1 TO S4

OUT

OUT_CMOS

FILTER

SYSTEM CLOCK

MULTIPLIER

SERIAL PORT,

I/O LOGIC

CLOCK

OUTPUT

DRIVERS

DIGITAL

INTERFACE

06763-001

DIRECT

DIGITAL

SYNTHESIS

CORE

STARTUP

CONFIGURATION

LOGIC

FEATURES

1 GSPS internal clock speed (up to 400 MHz output directly) Integrated 1 GSPS 14-bit DAC 48-bit frequency tuning word with 4 µHz resolution Differential HSTL comparator Flexible system clock input accepts either crystal or external

reference clock On-chip low noise PLL REFCLK multiplier 2 SpurKiller channels Low jitter clock doubler for frequencies up to 750 MHz Single-ended CMOS comparator; frequencies of <150 MHz Programmable output divider for CMOS output Serial I/O control Excellent dynamic performance Software controlled power-down Available in two 64-lead LFCSP packages Residual phase noise @ 250 MHz

10 Hz offset: −113 dBc/Hz

1 kHz offset: −133 dBc/Hz

100 kHz offset: −153 dBc/Hz

40 MHz offset: −161 dBc/Hz

Synthesizer with 14-Bit DAC

APPLICATIONS

Agile LO frequency synthesis Low jitter, fine tune clock generation Test and measurement equipment Wireless base stations and controllers Secure communications Fast frequency hopping

GENERAL DESCRIPTION

The AD9912 is a direct digital synthesizer (DDS) that features an integrated 14-bit digital-to-analog converter (DAC). The AD9912 features a 48-bit frequency tuning word (FTW) that can synthesize frequencies in step sizes no larger than 4 μHz. Absolute frequency accuracy can be achieved by adjusting the DAC system clock.

The AD9912 also features an integrated system clock phaselocked loop (PLL) that allows for system clock inputs as low as 25 MHz.

The AD9912 operates over an industrial temperature range, spanning −40°C to +85°C.

BASIC BLOCK DIAGRAM

Rev. D

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Figure 1.

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