Analog Devices AD9912 specifications Features, Applications, General Description

1 GSPS Direct Digital Synthesizer with 14-Bit DAC

AD9912

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

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 phase- locked 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

	AD9912
			DAC_OUT
S1 TO S4	STARTUP
	CONFIGURATION
	LOGIC	DIRECT	FDBK_IN	FILTER
		DIGITAL
		SYNTHESIS
		CORE		OUT
DIGITAL	SERIAL PORT,		CLOCK
			OUTPUT
INTERFACE	I/O LOGIC
			DRIVERS	OUT_CMOS
		SYSTEM CLOCK
		MULTIPLIER
				06763-001

Figure 1.

Rev. D

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