ANALOG DEVICES AD9954 Service Manual

400 MSPS, 14-Bit, 1.8 V CMOS,

FEATURES

400 MSPS internal clock speed Integrated 14-bit DAC Programmable phase/amplitude dithering 32-bit frequency tuning accuracy 14-bit phase tuning accuracy Phase noise better than –120 dBc/Hz Excellent dynamic performance

>80 dB narrowband SFDR Serial I/O control Ultrahigh speed analog comparator Automatic linear and nonlinear frequency sweeping 4 frequency/phase offset profiles

1.8 V power supply Software and hardware controlled power-down 48-lead TQFP Integrated 1024 word × 32-bit RAM Support for 5 V input levels on most digital inputs PLL-based REFCLK multiplier Internal oscillator, can be driven by a single crystal Phase modulation capability Multichip synchronization

Direct Digital Synthesizer

AD9954

GENERAL DESCRIPTION

The AD9954 is a direct digital synthesizer (DDS) that uses advanced technology, coupled with an internal high speed, high performance DAC to form a complete, digitally programmable, high frequency synthesizer capable of generating a frequencyagile analog output sinusoidal waveform at up to 160 MHz. The AD9954 enables fast frequency hopping coupled with fine tuning of both frequency (0.01 Hz or better) and phase (0.022° granularity).

The AD9954 is programmed via a high speed serial I/O port. The device includes static RAM to support flexible frequency sweep capability in several modes, plus a user-defined linear sweep mode of operation. Also included is an on-chip high speed comparator for applications requiring a square wave output. An on-chip oscillator and PLL circuitry provide users with multiple approaches to generate the device’s system clock.

The AD9954 is specified to operate over the extended industrial temperature range (see Table 2).

APPLICATIONS

Agile LO frequency synthesis Programmable clock generators FM chirp source for radar and scanning systems Automotive radars Test and measurement equipment Acousto-optic device drivers

BASIC BLOCK DIAGRAM

AD9954

400MSPS

DDS CORE

REF CLOCK

INPUT CIRCUIT RY

Rev. B

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TIMING AND

CONTROL

USER INTERFACE

14-BIT

DAC

COMPARATOR

Figure 1.

DIGITA SINE WAVE

03374-038