CMOS 180 MHz DDS/DAC Synthesizer AD9851 FEATURES FUNCTIONAL BLOCK DIAGRAM 180 MHz Clock Rate with Selectable 6 Reference Clock Multiplier +V GND S On-Chip High Performance 10-Bit DAC and High Speed AD9851 DAC R Comparator with Hysteresis SET REF 6 REFCLK SFDR >43 dB 70 MHz A OUT CLOCK IN MULTIPLIER 10-BIT ANALOG HIGH SPEED DAC 32-Bit Frequency Tuning Word OUT DDS MASTER RESET Simpli ed Contfi rol Interface: Parallel or Serial PHASE 32-BIT Asynchronous Loading Format AND TUNING CONTROL ANALOG WORD 5-Bit Phase Modulation and Offset Capability WORDS IN FREQUENCY Comparator Jitter <80 ps p-p 20 MHz FREQUENCY/PHASE UPDATE/DATA DATA REGISTER REGISTER CLOCK OUT 2.7 V to 5.25 V Single-Supply Operation RESET Low Power: 555 mW 180 MHz WORD LOAD DATA INPUT REGISTER CLOCK OUT CLOCK Power-Down Function, 4 mW 2.7 V SERIAL COMPARATOR PARALLEL LOAD LOAD Ultrasmall 28-Lead SSOP Packaging 1 BIT 8 BITS APPLICATIONS 40 LOADS 5 LOADS Frequency/Phase-Agile Sine Wave Synthesis FREQUENCY, PHASE AND CONTROL DATA INPUT Clock Recovery and Locking Circuitry for Digital Communications Digitally Controlled ADC Encode Generator Agile Local Oscillator Applications in Communications Quadrature Oscillator CW, AM, FM, FSK, MSK Mode Transmitter GENERAL DESCRIPTION The AD9851 contains an internal high speed comparator that The AD9851 is a highly integrated device that uses advanced can be confi gured to accept the (externally) fi ltered output of the DDS technology, coupled with an internal high speed, high DAC to generate a low jitter output pulse. performance D/A converter, and comparator, to form a dig i tal ly The frequency tuning, control, and phase modulation words are programmable frequency synthesizer and clock generator func- asynchronously loaded into the AD9851 via a parallel or serial tion. When referenced to an accurate clock source, the AD9851 loading format. The parallel load format consists of vfi e it era tive generates a stable frequency and phase-programmable digitized loads of an 8-bit control word (byte). The rfi st 8-bit byte controls analog output sine wave. This sine wave can be used directly as output phase, 6 REFCLK Multiplier, power-down enable and a frequency source, or internally converted to a square wave for loading form at the remaining bytes comprise the 32-bit frequency agile-clock generator applications. The AD9851s innovative tuning word. Serial loading is accomplished via a 40-bit serial data high speed DDS core accepts a 32-bit frequency tuning word, stream entering through one of the parallel input bus lines. The which results in an output tuning res ol u tion of approximately AD9851 uses advanced CMOS technology to provide this break- 0.04 Hz with a 180 MHz system clock. The AD9851 con tains t hrough level of functionality on just 555 mW of power dissipation a unique 6 REFCLK Multiplier circuit that eliminates the (5 V supply), at the maximum clock rate of 180 MHz. need for a high speed reference oscillator. The 6 REFCLK The AD9851 is available in a space-saving 28-lead SSOP, Multiplier has mini m al impact on SFDR and phase noise char- surface-mount package that is pin-for-pin compatible with the act eri s tics. The AD9851 provides five bits of programmable popular AD9850 125 MHz DDS. It is spec ified to operate over phase modu lat ion resolution to enable phase shifting of its the extended industrial temperature range of 40C to +85C output in inc re ments of 11.25. at >3.0 V supply voltage. Below 3.0 V, the spec ifications apply over the commercial temperature range of 0C to 85C. REV. D Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. that may result from its use. No license is granted by implication or oth- Tel: 781/329-4700 www.analog.com erwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Fax: 781/326-8703 2004 Analog Devices, Inc. All rights reserved.1 (V = 5 V 5%, R = 3.9 k, 6 REFCLK Multiplier Disabled, External Ref er ence S SET AD9851SPECIFICATIONS Clock = 180 MHz, except as noted.) Test AD9851BRS Parameter Temp Level Min Typ Max Unit CLOCK INPUT CHARACTERISTICS Frequency Range (6 REFCLK Multiplier Disabled) 5.0 V Supply Full IV 1 180 MHz 3.3 V Supply Full IV 1 125 MHz 2.7 V Supply 0C to 85C IV 1 100 MHz Frequency Range (6 REFCLK Multiplier Enabled) 5.0 V Supply Full IV 5 30 MHz 3.3 V Supply Full IV 5 20.83 MHz 2.7 V Supply 0C to 85C IV 5 16.66 MHz Duty Cycle Full IV 45 60 % Duty Cycle (6 REFCLK Multiplier Enabled) Full IV 35 65 % Input Resistance 25C V 1 M 2 Minimum Switching Thresholds Logic 1, 5.0 V Supply 25C IV 3.5 V Logic 1, 3.3 V Supply 25C IV 2.3 V Logic 0, 5.0 V Supply 25C IV 1.5 V Logic 0, 3.3 V Supply 25C IV 1 V DAC OUTPUT CHARACTERISTICS Full-Scale Output Current 25C IV 5 10 20 mA Gain Error 25C I 10 +10 % FS Output Offset 25C I 10 A Differential Nonlinearity 25C I 0.75 LSB Integral Nonlinearity 25C I 1 LSB Residual Phase Noise, 5.2 MHz, 1 kHz Offset PLL On 25C V 125 dBc/Hz PLL Off 25C V 132 dBc/Hz Output Impedance 25C V 120 k Voltage Com pli ance Range 25C I 0.5 +1.5 V Wideband Spu ri ous-Free Dynamic Range 1.1 MHz Analog Out (DC to 72 MHz) 25C IV 60 64 dBc 20.1 MHz An a log Out (DC to 72 MHz) 25C IV 51 53 dBc 40.1 MHz Analog Out (DC to 72 MHz) 25C IV 51 55 dBc 50.1 MHz An a log Out (DC to 72 MHz) 25C IV 46 53 dBc 70.1 MHz Analog Out (DC to 72 MHz) 25C IV 42 43 dBc Narrowband Spurious-Free Dynamic Range 1.1 MHz (50 kHz) 25C V 85 dBc 1.1 MHz (200 kHz) 25C V 80 dBc 40.1 MHz (50 kHz) 25C V 85 dBc 40.1 MHz (200 kHz) 25C V 80 dBc 70.1 MHz (50 kHz) 25C V 85 dBc 70.1 MHz (200 kHz) 25C V 73 dBc COMPARATOR INPUT CHARACTERISTICS Input Capacitance 25C V 3 pF Input Re sis tance 25C IV 500 k Input Bias Current 25C I 12 A Input Voltage Range 25C IV 0 5 V COMPARATOR OUTPUT CHARACTERISTICS Logic 1 Voltage 5 V Supply 25C VI 4.8 V Logic 1 Voltage 3.3 V Supply 25C VI 3.1 V Logic 1 Voltage 2.7 V Supply 25C VI 2.3 V Logic 0 Voltage 25C VI +0.4 V Continuous Output Current 25C IV 20 mA Hysteresis 25C IV 10 mV Propagation Delay 25C IV 7 ns Toggle Frequency (1 V p-p Input Sine Wave) 25C IV 200 MHz Rise/Fall Time, 15 pF Output Load 25C IV 7 ns 3 Output Jitter (p-p) 25C IV 80 ps (p-p) CLOCK OUTPUT CHAR AC TER IS TICS Output Jitter (Clock Generator Confi guration, 40 MHz 1 V p-p Input Sine Wave) 25C V 250 ps (p-p) Clock Output Duty Cycle Full IV 50 10 % 2 REV. 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