AD9957 IC Chip

AD9957（1 GSPS Quadrature Digital Upconverter/18-Bit IQ Data Path and 14-Bit DAC）

Introduction

The AD9957 functions as a universal I/Q modulator and agile upconverter for communications systems where cost, size,power consumption and dynamic performance are critical. The AD9957 integrates a high speed Direct Digital Synthesizer(DDS), a high performance: high speed 14-bit digital to analog ,converter (DAC), clock multiplier circuitry, digital filters and other DSP functions onto a single chip. It provides for base band up-conversion for data transmission in a wired or wireless Communications system.

The AD9957 is the third offering in a family of a quadrature digital upconverters (QDUCs).It offers performance gains in operating speed, power consumption and spectral performance. Unlike its predecessors, it also supports a 16-bit serial input mode for I/Q base band data. The device can alternatively be programmed to operate as a single-tone sinusoidal source or as an interpolating DAC.

The Reference Clock input circuitry includes a crystal oscillator,a high speed divide-by-two input, and a low noise PLL for multiplication of the reference clock frequency.

The user interface to the control functions includes a serial port easily configured to interface to the SPORT of the Blackfin DSP and profile pins which enable fast and easy shift keying of any signal parameter (phase, frequency, and amplitude).

Features

• 1GSPS internal clock speed (up to 400MHz analog out)
• Integrated 1GSPS 14-bit DAC
• 250 MHz I/Q data throughput rate
• Phase noise < -123 dBc/Hz (400 MHz carrier)
• Excellent dynamic performance >80 dB narrowband SFDR
• 8 Programmable Profiles for shift keying
• SIN(X)/(X) Correction (Inverse SINC filter)
• Reference Clock Multiplier
• Internal oscillator for a single crystal operation
• Software and hardware controlled power-down
• Integrated RAM
• Phase modulation capability
• Multichip synchronization
• Easy interface to Blackfin™ SPORT
• Interpolation factors from 4x to 252x
• Test tone circuitry
• Interpolation DAC Mode
• Gain control DAC
• Internal divider allows references up to 2 GHz
• 1.8V & 3.3V Power Supplies 
• 100 Lead TQFP package 

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