●GENERAL DESCRIPTION
●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 baseband upconversion for data transmission in a wired or wireless communications system.
●The AD9957 is the third offering in a family of quadrature digital upconverters (QDUCs) that includes the AD9857 and AD9856. It offers performance gains in operating speed, power consumption, and spectral performance. Unlike its predecessors, it supports a 16-bit serial input mode for I/Q baseband data. The device can alternatively be programmed to operate either as a single tone, sinusoidal source or as an interpolating DAC.
●FEATURES
● 1 GSPS internal clock speed (up to 400 MHz analog output)
● Integrated 1 GSPS 14-bit DAC
● 250 MHz I/Q data throughput rate
● Phase noise ≤ −125 dBc/Hz (400 MHz carrier @ 1 kHz offset)
● Excellent dynamic performance >80 dB narrow-band 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 4× to 252×
● Interpolation DAC mode
● Gain control DAC
● Internal divider allows references up to 2 GHz
● 1.8 V and 3.3 V power supplies
● 100-lead TQFP_EP package
●APPLICATIONS
● HFC data, telephony, and video modems
● Wireless base station transmission
● Broadband communications transmissions
● Internet telephony
