ADI AD9957BSVZ

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 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.

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 to enable fast and easy shift keying of any signal parameter (phase, frequency, or amplitude).

• 1 GSPS internal clock speed (up to 400 MHz analog output)
• Integrated 1 GSPS 14-bit DAC
• 250 MSPS input data 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

• HFC data, telephony, and video modems
• Wireless base station transmissions
• Broadband communications transmissions
• Internet telephony