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Analog Devices 16-bit DAC provides transmit signal chain IF synthesis

A16-bit, 1.25-GSPS transmit D/A converter (DAC) with integrated complex digital modulation functionality provides a JESD204A-compatible serial input. The AD9128 from Analog Devices includes an on-chip 32-bit numerically-controlled oscillator that enables complex digital modulation, gain and offset compensation, and flexible placement of the intermediate frequency. High sampling rate and dynamic range that enables multicarrier generation up to the Nyquist frequency. Ultra low noise and intermodulation distortion enables high quality transmission of wideband signals from
baseband to high intermediate frequencies.

The device’s 1.25 GSPS capability supports IF bandwidths up to 500 MHz. Novel 2×/4×/8× interpolator/complex modulator allows carrier placement anywhere within the DAC’s bandwidth. With 3 dB of typical receiver equalization, the receiver is capable of capturing data sent across 0- to 20-cm traces on an FR4 board. A proprietary DAC output switching technique enhances
dynamic performance. The AD9128 also features multi-chip deterministic latency capability, allowing multiple dual DACs to be in alignment with one another. A serial port interface provides read/write access to on-chip registers. The AD9128 operates on 1.8 V and 3.3 V supply rails.

FEATURES

  • Wide dynamic range:
    • 80 dBc @ fDAC = 200 MSPS, fOUT = 50 MHz
    • 72 dBc @ fDAC = 800 MSPS, fOUT = 70 MHz
  • Single-carrier W-CDMA ACLR = 82 dBc @ 122.88 MHz IF
  • Analog output: adjustable 8.7 mA to 31.7 mA, RL = 25 O to 50 O
  • 4 lanes of high-speed JESD204A serial links (each capable of 3.125 Gbps)
  • Low power: 1.4 W @ 1.0 GSPS, 1.2 @ 614 MSPS,
  • Multi-chip synchronization interface with latency locking
  • High performance, low noise PLL clock multiplier
  • Digital inverse sinc filter
  • 56-lead, exposed paddle LFCSP package

A four-wire serial port interface provides for programming and read-back of many of the device’s internal parameters and functions. The AD9128 supports GSM, WCDMA, TD-SCDMA, CDMA2000, WiMAX, and LTE wireless communications standards. Applications include wireless infrastructure, transmit diversity, wideband communications: LMDS/MMDS, point-to-point.

The AD9128 high-speed D/A converter’s analog outputs are optimized to interface seamlessly with analog quadrature modulators, such as ADI’s ADL537x F-MOD series, and the ADCLK914 clock/data buffer that drives the AD9128 D/A converter with clock input jitter performance of 110 fs. Other complementary parts include the ADRF6702 quadrature modulator and ADRF6602 Rx mixer.

View the AD9128 D/A converter product page, order samples, and download the data sheet.

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