●The DAC5687 is a dual-channel 16-bit high-speed digital-to-analog converter (DAC) with integrated 2×, 4×, and 8× interpolation filters, a complex numerically controlled oscillator (NCO), onboard clock multiplier, IQ compensation, and on-chip voltage reference. The DAC5687 is pin-compatible to the DAC5686, requiring only changes in register settings for most applications, and offers additional features and superior linearity, noise, crosstalk, and PLL phase noise performance.
●The DAC5687 has six signal processing blocks: two interpolate-by-two digital filters, a fine frequency mixer with 32-bit NCO, a quadrature modulation compensation block, another interpolate-by-two digital filter, and a coarse frequency mixer with fS/2 or fS/4. The different modes of operation enable or bypass the signal processing blocks.
●The coarse and fine mixers can be combined to span a wider range of frequencies with fine resolution. The DAC5687 allows both complex or real output. Combining the frequency upconversion and complex output produces a Hilbert transform pair that is output from the two DACs. An external RF quadrature modulator then performs the final single-sideband upconversion.
●The IQ compensation feature allows optimization of phase, gain, and offset to maximize sideband rejection and minimize LO feedthrough for an analog quadrature modulator.
●The DAC5687 includes several input options: single-port interleaved data, even and odd multiplexing at half-rate, and an input FIFO with either external or internal clock to ease the input timing ambiguity when the DAC5687 is clocked at the DAC output sample rate.
● 500 MSPS
● Selectable 2×-8× Interpolation
● On-Chip PLL/VCO Clock Multiplier
● Full IQ Compensation Including Offset, Gain, and Phase
● Flexible Input Options:
● FIFO With Latch on External or Internal Clock
● Even/Odd Multiplexed Input
● Single Port Demultiplexed Input
● Complex Mixer With 32-Bit NCO
● Fixed Frequency Mixer With fS/4 and fS/2
● 1.8-V or 3.3-V I/O Voltage
● On-Chip 1.2-V Reference
● Differential Scalable Output: 2 mA to 20 mA
● Pin Compatible to DAC5686
● High Performance
● 81-dBc ACLR WCDMA TM1 at 30.72 MHz
● 72-dBc ACLR WCDMA TM1 at 153.6 MHz
● Package: 100-Pin HTQFP
● APPLICATIONS
● Cellular Base Transceiver Station Transmit Channel
● CDMA: W-CDMA, CDMA2000, TD-SCDMA
● TDMA: GSM, IS-136, EDGE/UWC-136
● OFDM: 802.16
● Cable Modem Termination System
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