14-Bit, 500Msps, Interpolating and Modulating Dual DAC with CMOS Inputs

The MAX5894 programmable interpolating, modulating, 500Msps, dual digital-to-analog converter (DAC) offers superior dynamic performance and is optimized for high-performance wideband, single-carrier transmit applications. The device integrates a selectable 2x/4x/8x interpolating filter, a digital quadrature modulator, and dual 14-bit, high-speed DACs on a single integrated circuit. At 30MHz output frequency and 500Msps update rate, the in-band SFDR is 86dBc while consuming 1.1W. The device also delivers 73dB ACLR for two-carrier WCDMA at a 61.44MHz output frequency.

The selectable interpolating filters allow lower input data rates while taking advantage of the high DAC update rates. These linear-phase interpolation filters ease reconstruction filter requirements and enhance the passband dynamic performance. Individual offset and gain programmability allow the user to calibrate out local oscillator (LO) feedthrough and sideband suppression errors generated by analog quadrature modulators.

The MAX5894 features a fIM/4 digital image-reject modulator. This modulator generates a quadrature-modulated IF signal that can be presented to an analog I/Q modulator to complete the upconversion process. A second digital modulation mode allows the signal to be frequency-translated with image pairs at fIM/2 or fIM/4.

The MAX5894 features a standard 1.8V CMOS, 3.3V tolerant data input bus for easy interface. A 3.3V SPI™ port is provided for mode configuration. The programmable modes include the selection of 2x/4x/8x interpolating filters, fIM/2, fIM/4 or no digital quadrature modulation with image rejection, channel gain and offset adjustment, and offset binary or two's complement data interface.

Pin-compatible 12- and 16-bit devices are also available. Refer to the MAX5893 data sheet for the 12-bit version and the MAX5895 data sheet for the 16-bit version.

See a parametric table of the complete family of pin-compatible 12-/14-/16-bit high-speed DACs.

Applications

* Analog Quadrature Modulation Architectures * Base Stations: 3G UMTS, CDMA, and GSM * Broadband Cable Infrastructure * Broadband Wireless Transmitters * Instrumentation and Automatic Test Equipment (ATE)

* 74dB ACLR at fOUT = 61.44MHz (Single-Carrier WCDMA)

* Meets 3G UMTS, cdma2000®, GSM Spectral Masks (fOUT = 122MHz)

* Noise Spectral Density = -154dBFS/Hz at fOUT = 16MHz

* 91dBc SFDR at Low-IF Frequency (10MHz)

* 88dBc SFDR at High-IF Frequency (50MHz)

* Low Power: 886mW (fCLK = 250MHz)

* User Programmable

* Selectable 2x, 4x, or 8x Interpolating Filters

* < 0.01dB Passband Ripple

* > 99dB Stopband Rejection

* Selectable Real or Complex Modulator Operation

* Selectable Modulator LO Frequency: OFF, fIM/2 or fIM/4

* Selectable Output Filter: Lowpass or Highpass

* Channel Gain and Offset Adjustment

* EV Kit Available (Order the MAX5894EVKIT)