Analog Devices Inc. AD9761ARSRL

Digital to Analog Converters - DAC 10-Bit Complete 40 MSPS Dual
IC DAC 10BIT DUAL 40MSPS 28-SSOP
The AD9761 is a complete dual channel, high speed, 10-bit CMOS DAC. The AD9761 has been developed specifically for use in wide bandwidth communication applications (e.g., spread spectrum) where digital I and Q information is being processed during transmit operations. It integrates two 10-bit, 40 MSPS DACs, dual 2x interpolation filters, a voltage reference, and digital input interface circuitry. The AD9761 supports a 20 MSPS per channel input data rate that is then interpolated by 2x up to 40 MSPS before simultaneously updating each DAC. The interleaved I and Q input data stream is presented to the digital interface circuitry, which consists of I and Q latches as well as some additional control logic. The data is de-interleaved back into its original I and Q data. An on-chip state machine ensures the proper pairing of I and Q data. The data output from each latch is then processed by a 2x digital interpolation filter that eases the reconstruction filter requirements. The interpolated output of each filter serves as the input of their respective 10-bit DAC. The DACs utilize a segmented current source architecture combined with a proprietary switching technique to reduce glitch energy and to maximize dynamic accuracy. Each DAC provides differential current output thus supporting single-ended or differential applications. Both DACs are simultaneously updated and provide a nominal full-scale current of 10 mA. Also, the full-scale currents between each DAC are matched to within 0.07 dB (i.e., 0.75%), thus eliminating the need for additional gain calibration circuitry. The AD9761 is manufactured on an advanced low cost CMOS process. It operates from a single supply of 2.7 V to 5.5 V and consumes 200 mW of power. To make the AD9761 complete it also offers an internal 1.20 V temperature-compensated bandgap reference. PRODUCT HIGHLIGHTS Dual 10-Bit, 40 MSPS DACs A pair of high performance 40 MSPS DACs optimized for low distortion performance provide for flexible transmission of I and Q information. 2x Digital Interpolation Filters Dual matching FIR interpolation filters with 62.5 dB stopband rejection precede each DAC input, thus reducing the DACs’ reconstruction filter requirements. Low Power Complete CMOS dual DAC function operates on a low 200 mW on a single supply from 3 V to 5.5 V. The DAC full-scale current can be reduced for lower power operation, and a sleep mode is provided for power reduction during idle periods. On-Chip Voltage Reference The AD9761 includes a 1.20 V temperature-compensated band gap voltage reference. Single 10-Bit Digital Input Bus The AD9761 features a flexible digital interface that allows each DAC to be addressed in a variety of ways including different update rates. Small Package The AD9761 offers the complete integrated function in a compact 28-lead SSOP package. Product Family The AD9761 Dual Transmit DAC has a pair of Dual Receive ADC companion products, the AD9281 (8 bits) and AD9201 (10 bits).