AD9778A Dual 14-Bit, 1 GSPS, Digital-to-Analog Converter

The AD9776A/AD9778A/AD9779A are dual, 12-/14-/16-bit, high dynamic range digital-to-analog converters (DACs) that provide a sample rate of 1 GSPS, permitting a multicarrier generation up to the Nyquist frequency. They include features optimized for direct conversion transmission applications, including complex digital modulation and gain and offset compensation. The DAC outputs are optimized to interface seamlessly with analog quadrature modulators such as the ADL537x FMOD series from Analog Devices, Inc. A 3-wire interface provides for programming/readback of many internal parameters. Full-scale output current can be programmed over a range of 10 mA to 30 mA. The devices are manufactured on an advanced 0.18 μm CMOS process and operate on 1.8 V and 3.3 V supplies for a total power consumption of 1.0 W. They are enclosed in a 100-lead thin quad flat package (TQFP). ul { margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:15px; padding-top:0px; padding-right:0px; padding-bottom:10px; padding-left:0px;} li { padding-top:0px; padding-right:0px; padding-bottom:5px; padding-left:0px; margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px;} ol { margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:25px; padding-top:0px; padding-right:0px; padding-bottom:10px; padding-left:0px;} li { padding-top:0px; padding-right:0px; padding-bottom:5px; padding-left:0px; margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px;} Ultralow noise and intermodulation distortion (IMD) enable high quality synthesis of wideband signals from baseband to high intermediate frequencies. A proprietary DAC output switching technique enhances dynamic performance. The current outputs are easily configured for various single-ended or differential circuit topologies. CMOS data input interface with adjustable setup and hold. Novel 2×, 4×, and 8× interpolator/coarse complex modulator allows carrier placement anywhere in DAC bandwidth.

Product Highlights

Ultralow noise and intermodulation distortion (IMD) enable high quality synthesis of wideband signals from baseband to high intermediate frequencies.
A proprietary DAC output switching technique enhances dynamic performance.
The current outputs are easily configured for various single-ended or differential circuit topologies.
CMOS data input interface with adjustable setup and hold.
Novel 2×, 4×, and 8× interpolator/coarse complex modulator allows carrier placement anywhere in DAC bandwidth.

Applications

Wireless infrastructure: W-CDMA, CDMA2000, TD-SCDMA, WiMax, GSM, LTE
Digital high or low IF synthesis
Internal digital upconversion capability
Transmit diversity
Wideband communications: LMDS/MMDS, point-to-point

Data Sheet, Rev. B, 9/08

Features and Benefits

Low power: 1.0 W @ 1 GSPS, 600 mW @ 500 MSPS, full operating conditions

Single carrier WCDMA ACLR = 80 dBc @ 80 MHz IF

Analog output: adjustable 8.7 mA to 31.7 mA, RL = 25 Ω to 50 Ω

Novel 2×, 4×, and 8× interpolator/coarse complex modulator allows carrier placement anywhere in DAC bandwidth

Auxiliary DACs allow control of external VGA and offset control

Multiple chip synchronization interface

High performance, low noise PLL clock multiplier

Digital inverse sinc filter

100-lead, exposed paddle TQFP

Digital to Analog Converters

Data Sheets

Document	note
AD9776A/AD9778A/AD9779A: Dual 12-/14-/16-Bit, 1 GSPS, Digital-to-Analog Converters Data Sheet (Rev. B)	PDF 1171 kB

Application Notes

Document	note
AN-912: Driving a Center-Tapped Transformer with a Balanced Current-Output DAC (Rev. 0)	PDF 246 kB
AN-320A: CMOS Multiplying DACs and Op Amps Combine to Build Programmable Gain Amplifier, Part 1	PDF 1295 kB

Order Information

Part Number	Package	Packing Qty	Temp Range	Price 100-499	Price 1000+	RoHS
AD9778ABSVZ Production	100 ld TQFP-ED(w/ 6.5mm exposed pad)	OTH 90	-40 to 85C	29.7	25.25	Y
AD9778ABSVZRL Production	100 ld TQFP-ED(w/ 6.5mm exposed pad)	REEL 1000	-40 to 85C	0	25.25	Y