DAC5675A Datasheet, PDF (1/26 Pages) Texas Instruments – 14-Bit, 400MSPS Digital-to-Analog Converter

DAC5675A
www.ti.com
SBAS334C – NOVEMBER 2004 – REVISED MARCH 2005
14-Bit, 400MSPS Digital-to-Analog Converter
FEATURES
• 400MSPS Update Rate
• LVDS-Compatible Input Interface
• Spurious-Free Dynamic Range (SFDR) to
Nyquist:
– 69dBc at 70MHz IF, 400MSPS
• W-CDMA Adjacent Channel Power Ratio
(ACPR):
– 73dBc at 30.72MHz IF, 122.88MSPS
– 71dBc at 61.44MHz IF, 245.76MSPS
• Differential Scalable Current Sink Outputs:
2mA to 20mA
• On-Chip 1.2V Reference
• Single 3.3V Supply Operation
• Power Dissipation: 660mW at f_CLK = 400MSPS,
f_OUT = 20MHz
• Package: 48-Pin HTQFP PowerPad™,
T_JA = 28.8°C/W
APPLICATIONS
• Cellular Base Transceiver Station Transmit
Channel:
– CDMA: WCDMA, CDMA2000, IS-95
– TDMA: GSM, IS-136, EDGE/GPRS
– Supports Single-Carrier and Multicarrier
Applications
• Test and Measurement: Arbitrary Waveform
Generation
• Direct Digital Synthesis (DDS)
• Cable Modem Headend
DESCRIPTION
The DAC5675A is a 14-bit resolution high-speed digital-to-analog converter. The DAC5675A is designed for
high-speed digital data transmission in wired and wireless communication systems, high-frequency direct-digital
synthesis (DDS), and waveform reconstruction in test and measurement applications. The DAC5675A has
excellent spurious-free dynamic range (SFDR) at high intermediate frequencies, which makes the DAC5675A
well-suited for multicarrier transmission in TDMA- and CDMA-based cellular base transceiver stations (BTSs).
The DAC5675A operates from a single-supply voltage of 3.3V. Power dissipation is 660mW at f_CLK = 400MSPS,
f_OUT = 70MHz. The DAC5675A provides a nominal full-scale differential current output of 20mA, supporting both
single-ended and differential applications. The output current can be directly fed to the load with no additional
external output buffer required. The output is referred to the analog supply voltage AV_DD.
The DAC5675A comprises a low-voltage differential signaling (LVDS) interface for high-speed digital data input.
LVDS features a low differential voltage swing with a low constant power consumption across frequency,
allowing for high-speed data transmission with low noise levels; that is, with low electromagnetic interference
(EMI). LVDS is typically implemented in low-voltage digital CMOS processes, making it the ideal technology for
high-speed interfacing between the DAC5675A and high-speed low-voltage CMOS ASICs or FPGAs. The
DAC5675A current-sink-array architecture supports update rates of up to 400MSPS. On-chip edge-triggered
input latches provide for minimum setup and hold times, thereby relaxing interface timing.
The DAC5675A has been specifically designed for a differential transformer-coupled output with a 50Ω doubly-
terminated load. With the 20mA full-scale output current, both a 4:1 impedance ratio (resulting in an output power
of 4dBm) and 1:1 impedance ratio transformer (–2dBm) are supported. The last configuration is preferred for
optimum performance at high output frequencies and update rates. The outputs are terminated to AVDD and
have voltage compliance ranges from AV_DD – 1 to AV_DD + 0.3V.
An accurate on-chip 1.2V temperature-compensated bandgap reference and control amplifier allows the user to
adjust this output current from 20mA down to 2mA. This provides 20dB gain range control capabilities.
Alternatively, an external reference voltage may be applied. The DAC5675A features a SLEEP mode, which
reduces the standby power to approximately 18mW.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPad is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2005, Texas Instruments Incorporated