10-/12-/14-Bit, 125 MSPS
Dual TxDAC+ Digital-to-Analog Converters
AD9763/AD9765/AD9767
FEATURES
FUNCTIONAL BLOCK DIAGRAM
10-/12-/14-bit dual transmit digital-to-analog converters (DACs)
125 MSPS update rate
Excellent SFDR to Nyquist @ 5 MHz output: 75 dBc
Excellent gain and offset matching: 0.1%
Fully independent or single-resistor gain control
Dual-port or interleaved data
On-chip 1.2 V reference
5 V or 3.3 V operation
Power dissipation: 380 mW @ 5 V
Power-down mode: 50 mW @ 5 V
48-lead LQFP
DVDD1/ DCOM1/
DVDD2 DCOM2
WRT2/IQSEL
GENERAL DESCRIPTION
The AD9763/AD9765/AD9767 are dual-port, high speed,
2-channel, 10-/12-/14-bit CMOS DACs. Each part integrates
two high quality TxDAC+® cores, a voltage reference, and digital
interface circuitry into a small 48-lead LQFP. The AD9763/
AD9765/AD9767 offer exceptional ac and dc performance
while supporting update rates of up to 125 MSPS.
The AD9763/AD9765/AD9767 have been optimized for
processing I and Q data in communications applications. The
digital interface consists of two double-buffered latches as well
as control logic. Separate write inputs allow data to be written to
the two DAC ports independent of one another. Separate clocks
control the update rate of the DACs.
A mode control pin allows the AD9763/AD9765/AD9767 to
interface to two separate data ports, or to a single interleaved
high speed data port. In interleaving mode, the input data
stream is demuxed into its original I and Q data and then
latched. The I and Q data is then converted by the two DACs
and updated at half the input data rate.
The GAINCTRL pin allows two modes for setting the full-scale
current (IOUTFS) of the two DACs. IOUTFS for each DAC can be set
independently using two external resistors, or IOUTFS for both
DACs can be set by using a single external resistor. See the
Gain Control Mode section for important date code
information on this feature.
DIGITAL
INTERFACE
AD9763/
AD9765/
AD9767
2
LATCH
PORT2
MODE
CLK1
1
DAC
IOUTA1
IOUTB1
REFERENCE
REFIO
FSADJ1
FSADJ2
GAINCTRL
BIAS
GENERATOR
SLEEP
2
DAC
IOUTA2
IOUTB2
CLK2/IQ RESET
00617-001
WRT1/IQWRT
ACOM
1
LATCH
PORT1
APPLICATIONS
Communications
Base stations
Digital synthesis
Quadrature modulation
3D ultrasound
AVDD
Figure 1.
The DACs utilize a segmented current source architecture
combined with a proprietary switching technique to reduce
glitch energy and maximize dynamic accuracy. Each DAC provides
differential current output, thus supporting single-ended or differential applications. Both DACs of the AD9763, AD9765, or
AD9767 can be simultaneously updated and can provide a
nominal full-scale current of 20 mA. The full-scale currents
between each DAC are matched to within 0.1%.
The AD9763/AD9765/AD9767 are manufactured on an
advanced, low cost CMOS process. They operate from a single
supply of 3.3 V to 5 V and consume 380 mW of power.
PRODUCT HIGHLIGHTS
1.
2.
3.
4.
5.
6.
The AD9763/AD9765/AD9767 are members of a pincompatible family of dual TxDACs providing 8-, 10-, 12-,
and 14-bit resolution.
Dual 10-/12-/14-Bit, 125 MSPS DACs. A pair of high
performance DACs for each part is optimized for low
distortion performance and provides flexible transmission
of I and Q information.
Matching. Gain matching is typically 0.1% of full scale, and
offset error is better than 0.02%.
Low Power. Complete CMOS dual DAC function operates on
380 mW from a 3.3 V to 5 V single supply. The DAC full-scale
current can be reduced for lower power operation, and a sleep
mode is provided for low power idle periods.
On-Chip Voltage Reference. The AD9763/AD9765/AD9767
each include a 1.20 V temperature-compensated band gap
voltage reference.
Dual 10-/12-/14-Bit Inputs. The AD9763/AD9765/AD9767
each feature a flexible dual-port interface, allowing dual or
interleaved input data.
Rev. E
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