AD9764ARZ Datasheet, PDF (1/22 Pages) Analog Devices – 14-Bit, 125 MSPS TxDAC D/A Converter

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14-Bit, 125 MSPS
TxDAC^® D/A Converter
AD9764
FEATURES
Member of Pin-Compatible TxDAC Product Family
125 MSPS Update Rate
14-Bit Resolution
Excellent SFDR and IMD
Differential Current Outputs: 2 mA to 20 mA
Power Dissipation: 190 mW @ 5 V to 45 mW @ 3 V
Power-Down Mode: 25 mW @ 5 V
On-Chip 1.20 V Reference
Single +5 V or +3 V Supply Operation
Packages: 28-Lead SOIC and TSSOP
Edge-Triggered Latches
APPLICATIONS
Communication Transmit Channel:
Basestations
ADSL/HFC Modems
Instrumentation
PRODUCT DESCRIPTION
The AD9764 is the 14-bit resolution member of the TxDAC
series of high performance, low power CMOS digital-to-analog
converters (DACs). The TxDAC family, which consists of pin
compatible 8-, 10-, 12-, and 14-bit DACs, is specifically opti-
mized for the transmit signal path of communication systems.
All of the devices share the same interface options, small outline
package and pinout, providing an upward or downward compo-
nent selection path based on performance, resolution and cost.
The AD9764 offers exceptional ac and dc performance while
supporting update rates up to 125 MSPS.
The AD9764’s flexible single-supply operating range of 2.7 V to
5.5 V and low power dissipation are well suited for portable and
low power applications. Its power dissipation can be further
reduced to a mere 45 mW with a slight degradation in performance
by lowering the full-scale current output. Also, a power-down
mode reduces the standby power dissipation to approximately
25 mW.
The AD9764 is manufactured on an advanced CMOS process.
A segmented current source architecture is combined with a
proprietary switching technique to reduce spurious components
and enhance dynamic performance. Edge-triggered input
latches and a 1.2 V temperature compensated bandgap refer-
ence have been integrated to provide a complete monolithic
DAC solution. Flexible supply options support +3 V and +5 V
CMOS logic families.
The AD9764 is a current-output DAC with a nominal full-scale
output current of 20 mA and > 100 kΩ output impedance.
TxDAC is a registered trademark of Analog Devices, Inc.
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
FUNCTIONAL BLOCK DIAGRAM
+5V
0.1␮F
0.1␮F
R_SET
+5V
CLOCK
REFLO
+1.20V REF
REFIO
FS ADJ
COMP1 AVDD ACOM
50pF
AD9764
CURRENT
SOURCE
ARRAY
0.1␮F
COMP2
DVDD
DCOM
SEGMENTED
SWITCHES
LSB
SWITCHES
I_OUTA
I_OUTB
CLOCK
SLEEP
LATCHES
DIGITAL DATA INPUTS (DB13–DB0)
Differential current outputs are provided to support single-
ended or differential applications. Matching between the two
current outputs ensures enhanced dynamic performance in a
differential output configuration. The current outputs may be
tied directly to an output resistor to provide two complemen-
tary, single-ended voltage outputs or fed directly into a trans-
former. The output voltage compliance range is 1.25 V.
The on-chip reference and control amplifier are configured for
maximum accuracy and flexibility. The AD9764 can be driven
by the on-chip reference or by a variety of external reference
voltages. The internal control amplifier, which provides a wide
(>10:1) adjustment span, allows the AD9764 full-scale current
to be adjusted over a 2 mA to 20 mA range while maintaining
excellent dynamic performance. Thus, the AD9764 may operate
at reduced power levels or be adjusted over a 20 dB range to
provide additional gain ranging capabilities.
The AD9764 is available in 28-lead SOIC and TSSOP packages.
It is specified for operation over the industrial temperature range.
PRODUCT HIGHLIGHTS
1. The AD9764 is a member of the TxDAC product family that
provides an upward or downward component selection path
based on resolution (8 to 14 bits), performance and cost.
2. Manufactured on a CMOS process, the AD9764 uses a pro-
prietary switching technique that enhances dynamic perfor-
mance beyond that previously attainable by higher power/cost
bipolar or BiCMOS devices.
3. On-chip, edge-triggered input CMOS latches readily interface
to +3 V and +5 V CMOS logic families. The AD9764 can
support update rates up to 125 MSPS.
4. A flexible single-supply operating range of 2.7 V to 5.5 V, and
a wide full-scale current adjustment span of 2 mA to 20 mA,
allows the AD9764 to operate at reduced power levels.
5. The current output(s) of the AD9764 can be easily config-
ured for various single-ended or differential circuit topologies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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© Analog Devices, Inc., 1999