REV. C
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a
AD9764
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel:781/329-4700 World Wide Web Site: http://www.analog.com
Fax:781/326-8703 © Analog Devices, Inc., 1999-2016
14-Bit, 125 MSPS
TxDAC
®
D/A Converter
FUNCTIONAL BLOCK DIAGRAM
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.
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.
50pF
COMP1
+1.20V REF
AVDD ACOM
REFLO
COMP2
CURRENT
SOURCE
ARRAY
0.1mF
+5V
SEGMENTED
SWITCHES
LSB
SWITCHES
REFIO
FS ADJ
DVDD
DCOM
CLOCK
+5V
R
SET
0.1mF
CLOCK
I
OUTA
I
OUTB
0.1mF
LATCHES
AD9764
SLEEP
DIGITAL DATA INPUTS
DB13–DB0
