AD9731BR ,10-Bit, 170 MSPS D/A ConverterSPECIFICATIONSREFParameter Temp Test Level Min Typ Max UnitsRESOLUTION 10 BitsTHROUGHPUT RATE +25
AD9731BR
10-Bit, 170 MSPS D/A Converter
REV.A
10-Bit, 170 MSPS
D/A Converter
FUNCTIONAL BLOCK DIAGRAM
FEATURES
170 MSPS Update Rate
TTL/High-Speed CMOS-Compatible Inputs
Wideband SFDR: 66 dB @ 2 MHz/50 dB @ 65 MHz
Pin-Compatible, Lower Cost Replacement for
Industry Standard AD9721 DAC
Low Power: 439 mW @ 170 MSPS
Fast Settling: 3.8 ns to 1/2 LSB
Internal Reference
Two Package Styles: 28-Lead SOIC and SSOP
APPLICATIONS
Digital Communications
Direct Digital Synthesis
Waveform Reconstruction
High Speed Imaging
5 MHz–65 MHz HFC Upstream Path
GENERAL DESCRIPTIONThe AD9731 is a 10-bit, 170 MSPS, bipolar D/A converter that
is optimized to provide high dynamic performance, yet offer
lower power dissipation and more economical pricing than
afforded by previous bipolar high performance DAC solutions.
The AD9731 was designed primarily for demanding communi-
cations systems applications where wideband spurious-free
dynamic range (SFDR) requirements are strenuous and could
previously only be met by using a high performance DAC such
as the industry-standard AD9721. The proliferation of digital
communications into basestation and high volume subscriber-
end markets has created a demand for excellent DAC perfor-
mance delivered at reduced levels of power dissipation and cost.
The AD9731 is the answer to that demand.
Optimized for direct digital synthesis (DDS) waveform recon-
struction, the AD9731 provides 50 dB of wideband harmonic
suppression over a dc-to-65 MHz analog output bandwidth.
This signal bandwidth addresses the transmit spectrum in many
of the emerging digital communications applications where
signal purity is critical. Narrowband, the AD9731 provides an
SFDR of greater than 79 dB. This excellent wideband and
narrowband ac performance, coupled with a lower pricing struc-
ture, make the AD9731 the optimum high performance DAC
value.
The AD9731 is packaged in 28-lead SOIC (same footprint
as the industry standard AD9721) and super space-saving
28-lead SSOP; both are specified to operate over the extended
industrial temperature range of –40°C to +85°C.
AD9731–SPECIFICATIONS5/27/99 8 PM
(+VS = +5 V, –VS = –5.2 V, CLOCK = 125 MHz, RSET = 1.96 kV for 20.4 mA IOUT,
VREF = –1.25 V, unless otherwise noted.)REFERENCE INPUT
OUTPUT PERFORMANCE
DIGITAL INPUTS
SFDR PERFORMANCE (Wideband)
AD97315/27/99 8 PM
INTERMODULATION DISTORTION
POWER SUPPLY
NOTESMeasured as an error in ratio of full-scale current to current through RSET (640 mA nominal); ratio is nominally 32. DAC load is virtual ground.Internal reference voltage is tested under load conditions specified in Internal Reference Output current specification.Internal reference output current defines load conditions applied during Internal Reference Voltage test.Full-scale current variations among devices are higher when driving REFERENCE IN directly.Frequency at which a 3 dB change in output of DAC is observed; RL = 50 W; 100 mV modulation at midscale.Based on IFS = 32 (CONTROL AMP IN/RSET) when using internal control amplifier. DAC load is virtual ground.Measured as voltage settling at midscale transition to –0.1%; RL = 50 W.Measured from 50% point of rising edge of CLOCK signal to 1/2 LSB change in output signal.Peak glitch impulse is measured as the largest area under a single positive or negative transient.Measured with RL = 50 W and DAC operating in latched mode.Data must remain stable for specified time prior to rising edge of CLOCK.Data must remain stable for specified time after rising edge of CLOCK.SFDR is defined as the difference in signal energy between the full-scale fundamental signal and worst case spurious frequencies in the output spectrum window.
The frequency span is dc-to-Nyquist unless otherwise noted.Intermodulation distortion is the measure of the sum and difference products produced when a two-tone input is driven into the DAC. The distortion products
created will manifest themselves at sum and difference frequencies of the two tones.Supply voltages should remain stable within –5% for nominal operation.
Specifications subject to change without notice.
AD9731
ABSOLUTE MAXIMUM RATINGS*Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . .–VS to +VS
+VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+6 V
Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . .–0.7 V to +VS
–VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –7 V
Analog Output Current . . . . . . . . . . . . . . . . . . . . . . . .30 mA
Control Amplifier Input Voltage Range . . . . . . . . .0 V to –4 V
Reference Input Voltage Range . . . . . . . . . . . . . . . .0 V to –VS
Maximum Junction Temperature . . . . . . . . . . . . . . . .+150°C
Operating Temperature Range . . . . . . . . . . .–40°C to +85°C
Internal Reference Output Current . . . . . . . . . . . . . . .500 mA
Lead Temperature (10 sec Soldering) . . . . . . . . . . . . .+300°C
Storage Temperature . . . . . . . . . . . . . . . . . .–65°C to +165°C
Control Amplifier Output Current . . . . . . . . . . . . . –2.5 mA
*Absolute maximum ratings are limiting values, to be applied individually, and
beyond which the serviceability of the circuit may be impaired. Functional
operability under any of these conditions is not necessarily implied. Exposure of
absolute maximum rating conditions for extended periods of time may affect
device reliability.
EXPLANATION OF TEST LEVELS
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD9731 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
ORDERING GUIDE
PIN FUNCTION DESCRIPTION
PIN CONFIGURATION
GND
DIGITAL –VS
CONTROL AMP IN
REF OUT
CONTROL AMP OUT
REF IN
ANALOG –VS
IOUTB
IOUT
ANALOG RETURN
GND
RSET
DIGITAL –VS
GND
D9(MSB)
D0(LSB)
CLOCK
DIGITAL +VS
NC = NO CONNECT
AD9731
–Typical Performance Characteristics
AOUT – MHz
SFDR – dB304050607080Figure 2.Narrowband SFDR (Clock = 170 MHz) vs.
AOUT Frequency
AOUT – MHz
SFDR – dB2030405060Figure 3.Narrowband SFDR (Clock = 125 MHz) vs.
AOUT Frequency
AOUT – MHz
SFDR – dB30405060708090Figure 4.Wideband SFDR (170 MHz Clock) vs. AOUT
Figure 5.SFDR vs. IOUT (Clock =125 MHz/AOUT = 40 MHz)
Figure 6.Typical Differential Nonlinearity Performance
(DNL)
Figure 7.Typical Integral Nonlinearity Performance (INL)
