AD7242KR ,LC2MOS Dual, Complete, 12-Bit/14-Bit Serial DACsSpecifications T to T unless otherwise noted.)MIN MAX AD72421 1Parameter J, A Ver ..
AD7243AN ,LC2MOS 12-Bit Serial DACPORTGENERAL DESCRIPTION2(LC MOS), an advanced, mixed technology process. It is pack-The AD7243 is a com ..
AD7243AR ,LC2MOS 12-Bit Serial DACPORTAPPLICATIONSDGND12Process ControlINPUT SHIFT REGISTERIndustrial AutomationVSSDigital Signal Process ..
AD7243BN ,LC2MOS 12-Bit Serial DACPORTCHARACTERISTICSVoltage Output Settling-Time Settling Time to Within ±1/2 LSB of Final ValuePositive ..
AD7243BR ,LC2MOS 12-Bit Serial DACPORTSpecifications T to T unless otherwise noted.)L L MIN MAX2 2 2Parameter A B S Unit Test Conditions/ ..
AD7244AQ ,LC2MOS Dual, Complete, 12-Bit/14-Bit Serial DACsCHARACTERISTICSVoltage Output Settling Time Settling Time to Within ±1/2 LSB of Final ValuePositive ..
ADCS-1021 ,CMOS Image Sensorsapplications. converters:from the full array down to a 4 x 4VGA (ADCS-2021): 10 bit, programmablep ..
ADCS-1120 ,ADCS-1120 · CMOS Monochrome CIF Image SensorFeatures• High quality, low cost CMOS ImageSensorsVGA resolution (640H x 480V) – ADCS-2120CIF re ..
ADCS-2021 ,CMOS Image Sensorscharacteristics. The VGA: 15 frames/secondsensitive active pixel photodiode devices operate from a ..
ADCS7476AIMF/NOPB ,1MSPS, 12-/10-/8-Bit A/D Converters in SOT-23 & LLP 6-SOT-23 -40 to 125 SNAS192G–APRIL 2003–REVISED MAY 20165 Pin Configuration and FunctionsDBV Package6-Pin SOT-23Top Vi ..
ADCS7476AIMF/NOPB ,1MSPS, 12-/10-/8-Bit A/D Converters in SOT-23 & LLP 6-SOT-23 -40 to 125Features 3 DescriptionThe ADCS7476, ADCS7477, and ADCS7478 devices1• Variable Power Managementare l ..
ADCS7476AIMFX ,1MSPS, 12-/10-/8-Bit A/D Converters in 6-Lead SOT-23Featuresn Variable power managementTheADCS7476,ADCS7477,andADCS7478arelowpower,monolithic CMOS 12-, ..
AD7242JN-AD7242JR-AD7242KR-AD7244AQ-AD7244JN-AD7244JR
LC2MOS Dual, Complete, 12-Bit/14-Bit Serial DACs
REV.A
LC2MOS Dual, Complete,
12-Bit/14-Bit Serial DACs
FUNCTIONAL BLOCK DIAGRAM
GENERAL DESCRIPTIONThe AD7242/AD7244 is a fast, complete, dual 12-bit/14-bit
voltage output D/A converter. It consists of a 12-bit/14-bit
DAC, 3 V buried Zener reference, DAC output amplifiers and
high speed serial interface logic.
Interfacing to both DACs is serial, minimizing pin count and
allowing a small package size. Standard control signals allow
interfacing to most DSP processors and microcontrollers.
Asynchronous control of DAC updating for both DACs is made
possible with a separate LDAC input for each DAC.
The AD7242/AD7244 operates from ±5 V power supplies,
providing an analog output range of ±3 V. A REF OUT/REF
IN function allows the DACs to be driven from the on-chip 3 V
reference or from an external reference source.
The AD7242/AD7244 is fabricated in Linear Compatible
CMOS (LC2MOS), an advanced mixed technology process that
combines precision bipolar circuits with low power CMOS
logic. Both parts are available in a 24-pin, 0.3-inch wide, plastic
or hermetic dual-in-line package (DIP) and in a 28-pin, plastic
small outline (SOIC) package. The AD7242 and AD7244 are
available in the same pinout to allow easy upgrade from 12-bit
to 14-bit performance.
FEATURES
Two 12-Bit/14-Bit DACs with Output Amplifiers
AD7242:12-Bit Resolution
AD7244: 14-Bit Resolution
On-Chip Voltage Reference
Fast Settling Time
AD7242:3 ms to 61/2 LSB
AD7244:4 ms to 61/2 LSB
High Speed Serial Interface
Operates from 65 V Supplies
Specified Over –408C to +858C in Plastic Packages
Low Power – 130 mW typ
PRODUCT HIGHLIGHTS1. Complete, Dual 12-Bit/14-Bit DACs
The AD7242/AD7244 provides the complete function for
generating voltages to 12-bit/14-bit resolution. The part
features an on-chip reference, output buffer amplifiers and
two 12-bit/14-bit D/A converters.
2. High Speed Serial Interface
The AD7242/AD7244 provides a high speed, easy-to-use,
serial interface allowing direct interfacing to DSP processors
and microcontrollers. A separate serial port is provided for
each DAC.
3. Small Package Size
The AD7242/AD7244 is available in a 24-pin DIP and a 28-
pin SOIC package offering considerable space saving over
comparable solutions.
AD7242/AD7244–SPECIFICATIONS
(VDD = +5 V 6 5% VSS = –5 V 6 5%, AGND = DGND = 0 V, REF INA =
REF INB = +3 V. VOUTA, VOUTB load to AGND: RL = 2 kV, CL = 100 pF.
All Specifications TMIN to TMAX unless otherwise noted.)NOTESTemperature ranges are as follows: J, K Versions:–40°C to +85°C; A, B Versions:–40°C to +85°C.Measured with respect to REF IN and includes bipolar offset error.For capacitive loads greater than 50 pF, a series resistor is required (see Internal Reference section).Sample tested @ +25°C to ensure compliance.
Specifications subject to change without notice.
AD7242 ORDERING GUIDE
DC ACCURACY
REFERENCE INPUTS
LOGIC INPUTS
AC CHARACTERISTICS
NOTESTemperature ranges are as follows:J Version: 0°C to +70°C; A Version:–40°C to +85°C; S Version:–55°C to +125°C.Measured with respect to REF IN and includes bipolar offset error.For capacitive loads greater than 50 pF, a series resistor is required (see Internal Reference section).Sample tested @ +25°C to ensure compliance.
Specifications subject to change without notice.
AD7242/AD7244
AD7244 ORDERING GUIDE
ModelAD7244JN
AD7244JR
AD7244AQ
AD7244SQ
AD7242/AD7244
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 AD7242/AD7244 feature 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.
TIMING CHARACTERISTICS1, 2NOTESTiming specifications are sample tested at +25°C to ensure compliance. All input signals are specified with tr = tf = 5 ns (10% to 90% of 5 V) and timed from a volt-
age level of 1.6 V.See Figure 6.TCLK Mark/Space ratio is 40/60 to 60/40.
ABSOLUTE MAXIMUM RATINGS*(TA = +25°C unless otherwise noted)
VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
VSS to AGND . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to –7 V
AGND to DGND . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
VOUT to AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . .VSS to VDD
REF OUT to AGND . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
REF INA, REF INB to AGND . . . . . . .–0.3 V to VDD + 0.3 V
Digital Inputs to DGND . . . . . . . . . . . .–0.3 V to VDD + 0.3 V
Operating Temperature Range
J, K Versions
AD7244 . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
AD7242 . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
A, B Versions . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
S Version . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C
(VDD = +5 V 6 5%, VSS = –5 V 6 5%, AGND = DGND = 0 V)
PIN CONFIGURATIONSStorage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . +300°C
Power Dissipation (Any Package) to +75°C . . . . . . . 550 mW
Derates above +75°C by . . . . . . . . . . . . . . . . . . . . . 6 mW/°C
*Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only, functional operation
of the device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
DIPSOIC
AD7242/AD7244 PIN FUNCTION DESCRIPTIONAD7242/AD7244
CIRCUIT DESCRIPTIONThe AD7242/AD7244 contains two 12-bit/14-bit D/A convert-
ers, each with an output buffer amplifier. The part also contains
a reference input buffer amplifier for each DAC, and an on-chip
3 V reference.
D/A SectionThe AD7242/AD7244 contains two 12-bit/14-bit voltage mode
D/A converters, each consisting of highly stable thin-film resistors
and high speed single-pole, double-throw switches. The simplified
circuit diagram for the DAC section is shown in Figure 1. The
three MSBs of the data word are decoded to drive the seven
switches A-G. On the AD7242, the 9 LSBs switch a
9-bit R-2R ladder structure while on the AD7244, the 11 LSBs
switch an 11-bit R-2R ladder structure. The output voltage
from this converter has the same polarity as the reference
voltage, REF IN.
The REF IN voltage is internally buffered by a unity gain
amplifier before being applied to the D/A converters and the
bipolar bias circuitry. The D/A converter is configured and
scaled for a 3 V reference, and the device is tested with 3 V
applied to REF IN. Operating the AD7242/AD7244 at refer-
ence voltages outside the ±5% tolerance range may result in
degraded performance from the part.
Figure 1.DAC Ladder Structure
Internal ReferenceThe on-chip reference is a temperature-compensated buried
Zener reference that is factory trimmed for 3 V ± 10 mV. The
reference can be used to provide both the reference voltage for
the two D/A converters and the bipolar biasing circuitry. This is
achieved by connecting REF OUT to REF INA and REF INB.
The reference voltage can also be used for other components
and is capable of providing up to 500 μA to an external load.
The maximum recommended capacitance on the reference
output pin for normal operation is 50 pF. If the reference
output is required to drive a capacitive load greater than 50 pF,
a 200 Ω resistor should be placed in series with the capacitive
load. Decoupling the REF OUT pin with a series 200Ω resistor
and a parallel combination of a 10 μF tantalum capacitor and a
0.1 μF ceramic capacitor as in Figure 2 reduces the noise
spectral density of the reference (see Figure 4). Using this
decoupling scheme to generate the reference voltage for REF
INA and REF INB gives a channel-to-channel isolation number
of 110 dB (connecting REF OUT directly to REF INA and
REF INB gives 80 dB). The channel-to-channel isolation is 110
dB using an external reference.
External ReferenceIn some applications, the user may require a system reference or
some other external reference to drive the AD7242/AD7244
reference inputs. Figure 3 shows how the AD586 reference can
be conditioned to provide the 3 V reference required by the
Figure 2. Circuit Connection for REF OUT with an External
Capacitive Load of Greater Than 50 pF
