AD7945AN-B资料
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FUNCTIONAL BLOCK DIAGRAMS
VDDRFB
DGNDAD7948
DB7–DB0DF/DORCTRL
LDACWRCSLSBCSMSBIOUT1AGNDV
REF12-BIT DAC12
12DATA OVERRIDE LOGIC
12DAC REGISTER
12INPUT REGISTERSCONTROLLOGIC
DATA STEERING LOGIC8CSWRVDDRFBIOUT1AGNDVREF
DGNDDB11–DB0AD794512-BIT DAC12INPUT LATCH
12AD7943VDDRFBIOUT1
AGNDIOUT2
SRO
STB1DGNDSTB2STB3STB4CLRLD1LD2SRIVREF12-BIT DAC
DAC REGISTER
INPUT SHIFT REGISTER
REV.BInformation furnished by Analog Devices is believed to be accurate andreliable. However, no responsibility is assumed by Analog Devices for itsuse, nor for any infringements of patents or other rights of third partieswhich may result from its use. No license is granted by implication orotherwise under any patent or patent rights of Analog Devices.a+3.3 V/+5 V Multiplying
12-Bit DACs
AD7943/AD7945/AD7948
FEATURES12-Bit Multiplying DACsGuaranteed Specifications with +3.3 V/+5 V Supply0.5 LSBs INL and DNLLow Power: 5 W typFast Interface40 ns Strobe Pulsewidth (AD7943)40 ns Write Pulsewidth (AD7945, AD7948)Low Glitch: 60 nV-s with Amplifier ConnectedFast Settling: 600 ns to 0.01% with AD843APPLICATIONSBattery-Powered InstrumentationLaptop ComputersUpgrades for All 754x Series DACs (5 V Designs)
GENERAL DESCRIPTIONThe AD7943, AD7945 and AD7948 are fast 12-bit multiplyingDACs that operate from a single +5 V supply (Normal Mode)and a single +3.3 V to +5 V supply (Biased Mode). TheAD7943 has a serial interface, the AD7945 has a 12-bit parallelinterface, and the AD7948 has an 8-bit byte interface. They willreplace the industry-standard AD7543, AD7545 and AD7548in many applications, and they offer superior speed and powerconsumption performance.The AD7943 is available in 16-lead DIP, 16-lead SOP (SmallOutline Package) and 20-lead SSOP (Shrink Small OutlinePackage).The AD7945 is available in 20-lead DIP, 20-lead SOP and 20-lead SSOP.The AD7948 is available in 20-lead DIP, 20-lead SOP and 20-lead SSOP.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.Tel: 781/329-4700World Wide Web Site: http://www.analog.comFax: 781/326-8703© Analog Devices, Inc., 1998元器件交易网www.cecb2b.com–2–AD7943/AD7945/AD7948–SPECIFICATIONS1ParameterB Grades2T Grade2, 3UnitsTest Conditions/CommentsACCURACYResolution1212Bits1LSB=VREF/212=2.44mVwhenVREF=10VRelative Accuracy±0.5±0.5LSB maxDifferential Nonlinearity±0.5±0.5LSB maxAll Grades Guaranteed Monotonic overTemperatureGain ErrorTMIN to TMAX±2±2LSB maxGain Temperature Coefficient422ppm FSR/°C typ55ppm FSR/°C maxOutput Leakage CurrentIOUT1@ +25°C1010nA maxSee Terminology SectionTMIN to TMAX100100nA maxTypically 20 nA over TemperatureREFERENCE INPUTInput Resistance66kΩ minTypical Input Resistance = 9 kΩ1212kΩ maxDIGITAL INPUTSVINH, Input High Voltage2.42.4V minVINL, Input Low Voltage0.80.8V maxIINH, Input Current±1±1µA maxCIN, Input Capacitance41010pF maxDIGITAL OUTPUT (AD7943 SRO)For 1 CMOS LoadOutput Low Voltage (VOL)0.20.2V maxOutput High Voltage (VOH)VDD – 0.2VDD – 0.2V minPOWER REQUIREMENTSVDD Range4.5/5.54.5/5.5V min/V maxPower Supply Sensitivity4∆Gain/∆VDD–75–75dB typIDD (AD7943)55µA maxVINH = VDD – 0.1 V min, VINL = 0.1 V max.SRO Open Circuit. No STB Signal. Typically1 µA. Typically 100 µA with a 1 MHz STBFrequency. At Input Levels of 0.8 V and 2.4 V,IDD Is Typically 2.5 mA.IDD (AD7945, AD7948)55µA maxVINH = VDD – 0.1 V min, VINL = 0.1 V max.Typically 1 µA. At Input Levels of 0.8 V and2.4 V, IDD Is Typically 2.5 mA.NOTES1The AD7943, AD7945 and AD7948 are specified in the normal current mode configuration and in the biased current mode for single-supply applications.Figures 14 and 15 are examples of normal mode operation.2Temperature ranges as follows: B Grades: –40°C to +85°C; T Grade: –55°C to +125°C.3The T Grade applies to the AD7945 only.4Guaranteed by design.Specifications subject to change without notice.NORMAL MODE(AD7943: VDD = +4.5 V to +5.5 V; VIOUT1 = VIOUT2 = AGND = 0 V; VREF = +10 V; TA = TMIN to TMAX, unless otherwise noted.AD7945, AD7948: VDD = +4.5 V to +5.5 V; VIOUT1 = AGND = 0 V; VREF = +10 V; TA = TMIN to TMAX, unless otherwise noted.)元器件交易网www.cecb2b.comAD7943/AD7945/AD7948
REV. B–3–ParameterA Grades2UnitsTest Conditions/CommentsACCURACYResolution12Bits1 LSB = (VIOUT1 – VREF)/212 = 300 µV WhenVIOUT1 = 1.23 V and VREF = 0 VRelative Accuracy±1LSB maxDifferential Nonlinearity±0.9LSB maxAll Grades Guaranteed Monotonicover TemperatureGain Error @ +25°C±3LSB maxTMIN to TMAX±4LSB maxGain Temperature Coefficient32ppm FSR/°C typ5ppm FSR/°C maxOutput Leakage CurrentSee Terminology SectionIOUT1@ +25°C10nA maxTMIN to TMAX100nA maxTypically 20 nA over TemperatureInput ResistanceThis Varies with DAC Input Code@ IOUT2 Pin (AD7943)6kΩ min@ AGND Pin (AD7945, AD7948)6kΩ minDIGITAL INPUTSVINH, Input High Voltage @ VDD = +5 V2.4V minVINH, Input High Voltage @ VDD = +3.3 V2.1V minVINL, Input Low Voltage @ VDD = +5 V0.8V maxVINL, Input Low Voltage @ VDD = +3.3 V0.6V maxIINH, Input Current±1µA maxCIN, Input Capacitance310pF maxDIGITAL OUTPUT (SRO)For 1 CMOS LoadOutput Low Voltage (VOL)0.2V maxOutput High Voltage (VOH)VDD – 0.2V minPOWER REQUIREMENTSVDD Range3.0/5.5V min/V maxPower Supply Sensitivity3∆Gain/∆VDD–75dB typIDD (AD7943)5µA maxVINH = VDD – 0.1 V min, VINL = 0.1 V max.SRO Open Circuit; No STB Signal; Typically1 µA. Typically 100 µA with 1 MHz STBFrequency.IDD (AD7945, AD7948)5µA maxVINH = VDD – 0.1 V min, VINL = 0.1 V max.Typically 1 µA.NOTES1These specifications apply with the devices biased up at 1.23 V for single supply applications. The model numbering reflects this by means of a “–B” suffix(for example: AD7943AN-B). Figure 16 is an example of Biased Mode Operation.2Temperature ranges as follows: A Versions: –40°C to +85°C.3Guaranteed by design.Specifications subject to change without notice.BIASEDMODESPECIFICATIONS1
