Datasheet AD7946 (Analog Devices) - 9

AD7946 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS 1.0 1.0 POSITIVE INL = +0.17LSB POSITIVE DNL = +0.20LSB 0.8 NEGATIVE INL = –0.26LSB 0.8 NEGATIVE DNL = –0.13LSB 0.6 0.6 0.4 0.4 0.2 0.2 0 0 INL (LSB) –0.2 DNL (LSB) –0.2 –0.4 –0.4 –0.6 –0.6 –0.8 –0.8
04656-006
–1.0
04656-009
–1.0 0 4096 8192 12288 16384 0 4096 8192 12288 16384 CODE CODE
Figure 6. Integral Nonlinearity vs. Code Figure 9. Differential Nonlinearity vs. Code
300000 150000 261120 VDD = REF = 5V 131592 VDD = REF = 5V 129528 250000 125000 200000 100000 150000 75000 COUNTS COUNTS 100000 50000 50000 25000 0 0 0 0 0 0 0 0 0 0 0
04656-047
0 2009 200A 200B 200C 200D 200E 200F 2059 205A 205B 205C 205D 205E CODE IN HEX
04656-046
CODE IN HEX
Figure 7. Histogram of a DC Input at the Code Center Figure 10. Histogram of a DC Input at the Code Transition
0 90 8192 POINT FFT –20 VDD = REF = 5V fS = 500kSPS ) fIN = 20.14kHz le –40 88 a SNR = 85.3dB c THD = –105.2dB –60 SECOND HARMONIC = –106dB Full S THIRD HARMONIC = –110dB 86 of –80 dB ( E –100 D 84 LITU –120 P M A –140 82 –160 SNR REFERENCE TO FULL SCALE (dB)
008 04656-
–180
04656-011
80 0 20 40 60 80 100 120 140 160 180 200 220 240 –10 –8 –6 –4 –2 FREQUENCY (kHz) INPUT LEVEL (dB)
Figure 8. FFT Plot Figure 11. SNR vs. Input Level Rev. B | Page 8 of 24 Document Outline Features Applications Typical Application Circuit General Description Table of Contents Revision History Specifications Timing Specifications Absolute Maximum Ratings ESD Caution Pin Configurations and Function Descriptions Typical Performance Characteristics Terminology Theory of Operation Circuit Information Converter Operation Transfer Functions Typical Connection Diagram Analog Input Driver Amplifier Choice Voltage Reference Input Power Supply Supplying the ADC from the Reference Single-Supply Application Digital Interface CS/ MODE 3-Wire, No BUSY Indicator CS/ Mode 3-Wire with BUSY Indicator CS/ Mode 4-Wire, No BUSY Indicator CS/ Mode 4-Wire with BUSY Indicator Chain Mode, No BUSY Indicator Chain Mode with BUSY Indicator Application Guidelines Layout Evaluating the Performance of the AD7946 Outline Dimensions Ordering Guide