AD7946Data SheetTYPICAL PERFORMANCE CHARACTERISTICS1.01.0POSITIVE INL = +0.17LSBPOSITIVE DNL = +0.20LSB0.8NEGATIVE INL = –0.26LSB0.8NEGATIVE DNL = –0.13LSB0.60.60.40.40.20.200INL (LSB) –0.2DNL (LSB)–0.2–0.4–0.4–0.6–0.6–0.8–0.8 04656-006 –1.0 04656-009 –1.004096819212288163840409681921228816384CODECODE Figure 6. Integral Nonlinearity vs. Code Figure 9. Differential Nonlinearity vs. Code 300000150000261120VDD = REF = 5V131592VDD = REF = 5V12952825000012500020000010000015000075000COUNTSCOUNTS10000050000500002500000000000000 04656-047 02009200A200B200C200D200E200F2059205A205B205C205D205ECODE 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 0908192 POINT FFT–20VDD = REF = 5V fS = 500kSPS)fIN = 20.14kHzle–4088aSNR = 85.3dBcTHD = –105.2dB–60SECOND HARMONIC = –106dBFull STHIRD HARMONIC = –110dB86of–80dB ( E –100D84LITU –120P M A –14082–160SNR REFERENCE TO FULL SCALE (dB) 008 04656- –180 04656-011 80020406080100 120 140 160 180 200 220 240–10–8–6–4–2FREQUENCY (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