Data SheetAD7944TYPICAL PERFORMANCE CHARACTERISTICS AVDD = DVDD = VIO = 2.5 V, BVDD = 5.0 V, VREF = 5.0 V, external reference (PDREF is high, REFIN is low), unless otherwise noted. 1.01.0POSITIVE INL = +0.12 LSBPOSITIVE DNL = +0.11LSBNEGATIVE INL = –0.20 LSB0.80.8NEGATIVE DNL = –0.11LSB0.60.60.40.4)0.2)0.2SBSB0(L(L0LLIN –0.2DN –0.2–0.4–0.4–0.6–0.6–0.8–0.8–1.0–1.004096819212,28816,384 105 04096819212,28816,384 108 CODE 04658- CODE 04658- Figure 5. Integral Nonlinearity vs. Code Figure 8. Differential Nonlinearity vs. Code 140,00080,000126,02270,00067,766120,00062,98260,000100,00050,00080,000UNTUNT40,000CO 60,000CO30,00040,00020,00020,00010,00048990021490000032400000 106 81888189819081918192819381948195819681888189819081918192819381948195 109 CODE IN HEX 04658- CODE IN HEX 04658- Figure 6. Histogram of DC Input at Code Center (External Reference) Figure 9. Histogram of DC Input at Code Transition (External Reference) 140,00080,000124,39667,825120,00070,00063,23860,000100,00050,00080,000UNTUNT 40,000CO 60,000CO30,00040,00020,00020,00010,0005236002143800000720000818881898190819181928193819481958196 110 81898190819181928193819481958196 107 CODE IN HEXCODE IN HEX 04658- 04658- Figure 7. Histogram of DC Input at Code Center (Internal Reference) Figure 10. Histogram of DC Input at Code Transition (Internal Reference) Rev. C | Page 9 of 28 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION APPLICATION DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER OPERATION CONVERSION MODES OF OPERATION Transfer Functions TYPICAL APPLICATION DIAGRAM ANALOG INPUTS DRIVER AMPLIFIER CHOICE VOLTAGE REFERENCE INPUT Internal Reference, REF = 4.096 V (PDREF Low) External 1.2 V Reference and Internal Buffer (PDREF High) External Reference (PDREF High, REFIN Low) Reference Decoupling POWER SUPPLY DIGITAL INTERFACE DATA READING OPTIONS Reading During Conversion, Fast Host (Turbo or Normal Mode) Split Reading, Any Speed Host (Turbo or Normal Mode) Reading During Acquisition, Any Speed Host (Turbo or Normal Mode) CS\ MODE, 3-WIRE WITHOUT BUSY INDICATOR CS\ MODE, 3-WIRE WITH BUSY INDICATOR CS\ MODE, 4-WIRE WITHOUT BUSY INDICATOR CS\ MODE, 4-WIRE WITH BUSY INDICATOR CHAIN MODE WITHOUT BUSY INDICATOR CHAIN MODE WITH BUSY INDICATOR APPLICATIONS INFORMATION LAYOUT EVALUATING AD7944 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE