link to page 16 link to page 13 Data SheetAD7944SPECIFICATIONS AVDD = DVDD = 2.5 V, BVDD = 5 V, VIO = 1.8 V to 2.7 V, VREF = 4.096 V, TA = −40°C to +85°C, unless otherwise noted. Table 2. ParameterTest Conditions/CommentsMinTypMaxUnit RESOLUTION 14 Bits ANALOG INPUT Voltage Range (IN+) − (IN−) 0 VREF V Absolute Input Voltage IN+ −0.1 VREF + 0.1 V IN− −0.1 +0.1 V Leakage Current at 25°C Acquisition phase 250 nA Input Impedance See the Analog Inputs section ACCURACY No Missing Codes 14 Bits Differential Nonlinearity Error, DNL −0.90 ±0.25 +0.90 LSB1 Integral Nonlinearity Error, INL −1.00 ±0.25 +1.00 LSB1 Transition Noise 0.4 LSB1 Gain Error2 TMIN to TMAX −15 ±2 +15 LSB1 Gain Error Temperature Drift ±0.8 ppm/°C Zero Error2 TMIN to TMAX −0.65 ±0.08 +0.65 mV Zero Error Temperature Drift 0.55 ppm/°C Power Supply Sensitivity3 AVDD = 2.5 V ± 5% 84.3 dB THROUGHPUT Conversion Rate 0 2.5 MSPS Transient Response Full-scale step 100 ns AC ACCURACY3 Dynamic Range VREF = 4.096 V, internal reference 83.5 84.5 dB VREF = 5.0 V, external reference 84 85 dB Signal-to-Noise Ratio, SNR fIN = 20 kHz VREF = 4.096 V, internal reference 83.5 84 dB VREF = 5.0 V, external reference 84 84.5 dB Spurious-Free Dynamic Range, SFDR fIN = 20 kHz 103 dB Total Harmonic Distortion, THD fIN = 20 kHz, VREF = 4.096 V, internal −102 dB reference Signal-to-Noise-and-Distortion Ratio, fIN = 20 kHz, VREF = 4.096 V 84 dB SINAD SAMPLING DYNAMICS −3 dB Input Bandwidth 19 MHz Aperture Delay 0.7 ns 1 LSB means least significant bit. With the 4.096 V input range, one LSB is 250 µV. 2 See the Terminology section. These specifications include full temperature range variation but not the error contribution from the external reference. 3 All specifications expressed in decibels are referred to a full-scale input FSR and tested with an input signal at 0.5 dB below full scale, unless otherwise specified. Rev. C | Page 3 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