Datasheet

AD7944
Rev. A | Page 3 of 28
SPECIFICATIONS
AVDD = DVDD = 2.5 V, BVDD = 5 V, VIO = 1.8 V to 2.7 V, V
REF
= 4.096 V, T
A
= −40°C to +85°C, unless otherwise noted.
Table 2.
Parameter Test Conditions/Comments Min Typ Max Unit
RESOLUTION 14 Bits
ANALOG INPUT
Voltage Range (IN+) − (IN−) 0 V
REF
V
Absolute Input Voltage IN+ −0.1 V
REF
+ 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 LSB
1
Integral Nonlinearity Error, INL −1.00 ±0.25 +1.00 LSB
1
Transition Noise 0.9 LSB
1
Gain Error
2
T
MIN
to T
MAX
−15 ±2 +15 LSB
1
Gain Error Temperature Drift ±0.8 ppm/°C
Zero Error
2
T
MIN
to T
MAX
−0.65 ±0.08 +0.65 mV
Zero Error Temperature Drift 0.55 ppm/°C
Power Supply Sensitivity
3
AVDD = 2.5 V ± 5% 84.3 dB
THROUGHPUT
Conversion Rate 0 2.5 MSPS
Transient Response Full-scale step 100 ns
AC ACCURACY
3
Dynamic Range V
REF
= 4.096 V, internal reference 83.5 84.5 dB
V
REF
= 5.0 V, external reference 84 85 dB
Signal-to-Noise Ratio, SNR f
IN
= 20 kHz
V
REF
= 4.096 V, internal reference 83.5 84 dB
V
REF
= 5.0 V, external reference 84 84.5 dB
Spurious-Free Dynamic Range, SFDR f
IN
= 20 kHz 103 dB
Total Harmonic Distortion, THD
4
f
IN
= 20 kHz, V
REF
= 4.096 V, internal
reference
−102 dB
Signal-to-Noise-and-Distortion Ratio,
SINAD
f
IN
= 20 kHz, V
REF
= 4.096 V 84 dB
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.
4
Tested fully in production at f
IN
= 1 kHz.