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Data Sheet
AD7938-6
Rev. C | Page 3 of 32
SPECIFICATIONS
VDD = VDRIVE = 2.7 V to 5.25 V, internal/external VREF = 2.5 V, unless otherwise noted; fCLKIN = 10 MHz, fSAMPLE = 625 kSPS; TA = TMIN to
T
MAX1, unless otherwise noted.
Table 2.
Parameter
Unit
Test Conditions/Comments
DYNAMIC PERFORMANCE
fIN = 50 kHz sine wave
Signal-to-Noise + Distortion (SINA
D)269
dB min
Differential mode
67
dB min
Single-ended mode
71
dB min
Differential mode
69
dB min
Single-ended mode
Total Harmonic Distortion
(THD)273
dB max
85 dB typ, differential mode
69.5
dB max
80 dB typ, single-ended mode
Peak Harmonic or Spurious Noise (SFD
R)272
dB max
82 dB typ
Intermodulation Distortion (IM
D)2fa = 30 kHz, fb = 50 kHz
Second-Order Terms
86
dB typ
Third-Order Terms
90
dB typ
Channel-to-Channel Isolation
85
dB typ
fIN = 50 kHz, fNOISE = 300 kHz
5
ns typ
72
ps typ
50
MHz typ
@ 3 dB
10
MHz typ
@ 0.1 dB
DC ACCURACY
Resolution
12
Bits
±1
LSB max
Differential mode
±1.5
LSB max
Single-ended mode
Differential Mode
±0.95
LSB max
Guaranteed no missed codes to 12 bits
Single-Ended Mode
0.95/+1.5
LSB max
Guaranteed no missed codes to 12 bits
Single-Ended and Pseudo Differential Input
Straight binary output coding
±12
LSB max
±3
LSB max
±3
LSB max
±2
LSB max
Fully Differential Input
Twos complement output coding
±3
LSB max
±1.5
LSB typ
±9.5
LSB max
±1
LSB typ
±3
LSB max
Negative Gain Error Matc
h2±1.5
LSB typ
ANALOG INPUT
Single-Ended Input Range
0 to VREF
V
RANGE bit = 0
0 to 2 × VREF
V
RANGE bit = 1
Pseudo Differential Input Range:
VIN+
0 to VREF
V
RANGE bit = 0
0 to 2 × VREF
V
RANGE bit = 1
VIN
0.3 to +0.7
V typ
VDD = 3 V
0.3 to +1.8
V typ
VDD = 5 V
Fully Differential Input Range
VIN+ and VIN
VCM ± VREF/2
V
VCM = common-mode voltage3 = VREF/2 VIN+ and VIN
VCM ± VREF
V
VCM = VREF, VIN+ or VIN must remain within GND/VDD