AD7944
Rev. A | Page 5 of 28
TIMING SPECIFICATIONS
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.1 Table 4.
Parameter
Symbol
Test Conditions/Comments
Min
Typ
Max
Unit
Conversion Time: CNV Rising Edge
to Data Available
tCONV
Turbo mode
320
ns
tCONV
Normal mode
420
ns
Acquisition Time
tACQ
80
ns
Time Between Conversions
tCYC
Turbo mode
400
ns
tCYC
Normal mode
500
ns
CNV Pulse Width
tCNVH
CS mode
10
ns
Data Read During Conversion
tDATA
Turbo mode
190
ns
tDATA
Normal mode
290
ns
Quiet Time During Acquisition from Last SCK
Falling Edge to CNV Rising Edge
tQUIET
20
ns
SCK Period
tSCK
CS mode
9
ns
tSCK
Chain mode
11
ns
SCK Low Time
tSCKL
3.5
ns
SCK High Time
tSCKH
3.5
ns
SCK Falling Edge to Data Remains Valid
tHSDO
2
ns
SCK Falling Edge to Data Valid Delay
tDSDO
4
ns
CNV or SDI Low to SDO D13 MSB Valid
tEN
5
ns
CNV or SDI High or Last SCK Falling Edge
to SDO High Impedance
tDIS
CS mode
8
ns
SDI Valid Setup Time from CNV Rising Edge
tSSDICNV
4
ns
SDI Valid Hold Time from CNV Rising Edge
tHSDICNV
CS mode
0
ns
tHSDICNV
Chain mode
0
ns
SCK Valid Setup Time from CNV Rising Edge
tSSCKCNV
Chain mode
5
ns
SCK Valid Hold Time from CNV Rising Edge
tHSCKCNV
Chain mode
5
ns
SDI Valid Setup Time from SCK Falling Edge
tSSDISCK
Chain mode
2
ns
SDI Valid Hold Time from SCK Falling Edge
tHSDISCK
Chain mode
3
ns
SDI High to SDO High
tDSDOSDI
Chain mode with busy indicator
15
ns
1
500A
IOL
500A
IOH
1.4V
TO SDO
CL
20pF
04658-
002
Figure 2. Load Circuit for Digital Interface Timing
90% VIO
10% VIO
VIH1
VIL1
VIH1
tDELAY
1MINIMUM VIH AND MAXIMUM VIL USED. SEE DIGITAL INPUTS
SPECIFICATIONS IN TABLE 3.
04658-
003
Figure 3. Voltage Levels for Timing