AD7795 Analog Devices, AD7795 Datasheet - Page 8

• Manufacturer Part Number: AD7795
• Description: 6-Channel, Low Noise, Low Power, 16-Bit Sigma Delta ADC with On-Chip In-Amp and Reference
• Manufacturer: Analog Devices

Specifications of AD7795

• Resolution (bits): 16bit
• # Chan: 6
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref/PGA Gain) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7794/AD7795
TIMING CHARACTERISTICS
AV
Table 2.
Parameter
t
t
Read Operation
Write Operation
1
2
3
4
5
6
3
4
Sample tested during initial release to ensure compliance. All input signals are specified with t
See Figure 3 and Figure 4.
These numbers are measured with the load circuit shown in Figure 2 and defined as the time required for the output to cross the V
SCLK active edge is falling edge of SCLK.
These numbers are derived from the measured time taken by the data output to change 0.5 V when loaded with the circuit shown in Figure 2. The measured number
is then extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the times quoted in the timing characteristics are the
true bus relinquish times of the part and, therefore, are independent of external bus loading capacitances.
RDY returns high after a read of the ADC. In single conversion mode and continuous conversion mode, the same data can be read again, if required, while RDY is high,
although care should be taken to ensure that subsequent reads do not occur close to the next output update. In continuous read mode, the digital word can be read
only once.
t
t
t
t
t
t
t
t
t
DD
1
2
5
6
7
8
9
10
11
3
5, 6
= 2.7 V to 5.25 V, DV
1, 2
Limit at T
100
100
0
60
80
0
60
80
10
80
0
10
0
30
25
0
DD
= 2.7 V to 5.25 V, GND = 0 V, Input Logic 0 = 0 V, Input Logic 1 = DV
MIN
, T
MAX
(B Version)
OUTPUT
Figure 2. Load Circuit for Timing Characterization
PIN
TO
50pF
Rev. D | Page 8 of 36
Unit
ns min
ns min
ns min
ns max
ns max
ns min
ns max
ns max
ns min
ns max
ns min
ns min
ns min
ns min
ns min
ns min
I
100µA WITH DV
I
100µA WITH DV
SINK
SOURCE
(1.6mA WITH DV
(200µA WITH DV
1.6V
Conditions/Comments
DD
DD
SCLK high pulse width
SCLK low pulse width
CS falling edge to DOUT/RDY active time
DV
DV
SCLK active edge to data valid delay
DV
DV
Bus relinquish time after CS inactive edge
SCLK inactive edge to CS inactive edge
SCLK inactive edge to DOUT/RDY high
CS falling edge to SCLK active edge setup time
Data valid to SCLK edge setup time
Data valid to SCLK edge hold time
CS rising edge to SCLK edge hold time
R
= t
= 3V)
= 3V)
DD
DD
DD
DD
F
DD
= 5 ns (10% to 90% of DV
= 4.75 V to 5.25 V
= 2.7 V to 3.6 V
= 4.75 V to 5.25 V
= 2.7 V to 3.6 V
= 5V,
DD
= 5V,
DD
, unless otherwise noted.
DD
) and timed from a voltage level of 1.6 V.
OL
or V
OH
4
limits.
4