AD7910 Analog Devices, AD7910 Datasheet - Page 7

• Manufacturer Part Number: AD7910
• Description: 250 kSPS, 10-Bit ADC in 6 Lead SC70
• Manufacturer: Analog Devices

Specifications of AD7910

• Resolution (bits): 10bit
• # Chan: 1
• Sample Rate: 250kSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Uni
• Ain Range: Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SC70,SOP

TIMING EXAMPLES
Figure 3 and Figure 4 show some of the timing parameters from
Table 3.
TIMING EXAMPLE 1
From Figure 4, having f
250 kSPS gives a cycle time of t
With t
satisfies the requirement of 250 ns for t
comprises 2.5(1/f
allows a value of 954 ns for t
requirement of 50 ns.
2
SDATA
SCLK
= 10 ns min, this leaves t
SCLK
CS
CS
THREE-
STATE
SCLK
t
) + t
2
t
2
Z
SCLK
1
1
t
8
3
ZERO
+ t
= 5 MHz and a throughput rate of
4 LEADING ZEROS
QUIET
QUIET
2
2
+ 12.5(1/f
ACQ
2
, satisfying the minimum
, where t
ZERO
to be 1.49 μs. This 1.49 μs
ACQ
3
3
ZERO
t
. From Figure 4, t
SCLK
8
4
= 36 ns max. This
12.5(1/f
) + t
4
4
Figure 3. AD7920 Serial Interface Timing Diagram
SCLK
DB11
ACQ
t
t
Figure 4. Serial Interface Timing Example
6
CONVERT
)
= 4 μs.
5
t
5
CONVERT
t
DB10
7
ACQ
Rev. C | Page 7 of 24
1/THROUGHPUT
13
13
B
B
DB2
TIMING EXAMPLE 2
The AD7920 can also operate with slower clock frequencies.
From Figure 4, having f
150 kSPS gives a cycle time of t
With t
satisfies the requirement of 250 ns for t
comprises 2.5(1/f
value of 2.19 μs for t
of 50 ns. As in this example and with other slower clock values,
the signal may already be acquired before the conversion is
complete, but it is still necessary to leave 50 ns minimum t
between conversions. In this example, the signal should be fully
acquired at approximately Point C in Figure 4.
14
14
t
5
2
C
DB1
= 10 ns min, this leaves t
15
15
t
8
DB0
SCLK
t
ACQ
QUIET
16
t
) + t
16
8
SCLK
, satisfying the minimum requirement
8
+ t
THREE-STATE
= 3.4 MHz and a throughput rate of
QUIET
2
+ 12.5(1/f
ACQ
t
t
, t
QUIET
QUIET
8
to be 2.97 μs. This 2.97 μs
= 36 ns max. This allows a
t
1
AD7910/AD7920
ACQ
. From Figure 4, t
SCLK
) + t
ACQ
= 6.66 μs.
QUIET
ACQ