EVAL-AD7651EDZ Analog Devices, EVAL-AD7651EDZ Datasheet - Page 21

• Manufacturer Part Number: EVAL-AD7651EDZ
• Description: Data Conversion IC Development Tools AD7651 Eval Board 16bit 100 kSPS ADC
• Manufacturer: Analog Devices
• Type: ADCr
• Series: AD7651r

Specifications of EVAL-AD7651EDZ

• Rohs: yes
• Product: Evaluation Boards
• Tool Is For Evaluation Of: AD7651
• Interface Type: SPI
• Operating Supply Voltage: 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Factory Pack Quantity: 1

MASTER SERIAL INTERFACE
Internal Clock
The AD7651 is configured to generate and provide the serial data
clock SCLK when the EXT/INT pin is held LOW. The AD7651 also
generates a SYNC signal to indicate to the host when the serial data
is valid. The serial clock SCLK and the SYNC signal can be inverted
if desired. Depending on the RDC/SDIN input, the data can be read
after each conversion or during the following conversion. Figure 32
and Figure 33 show detailed timing diagrams of these two modes.
CS, RD
CS, RD
SDOUT
CNVST
SDOUT
CNVST
BUSY
SYNC
SCLK
BUSY
SYNC
SCLK
t
16
t
3
Figure 33. Master Serial Data Timing for Reading (Read Previous Conversion during Convert)
t
t
t
14
15
16
t
t
t
14
15
29
t
17
X
t
t
Figure 32. Master Serial Data Timing for Reading (Read after Convert)
18
22
EXT/INT = 0
t
EXT/INT = 0
1
t
D15
3
X
t
t
1
20
22
t
19
t
21
t
20
D14
t
D15
2
23
1
t
19
t
18
Rev. 0 | Page 21 of 28
RDC/SDIN = 0
RDC/SDIN = 1
D14
t
2
t
21
3
23
t
28
3
Usually, because the AD7651 has a longer acquisition phase than
the conversion phase, the data is read immediately after conversion.
This makes the Master Read After Conversion the most recom-
mended serial mode when it can be used. In this mode, it should be
noted that unlike in other modes, the BUSY signal returns LOW
after the 16 data bits are pulsed out and not at the end of the
conversion phase, which results in a longer BUSY width.
In the Read During Conversion mode, the serial clock and data
toggle at appropriate instants, which minimize potential feed-
through between digital activity and critical conversion decisions
INVSCLK = INVSYNC = 0
14
D2
INVSCLK = INVSYNC = 0
14
D2
15
D1
15
D1
16
t
24
16
t
30
D0
t
D0
24
02964-0-015
02964-0-016
t
t
t
t
t
t
25
26
27
25
26
27
AD7651