AD7266 데이터 시트보기 (PDF) - Analog Devices
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AD7266 Datasheet PDF : 20 Pages
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AD7357
FULL POWER-DOWN MODE
This mode is intended for use in applications where throughput
rates slower than those in the partial power-down mode are
required, as power-up from a full power-down takes
substantially longer than that from a partial power-down. This
mode is more suited to applications where a series of
conversions performed at a relatively high throughput rate are
followed by a long period of inactivity and thus, power-down.
When the AD7357 is in full power-down, all analog circuitry is
powered down. Full power-down is entered in a similar way as
partial power-down, except that the timing sequence shown in
Figure 25 must be executed twice. The conversion process must
be interrupted in a similar fashion by bringing CS high
anywhere after the second falling edge of SCLK and before the
THE PART BEGINS
TO POWER UP.
CS
1
SCLK
tPOWER-UP1
10
14
Preliminary Technical Data
10th falling edge of SCLK. The device enters partial power-down
mode at this point.
To reach full power-down, the next conversion cycle must be
interrupted in the same way, as shown in Figure 27. Once CS
has been brought high in this window of SCLKs, the part
completely powers down.
Note that it is not necessary to complete the 16 SCLKs once CS
has been brought high to enter a power-down mode.
To exit full power-down mode and power-up the AD7357,
perform a dummy conversion, such as powering up from partial
power-down. On the falling edge of CS, the device begins to
power up, as long as CS is held low until after the falling edge of
the 10th SCLK. The required power-up time must elapse before
a conversion can be initiated, as shown in Figure 28.
THE PART IS FULLY
POWERED UP; SEE
POWER-UP TIMES
SECTION.
1
14
DOUTA
DOUTB
INVALID DATA
Figure 26. Exiting Partial Power-Down Mode
VALID DATA
THE PART ENTERS
PARTIAL POWER DOWN.
THE PART BEGINS
TO POWER UP.
THE PART ENTERS
FULL POWER DOWN.
CS
SCLK
12
10
14
12
10
14
DOUTA
DOUTB
CS
SCLK
INVALID DATA
THREE-STATE
INVALID DATA
Figure 27. Entering Full Power-Down Mode
THREE-STATE
THE PART BEGINS
TO POWER UP.
tPOWER-UP2
THE PART IS FULLY POWERED UP,
SEE POWER-UP TIMES SECTION.
1
10
14
1
14
DOUTA
DOUTB
INVALID DATA
Figure 28. Exiting Full Power-Down Mode
VALID DATA
Rev. PrF | Page 16 of 20
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