AD7329 Analog Devices, AD7329 Datasheet - Page 32

• Manufacturer Part Number: AD7329
• Description: 1 MSPS , 8-Channel, Software Selectable True Bipolar Input, 12-Bit Plus Sign A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7329

• Resolution (bits): 13bit
• # Chan: 8
• Sample Rate: 1MSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni,SE-Uni
• Ain Range: Bip (Vref),Bip (Vref) x 2,Bip (Vref) x 4,Bip 10V,Bip 2.5V,Bip 5.0V,Uni (Vref),Uni 10V
• Adc Architecture: SAR
• Pkg Type: SOP

AD7329
MODES OF OPERATION
The AD7329 has several modes of operation that are designed
to provide flexible power management options. These options
can be chosen to optimize the power dissipation/throughput
rate ratio for different application requirements. The mode of
operation of the AD7329 is controlled by the power management
bits, Bit PM1 and Bit PM0, in the control register as shown in
Table 13. The default mode is normal mode, where all internal
circuitry is fully powered up.
NORMAL MODE
(PM1 = PM0 = 0)
This mode is intended for the fastest throughput rate
performance with the AD7329 being fully powered up at all
times. Figure 52 shows the general operation of the AD7329
in normal mode.
The conversion is initiated on the falling edge of CS , and the
track-and-hold section enters hold mode, as described in the
Serial Interface
16 SCLK transfer is loaded into one of the on-chip registers if
the write bit is set. The register is selected by programming the
register select bits (see
DOUT
SCLK
DIN
CS
SDATA
SCLK
PART IS IN FULL
SHUTDOWN
DIN
CS
section. The data on the DIN line during the
1
3 CHANNEL I.D. BITS, SIGN BIT + CONVERSION RESULT
CONTROL REGISTER IS LOADED ON THE FIRST 15 CLOCKS.
DATA INTO CONTROL/SEQUENCE/RANGE1/RANGE2
1
Figure 52. Normal Mode
Table 10
THE PART BEGINS TO POWER UP ON THE
15TH SCLK RISING EDGE AS PM1 = PM0 = 0
DATA INTO CONTROL REGISTER
).
REGISTER
PM1 = PM0 = 0
INVALID DATA
Figure 53. Exiting Full Shutdown Mode
16
16
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t
POWER-UP
The AD7329 remains fully powered up at the end of the
conversion if both PM1 and PM0 contain 0 in the control
register.
To complete the conversion and access the conversion result,
16 serial clock cycles are required. At the end of the conversion,
CS can idle either high or low until the next conversion.
After the data transfer is complete, another conversion can be
initiated after the quiet time, t
FULL SHUTDOWN MODE
(PM1 = PM0 = 1)
In this mode, all internal circuitry on the AD7329 is powered
down. The part retains information in the registers during full
shutdown. The AD7329 remains in full shutdown mode until
the power management bits, Bit PM1 and Bit PM0, in the
control register are changed.
A write to the control register with PM1 = PM0 = 1 places the
part into full shutdown mode. The AD7329 enters full shutdown
mode on the 15
updated.
If a write to the control register occurs while the part is in full
shutdown mode with the power management bits, Bit PM1 and
Bit PM0, set to 0 (normal mode), the part begins to power up on
the 15
Figure 53 shows how the AD7329 is configured to exit full
shutdown mode. To ensure that the AD7329 is fully powered
up, t
THE PART IS FULLY POWERED UP
ONCE
TO KEEP THE PART IN NORMAL MODE, LOAD PM1 = PM0 = 0
1
CHANNEL IDENTIFIER BITS + CONVERSION RESULT
POWER-UP
t
POWER-UP
th
DATA INTO CONTROL/SHADOW REGISTER
SCLK rising edge when the control register is updated.
should elapse before the next CS falling edge.
HAS ELAPSED
IN CONTROL REGISTER
th
SCLK rising edge when the control register is
QUIET
, has elapsed.
16