Datasheet

CS
SCLK
DOUT
DIN
1
16
InvalidData
CS
SCLK
DOUT
DIN
1
16
1
16
1 16 1 16
1 16
InvalidData
NoWritetotheControlRegister
NoWritetotheControlRegister
NoWritetotheControlRegister NoWritetotheControlRegister
NoWritetotheControlRegister
Command:SelectChannels
AIN2,AIN5,andAIN7,Repeat=1
ConversionResultfor
ChannelAIN2
ConversionResultfor
ChannelAIN5
ConversionResultfor
ChannelAIN7
ConversionResultfor
ChannelAIN2
WaitingforConfiguration ConvertingforChannelAIN2 ConvertingforChannelAIN5
ConvertingforChannelAIN2 ConvertingforChannelAIN5ConvertingforChannelAIN7
¼
¼
¼
¼
ADS8028
SBAS549B –MAY 2011–REVISED MARCH 2012 www.ti.com
The ADS8028 continues to operate in repeat mode until a valid write operation is executed to reprogram the
Control Register. When the Control Register is updated, the ADS8028 comes out of repeat mode and begins
operating as per the new programmed settings. Therefore, to continue in repeat mode and to avoid accidentally
overwriting the Control Register, it is recommended that the WRITE bit in the Control Register be set to '0' while
operating in repeat mode. Figure 37 illustrates the repeat mode of operation.
Figure 37. Configuring a Conversion and Read in Repeat Mode
Low-Power Modes
In normal mode of operation, all internal ADS8028 blocks are always powered up and the device is always ready
to initiate a new conversion. This architecture enables the ADS8028 to support the 1-MSPS rated throughput
rate. However, the ADS8028 also supports two low-power modes that can be used to optimize the power
consumption and throughput rate ratio. In these low-power modes, some internal ADS8028 blocks are powered
up or down as the operation requires. This flexibility reduces the overall power consumption at lower throughput
rates.
STANDBY Mode
In STANDBY mode, only part of the ADS8028 internal circuitry is powered down. The internal reference is not
powered down and, therefore, the ADS8028 can be fully powered up within 1 µs. To enter STANDBY mode, a
valid write operation should be executed to the Control Register with the STANDBY bit set to '1'. The ADS8028
enters STANDBY mode on the CS rising edge following this write operation.
The temperature sensor averaging function is also reset when the device enters STANDBY mode. While in
STANDBY mode, any read operation on the ADS8028 returns all '1's on the DOUT pin.
The ADS8028 remains in STANDBY mode until the STANDBY bit in the Control Register is reset to '0' using a
valid write operation. Then, the ADS8028 starts powering up on the CS rising edge following this write operation.
One valid Control Register write cycle must complete in order to update the desired channels for subsequent
conversions. After successful completion of these two write cycles, the device enters a normal mode of operation
and operates with one cycle latency.
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