ADS8028 Datasheet, PDF (23/34 Pages) Texas Instruments – 12-Bit, 1-MSPS, 8-Channel, SAR ADC

ADS8028
www.ti.com
SBAS549B – MAY 2011 – REVISED MARCH 2012
It takes four serial transfer cycles for the ADS8028 to exit STANDBY mode and transmit the first valid conversion
data, as shown in Figure 38. The first cycle updates the STANDBY bit to '0'; the second cycle selects the
channels and operation mode; the third cycle converts the selected channel; and the result of this conversion can
be clocked out in the fourth cycle.
CS
SCLK
DOUT
Device Enters
Standby Mode
Waiting for Configuration
In Standby Mode
1
16
1
16
Invalid Data
1111 1111 1111
Device Starts to Exit
Standby Mode
In Standby Mode
¼
1
16
¼
1111 1111 1111
¼
DIN
CS
SCLK
DOUT
Command: Enter Standby Mode,
STANDBY = 1
No Write to the
Control Register
Device Exits
Standby Mode
Waiting for Configuration
Converting for Channel AIN1
1
16
1
16
Invalid Data
Invalid Data
Command: Exit Standby Mode,
STANDBY = 0
¼
Converting for Channel AIN4
1
16
Conversion Result for
Channel AIN1
DIN
Command: Select Channel AIN1,
STANDBY = 0
Command:
Select Channel AIN4
No Write to the
Control Register
Figure 38. STANDBY Mode of Operation
Power-Down Mode
In power-down mode, all internal ADS8028 circuitry (including the internal reference) is powered down and the
Control Register is reset to the default values. The temperature sensor averaging feature is reset and disabled.
The ADS8028 can be placed into power-down mode by pulling the PD/RST pin to a logic low state for at least 90
ns. The PD/RST pin is asynchronous to the clock; thus, it can be triggered at any time regardless of the status of
other ADS8028 pins (including the analog input channels). When the device is in power-down mode, any activity
on the digital input pins (apart from the PD/RST pin) is ignored and the device does not take input-dependent
current from the analog input pins.
The ADS8028 powers up in default condition when the PD/RST pin is pulled back to a logic high level.
Conversions can begin when t_{POWER_UP} has elapsed.
Copyright © 2011–2012, Texas Instruments Incorporated
Product Folder Link(s): ADS8028
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