Datasheet ADS1015

17
ADS1013 , ADS1014 , ADS1015
www.ti.com SBAS473E –MAY 2009–REVISED JANUARY 2018
Product Folder Links: ADS1013 ADS1014 ADS1015
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8.4 Device Functional Modes
8.4.1 Reset and Power-Up
The ADS101x reset on power-up and set all the bits in the Config register to the respective default settings. The
ADS101x enter a power-down state after completion of the reset process. The device interface and digital blocks
are active, but no data conversions are performed. The initial power-down state of the ADS101x relieves systems
with tight power-supply requirements from encountering a surge during power-up.
The ADS101x respond to the I
2
C general-call reset command. When the ADS101x receive a general-call reset
command (06h), an internal reset is performed as if the device is powered-up.
8.4.2 Operating Modes
The ADS101x operate in one of two modes: continuous-conversion or single-shot. The MODE bit in the Config
register selects the respective operating mode.
8.4.2.1 Single-Shot Mode
When the MODE bit in the Config register is set to 1, the ADS101x enter a power-down state, and operate in
single-shot mode. This power-down state is the default state for the ADS101x when power is first applied.
Although powered down, the devices still respond to commands. The ADS101x remain in this power-down state
until a 1 is written to the operational status (OS) bit in the Config register. When the OS bit is asserted, the
device powers up in approximately 25 μs, resets the OS bit to 0, and starts a single conversion. When
conversion data are ready for retrieval, the device powers down again. Writing a 1 to the OS bit while a
conversion is ongoing has no effect. To switch to continuous-conversion mode, write a 0 to the MODE bit in the
Config register.
8.4.2.2 Continuous-Conversion Mode
In continuous-conversion mode (MODE bit set to 0), the ADS101x perform conversions continuously. When a
conversion is complete, the ADS101x place the result in the Conversion register and immediately begin another
conversion. When writing new configuration settings, the currently ongoing conversion completes with the
previous configuration settings. Thereafter, continuous conversions with the new configuration settings start. To
switch to single-shot conversion mode, write a 1 to the MODE bit in the configuration register or reset the device.
8.4.3 Duty Cycling For Low Power
The noise performance of a ΔΣ ADC generally improves when lowering the output data rate because more
samples of the internal modulator are averaged to yield one conversion result. In applications where power
consumption is critical, the improved noise performance at low data rates may not be required. For these
applications, the ADS101x support duty cycling that yield significant power savings by periodically requesting
high data rate readings at an effectively lower data rate. For example, an ADS101x in power-down state with a
data rate set to 3300 SPS can be operated by a microcontroller that instructs a single-shot conversion every 7.8
ms (128 SPS). A conversion at 3300 SPS only requires approximately 0.3 ms, so the ADS101x enter power-
down state for the remaining 7.5 ms. In this configuration, the ADS101x consume approximately 1/25th the
power that is otherwise consumed in continuous-conversion mode. The duty cycling rate is completely arbitrary
and is defined by the master controller. The ADS101x offer lower data rates that do not implement duty cycling
and also offer improved noise performance if required.