Datasheet
Table Of Contents
- FEATURES
- Key Specifications
- Applications
- DESCRIPTION
- Absolute Maximum Ratings
- Operating Ratings
- Electrical Characteristics
- Specific Definitions
- Typical Performance Characteristics
- Functional Description
- Applications Information
- Revision History
Active
Power-downStand-by
PWRCN
= 01b
PWRCN
= 11b
PWRCN
= 00b
PWRCN
= 00b
LMP90077, LMP90078, LMP90079, LMP90080
www.ti.com
SNAS521F –JULY 2011–REVISED MARCH 2013
POWER MANAGEMENT
The device can be placed in Active, Power-Down, or Stand-By state.
In Power-Down, the ADC is not converting data, contents of the registers are unaffected, and there is a drastic
power reduction. In Stand-By, the ADC is not converting data, but the power is only slightly reduced so that the
device can quickly transition into the active state if desired.
These states can be selected using the PWRCN register. When written, PWRCN brings the device into the
Active, Power-Down, or Stand-By state. When read, PWRCN indicates the state of the device.
The read value would confirm the write value after a small latency (approximately 15 µs with the internal CLK). It
may be appropriate to wait for this latency to confirm the state change. Requests not adhering to this latency
requirement may be rejected.
It is not possible to make a direct transition from the power-down state to the stand-by state. This state diagram
is shown below.
Figure 57. Active, Power-Down, Stand-by State Diagram
RESET and RESTART
Writing 0xC3 to the REG_AND_CNV_RST field will reset the conversion and most of the programmable registers
to their default values. The only registers that will not be reset are the System Calibration Registers
(CHx_SCAL_OFFSET, CHx_SCAL_GAIN) and the DT_AVAIL_B bit.
If it is desirable to reset the System Calibration Coefficient Registers, then set RESET_SYSCAL = 1 before
writing 0xC3 to REG_AND_CNV_RST. If the device is operating in the “System Calibration Offset/Gain
Coefficient Determination” mode (SCALCN register), then write REG_AND_CNV_RST = 0xC3 twice to get out of
this mode.
After a register reset, any on-going conversions will be aborted and restarted. If the device is in the power-down
state, then a register reset will bring it out of the power-down state.
To restart a conversion, write 1 to the RESTART bit. This bit can be used to synchronize the conversion to an
external event.
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