AMC7823 Datasheet, PDF (45/48 Pages) Texas Instruments – ANALOG MONITORING AND CONTROL CIRCUIT

AMC7823
www.ti.com
SLAS453A – APRIL 2005 – REVISED OCTOBER 2005
Power-Down Register (Read/Write)
NOTE: After power-on or reset, all bits in the Power-Down Register are cleared to '0', and all the components
controlled by this register are in the powered-down or Off state. To avoid loss of alarm data during power-down
of the ADC, change to direct conversion mode (see ADC Control Register) before power-down and do not issue
a convert command while the ADC is powered down.
The Power-Down Register allows the host to manage power dissipation of the AMC7823. When not required, the
ADC, the precision current source, the reference buffer amplifier or any of the DACs may be put in power-down
mode to reduce current drain from the supply. Bits in the Power-Down Register control this power-down function.
Bit 15
MSB
PADC
Bit 14
PDAC7
Bit 13 Bit 12
PDAC6 PDAC5
Bit 11
PDAC4
Bit 10
PDAC3
Bit 9
PDAC2
Bit 8
PDAC1
Bit 7
PDAC0
Bit 6
PTS
Bit 5
PREFB
Bit 4 Bit 3 Bit 2 Bit 1
X
X
X
X
Bit 0
LSB
X
X : Don't Care
PADC
PDAC- n
(n = 0, 1, 2, 3, 4, 5, 6, 7)
PTS
PREFB
ADC power-down control bit.
PADC = 0: The ADC is in power-down mode and ADC conversion is halted.
PADC = 1: The ADC is in normal operating mode.
DAC-n output buffer amplifier power-down control bit.
PDAC-n = 0: DAC-n output buffer amplifier is in power-down mode. The output pin
of DAC-n is internally switched from the buffer output to analog ground through an
internal 5-kΩ resistor. Each DAC output buffer may be independently powered
down. (See the DAC Operation section for details.)
PDAC-n = 1 and PREFB = 1: DAC-n is in normal operating mode.
Precision current source power-down control bit.
PTS = 0: Precision current source is in power-down mode and the current output is
zero.
PTS = 1: Precision current source is in normal operating mode (see the Precision
Current Source section for details).
Reference buffer amplifier power-down control bit. This bit controls the power-down
condition of the amplifier that supplies a buffered reference voltage to all DAC-n
resistor strings and to the precision current source. This bit also provides
configuration information to the precision current source (see the Precision Current
Source Configuration table, Table 7).
PREFB = 0: Reference buffer amplifier is in power-down mode. All DACs are
inoperative. The precision current source may be used only if GREF = 0 (see the
Precision Current Source Configuration table, Table 7).
PREFB = 1: Reference buffer amplifier is powered on. This mode is required for any
DAC-n operation. The precision current source may be used with either value of
GREF.
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