Datasheet

AMC7823

SLAS453F –APRIL 2005–REVISED MARCH 2012

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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 the ADC conversion to direct 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 must be set properly

before operating the ADC, DAC, precision current source, and reference of this device. It is recommended that

the Power-Down Register be programmed after all other registers have been initialized.

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 Bit 0

MSB Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB

PAD PDAC7 PDAC PDAC PDAC4 PDAC PDAC2 PDAC1 PDAC0 PTS PREFB X X X X X

C 6 5 3

X : Don't Care

PADC 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.

PDAC-n DAC-n output buffer amplifier power-down control bit.

(n = 0, 1, 2, 3, 4, 5, 6, 7)

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 5kΩ 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.

PTS 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).

PREFB 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.

Product Folder Link(s): AMC7823