AMC7823 datasheet(45/48 Pages) TI

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Power-Down Register (Read/Write)

AMC7823

SLAS453A – APRIL 2005 – REVISED OCTOBER 2005

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

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

Bit 0

MSB

LSB

PADC

PDAC7

PDAC6

PDAC5

PDAC4

PDAC3

PDAC2

PDAC1

PDAC0

PTS

PREFB

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 5-k

Ω 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.

AMC7823 Datasheet(PDF) 45 Page - Texas Instruments

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