LTC7871

39

Rev. 0

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MFR_IDAC_SETCUR

The MFR_IDAC_SETCUR stores the current DAC value to program the sourcing current of the SETCUR pin. It is for-

matted as a 5-bit two’s complement value. The default value for this register is 0x00 and the SETCUR pin originally

sources 16µA. This register can program the SETCUR pin sourcing current from 0 to 31µA as shown in the Table 9.

Writes to this register are inhibited when the WP, BIT[0] in MFR_CHIP_CTRL, is set high.

MFR_IDAC_SETCUR Message Contents:

BIT

VALUE

MEANING

7:5

RESERVED

4

0

1

16µA

0µA

3

0

1

0µA

8µA

2

0

1

0µA

4µA

1

0

1

0µA

2µA

0

0

1

0µA

1µA

MFR_SSFM

The MFR_SSFM is for spread spectrum frequency modulation control. The default value for this register is 0x00. Writes

to this register are inhibited when the WP, BIT[0] in MFR_CHIP_CTRL, is set high.

MFR_SSFM Message Contents:

BIT

NAME

VALUE MEANING

7:5

Reserved

4:3

Frequency Spread

Range

00

±12%

01

±15%

10

±10%

11

±8%

2:0

Modulation Signal

Frequency

000

Controller Switching Frequency/512

001

Controller Switching Frequency/1024

010

Controller Switching Frequency/2048

011

Controller Switching Frequency/4096

100

Controller Switching Frequency/256

101

Controller Switching Frequency/128

110

Controller Switching Frequency/64

111

Controller Switching Frequency/512

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