User guide

DS1875
Table 03h Register Descriptions
Table 03h, Register 80h to FFh: PW2 EEPROM
FACTORY DEFAULT 00h
READ ACCESS PW2
WRITE ACCESS PW2
MEMORY TYPE Nonvolatile (EE)
80h to FFh EE EE EE EE EE EE EE EE
BIT 7 BIT 0
PW2-protected EEPROM.
Table 04h Register Descriptions
Table 04h, Register 80h to C7h: MODULATION LUT
FACTORY DEFAULT 00h
READ ACCESS PW2
WRITE ACCESS PW2
MEMORY TYPE Nonvolatile (EE)
80h to C7h 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
BIT 7 BIT 0
The digital value for the modulation DAC output.
The MODULATION LUT is a set of registers assigned to hold the temperature profile for the modulation DAC.
The values in this table combined with the MOD bits in the MOD RANGING register (Table 02h, Register 8Bh)
determine the set point for the modulation voltage. The temperature measurement is used to index the LUT
(TINDEX, Table 02h, Register 81h) in 2°C increments from -40°C to +102°C, starting at 80h in Table 04h.
Register 80h defines the -40°C to -38°C MOD output, Register 81h defines the -38°C to -36°C MOD output, and
so on. Values recalled from this EEPROM memory table are written into the MOD DAC (Table 02h, Register 82h)
location that holds the value until the next temperature conversion. The DS1875 can be placed into a manual
mode (MOD EN bit, Table 02h, Register 80h), where MOD DAC is directly controlled for calibration. If the
temperature compensation functionality is not required, then program the entire Table 04h, to the desired
modulation setting.
PON Triplexer and SFP Controller
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