User guide

DS1875
Note 1: All voltages are referenced to ground. Current into IC is positive, and current out of the IC is negative.
Note 2: Digital inputs are at rail. FETG is disconnected. SDA = SCL = V
CC
. SW, DAC1, and M4DAC are not loaded.
Note 3: See the
Safety Shutdown (FETG) Output section for details.
Note 4: Eight ranges allow the full scale to change from 625mV to 2.5V.
Note 5: Eight ranges allow the full scale to change from 312.5mV to 1.25V.
Note 6: This specification applies to the expected full-scale value for the selected range. See the COMP RANGING register
description for available full-scale ranges.
Note 7: The output impedance of the DS1875 is proportional to its scale setting. For instance, if using the 1/2 scale, the output
impedance would be approximately 1.56kΩ.
Note 8: This specification applies to the expected full-scale value for the selected range. See the MOD RANGING register
description for available full-scale ranges.
Note 9: The switching frequency is selectable between four values: 131.25kHz, 262.5kHz, 525kHz, and 1050kHz.
Note 10: See the
APC and Quick-Trip Shared Comparator Timing section for details.
Note 11: Guaranteed by design.
Note 12: I
2
C interface timing shown is for fast-mode (400kHz) operation. This device is also backward compatible with I
2
C stan-
dard mode.
Note 13: C
B
—Total capacitance of one bus line in pF.
Note 14: EEPROM write begins after a STOP condition occurs.
I
2
C TIMING SPECIFICATIONS
(V
CC
= +2.85V to +3.9V, T
A
= -40°C to +95°C, timing referenced to V
IL(MAX)
and V
IH(MIN)
.) (See Figure 15.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SCL Clock Frequency f
SCL
(Note 12) 0 400 kHz
Clock Pulse-Width Low t
LOW
1.3 μs
Clock Pulse-Width High t
HIGH
0.6 μs
Bus-Free Time Between STOP
and START Condition
t
BUF
1.3 μs
START Hold Time t
HD:STA
0.6 μs
START Setup Time t
SU:STA
0.6 μs
Data in Hold Time t
HD:DAT
0 0.9 μs
Data in Setup Time t
SU:DAT
100 ns
Capacitive Load for Each Bus Line C
B
400 pF
Rise Time of Both SDA and SCL
Signals
t
R
(Note 13)
20 +
0.1C
B
300 ns
Fall Time of Both SDA and SCL
Signals
t
F
(Note 13)
20 +
0.1C
B
300 ns
STOP Setup Time t
SU:STO
0.6 μs
EEPROM Write Time t
W
(Note 14) 20 ms
PON Triplexer and SFP Controller
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