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DS1886_V1 Datasheet - Page 24

Download or read online Maxim Integrated DS1886_V1 SFP and PON ONU Controller with Digital LDD Interface pdf datasheet.



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circuitry is disabled. When V
CC
recalled, and the analog circuitry is enabled. While V
remains above POA, the device is in its normal operating
state, and it responds based on its nonvolatile configura-
tion. If during operation V
falls below POA, but is still
CC
above POD, the SRAM retains the SEE settings from the
first SEE recall, but the device analog is shut down and
the outputs are disabled. If the supply voltage recovers
back above POA, the device immediately resumes nor-
mal operation. If the supply voltage falls below POD, the
device SRAM is placed in its default state and another
SEE recall is required to reload the nonvolatile settings.
The EEPROM recall occurs the next time V
exceeds POA.
Figure 7
shows the sequence of events
as the voltage varies.
Any time V
is above POD, the I
CC
used to determine if V
is below the POA level. This is
CC
accomplished by checking the RDYB bit in the STATUS
byte
(A2h Lower Memory, Register
when V
is below POA; when V
CC
SEE RECALL
V
POA
V
CC
V
POD
PRECHARGED
SEE
RECALLED VALUE
TO 0
Figure 7. Low-Voltage Hysteresis Example
SFP and PON ONU Controller
with Digital LDD Interface
reaches POA, the SEE is
RDYB is timed (within 500Fs) to go to 0, at which point
the part is fully functional.
CC
For all device addresses sourced from EEPROM
Table 02h, Register
is A2h until V
address to be recalled from the EEPROM.
POA holds the DS1886 in reset until V
level (V
with its ADC and compare analog signals with its quick-
trip monitors. Because V
ADC when V
next
CC
VCC LO alarm, which is cleared by a V
sion greater than the customer-programmable V
ADC limit. This allows a programmable limit to ensure
2
C interface can be
that the head room requirements of the transceiver are
satisfied during a slow power-up. The TXFOUT output
does not latch until there is a conversion above the V
6Eh). RDYB is set
low limit. The POA alarm is nonmaskable. See the
rises above POA,
CC
Voltage Operation
SEE RECALL
PRECHARGED TO 0
DS1886
8Ch), the default DEVICE ADDRESS
exceeds POA, allowing the device
CC
Power-On Analog (POA)
CC
> POA) for the device to accurately measure
CC
cannot be measured by the
CC
is less than POA, POA also asserts the
CC
section for more information.
RECALLED VALUE
(A2h
is at a suitable
ADC conver-
CC
low
CC
CC
Low-
PRECHARGED
TO 0
24

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