DS1876T+ Maxim Integrated Products, DS1876T+ Datasheet - Page 13

• Manufacturer Part Number: DS1876T+
• Description: IC CTRLR SFP DUAL LDD 28TQFN
• Manufacturer: Maxim Integrated Products
• Type: SFP Laser Controllerr

Specifications of DS1876T+

• Input Type: Logic
• Output Type: Logic
• Interface: I²C
• Current - Supply: 10mA
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 1. Acronyms
Figure 1. Power-Up Timing
Figure 2. TXD1, TXD2 Timing
ACRONYM
SFF-8472
ROSA
TOSA
SFP+
AGC
ADC
APC
APD
DAC
ATB
LOS
LUT
SEE
SFF
SFP
TXP
TIA
NV
QT
TE
SETTINGS
DAC
V
CC
Analog-to-Digital Converter
Automatic Gain Control
Automatic Power Control
Avalanche Photodiode
Alarm Trap Bytes
Digital-to-Analog Converter
Loss of Signal
Lookup Table
Nonvolatile
Quick Trip
Tracking Error
Transimpedance Amplifier
Receiver Optical Subassembly
Shadowed EEPROM
Small Form Factor
Document Defining Register Map of SFPs
and SFFs
Small Form Factor Pluggable
Enhanced SFP
Transmit Optical Subassembly
Transmit Power
______________________________________________________________________________________
SFP Controller with Dual LDD Interface
V
POA
SETTINGS
DESCRIPTION
HIGH IMPEDANCE
TXD_
DAC
500µs
LUT VALUE
t
OFF
OFF STATE
OFF STATE
t
INIT
only difference is that the DS1876 already has deter-
mined the present temperature, so the t
required for the DS1876 to recall the APC and MOD
set points from EEPROM. See Figure 1.
If TXD1 or TXD2 are asserted (logic 1) during normal
operation, the associated outputs are disabled within
t
DS1876 sets the DACs with the value associated with
the present temperature. When asserted, soft TXD1 or
soft TXD2 (TXDC) (Lower Memory, Register 6Eh) would
allow a software control identical to the TXD1 or TXD2 pin
(Figure 2). The POLARITY register (Table 02h, Register
C6h) determines if the off-state value of the DACs is
V
As shown in Figure 3, the DS1876’s input compara-
tor is shared among the six quick-trip alarms (TXP1
HI, TXP1 LO, TXP2 HI, TXP2 LO, BIAS1 HI, and BIAS2
HI). The comparator polls the alarms in a multiplexed
sequence. The updates are used to compare the HTXP1,
LTXP1, HTXP2, and LTXP2 (monitor diode voltages) and
the HBATH1 and HBATH2 (BMON1, BMON2) signals
against the internal APC and BIAS reference, respec-
tively. Depending on the results of the comparison, the
t
ON
OFF
REFIN
. When TXD1 or TXD2 are deasserted (logic 0), the
DACs as a Function of Transmit Disable
or 0V.
LUT VALUE
LUT VALUE
Quick-Trip Timing
(TXD1, TXD2)
INIT
time is not
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