DS1874T+ Maxim Integrated Products, DS1874T+ Datasheet - Page 25

• Manufacturer Part Number: DS1874T+
• Description: IC CTLR SFP+ ANLG LDD 28-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Laser Diode Controllerr

Specifications of DS1874T+

• Number Of Channels: 1
• Voltage - Supply: 2.85 V ~ 3.9 V
• Current - Supply: 2.5mA
• Operating Temperature: -40°C ~ 95°C
• Package / Case: 28-WFQFN Exposed Pad
• Mounting Type: Surface Mount
• Number Of Outputs: 5
• Duty Cycle (max): 50 %
• Output Voltage: 0 V to 3.9 V
• Mounting Style: SMD/SMT
• Switching Frequency: 0 KHz to 400 KHz
• Operating Supply Voltage: 2.85 V to 3.9 V
• Supply Current: 2.5 mA to 10 mA
• Maximum Operating Temperature: + 95 C
• Fall Time: 300 ns
• Minimum Operating Temperature: - 40 C
• Rise Time: 300 ns
• Synchronous Pin: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 90-1874T+000

During initialization, the DS1874 transfers all its 3-wire
EEPROM control registers to the MAX3798/MAX3799.
The 3-wire control registers include the following:
• RXCTRL1
• RXCTRL2
• SET_CML
• SET_LOS
• TXCTRL
• IMODMAX
Note: This register is not present in the DS1874. To access this register, use manual operation (see the Manual Operation section).
Receiver Control 1
Receiver Control 2
Receiver Status
Output CML Level Setting
LOS Threshold Level Setting
Transmitter Control
Transmitter Status 1
Transmitter Status 2
Bias Current Setting
Modulation Current Setting
Maximum Modulation Current Setting
Maximum Bias Current Setting
Modulation Current Increment Setting
Bias Current Increment Setting
Mode Control
Transmitter Pulse-Width Control
Transmitter Deemphasis Control
MAX3798/MAX3799 REGISTER FUNCTION
SFP+ Controller with Digital LDD Interface
______________________________________________________________________________________
MAX3798/MAX3799 Register Map and DS1874 Corresponding Location
Initialization
SET_IMOD/MODULATION Table 02h, 82h–83h
REGISTER NAME
SET_IBIAS/BIAS
SET_PWCTRL
MODECTRL
IMODMAX
IBIASMAX
SET_TXDE
RXCTRL1
RXCTRL2
SET_CML
SET_LOS
TXSTAT1
TXSTAT2
MODINC
BIASINC
RXSTAT
TXCTRL
• IBIASMAX
• SET_PWCTRL
• SET_TXDE
The control registers are first written when V
POA. They are also written if the MAX3798/MAX3799
TX_POR bit is set high (visible in 3W TXSTAT1, bit 7). In
the MAX3798/MAX3799, this bit is “sticky” (latches high
and is cleared on a read). They are also updated on a
rising edge of TXD. Any time one of these events
occurs, the DS1874 reads and updates TXSTAT1 and
TXSTAT2 and sets SET_IBIAS and SET_IMOD in the
MAX3798/MAX3799 to 0.
Table 02h, E8h
Table 02h, E9h
Lower Memory, 6Eh, Bit1
Table 02h, EAh
Table 02h, EBh
Table 02h, ECh
Table 02h, FCh
Table 02h, FDh
Table 02h, CBh–CCh
Table 02h, EDh
Table 02h, EEh
(see Note)
Automatically performed by APC loop. Disable
APC before using 3-wire manual mode. Manual
Mode: Table 02h, F8h–FBh
(see Note)
Table 02h, EFh
Table 02h, F0h
DS1874 LOCATION
CC
exceeds
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