DS1878T+T&R Maxim Integrated Products, DS1878T+T&R Datasheet - Page 24

• Manufacturer Part Number: DS1878T+T&R
• Description: IC CTLR SFP W/DGTL LDD RX 28TQFN
• Manufacturer: Maxim Integrated Products
• Type: SFP+ Controllerr

Specifications of DS1878T+T&R

• Input Type: *
• Output Type: *
• Interface: *
• Current - Supply: *
• Mounting Type: Surface Mount
• Package / Case: 28-WFQFN exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 17 shows the 3-wire interface timing. Figure 18
shows the 3-wire state machine. See the 3-Wire Digital
Interface Specification table for more information.
The majority of the communications consist of bias
adjustments for the APC loop. After each temperature
conversion, the laser modulation setting must be updat-
ed. All registers are rewritten after every temperature
conversion. Status registers TXSTAT1 and TXSTAT2 are
read between temperature updates at a regular inter-
val, t
Characteristics table). The results are stored in 3W
TXSTAT1 and 3W TXSTAT2 (Table 02h, FCh–FDh). Two
chip selects are provided: CSEL1OUT and CSEL2OUT.
In the case where a separate limiting amplifier and
laser driver are used, CSEL2OUT should be connected
to the limiting amplifier. CSEL2OUT is only active when
receiver-related registers are accessed. This minimizes
noise caused by the digital interface.
The master interface is controllable using four registers in
the device: 3WCTRL, ADDRESS, WRITE, and READ.
SFP+ Controller with Digital LDD Interface
Figure 17. 3-Wire Timing
24
CSEL_OUT
CSEL_OUT
NOTE: SEE THE 3-WIRE DIGITAL INTERFACE SPECIFICATION TABLE FOR DETAILS. CSEL_OUT IMPLIES CSEL1OUT OR CSEL2OUT.
SDAOUT
SDAOUT
SCLOUT
SCLOUT
______________________________________________________________________________________
DS1878 Master Communication
RR
WRITE MODE
READ MODE
(see the Analog Voltage Monitoring
t
t
L
L
A6
A6
t
t
CH
CH
0
0
t
t
CL
CL
3-Wire Interface Timing
A5
A5
1
1
t
t
DS
DS
A4
A4
2
2
Normal Operation
Manual Operation
A3
A3
t
t
3
3
DH
DH
Interface
A2
A2
4
4
A1
A1
5
5
A0
A0
6
6
RWN
RWN
7
7
Commands can be manually issued while the device is
in normal operation mode. It is also possible to suspend
normal 3-wire commands so that only manual operation
commands are sent (3WCTRL, Table 02h, Register F8h).
During initialization, the device transfers all its 3-wire
EEPROM control registers to a Maxim laser driver and
limiting amplifier. The 3-wire control registers include
the following:
• RXCTRL1
• RXCTRL2
• SETCML
• SETLOS
• TXCTRL
• IMODMAX
• IBIASMAX
• SETPWCTL
• SETTXDE
• SETTXEQ
• SETLOSTIMER
• RXCTRL3
• TXCTRL2
• TXCTRL3
D7
8
8
D7
D6
9
9
D6
t
D5
RS
10
10
D5
D4
11
11
D4
D3
12
12
D3
D2
13
13
D2
D1
14
14
D1
D0
Initialization
15
15
D0
t
t
T
T