Datasheet

DS1878
SFP+ Controller with Digital LDD Interface
10 ______________________________________________________________________________________
Pin Description
Pin Configuration
PIN NAME FUNCTION
1 RSELOUT Rate-Select Output
2 SCL I
2
C Serial-Clock Input
3 SDA I
2
C Serial-Data Input/Output
4 TXFOUT Transmit Fault Output, Open Drain
5 LOS Loss of Signal Input
6 IN1
Digital Input. General-purpose
input, AS1 in SFF-8079, or RS1 in
SFF-8431.
7 TXD Transmit Disable Input
8, 17, 21 GND Ground Connection
9 RSEL Rate-Select Input
10 TXDOUT Transmit Disable Output
11 MON4 External Monitor Input 4
12, 13
MON3P,
MON3N
Differential External Monitor Input 3
and LOS Quick Trip
14 MON1
External Monitor Input 1 and
HBATH Quick Trip
15, 23 V
CC
Power-Supply Input
16 MON2
External Monitor Input 2, Feedback
Voltage for APC Loop, and TXP
HI/TXP LO Quick Trip
PIN NAME FUNCTION
18 REFIN
Reference Input for DAC1 and
19 DAC1 Delta-Sigma Output 1
20 DAC2 Delta-Sigma Output 2
22 CSEL2OUT
Chip-Select Output 2. Part of 3-wire
interface to a laser driver/limiting
amplifier.
24 CSEL1OUT
Chip-Select Output 1. Part of 3-wire
interface to a laser driver/limiting
amplifier.
25 SCLOUT
Serial-Clock Output. Part of 3-wire
interface to a laser driver/limiting
amplifier.
26 SDAOUT
Serial-Data Input/Output. Part of
3-wire interface to a laser
driver/limiting amplifier.
27 LOSOUT Receive Loss-of-Signal Output
28 TXF Transmit Fault Input
— EP Exposed Pad. Connect to ground.
THIN QFN
(5mm
×
5mm
×
0.75mm)
TOP VIEW
26
27
25
24
10
9
11
SCL
TXFOUT
LOS
IN1
TXD
12
RSELOUT
DAC2 REFIN GND GND MON2 V
CC
12
SCLOUT
4567
2021 19 17 16 15
SDAOUT
LOSOUT
MON3P
MON4
TXDOUT
RSEL
SDA
DAC1
3
18
28
8
TXF
GND
CSEL1OUT
23
13
MON3N
V
CC
22
14
MON1
CSEL2OUT
DS1878
EP
+