DS1873T+ Maxim Integrated Products, DS1873T+ Datasheet - Page 22

• Manufacturer Part Number: DS1873T+
• Description: IC CTLR SFP+ ANLG LDD 28-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Laser Diode Controllerr

Specifications of DS1873T+

• 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
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 90-1873T+000

TXDOUT is generated from a combination of TXF, TXD,
and the internal signal FETG. A software control identical
to TXD is available (TXDC, Lower Memory, Register
6Eh). A TXD pulse is internally extended (TXD
time t
warnings related to the APC loop to allow for the loop to
stabilize. The nonlatching alarms and warnings are TXP
LO, LOS LO, and MON1–MON4 LO alarms and warn-
ings. In addition, TXP LO is disabled from creating FETG.
TXF is both an input and an output (Figure 13). See the
Transmit Fault (TXF) Output section for a detailed expla-
nation of TXF. Figure 13 shows that the same signals and
faults can also be used to generate the internal signal
FETG (Table 01h/05h, Registers FAh and FBh). FETG is
used to send a fast “turn-off” command to the laser dri-
ver. The intended use is a direct connection to the laser
driver’s TXD input if this is desired. When V
TXDOUT is high impedance.
SFP+ Controller with Analog LDD Interface
Figure 13. Logic Diagram 1
22
BIAS MAX ENABLE
TXP LO ENABLE
TXP HI ENABLE
TXDC
HBAL ENABLE
TXP LO FLAG
TXD
TXP HI FLAG
______________________________________________________________________________________
HBAL FLAG
INITR1
BIAS MAX
R
PU
V
CC
to inhibit the latching of low alarms and
TXDS
TXD
EXT
OUT
FAULT RESET TIMER
OUT
IN
(130ms)
TXF, TXD, TXDOUT
IN
C
C
D
CC
R
S
Q
Q
EXT
< POA,
) by
POWER-ON
Figure 14. Logic Diagram 2
RESET
LOS LO
RSEL
SET BIAS DAC AND
MOD DAC TO 0
LOS
IN1
FETG
BIAS MAX FLAG
TXP LO FLAG
TXP HI FLAG
HBAL FLAG
RSELC
LOSC
MUX
IN1S
IN1C
RSELS
MINT
INV LOS
TXDFLT
TXDFG
INVOUT1
TXDIO
= PINS
TXD
RXL
= PINS
TXF
OUT1
RSELOUT
LOSOUT
TXDOUT
TXF