Rainbow Electronics DS1862 - Manual (Page 41)

DS1862
XFP Laser Control and Digital Diagnostic IC
____________________________________________________________________ 41
Power-Supply Decoupling
To achieve best results, it is recommended that the
power supply is decoupled with a 0.01µF or a 0.1µF
capacitor. Use high-quality, ceramic, surface-mount
capacitors, and mount the capacitors as close as pos-
sible to the V
CC2 /V CC3 and GND pins to minimize lead
inductance.
SDA and SCL Pullup Resistors
SDA is an open-collector bidirectional data pin on the
DS1862 that requires a pullup resistor to realize high
logic levels. Either an open-collector output with a
pullup resistor or a push-pull output driver can be uti-
lized for the SCL input. Pullup resistor values should be
chosen to ensure that the rise and fall times listed in the
AC Electrical Characteristics are within specification.
*ADDITIONAL MONITORS NOT USED IN THIS EXAMPLE.
SDA
SCL
4.7k Ω
RX-LOS
MOD-NR
V CC2
TX-D
INTERRUPT
MOD-DESEL
V CC3
EN1
SC-TX-LOS
GND
EN2
BMD
BIASSET
MODSET
FETG
BIASMON
RSSI
SC-RX-LOL
SC-RX-LOS
THRSET
AUX1MON
AUX2MON
P-DOWN/RST
HOST
1.8V 3.3V
3.3V
0.1 µF 0.1 µF
BIASSET
MODSET
MON
LASER
DRIVER
10nF
OUT
LIMITING
AMP
LOS
LOL
FCTL2
FCTL1
VTH
LOS
FCTL2
FCTL1
EQUALIZER
RECEIVER CURRENT SENSE (VOLTAGE)
TX-DISABLE
TX-DISABLE DISABLE
1nF
*
1k Ω
DS1862
MAX3975
MAX3991
MAX3992
4.7k Ω
3.3V
10k Ω
3.3V
10k Ω
3.3V
10k Ω
3.3V
Typical Operating Circuit