MAX3296CGI Maxim Integrated Products, MAX3296CGI Datasheet - Page 13

• Manufacturer Part Number: MAX3296CGI
• Description: Laser Driver 3.0V to 5.5V 1.25Gbp s/2.5Gbps LAN Laser
• Manufacturer: Maxim Integrated Products

Specifications of MAX3296CGI

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 8a. R
Figure 8b. Laser-Modulation Current vs. R
Table 4. POL Pin Setup for Each Laser Configuration Type
MAX3286/MAX3296
MAX3287/MAX3297
MAX3286/MAX3296
MAX3288/MAX3298
MAX3286/MAX3296
MAX3289/MAX3299
MAX3286/MAX3296
MAX3286/MAX3296
DEVICE
1000
10
1
TC
40
35
30
25
20
15
10
5
0
1
vs. R
0
1000ppm
500ppm
1500ppm
R
L
= 25
MOD
2
______________________________________________________________________________________
4
for Various Conditions
10
LOAD
GND
GND
R
POL
V CC
V CC
V CC
10
R
MOD
—
—
—
6
MOD
LOAD
2000ppm
25
(k )
(k )
NOTE: R
8
30mA
100
25mA
GND
GND
GND
POL
V CC
V CC
20mA
—
—
—
TC
10
3000ppm
3500ppm
15mA
2500ppm
= OPEN
10mA
LOAD
50
MOD
5mA
12
3.0V to 5.5V, 1.25Gbps/2.5Gbps
Common cathode with
photodiode
Common cathode without
photodiode
Common anode with
photodiode
Not allowed; fault occurs
Not allowed; fault occurs
1000
14
DESCRIPTION
with photodiode. The POL and POL inputs determine
the laser pinning (common cathode, common anode)
and affect the smooth-start circuits (Table 4).
In the common cathode with photodiode configuration,
a servo control loop is formed by external PNP Q1, the
laser diode, the monitor diode, R
control amplifier (Figure 9). The voltage at MD is stabi-
lized to 1.7V. The monitor photodiode current (I
by (V
desired monitor current (I
The APC loop is compensated by C
must be placed from BIASDRV to V
noise operation and to reject power-supply noise. The
time constant governs how quickly the laser bias current
reacts to a change in the average total laser current
(I
to obtain a loop time constant in excess of 1µs, provid-
ed that R
might be necessary to ensure the APC loop’s stability
when low bias currents are desired.
The voltage across R
250mV at maximum bias current.
The discrete components used with the common cath-
ode with photodiode configuration are:
R
C
R
BIASDRV
SET
DEG
BIASDRV
REF
= 0.95 / I
= 0.25 / I
DEG
- V
+ I
= 0.1µF (typ)
LAN Laser Drivers
MD
MOD
D
is chosen appropriately. Resistor R
BIAS(MAX)
) / R
). A capacitance of 0.1µF is sufficient
Common Cathode with Photodiode
SET
DEG
D
= 0.95 / R
), then select R
LASER PINNING
should not be larger than
—
—
V
SET
BIASDRV
CC
(Optical Feedback)
SET
CC
, and the power-
. Determine the
SET
to ensure low-
. A capacitor
= 0.95 / I
D
) is set
DEG
D
13
.