LTC5100EUF#TRPBF Linear Technology, LTC5100EUF#TRPBF Datasheet - Page 18

• Manufacturer Part Number: LTC5100EUF#TRPBF
• Description: IC DRIVER VCSEL 3.2GBPS 16QFN
• Manufacturer: Linear Technology
• Type: Laser Diode Driverr

Specifications of LTC5100EUF#TRPBF

• Data Rate: 3.2Gbps
• Number Of Channels: 1
• Voltage - Supply: 3.135 V ~ 3.465 V
• Current - Supply: 54mA
• Current - Modulation: 12mA
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-QFN
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

OPERATIO
LTC5100
current, I
Electrical Characteristics and the value of I
the laser characteristics and the termination resistor value.
The logic “1” and “0” current levels in the laser are given
by:
The power levels corresponding to I1 and I0 are P1 and P0,
as shown in Figure 16.
where is the slope efficiency and Ith is the laser threshold
current, defined in Figure 16.
The average optical power and extinction ratio are given
by:
The average voltage on the laser diode relative to ground
is V
SRC pin is:
The value V
limits given in the Electrical Characteristics.
18
P1 = (I1 – I
P0 = (I0 – I
V
I
I
P
ER
1
0
LD
AVG
S
= V
= V
(see Figure 12 and Figure 15). The voltage on the
I
I
B
B
P
P
LD
LD
–
M
0
Figure 14. Components of the Laser Bias
and Modulation Currents
1
P
I
. The maximum value of I
S
I
MOD
1
+ I
+ (I
MOD
is important because V
2
2
2
S
P
TH
TH
B
• R
0
I
U
+ I
TH
)
)
I
B
0
T
M
) • R
T
5100 F14
S
I
must not exceed the
MOD
S
is given in the
M
depends on
(10)
(4)
(5)
(6)
(7)
(8)
(9)
The voltage across the termination resistor is:
The LTC5100 can digitize the voltage across the termina-
tion resistor using the on-chip ADC, which can give a more
accurate measurement of Is than that given by digitizing
the current internally. See the Electrical Characteristics for
details.
Temperature Compensation
The LTC5100 digitally compensates the temperature drift
of the laser bias current, laser modulation current and
V
TERM
Figure 15. Approximate VI Curve for a Laser Diode
Figure 16. Approximate LI Curve for a Laser Diode
= V
= Is • R
P
V
AVG
LD
P1
P0
SRC
V
L
– V
I
T
TH
MODA
I0
I0
R
LD
I
MOD
I
I
B
B
I1
I1
5100 F15
I
5100 F15
I
LD
LD
sn5100 5100fs
(11)