•ITEC: TEC current monitoring pin. The TEC current I
TEC
is given by I
TEC
= 1
A/V × (V
ITEC
−2.5V), where V
ITEC
is the voltage measured at the ITEC pin. The output current
is limited with a 1 k
Ω
resistor.
•TMOD: Temperature modulation pin. Apply a voltage between -3 V and +3V at this pin to
control the temperature setpoint externally (see description of the TSET pin).
•ILAS: Laser current monitoring pin. The laser current I
LAS
is given by
ILAS
= 100
mA/V × V
ILAS
, where V
ILAS
is the voltage measured at the ILAS pin. The output current is
limited with a 1 k
Ω
resistor.
•DIS: Laser disable. Apply a voltage between 2 V and 5 V to disable the laser current.
•PD: Output of the transimpedance amplifier that monitors the laser power. This output has
3.9 V/mA gain, a bandwidth from DC to 50 MHz, and is terminated with a 50
Ω
resistor. The
actual laser power depends on the photodiode integrated in the laser and should be
calibrated by the user.
Thermal considerations
The temperature controller dissipates a power equal to (5V−|V
TEC
|)×I
TEC
(5V−|V
TEC
|)×I
TEC
. For
reliable operation, do not dissipate more than 2.5 W in the temperature controller (derate
400mW per 10 °C above 30 °C). The power dissipation can be a problem for lasers with low
resistance Peltier element (e.g. 400 mV at 1A).
Note that you can protect your laser against over-temperature by connecting a
resistor R1 between DIS and TACT pins and a resistor R2R2 between DIS and GND pins. The
laser will shutdown when V
TACT
> 2V×(R2+R1+1k
Ω
)/(R1+1k
Ω
)
Extended temperature option
The CTL100 is also available with an extended temperature range option (7-38 °C instead of
12-25 °C). In this case, the thermistor value is given by R
th
= 10
k
Ω
×(8.5V−V
TACT
)/(3.5V+V
TACT
).
The gain at the TMOD pin is also increased: V
TSET
=V
TREF
+V
TMOD
/3.