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4

LDTC0520 / LDTC1020 LASER DIODE AND TEMPERATURE CONTROLLER

PIN DESCRIPTIONS

Table 1. Pin Descriptions and Wire Colors

PIN

NAME

CABLE

COLOR

PIN DESCRIPTION

Connector J1, Cable WCB303 (included with LDTC0520 and LDTC1020)

1

V

DD_FL

Green

Laser driver and laser diode power supply input; 3 to 11 VDC. Current rated to at least 1.1‑times

the laser diode forward current plus the driver quiescent current. Low-noise switching power supply

recommended.

Reference the Safe Operating Area calculator.

2

V

DD_WTC

Red

Temperature controller power supply input; 5 to 12 VDC. Current rated to at least 100 mA. Low‑

noise switching power supply recommended.

Reference the Safe Operating Area calculator.

3

V

S

White

Power supply input for driving the TEC or resistive heater; 5 to 30 VDC. Current rated to at least

1.1-times the TEC maximum drive current. Low-noise switching power supply recommended.

Reference the Safe Operating Area calculator.

4

GND

Black

Power supply ground.

This is the only ground connection designed as a high current power supply return.

Connector J2, Cable WCB302 (included with LDTC0520 and LDTC1020)

1

SP1

—

No connection

2

SP2

—

No connection

3

LD SHD

Red

Laser diode shutdown / interlock input. The onboard Enable switch must be set to ENABLE when

this external enable function is used. TTL-compatible.

Enable = Ground; Disable = OPEN or 3 to 5 V.

4

COM

Green/Blk

Low current return for monitors, inputs, and status pins.

Do not use for high current return.

5

EXT LD SET White

External laser diode setpoint input, optional. Range 0 to 2 V. Input impedance 5 kΩ. Transfer function

shown in

Table 2. Set the LDREF switch to EXT to reference this input signal. The EXT LD SET

voltage does not sum with the onboard trimpot setting. Not TTL-compatible.

6

COM

Green

Low current return for monitors, inputs, and status pins.

Do not use for high current return.

7

LD P M

Orange/Blk Photodiode current monitor output. The signal on this pin is proportional to the photodiode current.

Voltage range 0 to 2 V. Transfer function shown in

Table 2.

8

LD I M

Blue

Laser current monitor output. The signal on this pin is proportional to the actual laser output current.

Transfer function shown in

Table 2.

9

ACT T M

Red/Blk

Actual temperature sensor voltage monitor output. Output voltage equals the voltage drop across

the temperature sensor. Voltage range 0 V to V

DD_WTC.

10

SET T M

White/Blk

Temperature setpoint voltage monitor output. Output voltage equals the temperature sensor

setpoint voltage set by the onboard trimpot or the EXT T SET input.

11

EXT T SET

Orange

External temperature setpoint input, optional. Range 0.3 to (V

DD_WTC ‑ 2). Input impedance > 1 MΩ.

Transfer function shown in

Table 2. This voltage does not sum with the onboard trimpot setting.

Set the TREF switch to EXT to reference the EXT T SET input signal. Not TTL-compatible. If the

signal falls below 0.3 V the setpoint will default to 1 V. To reset the default safety circuit, the EXT T

SET voltage must be > 0.4 V.

12

COM

Black

Low current return for monitors, inputs, and status pins.

Do not use for high current return.

Connector J3, Cable WCB301 (included with LDTC0520 and LDTC1020)

1

LDC

Black

Laser diode cathode connection

2

PDA

White

Photodiode anode connection

3

SP3

Blue

No connection

4

LDA

Red

Laser diode anode connection

5

COM

Green

Low current return for monitors, inputs, and status pins.

Do not use for high current return.

6

TEC+

Red/Blk

Positive side of TEC. This pin supplies the current to the TEC (when using NTC sensors).

Refer

to the operating instructions for proper connections to a TEC or Resistive Heater based on

the type of sensor being used.

7

TEC–

Orange

Negative side of TEC. This pin sinks the current from the TEC (when using NTC sensors).

8

SEN+

White/Blk

Positive side of temperature sensor. Bias current is driven from SEN+ to SEN–.

9

SEN–

Orange/Blk Ground connection for the temperature sensor. Refer to the Specifications table for input voltage

range.

Do not use for high current return.

10

COM

Green/Blk

Low current return for monitors, inputs, and status pins.

Do not use for high current return.