Laser Diode Controllers
LDC500 series — Laser diode drivers with integrated temperature controllers

LDC500 Series Laser Diode Controllers
Laser Diode Driver· 100 mA, 500 mA or 2 A source· Ultra-low drift (<10 ppm/°C)· <0.3 µA current noise (LDC500)· CC & CP mode dynamic switching· GPIB, RS-232 and Ethernet
TEC Controller· 36 W output power· Ultra-high stability (0.0005 °C/°C)· Thermistor, RTD and IC sensors· Auto-tuning of loop parameters· CC & CT mode dynamic switching

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Introducing the LDC500 Series Laser Diode Controllers— highly stable, low-noise current sources, with integrated
temperature controllers — all at very affordable prices.
The LDC500 series are the ideal instruments for controllingthe current and temperature of your laser diodes. They havethe performance and features you expect from instruments
costing twice as much. The LDC501 has up to 500 mA ofoutput current with less than 1.1 µA of rms noise, while theLDC500 has up to 100 mA of current and less than 0.3 µA ofnoise. The LDC502 provides up to 2 A of current.
With a low-noise current source, a 36 W high-precision
temperature controller, and standard computer interfaces
including Ethernet, the LDC500 series is the right choice foryour laser diode testing and control applications.
Easy-To-Use Interface
The LDC500 series have an intuitive user interface, and manyfirst time users will be able to operate the instrument without
having to crack open the manual (although we do recommend
reading the manual). Unlike competitive models, the LDC500
series controllers have a dedicated front-panel display forparameter entry. You don’t have to sacrifice monitoring
temperature or current to simply change an instrument
setting — you have a separate two-line, blue alpha-numeric
display for that. In addition, bright 5-digit green LED displays
constantly monitor current and temperature, and are large
enough to easily read from anywhere in the lab.

LDC500 Series Laser Diode Controllers

Laser Diode Protection
Multiple laser diode protection features, including slow startturn-on, adjustable current limits, and adjustable compliancevoltage, keep your laser diodes safe when unexpected eventsoccur. Fast clamping and shut down provide extra protection
against intermittent contact with the laser. Combined, thesefeatures provide trouble-free, safe control of your laser diode.

modulation signal, with adjustable bandwidth up to 1 MHz (inCC mode) or 10 kHz (in CP mode).
Another convenient feature that the LDC500 series offers is afully programmable photodiode bias voltage. You can set thebias between 0 and 5 V from the front panel, or remotely using
one of the computer interfaces.
Bumpless Transfer

Linear Power Supplies
Independent linear power supplies are used for the laser diodecontroller and the temperature controller. The supplies aredesigned with a magnetically shielded toroidal transformer,and provide ultra-clean, stable isolated power.

A unique feature of the LDC500 series is dynamic “BumplessTransfer” between CC and CP modes. This feature means you
don’t have to shut down your laser to switch modes — simply
press the Current/Power button.
36 W Temperature Controller

Computer Control
Remote operation of the LDC500 series is supported withGPIB, RS-232 and Ethernet interfaces. All instrument
functions can be controlled and read over any of the interfaces.
Up to nine complete instrument configurations can be savedin non-volatile RAM and recalled at any time. A TTL trigger
output is also available to synchronize other test equipment.
Stable Laser Diode Controller
To ensure a stable optical output from your laser diode, theLDC500 series LD controllers were designed to deliver noisefree, precision operation. They are accurate to ±0.01 % FS,
have automated testing setups, noise is as low as 0.3 µA rms,
and they meet a drift specification of 10 ppm/°C.
The controllers have two modes of operation for the laser
diode: constant current and constant power. Constant currentmode (CC) programs the source to a precise DC amplitude.
Alternatively, the constant optical power mode (CP) servos
the current source to maintain a constant signal on a monitor
photodiode. Both control modes allow you to add an external

LDC500 front panel

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The LDC500 series integrated 36 W temperature controller
lets you adjust temperature with 0.001 °C resolution, andmeasure temperature with 0.01 °C accuracy (with a calibratedsensor). It maintains a typical stability of 0.0005 °C/°C withrespect to room temperature, and has a very wide temperaturecontrol range.
The TEC controller also has two modes of operation: constanttemperature mode (CT) controls the TEC current to maintaina fixed temperature (or raw sensor value), while constantcurrent mode (CC) operates the TEC at a fixed current.
Thermistor, RTD and IC sensors are all supported.
The LDC500 series offers an auto-tuning feature which
automatically optimizes the PID loop parameters of thecontroller. Of course, full manual control is provided too.
Dynamic transfer between CT and CC modes for the TEC isalso easy — just press the Temp/Current button.

LDC501 rear panel

LDC500 Series Specifications

Laser Diode Current Source
Current Source
Range

Setpoint resolution

0 to 100 mA, 0 to 50 mA (LDC500)
0 to 500 mA, 0 to 250 mA (LDC501)
0 to 2 A, 0 to 1 A (LDC502)
1 µA (LDC500), 10 µA (LDC501),
0.1 mA (LDC502)±0.02 % of full scale>1 MΩ (DC)

Accuracy
Output impedanceStabilityThermal<10 ppm/°C
Short-term (1 hr.)
<5 ppm full scale
Long-term (24 hr.) <15 ppm full scale
Noise (10 Hz to 1 MHz) LDC500
0.9 µA rms (high range / high BW)
0.6 µA rms (high range / low BW)
0.5 µA rms (low range / high BW)
0.3 µA rms (low range / low BW)
LDC501
4.5 µA rms (high range / high BW)
1.5 µA rms (high range / low BW)
2.3 µA rms (low range / high BW)
1.0 µA rms (low range / low BW)
LDC50225 µA rms (high range / high BW)
5.0 µA rms (high range / low BW)
10 µA rms (low range / high BW)
3.5 µA rms (low range / low BW)
Compliance voltageRange
0 to 10 V, programmable
Resolution
10 mV
Accuracy
0.2 V
Current Limit
Range
0 to 100 mA, 0 to 50 mA (LDC500)
0 to 500 mA, 0 to 250 mA (LDC501)
0 to 1 A, 0 to 2 A (LDC502)
Resolution
10 µA (LDC500 & LDC501),
0.1 mA (LDC502)
Accuracy±0.1 mA (LDC500 & LDC501),±0.4 mA (LDC502)
Analog Modulation
Input range
Input impedanceGain
CC mode–10 V to +10 V
2 kΩ, typ.
LDC50010 mA/V (high range)
5 mA/V (low range)
LDC501
50 mA/V (high range)
25 mA/V (low range)
LDC502200 mA/V (high range)
100 mA/V (low range)

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CP mode(PD current)
Bandwidth (–3 dB)
CC modeCP modeLDC500 & LDC501: 500 µA/V
LDC502: 1000 µA/V
DC to 1.0 MHz(high BW, LDC500 & LDC501)
DC to 0.8 MHz(high BW, LDC502)
DC to 10 kHz (low BW, all LDCs)
DC to 5 kHz (high bandwidth)
DC to 100 Hz (low bandwidth)

Monitor Photodiode
Bias voltage
PD current range
Setpoint resolution
Setpoint accuracy

0 to 5 V, programmable
0 to 5,000 µA (LDC500 & LDC501)
0 to 10,000 µA (LDC502)
0.1 µA (CP mode)±2 µA (LDC500 & LDC501)±4 µA (LDC502)

Measurement & Display
Output current
Resolution

1 µA (LDC500), 10 µA (LDC501),
0.1 mA (LDC502)±0.02 % FS

Accuracy
Photodiode current
Resolution
0.1 µA
Accuracy±0.02 % FS
Laser diode forward voltage
Resolution
1 mV
Accuracy±0.02 % FS (4 wire)

Temperature Controller
Temperature Control
Control range
IC sensor
Resistor sensor
Setpoint resolution
Temperature
Resistance
Setpoint accuracy
Temperature
ResistanceStability (typ.)ThermalShort-term (1 hr.)Long-term (24 hr.)
Control algorithm
Auto-tuning–55 °C to +150 °C–150 °C to +250 °C (10 Ω to 500 kΩ)
0.001 °C
0.1 Ω
±0.01 °C (sensor dependent)
0.1 % of sensor resistance(using a 10 k NTC thermistor)
0.0005 °C/°C (vs. ambient)±0.001 °C±0.002 °C
PID
Step response

TEC Output
Source type
Current range

Linear, bipolar current source–4.5 A to +4.5 A

LDC500 Series Specifications

Setpoint resolution
Setpoint accuracy
Max. power
Compliance voltage
Current noise
Current limitsRangeAccuracy

1 mA
±5 mA
36 W
>8 VDC<0.1 mA rms @ 1 A output<0.2 mA rms @ 4 A output
0 to 4.5 A±5 mA

Temperature Sensors
Thermistors
RTD
IC voltage sensors
IC current sensors

10 to 500 kΩ (10 µA, 100 µA,1000 µA excitation)
Pt-100, Pt-1000 (1 mA excitation)
LM335 and equivalent
AD590 and equivalent

Measurement & Display
Temperature
Resolution
Thermistor
Resolution
Accuracy
TEC current
Resolution
Accuracy
TEC voltage
Resolution
Accuracy

About Thermal Stability
Temperature fluctuations in a typical laboratory environmentcan often exceed several degrees Celsius over the course of aday. Small temperature changes can mean significant current
changes in your laser diode if your controller is not up tothe task.
The LDC500, LDC501 and LDC502 have a temperature
coefficient of 10 ppm/°C, which is a factor of five better thancompeting models, making it the ideal controller for precisionlaser diode experiments.
The graphs below demonstrate the temperature performanceof the LDC500 series. Over a 24 hour period, the ambient
temperature change in the laboratory exceeds two degrees
Celsius. Note that the output current deviation of the LDC
after warm-up is stable to better than ±10 ppm.

0.001 °C

1 mA±5 mA
1 mV±5 mV (4 wire)

105LD Current Deviation (ppm)

0.1 Ω±0.2 % + 0.05 Ω05
101520250123456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
time (h)012345678

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
time (h )General26

Remote interfaces
PowerDimensions
WeightWarranty

DB9-F (laser diode), DB15-F (TEC)
BNC (modulate, trigger output)
GPIB (IEEE488.2), RS-232, Ethernet
100/120 VAC or 220/240 VAC,
50 Hz/60 Hz, 100 W
7" × 5"× 15" (WHL)
15 lbs.
One years parts and labor on defects
in material and workmanshipOrdering Information
LDC500LDC501LDC502
O500RM
O500C1O500C2O500C3
O500C4O500C5
O500C6

Laser Diode Controller
Laser Diode Controller
Laser Diode Controller
Rack mount tray for LDC series
6' LD cable w/ flying leads
6' TEC cable w/ flying leads
6' LD cable w/ D connector
6' TEC cable w/ D connector
12' LD cable w/ D connector
12' TEC cable w/ D connector

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25. 5
Room Temperature (°C)

Instrument connectors

25
24. 524
23. 523