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4320-QCW LaserSource, 20A, QCW

US List Price* How to Buy
4320-QCW LaserSource, 20A, QCW

The 4320-QCW LaserSource provides up to 20A of current, and is the highest current offered in the 4300 series. When your application demands up to 20A of current, the 4320-QCW is an excellent choice as a low cost, high value solution. The 4320-QCW supports both CW and Quasi-CW (QCW) mode.

Simple User Interface
The 4320-QCW’s user interface is remarkably simple… so easy to use, you’ll have it up and running in no time. Unlike other instruments which rely on 7-segment LED displays and a confusing array of indicators and buttons, the 4320-QCW instead presents information on a high contrast VFD display in an easy-to-read format. The 4320-QCW displays current, voltage, and photodiode current simultaneously… no need to toggle though the readings as you would on most instruments. Settings and error messages are in clear English, not cryptic codes and flashing status lights.

Quasi-CW (QCW) Mode
The 4320-QCW adds QCW mode, a feature not found in most other laser drivers in this price range. Many applications require the low duty cycle, high current pulses that QCW offers to manage thermal loading on the device. With rise times of less than 50µs, and pulse widths as narrow as 100µs, the 4320-QCW offers an effective and low-cost QCW solution. If you are looking for the non-QCW driver, see the 4320 LaserSource.

  • 20A range
  • Both CW and QCW operation
  • 1mA resolution
  • <5mA noise
  • USB and RS-232 interfaces





Standard Computer Interfaces
The 4320-QCW includes both USB and RS232 computer interfaces, allowing for quick and easy connection to a PC for remote operation. In addition, the LaserSource’s command set is compatible with ILX and Newport controllers, allowing you to leverage any existing software you may have already developed.
                                    USB & RS232 Connectors.gif

Ground Loops Eliminated
Like all LaserSources, the 4320-QCW includes isolated inputs and outputs. In technical terms, this means that every input and output signal is electrically isolated, so that offset voltages, ground connections, and AC noise will not “bleed” into other parts of the electronics. Even the photodiode input is fully isolated from the laser output, ensuring full isolation of the laser output. In practical terms, this means it’s impossible to create a ground loop through the LaserSource, a common problem in laboratory setups where several different instruments are used in the same test. No other driver on the market has this capability.

Analog Modulation
The 4320-QCW’s analog interface supports modulation rates up to 10kHz.



CW Mode Specifications

    Range (mA)

0 – 20,000

    Resolution (mA)


    Accuracy (±[% set+mA])

0.05% + 4

    Stability (ppm, time)

< 10, 1 hour

    Temperature Coeff (ppm/°C)


    Noise/Ripple (μA rms, low BW)

< 5000

    Transients (μA)

< 50mA

    Compliance Voltage (V)


    Modulation Bandwidth (kHz)


    Modulation Input Range

0 – 10V, 10kΩ

    Range (μA)

25 – 20000

    Resolution (μA)


    Accuracy (±[% set+μA])

0.05% + 2

    Stability (ppm, time)

< 200, 24 hours

    Temperature Coeff (ppm/°C)

< 200

    PD Bias (V)

0 to -5V, software programmable

    Range (V)

0 – 4

    Resolution (V)


    Setpoint Accuracy (±[% set+V])

0.05% + 0.005

    Measurement Accuracy (±[% reading+V])

0.05% + 0.004


QCW Mode Specifications

    Range (mA)

150 – 20,000

    Resolution (mA)


    Setpoint Accuracy (±[% set+mA])

0.5% + 25

    Measurement Accuracy (±[% reading+mA])

3% + 30

    Resolution (V)


    Measurement Accuracy (±[% reading+V])

2% + 0.04

    Resolution (μA)


    Measurement Accuracy (±[% reading+μA])

2% + 100

    Range (ms)

0.1 – 600

    Resolution (ms)


    Accuracy (ms)


    Range (Hz)

1 – 1000

    Resolution (Hz)


    Accuracy (Hz)


    Range (%)

0.1 – 90

    Resolution (%)


    Rise/Fall Times (µs)

< 50 / < 10

    Overshoot (%)

< 7

    Zero Current (% of set)




    Current Limit Accuracy (mA)


    Voltage Limit Accuracy (±% FS)




    Display Type

2x20 VFD

    Laser Connector

9W4, female


DB-9, female

    Computer Interface

USB 2.0 Full Speed (Type B),
RS-232 (DB-9, male)

    Input Power

100V / 120V / 230V, 50 / 60Hz

    Size (H x W x D) [inches (mm)]

3.47 (89) x 8.5 (215) x 12 (305)

    Weight (lbs [kg])

7.8 [3.5]

    Storage Temperature

-20°C to +60°C

    Operating Temperature

+10°C to +40°C


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