INSTRUCTIONS FOR OPERATION OF DETECTORS AND AMPLIFIERS--GENERAL
NOTES FOR ALL MODELS.
1. DETECTOR AND AMPLIFIER SEPARATE UNITS -- AC (CAPACITOR) COUPLED AMPLIFIERS
Photoconductive HgCdTe detectors and some high speed photodiodes are capacitor coupled to the amplifier. A bias T connection is located between the detector and capacitor . The bias current value is set with a resistor, attached to two external pins on the amplifier. Use CAUTION when connecting power to capacitor coupled [AC coupled] amplifier-detector combinations.
- CAUTION 1. - Never connect the power to AC coupled
amplifiers without the detectors correctly
connected. Without the detector in place, the
full bias voltage will appear at the amplifier
input and may destroy the unit.
- CAUTION 2. - Never connect the detector to an AC coupled or DC coupled amplifier which has a built in bias when the circuit is activated [ON]. The
input circuit may produce excess current
into the detectors, which may destroy the
detectors. Always follow ESD procedures when working with photodiodes. Also, do not use multimeters to test MCT or INSB photodiodes.
Solder all wires to detectors and amplifiers or use a tight SMA connection at all times. Avoid clip connections because they may
be intermittent and will allow large bias voltage spikes to enter
the detector-preamplifier input. Also, a lead may come off and
cause single supply operation which may degrade some components. With capacitor coupled amplifiers a loose connection can destroy the detector.
2. INTEGRAL DETECTOR/AMPLIFIER -- AMPLIFIERS BUILT INTO DETECTOR DEWAR
- CAUTION 3. - Always power the negative and positive voltages
simultaneously. [ Including Series KMPV11-X-JX AND KMPV50-X-JX ]
- CAUTION 4. - Do not leave power on for extended periods with the detector at room temperature. It takes several hours for the detector to warm up, so there is time for an orderly shut down. The Detector impedance changes when it warms, which can put the amplifier in an unstable condition.
Extended time in this state can degrade amplifier performance and shorten its life. An AUTOMATIC POWER SHUTOFF option is available for dual amplifIer models.