- Compensates for device gain change over temperature.
Any active device will vary with ambient temperature , and GaAs FET’s or HEMT’s are not an exception. A typical single gain stage variation is on the order of 0.01dB/°C, therefore, the gain of a narrowband amplifier with 5 stages, may vary as much as 6.5 dB from -40°C to +85°C, which is the standard military temperature of operation. Such a large gain variation may adversely impact system performance.
AML is employing temperature compensated circuits in most amplifiers to bring the gain variation down to a minimal and meet the customer specifications. Narrowband temperature compensated amplifiers can have their gain variation reduced by as much as 70%, by implementing negative temperature coefficient attenuators, or in case of multioctave band amplifiers via proprietary designs of fixed resistors in conjunction with PIN diodes. Using this approach, the depicted gain variation (see graph) over 2 to 18 GHz amounts to less than ± 1.5 dB from -40°C to +75°C for a 31 dB gain amplifier.
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