LF442MH National Semiconductor, LF442MH Datasheet - Page 9

• Manufacturer Part Number: LF442MH
• Description: Dual Low Power JFET Input Operational Amplifier
• Manufacturer: National Semiconductor

Typical Applications
(Continued)
Unconventional Log Amplifier
DS009155-15
Q1, Q2, Q3 are included on LM389 amplifier chip which is temperature-stabilized by the LM389 and Q2-Q3, which act as a heater-sensor pair.
Q1, the logging transistor, is thus immune to ambient temperature variation and requires no temperature compensation at all.
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