The AS194 and AS394 are junction isolated ultra well-matched monolithic NPN transistor pairs with an
order of magnitude improvement in matching over conventional transistor pairs.
Electrical characteristics of these devices such as drift versus initial offset voltage, noise, and the
exponential relationship of base-emitter voltage to collector current closely approach those of a theoretical
transistor. Extrinsic base and emitter resistances is very low, giving very low noise and operating over a wide current range.
To guarantee long term stability of matching parameters, internal clamp diodes have been added across
the emitter-base junction of each transistor. These prevent degradation due to reverse biased emitter currentthe most common cause of field failures in matched devices. The parasitic isolation junction formed by the diodes also clamps the substrate region to the most negative emitter to ensure complete isolation between devices.
The AS194H, AS394H, AS394CH are available in the 8-pin metal can TO5-8 package and the AS394DE
and AS394CDE in the 8-lead plastic SOIC-8 (150mil) EPAD package.