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 current the 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.
- "Ideal" and identical transistors
- Common-mode rejection ratio > 120dB
- Emitter-base offset voltage < 100μV
- Emitter-base offset voltage temperature drift 0,1μV/C
- Current gain (hFE) matched < 2%
- Parameters are guaranteed in the range of collector current of 10μА tо 1mА
- Noise Voltage Density of 1,8 nV/Hz
- Ideal logarithmic properties