The MAT12 is a dual， NPN-matched transistor pair that is specifically designed to meet the requirements of ultralow noise audio systems. With its extremely low input base spreading resistance （rbb‘ is typically 28 Ω） and high current gain （hFE typically exceeds 600 at IC = 1 mA）， the MAT12 can achieve outstanding signalto-noise ratios. The high current gain results in superior performance compared to systems incorporating commercially available monolithic amplifiers. Excellent matching of the current gain （ΔhFE） to about 0.5% and low VOS of less than 10 μV typical make the MAT12 ideal for symmetrically balanced designs， which reduce high-order amplifier harmonic distortion. Stability of the matching parameters is guaranteed by protection diodes across the base emitter junction. These diodes prevent degradation of beta and matching characteristics due to reverse biasing of the base emitter junction. The MAT12 is also an ideal choice for accurate and reliable current biasing and mirroring circuits. Furthermore， because the accuracy of a current mirror degrades exponentially with mismatches of VBE between transistor pairs， the low VOS of the MAT12 does not need offset trimming in most circuit applications. The MAT12 is a good replacement for the MAT02， and its performance and characteristics are guaranteed over the extended temperature range of ?40°C to +85°C.