
Analog Devices
GENERAL DESCRIPTION
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 signal to-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.
FEATURES
Very low voltage noise: 1 nV/√Hz maximum @ 100 Hz
Excellent current gain match: 0.5% typical
Low offset voltage (VOS): 200 μV maximum
Outstanding offset voltage drift: 0.03 μV/°C typical
High gain bandwidth product: 200 MHz