Analog Devices Inc. SSM2212 Dual-Matched NPN Transistor

Analog Devices SSM2212 Dual-Matched NPN Transistors are dual, NPN-matched transistor pairs specifically designed to meet the requirements of ultra-low noise audio systems. With its extremely low input base spreading resistance (rbb' is typically 28Ω) and high current gain (hFE typically exceeds 600 at IC = 1mA), the SSM2212 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 approximately 0.5% and low VOS of less than 10μV typical make the SSM2212 ideal for symmetrically balanced designs, which reduce high order amplifier harmonic distortion. The 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 SSM2212 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 SSM2212 does not need offset trimming in most circuit applications.