Audio, Dual-Matched
NPN Transistor
SSM2212
PIN CONFIGURATION
FEATURES
Very low voltage noise: 1 nV/√Hz maximum @ 100 Hz
Excellent current gain match: 0.5%
Low offset voltage (VOS): 200 μV maximum
Outstanding offset voltage drift: 0.03 μV/°C
High gain bandwidth product: 200 MHz
C
B
E
1
2
3
4
8
7
6
5
C
B
1
1
1
2
2
2
E
NIC
NIC
SSM2212
NIC = NO INTERNAL CONNECTION
Figure 1. 8-Lead SOIC_N
GENERAL DESCRIPTION
The SSM2212 is a dual, NPN-matched transistor pair that is
specifically designed to meet the requirements of ultralow noise
audio systems.
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.
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 SSM2212 can achieve outstanding signal-to-
noise ratios. The high current gain results in superior
performance compared to systems incorporating commercially
available monolithic amplifiers.
The SSM2212 is also an ideal choice for accurate and reliable
current biasing and mirroring circuits. Furthermore, because a
current mirror’s accuracy degrades exponentially with mismatches
of VBE between transistor pairs, the low VOS of the SSM2212
does not need offset trimming in most circuit applications.
Excellent matching of the current gain (ΔhFE) to about 0.5% and
low VOS of less than 10 μV typical make the SSM2212 ideal for
symmetrically balanced designs, which reduce high-order
amplifier harmonic distortion.
The SSM2212 performance and characteristics are guaranteed
over the extended temperature range of −40°C to +85°C.
Rev. B
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