Very Low Noise, Differential
Ampliﬁer and 5MHz Lowpass Filter
n Programmable Differential Gain via Two External
n Adjustable Output Common Mode Voltage
n Operates and Speciﬁed with 3V, 5V, ±5V Supplies
n 0.5dB Ripple 4th Order Lowpass Filter with 5MHz
n 82dB S/N with 3V Supply and 2VP-P Output
n Low Distortion, 2VP-P, 800Ω Load
1MHz: 93dBc 2nd, 96dBc 3rd
n Fully Differential Inputs and Outputs
n Compatible with Popular Differential Ampliﬁer
n Available in an SO-8 Package
n High Speed ADC Antialiasing and DAC Smoothing in
Networking or Cellular Base Station Applications
n High Speed Test and Measurement Equipment
n Medical Imaging
n Drop-in Replacement for Differential Ampliﬁers
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
The LT®6600-5 combines a fully differential ampliﬁer with a
4th order 5MHz lowpass ﬁlter approximating a Chebyshev
frequency response. Most differential ampliﬁers require
many precision external components to tailor gain and
bandwidth. In contrast, with the LT6600-5, two external
resistors program differential gain, and the ﬁlter’s 5MHz
cutoff frequency and passband ripple are internally set.
The LT6600-5 also provides the necessary level shifting
to set its output common mode voltage to accommodate
the reference voltage requirements of A/Ds.
Using a proprietary internal architecture, the LT6600-5
integrates an antialiasing ﬁlter and a differential ampli-
ﬁer/driver without compromising distortion or low noise
performance. At unity gain the measured in band sig-
nal-to-noise ratio is an impressive 82dB. At higher gains
the input referred noise decreases so the part can process
smaller input differential signals without signiﬁcantly
degrading the output signal-to-noise ratio.
The LT6600-5 also features low voltage operation. The
differential design provides outstanding performance for
a 2VP-P signal level while the part operates with a single
For similar devices with other cutoff frequencies, refer to
the LT6600-20, LT6600-10 and LT6600-2.5.
Dual, Matched, 5MHz Lowpass Filter
GAIN = 806Ω
5MHz Phase Distribution
–135 –134.5 –134–133.5–133 –132.5–132 –131.5
5MHz PHASE (DEG)