LT6600-15_15 Datasheet, PDF (1/12 Pages) Linear Technology – Very Low Noise, Differential Amplifier and 15MHz Lowpass Filter

LT6600-15
Very Low Noise, Differential
Amplifier and 15MHz Lowpass Filter
FEATURES
n _{Programmable Differential Gain via Two External}
Resistors
n _{Adjustable Output Common Mode Voltage}
n _{Operates and Specified with 3V, 5V, ±5V Supplies}
n _{0.5dB Ripple 4th Order Lowpass Filter with 15MHz}
Cutoff
n _{76dB S/N with 3V Supply and 2VP-P Output}
n _{Low Distortion, 2VP-P, 800Ω Load, VS = 3V}
1MHz: 86dBc 2nd, 90dBc 3rd
10MHz: 63dBc 2nd, 69dBc 3rd
n _{Fully Differential Inputs and Outputs}
n _{Compatible with Popular Differential Amplifier}
Pinouts
n _{SO-8 Package}
APPLICATIONS
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.
DESCRIPTION
The LT^®6600-15 combines a fully differential amplifier with a
4th order 15MHz lowpass filter approximating a Chebyshev
frequency response. Most differential amplifiers require
many precision external components to tailor gain and
bandwidth. In contrast, with the LT6600-15, two external
resistors program differential gain, and the filter’s 15MHz
cutoff frequency and passband ripple are internally set.
The LT6600-15 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 LT6600-15
integrates an antialiasing filter and a differential amplifier/
driver without compromising distortion or low noise perfor-
mance. At unity gain the measured in band signal-to-noise
ratio is an impressive 76dB. 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 LT6600-15 also features low voltage operation. The
differential design provides outstanding performance for
a 2V_P-P signal level while the part operates with a single
3V supply.
The LT6600-15 is packaged in an SO-8 and is pin compat-
ible with standalone differential amplifiers.
TYPICAL APPLICATION
LT6600-15
3V
0.1μF
R_IN
536Ω
1
7
3
–
V_MID
+
4
25Ω
0.01μF
V_IN
2
8
V_OCM
+
–
5
25Ω
R_IN
6
536Ω
GAIN = 536Ω/R_IN
LTC2249
3V
5.6pF
V⁺
+
5.6pF
5.6pF
A_IN
–
V_CM
D_OUT
V^–
2.2μF
660015 TA01a
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
0
An 8192 Point FFT Spectrum
INPUT 10.7MHz
2V_P-P
f_SAMPLE = 80MHz
10
20
30
40
FREQUENCY (MHz)
660015 TA01b
660015fb
1