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LT6600-2.5_15 Datasheet, PDF (1/16 Pages) Linear Technology – Very Low Noise, Differential Amplifi er and 2.5MHz Lowpass Filter | |||
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LT6600-2.5
Very Low Noise, Differential
Ampliï¬er and 2.5MHz Lowpass Filter
FEATURES
DESCRIPTION
n ±0.6dB (Max) Ripple 4th Order Lowpass Filter with
2.5MHz Cutoff
n Programmable Differential Gain via Two External
Resistors
n Adjustable Output Common Mode Voltage
n Operates and Speciï¬ed with 3V, 5V, ±5V Supplies
n 86dB S/N with 3V Supply and 1VRMS Output
n Low Distortion, 1VRMS, 800Ω Load
1MHz: 95dBc 2nd, 88dBc 3rd
n Fully Differential Inputs and Outputs
n Compatible with Popular Differential Ampliï¬er
Pinouts
n SO-8 and DFN-12 Packages
APPLICATIONS
n High Speed ADC Antialiasing and DAC Smoothing in
Networking or Cellular Basestation Applications
n High Speed Test and Measurement Equipment
n Medical Imaging
n Drop-in Replacement for Differential Ampliï¬ers
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
The LT®6600-2.5 combines a fully differential ampliï¬er
with a 4th order 2.5MHz lowpass ï¬lter approximating a
Chebyshev frequency response. Most differential ampli-
ï¬ers require many precision external components to tail
or gain and bandwidth. In contrast, with the LT6600-2.5,
two external resistors program differential gain, and the
ï¬lterâs 2.5MHz cutoff frequency and passband ripple are
internally set. The LT6600-2.5 also provides the necessary
level shifting to set its output common mode voltage to ac-
commodate the reference voltage requirements of A/Ds.
Using a proprietary internal architecture, the LT6600-2.5
integrates an antialiasing ï¬lter and a differential ampli-
ï¬er/driver without compromising distortion or low noise
performance. At unity gain the measured in band signal-
to-noise ratio is an impressive 86dB. At higher gains the
input referred noise decreases so the part can process
smaller input differential signals without signiï¬cantly
degrading the output signal-to-noise ratio.
The LT6600-2.5 also features low voltage operation. The
differential design provides outstanding performance for a
4VP-P signal level while the part operates with a single 3V
supply. The LT6600-2.5 is available in SO-8 and DFN-12
packages.
For similar devices with higher cutoff frequency, refer
to the LT6600-5, LT6600-10, LT6600-15 and LT6600-20
data sheets.
TYPICAL APPLICATION (S8 Pin Numbers Shown)
DAC Output Filter
16-BIT 4kHz to 2.5MHz
DISCRETE MULTI-TONE
SIGNAL AT 50MSPS
5V
LADCOM
IOUT A
LTC1668
IOUT B
CLK
â5V 50MHz
52.3Ω
52.3Ω
5V
0.1μF
1580Ω 1 â
7
3
+4
2 LT6600-2.5
8+
1580Ω
â5
6
0.1μF
VOUT+
VOUTâ
â5V
660025 TA01a
DAC Output Spectrum
0
â10
â20 BASEBAND SIGNAL
â30
â40
â50
DAC OUTPUT IMAGE
â60
â70
â80
â90
0 12 24 36 48 60 72 84 96 108 120
FREQUENCY (MHz)
660025 TA01b
LT6600-2.5 Output Spectrum
0
â10
â20
â30
â40
â50
â60
â70
â80
â90
0 12 24 36 48 60 72 84 96 108 120
FREQUENCY (MHz)
660025 TA01c
660025fe
1
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