LT6604-5
Dual Very Low Noise,
Differential Amplifier and
5MHz Lowpass Filter
DESCRIPTION
The LT®6604-5 consists of two matched, fully differential
amplifiers, each with a 4th order, 5MHz lowpass filter. The
fixed frequency lowpass filter approximates a Chebyshev
response. By integrating a filter and a differential ampli-
fier, distortion and noise are made exceptionally low. At
unity gain, the measured in-band signal-to-noise ratio is
an impressive 82dB. At higher gains, the input referred
noise decreases, allowing the part to process smaller
input differential signals without significantly degrading
the signal-to-noise ratio.
FEATURES
n
Dual Differential Amplifier with 5MHz Lowpass Filters
4th Order Filters
Approximates Chebyshev Response
Guaranteed Phase and Gain Matching
Resistor-Programmable Differential Gain
n
>82dB Signal-to-Noise (3V Supply, 2V Output)
P-P
n
Low Distortion (1MHz, 2V Output, 800Ω Load)
P-P
HD2: 93dBc
HD3: 96dBc
n
Specified for Operation with 3V, 5V and 5V Supplies
n
Fully Differential Inputs and Outputs
Gain and phase are well matched between the two chan-
nels. Gain for each channel is independently programmed
using two external resistors. The LT6604-5 enables level
shifting by providing an adjustable output common mode
voltage, making it ideal for directly interfacing to ADCs.
The LT6604-5 is fully specified for 3V operation. The dif-
ferential design enables outstanding performance at a
n
Adjustable Output Common Mode Voltage
n
Small 4mm × 7mm × 0.75mm QFN Package
APPLICATIONS
n
Dual Differential ADC Driver and Filter
n
Single-Ended to Differential Converter
2V signal level for a single 3V supply.
P-P
n
Matched, Dual, Differential Gain or Filter Stage
n
See the back page of this datasheet for a complete list of
relatedsingleanddualdifferentialamplifierswithintegrated
2.5MHz to 20MHz lowpass filters.
Common Mode Translation of Differential Signals
n
High Speed ADC Antialiasing and DAC Smoothing in
Wireless Infrastructure or Networking Applications
n
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
High Speed Test and Measurement Equipment
n
Medical Imaging
TYPICAL APPLICATION
Channel to Channel Gain Matching
3V
25
50 TYPICAL UNITS
LT6604-5
+INA
LTC22xx
DUAL ADC
+
T
= 25°C
A
V A
3V
3V
GAIN = 1
806Ω
20
15
10
5
50Ω
50Ω
f
= 5MHz
–
+
–OUTA
+OUTA
IN
V
+
AIN
–
–
+
MIDA
18pF
18pF
V
DOUT
OCMA
0.01μF
–INA
+
–
–
+
806Ω
806Ω
+
V B
+INB
V
50Ω
–OUTB
+OUTB
+
AIN
–
–
MIDB
V
DOUT
OCMB
50Ω
0.01μF
+
–INB
+
–
0
–
806Ω
–0.20
–0.10
0
0.10
0.20
V
66045 TA01
GAIN MATCH (dB)
66045 TA01b
66045f
1