LT6604-5_15 Datasheet, PDF (1/16 Pages) Linear Technology – Dual Very Low Noise, Differential Amplifier and 5MHz Lowpass Filter

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, 2VP-P Output)}
n _{Low Distortion (1MHz, 2VP-P Output, 800Ω Load)}
HD2: 93dBc
HD3: 96dBc
n _{Specified for Operation with 3V, 5V and ±5V Supplies}
n _{Fully Differential Inputs and Outputs}
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}
n _{Matched, Dual, Differential Gain or Filter Stage}
n _{Common Mode Translation of Differential Signals}
n _{High Speed ADC Antialiasing and DAC Smoothing in}
Wireless Infrastructure or Networking Applications
n _{High Speed Test and Measurement Equipment}
n _{Medical Imaging}
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.
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
2V_P-P signal level for a single 3V supply.
See the back page of this datasheet for a complete list of
related single and dual differential amplifiers with integrated
2.5MHz to 20MHz lowpass filters.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
806Ω
–
0.01μF
+
806Ω
806Ω
–
0.01μF
+
806Ω
LT6604-5
+INA ₊
V_MIDA
–
V_OCMA
–INA _– ⁺
+INB ₊
V_MIDB
–
V_OCMB
–INB _– ⁺
V^–
V⁺A
–OUTA
3V
50Ω
+OUTA
50Ω
V⁺B
–OUTB
3V
50Ω
+OUTB
50Ω
3V
LTC22xx
DUAL ADC
18pF AIN
DOUT
18pF AIN
DOUT
66045 TA01
Channel to Channel Gain Matching
25
50 TYPICAL UNITS
T_A = 25°C
GAIN = 1
20 _{fIN = 5MHz}
15
10
5
0
–0.20
–0.10
0
0.10
GAIN MATCH (dB)
0.20
66045 TA01b
66045fa
1