LTC6400-20_15 Datasheet, PDF (1/16 Pages) Linear Technology – 1.8GHz Low Noise, Low Distortion Differential ADC Driver for 300MHz IF

LTC6400-20
1.8GHz Low Noise, Low
Distortion Differential ADC
Driver for 300MHz IF
FEATURES
■ _{1.8GHz –3dB Bandwidth}
■ _{Fixed Gain of 10V/V (20dB)}
■ _{–94dBc IMD3 at 70MHz (Equivalent OIP3 = 51dBm)}
■ _{–65dBc IMD3 at 300MHz (Equivalent OIP3 = 36.5dBm)}
■ _{1nV/√Hz Internal Op Amp Noise}
■ _{2.1nV/√Hz Total Input Noise}
■ _{6.2dB Noise Figure}
■ _{Differential Inputs and Outputs}
■ _{200Ω Input Impedance}
■ _{2.85V to 3.5V Supply Voltage}
■ _{90mA Supply Current (270mW)}
■ _{1V to 1.6V Output Common Mode Voltage,}
Adjustable
■ _{DC- or AC-Coupled Operation}
■ _{Max Differential Output Swing 4.4VP-P}
■ _{Small 16-Lead 3mm × 3mm × 0.75mm QFN Package}
APPLICATIONS
■ _{Differential ADC Driver}
■ _{Differential Driver/Receiver}
■ _{Single Ended to Differential Conversion}
■ _{IF Sampling Receivers}
■ _{SAW Filter Interfacing}
DESCRIPTION
The LTC^®6400-20 is a high-speed differential amplifier
targeted at processing signals from DC to 300MHz. The
part has been specifically designed to drive 12-, 14- and
16-bit ADCs with low noise and low distortion, but can also
be used as a general-purpose broadband gain block.
The LTC6400-20 is easy to use, with minimal support
circuitry required. The output common mode voltage is
set using an external pin, independent of the inputs, which
eliminates the need for transformers or AC-coupling ca-
pacitors in many applications. The gain is internally fixed
at 20dB (10V/V).
The LTC6400-20 saves space and power compared to
alternative solutions using IF gain blocks and transform-
ers. The LTC6400-20 is packaged in a compact 16-lead
3mm × 3mm QFN package and operates over the –40°C
to 85°C temperature range.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Single-Ended to Differential ADC Driver
0.1μF
1000pF
3.3V
1.25V
V⁺
INPUT
0.1μF
V_OCM
10Ω
+IN
+OUT
66.5Ω
0.1μF
+OUTF
LTC6400-20
–OUTF
–IN
V––OUT
10Ω
29Ω
ENABLE
20dB GAIN
AIN^{+ VCM VDD}
LTC2208
AIN^–
LTC2208 130Msps
16-Bit ADC
640020 TA01a
0.1μF
Equivalent Output IP3 vs
Frequency
60
(NOTE 7)
50
40
30
20
10
0
0 50 100 150 200 250 300
FREQUENCY (MHz)
640020 TA01b
640020f
1