LTC6401-14
1
640114f
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
2GHz Low Noise, Low
Distortion Differential ADC
Driver for DC-140MHz
The LTC
®
6401-14 is a high-speed differential amplifi er
targeted at processing signals from DC to 140MHz. The
part has been specifi cally 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 LTC6401-14 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 fi xed
at 14dB (5V/V).
The LTC6401-14 saves space and power compared to
alternative solutions using IF gain blocks and transform-
ers. The LTC6401-14 is packaged in a compact 16-lead
3mm × 3mm QFN package and operates over the –40°C
to 85°C temperature range.
Equivalent Output IP3 vs Frequency
■
2GHz –3dB Bandwidth
■
Fixed Gain of 5V/V (14dB)
■
–91dBc IMD3 at 70MHz (Equivalent OIP3 = 49.3dBm)
■
–81dBc IMD3 at 140MHz (Equivalent OIP3 = 44.5dBm)
■
1.1nV/√
⎯
H
⎯
z Internal Op Amp Noise
■
7.3dB Noise Figure
■
Differential Inputs and Outputs
■
200Ω Input Impedance
■
2.85V to 3.5V Supply Voltage
■
45mA Supply Current (135mW)
■
1V to 1.6V Output Common Mode, Adjustable
■
DC- or AC-Coupled Operation
■
Max Differential Output Swing 4.6V
P-P
■
Small 16-Lead 3mm × 3mm × 0.75mm QFN Package
■
Differential ADC Driver
■
Differential Driver/Receiver
■
Single Ended to Differential Conversion
■
IF Sampling Receivers
■
SAW Filter Interfacing
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
R2
29Ω
R1
68.5Ω
C4
0.1μF
C3
0.1μF
640114 TA01a
LTC6401-14
LTC2208
R
S1
15Ω
C2
0.1μF
V
IN
C1
1000pF
3.3V3.3V
R
S2
15Ω
R
S3
10Ω
R
S4
10Ω
R3
100Ω
V
OCM
C5
0.1μF
1.25V
C
F2
33pF
COILCRAFT
0603CS
C
F1
33pF
L1
24nH
C
F3
33pF
V
+
–IN
+IN
+OUT
–OUT
V
–
AIN
+
AIN
–
V
CM
V
DD
LTC2208
130Msps
16-Bit ADC
0 100 120 140 160 18020 40 60 80 200
FREQUENCY (MHz)
OUTPUT IP3 (dBm)
60
50
40
20
10
30
0
640114 TA01b
(NOTE 7)