LTC6401-8
1
64018f
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
2.2GHz Low Noise, Low
Distortion Differential ADC
Driver for DC-140MHz
The LTC
®
6401-8 is a high-speed differential amplifi er tar-
geted 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 LTC6401-8 is easy to use, with minimal support cir-
cuitry 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 8dB (2.5V/V).
The LTC6401-8 saves space and power compared to al-
ternative solutions using IF gain blocks and transformers.
The LTC6401-8 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
■
2.2GHz –3dB Bandwidth
■
Fixed Gain of 2.5V/V (8dB)
■
–92dBc IMD3 at 70MHz (Equivalent OIP3 = 50dBm)
■
–80.5dBc IMD3 at 140MHz (Equivalent OIP3 = 44dBm)
■
1nV/√
⎯
H
⎯
z Internal Op Amp Noise
■
12.1dB Noise Figure
■
Differential Inputs and Outputs
■
400Ω 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
27.4Ω
R1
59.0Ω
C4
0.1μF
C3
0.1μF
64018 TA01a
LTC6401-8
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
64018 TA01b
(NOTE 7)
