LTC6416
2 GHz Low Noise Differential
16-Bit ADC Buffer
FEATURES
DESCRIPTION
The LTC®6416 is a differential unity gain buffer designed
to drive 16-bit ADCs with extremely low output noise
and excellent linearity beyond 300MHz. Differential input
impedance is 12kΩ, allowing 1:4 and 1:8 transformers to
be used at the input to achieve additional system gain.
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2GHz –3dB Small Signal Bandwidth
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300MHz 0ꢀ1dB Bandwidth
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1ꢀ8nV/√Hz Output Noise
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46ꢀ25dBm Equivalent OIP3 at 140MHz
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40ꢀ25dBm Equivalent OIP3 Up to 300MHz
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–81dBc/–72dBc HD2/HD3 at 140MHz, 2V Out
P-P
With no external biasing or gain setting components and
a flow-through pinout, the LTC6416 is very easy to use.
It can be DC-coupled and has a common mode output
offset of –40mV. If the input signals are AC-coupled, the
LTC6416 input pins are internally biased to provide an
output common mode voltage that is set by the voltage
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–84ꢀ5dBc IM3 at 140MHz, 2V Out Composite
P-P
–74dBc/–67ꢀ5dBc HD2/HD3 at 300MHz, 2V Out
P-P
–72ꢀ5dBc IM3 at 300MHz, 2V Out Composite
P-P
Programmable High Speed, Fast Recovery
Output Clamping
DC-Coupled Signal Path
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on the V pin.
CM
Operates on Single 2.7V to 3.9V Supply
Low Power: 150mW on 3.6V
2mm × 3mm 10-Pin DFN Package
In addition the LTC6416 has high speed, fast recovery
clamping circuitry to limit output signal swing. Both the
high and low clamp voltages are internally biased to allow
maximum output swing but are also user programmable
via the CLLO and CLHI pins.
APPLICATIONS
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Differential ADC Driver
Supply current is nominally 42mA and the LTC6416 oper-
ates on supply voltages ranging from 2.7V to 3.9V.
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IF Sampling Receivers
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Impedance Transformer
SAW Filter Interface
CCD Buffer
The LTC6416 is packaged in a 10-lead 3mm × 2mm DFN
package.Pinoutisoptimizedforplacementdirectlyadjacent
to Linear’s high speed 12-, 14- and 16-bit ADCs.
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L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
LTC6416 Driving LTC2208 ADC
with 1:8 Transformer fIN =140MHz,
fS = 130MHz, –1dBFS, PGA = 1
TYPICAL APPLICATION
0
+
V
= 3.6V
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
HD2 = –94dBc
HD3 = –89.1dBc
LTC6416 Driving LTC2208 ADC – 140MHz IF
SFDR = 89.1dB
3.6V
SNR = 70.7dB
MEASURED USING DC1257B
WITH MINI-CIRCUIT TCM8-1+
1:8 TRANSFORMER
680pF
0.1μF
2.2μF
3.3V
CLHI
+
V
1.5pF
1pF
1:8
V
25Ω
CM
OUT
+
+
–
200Ω
IN
AIN
+
–
50Ω
16
LTC6416
–
LTC2208
PGA = 1
OUT
+
AIN
200Ω
IN
–
GND
25Ω
–110
–120
GND
CLLO
1.5pF
6416 TA01a
0.1μF
MINI-CIRCUITS
TCM8-1+
20
30
40
50
0
60
10
FREQUENCY (MHz)
CLOCK
(130MHz)
6416 TA01b
6416f
1