FEATURES
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LTC6416
2 GHz Low Noise Differential
16-Bit ADC Buffer
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.
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
on the V
CM
pin.
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.
Supply current is nominally 42mA and the LTC6416 oper-
ates on supply voltages ranging from 2.7V to 3.9V.
The LTC6416 is packaged in a 10-lead 3mm
×
2mm DFN
package. Pinout is optimized for placement directly adjacent
to Linear’s high speed 12-, 14- and 16-bit ADCs.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
2GHz –3dB Small Signal Bandwidth
300MHz ±0.1dB Bandwidth
1.8nV/√Hz Output Noise
46.25dBm Equivalent OIP3 at 140MHz
40.25dBm Equivalent OIP3 Up to 300MHz
–81dBc/–72dBc HD2/HD3 at 140MHz, 2V
P-P
Out
–84.5dBc IM3 at 140MHz, 2V
P-P
Out Composite
–74dBc/–67.5dBc HD2/HD3 at 300MHz, 2V
P-P
Out
–72.5dBc IM3 at 300MHz, 2V
P-P
Out Composite
Programmable High Speed, Fast Recovery
Output Clamping
DC-Coupled Signal Path
Operates on Single 2.7V to 3.9V Supply
Low Power: 150mW on 3.6V
2mm
×
3mm 10-Pin DFN Package
APPLICATIONS
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Differential ADC Driver
IF Sampling Receivers
Impedance Transformer
SAW Filter Interface
CCD Buffer
TYPICAL APPLICATION
LTC6416 Driving LTC2208 ADC – 140MHz IF
AMPLITUDE (dBFS)
3.6V
680pF
0.1μF
CLHI
1:8
50Ω
200Ω
IN
+
–
LTC6416 Driving LTC2208 ADC
with 1:8 Transformer f
IN
=140MHz,
f
S
= 130MHz, –1dBFS, PGA = 1
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
PGA = 1
6416 TA01a
2.2μF
V
+
3.3V
1.5pF
AIN
+
1pF
AIN
–
LTC2208
16
V
+
= 3.6V
HD2 =
–94dBc
HD3 =
–89.1dBc
SFDR = 89.1dB
SNR = 70.7dB
MEASURED USING DC1257B
WITH MINI-CIRCUIT TCM8-1+
1:8 TRANSFORMER
V
CM
OUT
+
OUT
–
GND
25Ω
+
–
MINI-CIRCUITS
TCM8-1+
LTC6416
200Ω
IN
GND
0.1μF CLLO
25Ω
1.5pF
–110
–120
0
10
20
30
40
FREQUENCY (MHz)
50
60
6416 TA01b
CLOCK
(130MHz)
6416f
1
LTC6416
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
V
CM
1
CLHI 2
IN
+
3
IN
–
4
CLLO 5
11
10 V
+
9
8
7
6
GND
OUT
+
OUT
–
GND
Total Supply Voltage (V
+
to GND)................................4V
Input Current (CLLO, CLHI, V
CM
, IN
+
, IN
–
)...........±10mA
Output Current (OUT
+
, OUT
–
) ...........................±22.5mA
Operating Temperature Range (Note 2).... –40°C to 85°C
Specified Temperature Range (Note 3) .... –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Junction Temperature ........................................... 150°C
DDB PACKAGE
10-LEAD (3mm 2mm) PLASTIC DFN
T
JMAX
= 150°C,
θ
JA
= 76°C/W,
θ
JC
= 13.5°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
LTC6416CDDB#TRMPBF
LTC6416CDDB#TRPBF
LDDY
10-Lead (3mm
×
2mm) Plastic DFN
LTC6416IDDB#TRMPBF
LTC6416IDDB#TRPBF
LDDY
10-Lead (3mm
×
2mm) Plastic DFN
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 3.6V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V,
.
+
, CLLO = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
+ OUT
–
)/2. V
CLHI = V
INCM
is defined as (IN
OUTCM
is defined as (OUT
INDIFF
is
+
– IN
–
). V
+
– OUT
–
). See DC test circuit schematic.
defined as (IN
OUTDIFF
is defined as (OUT
SYMBOL
G
DIFF
TCG
DIFF
V
SWINGDIFF
V
SWINGMIN
V
SWINGMAX
I
OUT
V
OS
TCV
OS
V
IOCM
PARAMETER
Differential Gain
Differential Gain Temperature Coefficient
Differential Output Voltage Swing
Output Voltage Swing Low
Output Voltage Swing High
Output Current Drive
Differential Input Offset Voltage
Differential Input Offset Voltage Drift
Common Mode Offset Voltage, Input to
Output
V
OUTCM
– V
INCM
V
OUTDIFF
, V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT+,
OUT
–
. V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT+,
OUT
–
. V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT+,
OUT
–
IN
+
= IN
–
= 1.25V, V
OS
= V
OUTDIFF
/
G
DIFF
CONDITIONS
V
INDIFF
= ±1.2V Differential
MIN
–0.3
–0.4
3.7
3.3
TYP
–0.15
–0.00033
4.2
0.2
2.15
2
±20
–5
–10
–65
–75
–0.5
1
–47
–15
–5
5
10
2.3
0.3
0.35
MAX
0
0
UNITS
dB
dB
dB/°C
V
P-P
V
P-P
V
V
V
V
mA
mV
mV
μV/°C
mV
mV
6416f
3.6V ELECTRICAL CHARACTERISTICS
Input/Output Characteristics
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LTC6416
The
l
denotes the specifications which apply over the full
.
operating temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 3.6V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V,
+
, CLLO = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
+ OUT
–
)/2. V
CLHI = V
INCM
is defined as (IN
OUTCM
is defined as (OUT
INDIFF
is
+
– IN
–
). V
+
– OUT
–
). See DC test circuit schematic.
defined as (IN
OUTDIFF
is defined as (OUT
SYMBOL
IVR
MIN
IVR
MAX
I
B
R
INDIFF
C
INDIFF
R
INCM
CMRR
e
N
i
N
G
CM
V
INCMDEFAULT
V
OS
(V
CM
– V
INCM
)
V
OUTCMDEFAULT
V
OS
(V
CM
– V
OUTCM
)
V
OUTCMMIN
V
OUTCMMAX
V
CMDEFAULT
R
VCM
C
VCM
I
BVCM
V
CLHIDEFAULT
V
CLLODEFAULT
R
CLHI
IB
CLHI
R
CLLO
I
BCLLO
Power Supply
V
S
I
S
PSRR
Supply Voltage Range
Supply Current
Power Supply Rejection Ratio
V
S
= 2.7V to 3.6V
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3.6V ELECTRICAL CHARACTERISTICS
PARAMETER
Input Voltage Range, IN
+
, IN
–
(Minimum) (Single-Ended)
Input Voltage Range IN
+
, IN
–
(Maximum) (Single-Ended)
Input Bias Current, IN
+
, IN
–
Differential Input Resistance
Differential Input Capacitance
Input Common Mode Resistance
Common Mode Rejection Ratio
Input Noise Voltage Density
Input Noise Current Density
V
CM
Pin Common Mode Gain
Default Input Common Mode Voltage
Offset Voltage, V
CM
to V
INCM
Default Output Common Mode Voltage
Offset Voltage, V
CM
to V
OUTCM
Output Common Mode Voltage Range
(Minimum)
Output Common Mode Voltage Range
(Maximum)
V
CM
Pin Default Voltage
V
CM
Pin Input Resistance
V
CM
Pin Input Capacitance
V
CM
Pin Bias Current
Default Output Clamp Voltage, High
Default Output Clamp Voltage, Low
CLHI Pin Input Resistance
CLHI Pin Bias Current
CLLO Pin Input Resistance
CLLO Pin Bias Current
CONDITIONS
Defined by Output Voltage Swing Test
Defined by Output Voltage Swing Test
IN
+
= IN
–
= 1.25V
V
INDIFF
= ±1.2V
IN
+
= IN
–
= 0.65V to 1.85V
IN
+
= IN
–
= 0.65V to 1.85V,
CMRR = (V
OUTDIFF
/G
DIFF
/1.2V)
f = 100kHz
f = 100kHz
V
CM
= 0.65V to 1.85V
V
INCM
. IN
+
, IN
–
, V
CM
Pin Floating
V
CM
– V
INCM
, V
CM
= 1.25V
Inputs Floating, V
CM
Pin Floating
V
CM
– V
OUTCM
, V
CM
= 1.25V
V
CM
= 0.1V
V
CM
= 2.7V
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MIN
TYP
MAX
0.1
UNITS
V
V
2.4
–15
9
–5
12
1
6
63.5
59.6
83
1.8
6.5
0.9
1.3
–70
1.25
–60
0.96
1.38
–28
1.34
15
0.37
2.3
2.25
1.325
2.5
–50
2.3
–55
0.125
–120
3
–25
1.5
–25
2.7
33
57.5
42
80
2.46
1.36
3.8
1
–32
2.45
13
0.265
–70
4.1
–1
2.3
4.5
1.425
5.1
50
2.6
55
0.425
0
5
25
3.2
25
3.9
51
54
1.05
1.45
70
1.45
60
0.5
0.55
15
15
μA
kΩ
pF
kΩ
dB
dB
nV/√Hz
pA/√Hz
V/V
V
mV
V
mV
V
V
V
V
V
kΩ
pF
μA
V
mV
V
mV
kΩ
μA
kΩ
μA
V
mA
mA
dB
Output Common Mode Voltage Control
V
CM
= 1.25V
DC Clamping Characteristics
V
OS
(CLHI – V
OUTCM
) Offset Voltage, CLHI to V
OUTCM
V
OS
(CLLO – V
OUTCM
) Offset Voltage, CLLO to V
OUTCM
V
CLHI
= 2.45V
V
CLHI
= 2.45V
V
CLLO
= 0.275V
V
CLLO
= 0.275V
6416f
3
LTC6416
The
l
denotes the specifications which apply over the full
.
operating temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 3.3V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V,
+
, CLLO = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
+ OUT
–
)/2. V
CLHI = V
INCM
is defined as (IN
OUTCM
is defined as (OUT
INDIFF
is
+
– IN
–
). V
+
– OUT
–
). See DC test circuit schematic.
defined as (IN
OUTDIFF
is defined as (OUT
SYMBOL
G
DIFF
TCG
DIFF
V
OUTDIFF
V
OUTMIN
V
OUTMAX
I
OUT
V
OS
TCV
OS
V
IOCM
IVR
MIN
IVR
MAX
I
B
R
INDIFF
C
INDIFF
R
INCM
CMRR
e
N
i
N
G
CM
V
INCMDEFAULT
V
OS
(V
CM
– V
INCM
)
V
OUTCMDEFAULT
V
OS
(V
CM
– V
OUTCM
)
V
OUTCMMIN
V
OUTCMMAX
V
CMDEFAULT
R
VCM
C
VCM
I
BVCM
PARAMETER
Differential Gain
Differential Gain Temperature Coefficient
Differential Output Voltage Swing
Output Voltage Swing Low
Output Voltage Swing High
Output Current Drive (Note 4)
Differential Input Offset Voltage
Differential Input Offset Voltage Drift
Common Mode Offset Voltage, Input to
Output
Input Voltage Range, IN
+
, IN
–
(Minimum) (Single-Ended)
Input Voltage Range, IN
+
, IN
–
(Maximum) (Single-Ended)
Input Bias Current, IN
+
, IN
–
Differential Input Resistance
Differential Input Capacitance
Input Common Mode Resistance
Common Mode Rejection Ratio
Input Noise Voltage Density
Input Noise Current Density
V
CM
Pin Common Mode Gain
Default Input Common Mode Voltage
Offset Voltage, V
CM
to V
INCM
Default Output Common Mode Voltage
Offset Voltage, V
CM
to V
OUTCM
Output Common Mode Voltage
(Minimum)
Output Common Mode Voltage
(Maximum)
V
CM
Pin Default Voltage
V
CM
Pin Input Resistance
V
CM
Pin Input Capacitance
V
CM
Pin Bias Current
V
CM
= 1.25V
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3.3V ELECTRICAL CHARACTERISTICS
CONDITIONS
V
INDIFF
= ±1.2V
MIN
–0.3
–0.4
3.5
3.2
TYP
–0.15
–0.00033
4
0.2
MAX
0
0
UNITS
dB
dB
dB/°C
V
P-P
V
P-P
Input/Output Characteristics
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V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT
+
,
OUT
–
. V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT
+
,
OUT
–
. V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT
+
,
OUT
–
IN
+
= IN
–
= 1.25V, V
OS
= V
OUTDIFF
/
G
DIFF
V
OUTCM
– V
INCM
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0.3
0.35
V
V
V
V
mA
2.05
1.95
±20
–5
–10
–65
–75
2.2
–0.1
1
–40
5
10
–15
–5
0.1
mV
mV
μV/°C
mV
mV
V
V
Defined by Output Voltage Swing Test
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Defined by Output Voltage Swing Test
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IN
+
= IN
–
= 1.25V
V
INDIFF
= ±1.2V
IN
+
= IN
–
= 0.65V to 1.85V
IN
+
= IN
–
= 0.65V to 1.85V = ΔV
INCM
,
CMRR = (V
OUTDIFF
/G
DIFF
/ΔV
INCM
)
f = 100kHz
f = 100kHz
V
CM
= 0.65V to 1.85V
V
INCM
. IN
+
, IN
–
, V
CM
Pin Floating
V
CM
– V
INCM
, V
CM
= 1.25V
Inputs Floating, V
CM
Pin Floating
V
CM
– V
OUTCM
, V
CM
= 1.25V
V
CM
= 0.1V
V
CM
= 2.4V
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2.4
–15
9
–4
12
1
6
63.5
59.6
83
1.8
6.5
0.9
1.2
–70
1.15
–60
0.96
1.28
–26
1.24
14
0.34
2.05
2
1.2
2.5
–10
2.16
1.25
3.8
1
0.2
10
1.3
5.1
1.05
1.35
70
1.35
60
0.5
0.55
15
15
μA
kΩ
pF
kΩ
dB
dB
nV/√Hz
pA/√Hz
V/V
V
mV
V
mV
V
V
V
V
V
kΩ
pF
μA
6416f
Output Common Mode Voltage Control
4
LTC6416
3.3V ELECTRICAL CHARACTERISTICS
SYMBOL
V
CLHIDEFAULT
V
OS
(CLHI – V
OUTCM
)
V
CLLODEFAULT
R
CLHI
IB
CLHI
R
CLLO
I
BCLLO
Power Supply
V
S
I
S
PSRR
Supply Voltage Range
Supply Current
Power Supply Rejection Ratio
V
S
= 2.7V to 3.6V
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l
The
l
denotes the specifications which apply over the full
.
operating temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 3.3V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V,
+
, CLLO = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
+ OUT
–
)/2. V
CLHI = V
INCM
is defined as (IN
OUTCM
is defined as (OUT
INDIFF
is
+
– IN
–
). V
+
– OUT
–
). See DC test circuit schematic.
defined as (IN
OUTDIFF
is defined as (OUT
PARAMETER
Default Output Clamp Voltage, High
Offset Voltage, CLHI to V
OUTCM
Default Output Clamp Voltage, Low
CLHI Pin Input Resistance
CLHI Pin Bias Current
CLLO Pin Input Resistance
CLLO Pin Bias Current
V
CLHI
= 2.25V
V
CLHI
= 2.25V
V
CLLO
= 0.25V
V
CLLO
= 0.25V
CONDITIONS
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MIN
2.1
–55
0.1
–120
3
–25
1.5
–25
2.7
33
57.5
TYP
2.23
4
0.25
–72
4.1
–1
2.3
3
MAX
2.4
55
0.4
0
5
25
3.2
25
3.9
UNITS
V
mV
V
mV
kΩ
μA
kΩ
μA
V
mA
mA
dB
DC Clamping Characteristics
V
OS
(CLLO – V
OUTCM
) Offset Voltage, CLLO to V
OUTCM
42
80
51
54
temperature range, otherwise specifications are at T
A
= 25°C. V = 3.3V and 3.6V unless otherwise noted, GND = 0V, No R
LOAD
,
C
LOAD
= 6pF V
CM
= 1.25V, CLHI = V
CC
, CLLO = 0V unless otherwise noted. V
INCM
is defined as (IN
+
+ IN
–
)/2. V
OUTCM
is defined as
.
(OUT
+
+ OUT
–
)/2. V
INDIFF
is defined as (IN
+
– IN
–
). V
OUTDIFF
is defined as (OUT
+
– OUT
–
). See DC test circuit schematic.
SYMBOL
–3dBBW
0.1dBBW
0.5dBBW
1/f
SR
t
S1%
–3dBBW
VCM
SR
CM
t
OVDR
AC Linearity
70MHz Signal
HD2
Second Harmonic Distortion
V
+
= 3.3V, V
CM
= 1.05V, V
OUTDIFF
= 2V
P-P
V
+
= 3.3V, V
CM
= 1.25V, V
OUTDIFF
= 2V
P-P
V
+
= 3.6V, V
CM
= 1.05V, V
OUTDIFF
= 2V
P-P
V
+
= 3.6V, V
CM
= 1.25V, V
OUTDIFF
= 2V
P-P
–83.5
–71
–78.5
–88.5
PARAMETER
–3dB Bandwidth
±0.1dB Bandwidth
±0.5dB Bandwidth
1/f Noise Corner
Slew Rate
1% Settling Time
V
CM
Pin Small Signal –3dB BW
Common Mode Slew Rate
Overdrive Recovery Time
Differential
2V
P-P,OUT
V
CM
= 0.1V
P-P
, Measured Single-Ended
at Output
Measured Single-Ended at Output
1.9V
P-P,OUT
CONDITIONS
200mV
P-P,OUT
Differential
200mV
P-P,OUT
Differential
200mV
P-P,OUT
Differential
MIN
TYP
2
0.3
1.4
25
3.4
1.8
9
40
5
MAX
Differential AC Characteristics
AC ELECTRICAL CHARACTERISTICS
+
The
l
denotes the specifications which apply over the full operating
UNITS
GHz
GHz
GHz
kHz
V/ns
ns
MHz
V/μs
ns
Common Mode AC Characteristics (V
CM
Pin)
AC Clamping Characteristics
dBc
dBc
dBc
dBc
6416f
5
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