FeaTures
n
n
LTC6417
1.6GHz Low Noise High Linearity
Differential Buffer/16-Bit ADC
Driver with Fast Clamp
DescripTion
The LTC
®
6417 is a differential unity gain buffer that can
drive a 50Ω load with extremely low noise and excellent
linearity. It is well suited for driving high speed 14- and
16-bit pipeline ADCs with input signals from DC to beyond
600MHz. Differential input impedance is 18.5kΩ, allowing
1:4 and 1:8 transformers to be used at the input providing
additional system gain in 50Ω systems.
With no external biasing or gain setting components and
a flow-through pinout, the LTC6417 is very easy to use. It
can be DC-coupled and has a common mode output offset
of –60mV. The LTC6417 input pins are internally biased to
provide an output common mode voltage that is set by
the voltage on the V
CM
pin for AC-coupled applications.
Supply current is typically 123mA and the LTC6417 operates
on supply voltages ranging from 4.75V to 5.25V. Power
consumption can be reduced to 74mA via the PWRADJ
pin. The LTC6417 also has a hardware shutdown feature
which reduces current consumption to 24mA.
The LTC6417 features fast, adjustable output voltage clamp-
ing to help protect subsequent circuitry. The CLHI pin sets
the maximum swing, while a symmetric minimum swing
is set up internally. LTC6417 V
OR
pin will signal overrange
when the clamps limit output voltage.
The LTC6417 is packaged in a 20-lead 3mm
×
4mm QFN
package. Pinout is optimized for placement directly adjacent
to Linear Technology’s high speed 14- and 16-bit ADCs.
LTC6417 Driving LTC2209
16-Bit ADC 32K Point FFT,
f
IN
= 140MHz, –1dBFS, PGA = 0
0
2.2µF
C43
27pF
E1
51nH
R36
60.4
19
C41
12pF
R12
60.4
C44
27pF
E2
51nH
C40
12pF
C10
12pF
E3
75nH
C45
18pF
AMPLITUDE (dBFS)
–10
–20
–30
R42
300
R53
120Ω
R43
300
E3
75nH
C46
18pF
10
10
A
IN+
A
IN–
LTC2209
–40
–50
–60
–70
–80
–90
–100
–110
CLOCK
(153.6MHz)
6417 TA01a
n
n
n
n
n
n
n
n
1.6GHz –3dB Small Signal Bandwidth
Low Distortion Driving 50Ω Load, 2.4V
P-P
Out
–100dBc/–69dBc HD2/HD3 at 140MHz
–80dBc IM3 and 46dBm OIP3 at 140MHz
–100dBc/–66dBc HD2/HD3 at 380MHz
–68dBc IM3 and 39dBm OIP3 at 380MHz
1.5nV/√Hz Output Noise
4.3pA/√Hz Input Current Noise
Programmable High Speed, Fast Recovery
Output Clamping
4.28V
P-P
Maximum Output Swing on a 50Ω
Differential Load
DC-Coupled Signal Path
Operates on Single 4.75V to 5.25V Supply
Power: 615mW on 5V, Can Be Reduced to 370mW,
Shutdown Mode 120mW
3mm
×
4mm 20-Lead QFN Package
applicaTions
n
n
n
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Differential ADC Driver
CCD Buffer
Cable Driver
50Ω Buffer
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion
5V
680pF
0.1µF
1,6,
11,16
5
V
+
PWRADJ
IN
+
IN
–
2
CLHI
OUT
+
LTC6417 Driving an LTC2209 16-Bit ADC at 140MHz IF
3.3V
T1
WBC4-14LB
4
3
50
2
6
100
100
0.01µF
8
HD2 = –88dBc
HD3 = –94dBc
SFDR = 88dBc
SNR = 75.4dB
SEE FIGURE 1/TABLE 1
1:4 BALUN
f
S
= 153.6Msps
DEMO BOARD DC1685A
+
–
•
•
9
LTC6417
1
0.01µF
V
CM
14
SHDN
15
GND
12
1k
V
OR
OUT
–
E5
51nH
16
18
V
CM
PGA = 0
3,7,10,
17, 20,21
2.2µF
–120
0
10
20
30 40 50 60
FREQUENCY (MHz)
70
80
6417 TA01b
6417f
1
LTC6417
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
OUT
+
OUT
–
GND
GND
16 V
+
15 V
CM
21
GND
14 V
OR
13 NC
12 SHDN
11 V
+
7
GND
8
IN
+
9 10
GND
IN
–
Total Supply Voltage (V
+
to GND).............................5.5V
Input Current (CLHI, V
CM
) .................................... ±10mA
Input Current (IN
+
, IN
–
) ........................................±30mA
Output Current (OUT
+
, OUT
–
) ............................. ±100mA
Output Current (V
OR
) ........................................... ±10mA
Operating Temperature Range
(T
C
) (Note 2) .......................................... –40°C to 105°C
Specified Temperature Range
(T
C
) (Note 3) .......................................... –40°C to 105°C
Storage Temperature Range .................. –65°C to 150°C
Junction Temperature (T
JMAX
) .............................. 150°C
20 19 18 17
V
+
1
2
3
4
5
6
CLHI
GND
NC
PWRADJ
V
+
UDC PACKAGE
20-LEAD (3mm
×
4mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 52°C/W,
θ
JC
= 6.8°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH
LTC6417CUDC#PBF
LTC6417IUDC#PBF
TAPE AND REEL
LTC6417CUDC#TRPBF
LTC6417IUDC#TRPBF
PART MARKING*
LFVN
LFVN
PACKAGE DESCRIPTION
20-Lead (3mm
×
4mm) Plastic QFN
20-Lead (3mm
×
4mm) Plastic QFN
TEMPERATURE RANGE
0°C to 70°C
–40°C to 105°C (T
C
)
*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/
Dc elecTrical characTerisTics
+
SYMBOL
G
DIFF
TCG
DIFF
V
SWINGDIFF
V
SWINGMIN
V
SWINGMAX
PARAMETER
Differential Gain
Differential Gain Temperature
Coefficient
Differential Output Voltage Swing
Output Voltage Swing Low
Output Voltage Swing High
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V = 5V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V, CLHI = V
+
,
.
+
, SHDN = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
–
PWRADJ = V
INCM
is defined as (IN
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.
CONDITIONS
V
INDIFF
= ±1.2V Differential
l
l
MIN
–0.15
–0.2
TYP
–0.1
0.0002
MAX
0
0
UNITS
dB
dB
dB/°C
V
P-P
V
P-P
Input/Output Characteristics
V
OUTDIFF
, V
INDIFF
= ±2.3V
l
4
3.3
4.28
0.19
0.28
0.4
Single-Ended Measurement of OUT
+
, OUT
–
l
V
INDIFF
= ±2.3V
Single-Ended Measurement of OUT
+
, OUT
–
l
V
INDIFF
= ±2.3V
2.25
2.05
V
V
V
V
2.33
6417f
2
LTC6417
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V = 5V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V, CLHI = V
+
,
.
+
, SHDN = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
–
PWRADJ = V
INCM
is defined as (IN
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
I
OUT
V
OS
TCV
OS
V
IOCM
IVR
MIN
IVR
MAX
I
B
R
INDIFF
C
INDIFF
R
INCM
CMRR
R
OUTDIFF
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
Output Current Drive (Notes 1, 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
Differential Output Resistance
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
f = 100kHz
f = 100kHz
V
CM
= 0.65V to 1.85V
l
Dc elecTrical characTerisTics
+
CONDITIONS
Single-Ended Measurement of OUT
+
, OUT
–
l
IN
+
= IN
–
= 1.25V, V
OS
= V
OUTDIFF
/G
DIFF
l
l
MIN
±100
–3.2
–4
–120
–140
TYP
–0.1
1
–60
MAX
3.2
4
–10
0
0.1
UNITS
mA
mV
mV
µV/°C
mV
mV
V
V
V
OUTCM
– V
INCM
l
Defined by Output Voltage Swing Test
Defined by Output Voltage Swing Test
IN
+
= IN
–
= 1.25V
l
l
2.4
–13
–18
12
11
5.8
5
63
60
2
18.5
1
13
18
25
27.5
13
15
l
µA
µA
kΩ
kΩ
pF
kΩ
kΩ
dB
dB
Ω
nV/√Hz
pA/√Hz
V/V
V/V
V
INDIFF
= ±1.2V
l
IN
+
= IN
–
= 0.65V to 1.85V
l
9.25
91
3
1.5
4.3
IN
+
= IN
–
= 0.65V to 1.85V,
CMRR = (V
OUTDIFF
/G
DIFF
/1.2V)
l
Output Common Mode Voltage Control
0.82
0.8
1.15
1.1
–85
–90
1.1
1
–50
–45
0.92
1.25
15
1.2
75
0.29
l
V
INCM
. IN
+
, IN
–
, V
CM
Pin Floating
l
1.35
1.4
115
135
1.3
1.35
200
230
0.63
0.65
V
V
mV
mV
V
V
mV
mV
V
V
V
V
V
CM
– V
INCM
, V
CM
= 1.25V
l
Default Output Common Mode Voltage Inputs Floating, V
CM
Pin Floating
l
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
– V
OUTCM
, V
CM
= 1.25V
l
V
CM
= 0.1V
V
CM
= 2.4V
l
l
2
1.85
1.15
1.1
2
1.9
–15
–27.5
2.25
1.25
2.7
1
1.35
1.4
3.4
3.7
15
27.5
V
V
kΩ
kΩ
pF
µA
µA
V
CM
Pin Input Resistance
V
CM
Pin Input Capacitance
V
CM
Pin Bias Current
V
CM
= 0.65V to 1.85V
l
V
CM
= 1.25V
l
1
6417f
3
LTC6417
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V = 5V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V, CLHI = V
+
,
.
+
, SHDN = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
–
PWRADJ = V
INCM
is defined as (IN
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
V
CLHIDEFAULT
PARAMETER
Default Output Clamp Voltage, High
l
Dc elecTrical characTerisTics
+
CONDITIONS
MIN
2.4
2.35
–60
–85
–100
–110
–1.2
–1.25
1.65
1.5
3.4
3.1
–12
–12.5
4.75
100
95
65
63
17
15
TYP
2.48
20
10
–1
1.9
4.8
3
MAX
2.55
2.6
80
85
100
110
–0.8
–0.75
2.2
2.25
5.7
6
18
18.5
5.25
UNITS
V
V
mV
mV
mV
mV
V/V
V/V
V/V
V/V
kΩ
kΩ
µA
µA
V
mA
mA
dB
dB
DC Clamping Characteristics
V
OS
(CLHI – V
OUTCM
) Offset Voltage, CLHI to V
OUTCM
l
V
OS
(CLLO – V
OUT
)
G
LOHI
G
LOCM
R
CLHI
IB
CLHI
Power Supply
V
S
I
S
PSRR
SHDN Pin
IS
SHDN
V
SHDNDEFAULT
V
IL,SHDN
V
IH,SHDN
I
IL,SHDN
I
IH,SHDN
C
SHDN
R
SHDN
PWRADJ Pin
V
PWRADJDEFAULT
IS
L
I
IL,PWRADJ
I
IH,PWRADJ
C
PWRADJ
Offset Voltage, CLLO to V
OUT
Low Side Clamp Gain with Respect to
CLHI Pin
Low Side Clamp Gain with Respect to
CM Pin
CLHI Pin Input Resistance
CLHI Pin Bias Current
V
CLHI
= 2.0V, V
CM
= 1.25V, IN
+
= 2.4V,
IN
–
= 0.1V
V
CLHI
= 2.0V, V
CM
= 1.25V, IN
+
= 2.4V,
IN
–
= 0.1V
V
CLHI
= 2.0V, V
CM
= 1.25V, IN
+
= 2.4V,
IN
–
= 0.1V
V
CLHI
= 1.5V to 2.5V
l
l
l
l
V
CLHI
= 2.5V
l
Supply Voltage Range
Supply Current
l
l
123
72
140
145
Power Supply Rejection Ratio
V
S
= 4.75V to 5.25V
l
Shutdown Current
Default Shutdown Voltage
SHDN Input Low Voltage
SHDN Input High Voltage
SHDN Input Low Current
SHDN Input High Current
SHDN Pin Input Capacitance
SHDN Pin Input Resistance
V
SHDN
= 5V
l
l
l
l
24
29
35
0.1
2
mA
mA
V
V
V
µA
µA
µA
µA
pF
kΩ
kΩ
V
V
mA
mA
µA
µA
µA
µA
pF
3.5
–1.6
–2
275
250
6
5
1.5
1.45
0
380
1
1.6
2
450
475
14
15
1.8
1.85
105
110
–80
–75
290
300
SHDN = 0V
l
SHDN = 5V
l
SHDN = 2.5V to 5V
l
10.5
Default PWRADJ Voltage
Supply Low Current
PWRADJ Input Low Current
PWRADJ Input High Current
PWRADJ Pin Input Capacitance
PWRADJ Floating
PWRADJ = 0V
l
1.65
74
–120
240
1
45
40
–145
–165
210
200
PWRADJ = 0V
l
PWRADJ = 5V
l
6417f
4
LTC6417
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V = 5V, GND = 0V, No R
LOAD
, C
LOAD
= 6pF V
CM
= 1.25V, CLHI = V
+
,
.
+
, SHDN = 0V unless otherwise noted. V
+
+ IN
–
)/2. V
+
–
PWRADJ = V
INCM
is defined as (IN
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
R
PWRADJ
V
OR
Pin
V
OR(HI)
I
OR(DEFAULT)
I
OR(MAX)
Maximum Voltage on V
OR
Pin
Default Pull-Down Current on V
OR
Pin
Maximum Pull-Down Current Both
Clamps are Active
V
CL
= 5.0V, V
CM
= 1.25V
l
Dc elecTrical characTerisTics
+
PARAMETER
PWRADJ Pin Input Resistance
CONDITIONS
PWRADJ = 2.5V to 5.0V
l
MIN
10.5
10
3.25
3.2
–900
–1150
TYP
14.5
MAX
19
20
3.55
3.6
–650
–500
1.5
2
UNITS
kΩ
kΩ
V
V
µA
µA
µA
µA
3.35
–770
1
V
CL
= 50V, V
CM
= 1.25V
l
V
CL
= 2.0V, V
CM
= 1.25V, IN
+
= 2.4V,
IN
–
= 0.1V
l
temperature range, otherwise specifications are at T
A
= 25°C. V = 5V unless otherwise noted, GND = 0V, R
LOAD
= 500Ω,C
LOAD
= 6pF
.
V
CM
= 1.25V, CLHI = V
+
, PWRADJ = V
CC
, SHDN = 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%
t
OFF
t
ON
t
PWRADJ,OFF
t
PWRADJ,ON
t
CL,OFF
10%
t
CL,ON
10%
PARAMETER
–3dB Bandwidth
±0.1dB Bandwidth
±0.5dB Bandwidth
1/f Noise Corner
Slew Rate
1% Settling Time
Shutdown Time
Enable Time
PWRADJ Off Time
PWRADJ On Time
Clamp Release Time
Clamp Engage Time
Differential
2V
P-P,OUT
SHDN = 0V to 5V
SHDN = 5V to 0V
PWRADJ = 5V to 0V
PWRADJ = 0V to 5V
CLHI = 1.5V, V
CM
= 1.25V, IN
+
= 1.625V to 1.25V,
IN
–
= 1.25V to 0.875V
CLHI = 1.5V, V
CM
= 1.25V, IN
+
= 1.25V to 1.625V,
IN
–
= 1.25V to 0.875V
V
CM
= 0.1V
P-P
, Measured Single-Ended at Output
Measured Single-Ended at Output
V
OR
= 0.1V
P-P
, CLHI = 2V, IN
+
= 2.4V, IN
–
= 0.1V,
R
VOR
= 1k, 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
1.6
0.18
0.45
25
10
0.8
40
15
10
5
1
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
ns
ns
ns
ns
ns
ns
Common Mode AC Characteristics (V
CM
Pin)
–3dBBW
SR
CM
–3dBBW
SR
VOR
t
OVDR
V
CM
Pin Small Signal –3dB BW
Common Mode Slew Rate
V
OR
Pin Small Signal –3dB BW
Overrange Slew Rate
Overdrive Recovery Time
10
2
200
40
2
MHz
V/µs
MHz
V/µs
ns
Overrange AC Characteristics (V
OR
Pin)
AC Clamping Characteristics
6417f
5
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