LTC6406
3GHz, Low Noise,
Rail-to-Rail Input Differential
Amplifier/Driver
FEATURES
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DESCRIPTION
Low Noise: 1.6nV/√Hz RTI
Low Power: 18mA at 3V
Low Distortion (HD2/HD3):
–80dBc/–69dBc at 50MHz, 2VP-P
–104dBc/–90dBc at 20MHz, 2VP-P
Rail-to-Rail Differential Input
2.7V to 3.5V Supply Voltage Range
Fully Differential Input and Output
Adjustable Output Common Mode Voltage
800MHz –3dB Bandwidth with A V = 1
Gain-Bandwidth Product: 3GHz
Low Power Shutdown
Available in 8-Lead MSOP and Tiny 16-Lead
3mm × 3mm × 0.75mm QFN Packages
The LTC®6406 is a very low noise, low distortion, fully
differential input/output amplifier optimized for 3V, single
supply operation. The LTC6406 input common mode range
is rail-to-rail, while the output common mode voltage is
independently adjustable by applying a voltage on the
VOCM pin. This makes the LTC6406 ideal for level-shifting
signals with a wide common mode range for driving 12-bit
to 16-bit single supply, differential input ADCs.
A 3GHz gain-bandwidth product results in 70dB linearity for
50MHz input signals. The LTC6406 is unity-gain stable and
the closed-loop bandwidth extends from DC to 800MHz.
The output voltage swing extends from near ground to
2V, to be compatible with a wide range of ADC converter
input requirements. The LTC6406 draws only 18mA, and
has a hardware shutdown feature which reduces current
consumption to 300μA.
APPLICATIONS
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The LTC6406 is available in a compact 3mm × 3mm 16-pin
leadless QFN package as well as an 8-lead MSOP package,
and operates over a –40°C to 85°C temperature range.
Differential Input ADC Driver
Single-Ended to Differential Conversion
Level-Shifting Ground-Referenced Signals
Level-Shifting VCC-Referenced Signals
High Linearity Direct Conversion Receivers
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
ADC Driver: Single-Ended Input to Differential Output with
Common Mode Level Shifting
Harmonic Distortion vs Frequency
–30
1.8pF
150Ω
150Ω
3V
3V
– +
VOCM
1.25V
LTC6406
+ –
+INA
VDD
LTC22xx ADC
–INA
DISTORTION (dBc)
VIN
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 800Ω
= 2VP-P
V
–50 OUTDIFF
DIFFERENTIAL INPUTS
–60
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–70
–80
–90
GND
–100
150Ω
–110
150Ω
6406 TA01
1
10
FREQUENCY (MHz)
100
6406 TA01b
1.8pF
6406fc
1
LTC6406
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Total Supply Voltage (V+ to V–) ................................3.5V
Input Current
+IN, –IN, VOCM, SHDN, VTIP (Note 2) ...............±10mA
Output Short-Circuit Duration (Note 3) ............ Indefinite
Operating Temperature Range (Note 4) .... –40°C to 85°C
Specified Temperature Range (Note 5) .... –40°C to 85°C
Junction Temperature ........................................... 150°C
Storage Temperature Range................... –65°C to 150°C
PIN CONFIGURATION
–OUTF
–OUT
+IN
NC
TOP VIEW
16 15 14 13
3
VOCM
4
–IN
VOCM
V+
+OUT
11 V+
17
5
6
7
8
+OUTF
2
V–
+OUT
V+
TOP VIEW
12 V–
–IN
1
VTIP
SHDN
10
V+
9
V–
1
2
3
4
9
8
7
6
5
+IN
SHDN
V–
–OUT
MS8E PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 40°C/W, θJC = 10°C/W
EXPOSED PAD (PIN 9) IS V–, MUST BE SOLDERED TO PCB
UD PACKAGE
16-LEAD (3mm × 3mm) PLASTIC QFN
TJMAX = 150°C, θJA = 68°C/W, θJC = 4.2°C/W
EXPOSED PAD (PIN 17) IS V–, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
SPECIFIED
TEMPERATURE RANGE
LTC6406CUD#PBF
LTC6406CUD#TRPBF
LCTC
16-Lead (3mm × 3mm) Plastic QFN
0°C to 70°C
LTC6406IUD#PBF
LTC6406IUD#TRPBF
LCTC
16-Lead (3mm × 3mm) Plastic QFN
–40°C to 85°C
LTC6406CMS8E#PBF
LTC6406CMS8E#TRPBF
LTCTB
8-Lead Plastic MSOP
0°C to 70°C
LTC6406IMS8E#PBF
LTC6406IMS8E#TRPBF
LTCTB
8-Lead Plastic MSOP
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard 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/
6406fc
2
LTC6406
DC ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = 0V, VCM = VOCM = VICM = 1.25V, VSHDN = open,
RBAL = 100kΩ, RI = 150Ω, RF = 150Ω (0.1% resistors), CF = 1.8pF (see Figure 1) unless otherwise noted. VS is defined as (V+ – V–).
VOUTCM is defined as (V+OUT + V–OUT)/2. VICM is defined as (V+IN + V–IN)/2. VOUTDIFF is defined as (V+OUT – V–OUT).
SYMBOL
PARAMETER
CONDITIONS
VOSDIFF
Differential Offset Voltage (Input Referred)
ΔVOSDIFF /ΔT
Differential Offset Voltage Drift (Input Referred)
IB
Input Bias Current (Note 6)
IOS
Input Offset Current (Note 6)
RIN
Input Resistance
VICM = 3V (Note 12)
VICM = 1.25V
VICM = 0V (Note 12)
VICM = 3V (Note 12)
VICM = 1.25V
VICM = 0V (Note 12)
VICM = 3V
VICM = 1.25V
VICM = 0V
VICM = 3V
VICM = 1.25V
VICM = 0V
Common Mode
Differential Mode
CIN
Input Capacitance
en
Differential Input Referred Noise Voltage Density
in
enVOCM
MIN
l
l
l
l
l
l
l
–24
l
Differential
TYP
MAX
UNITS
±1
±0.25
±1
12
1
7
6
–9
–17
±1
±1
±1
130
3
±5
±3.5
±5
mV
mV
mV
μV/°C
μV/°C
μV/°C
μA
μA
μA
μA
μA
μA
–1
±3
kΩ
kΩ
pF
1
f = 1MHz, Not Including
RI /RF Noise
Input Noise Current Density
f = 1MHz, Not Including
RI /RF Noise
Input Referred Common Mode Output Noise Voltage Density f = 1MHz
1.6
nV/√Hz
2.5
pA/√Hz
9
nV/√Hz
VICMR (Note 7)
Input Signal Common Mode Range
Op Amp Inputs
l
V–
V+
CMRRI
(Note 8)
CMRRIO
(Note 8)
PSRR
(Note 9)
PSRRCM
(Note 9)
GCM
Input Common Mode Rejection Ratio
(Input Referred) ΔVICM /ΔVOSDIFF
Output Common Mode Rejection Ratio (Input Referred)
ΔVOCM /ΔVOSDIFF
Differential Power Supply Rejection
(ΔVS /ΔVOSDIFF)
Output Common Mode Power Supply Rejection
(ΔVS /ΔVOSCM)
VICM from 0V to 3V
l
50
65
dB
VOCM from 0.5V to 2V
l
50
70
dB
VS = 2.7V to 3.5V
l
55
75
dB
VS = 2.7V to 3.5V
l
55
65
dB
Common Mode Gain (ΔVOUTCM /ΔVOCM)
VOCM from 0.5V to 2V
l
1
V/V
ΔGCM
Common Mode Gain Error 100 • (GCM – 1)
VOCM from 0.5V to 2V
l
±0.4
±0.8
%
BAL
Output Balance (ΔVOUTCM /ΔVOUTDIFF)
ΔVOUTDIFF = 2V
Single-Ended Input
Differential Input
l
l
–57
–65
–45
–45
dB
dB
±15
mV
VOSCM
Common Mode Offset Voltage (VOUTCM – VOCM)
l
±6
ΔVOSCM /ΔT
Common Mode Offset Voltage Drift
l
15
VOUTCMR
(Note 7)
RINVOCM
Output Signal Common Mode Range
(Voltage Range for the VOCM Pin)
Input Resistance, VOCM Pin
l
l
12
VOCM
Self-Biased Voltage at the VOCM Pin
VOCM = Open
l
1.15
VOUT
Output Voltage, High, +OUT/–OUT Pins
VS = 3.3V, IL = 0
VS = 3.3V, IL = –20mA
VS = 3V, IL = 0
VS = 3V, IL = –5mA
VS = 3V, IL = –20mA
VS = 3V, IL = 0
VS = 3V, IL = 5mA
VS = 3V, IL = 20mA
l
l
2.2
2
2
1.95
1.7
2.35
2.15
2.05
2
1.85
0.23
0.34
0.75
Output Voltage, Low, +OUT/–OUT Pins
l
l
l
l
l
l
0.5
V
μV/°C
2
V
18
24
kΩ
1.25
1.35
V
0.33
0.4
0.85
V
V
V
V
V
V
V
V
6406fc
3
LTC6406
DC ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = 0V, VCM = VOCM = VICM = 1.25V, VSHDN = open,
RBAL = 100kΩ, RI = 150Ω, RF = 150Ω (0.1% resistors), CF = 1.8pF (see Figure 1) unless otherwise noted. VS is defined as (V+ – V–).
VOUTCM is defined as (V+OUT + V–OUT)/2. VICM is defined as (V+IN + V–IN)/2. VOUTDIFF is defined as (V+OUT – V–OUT).
SYMBOL
PARAMETER
CONDITIONS
ISC
Output Short-Circuit Current, +OUT/–OUT Pins (Note 10)
AVOL
Large-Signal Open Loop Voltage Gain
VS
Supply Voltage Range
l
IS
Supply Current
l
ISHDN
Supply Current in Shutdown
VSHDN = 0V
l
RSHDN
SHDN Pull-Up Resistor
VSHDN = 0V to 0.5V
l
60
VIL
SHDN Input Logic Low
l
0.4
0.7
VIH
SHDN Input Logic High
l
tON
Turn-On Time
200
ns
tOFF
Turn-Off Time
50
ns
l
MIN
TYP
±35
±55
mA
90
dB
2.7
MAX
UNITS
3.5
V
18
22
mA
300
500
μA
100
140
kΩ
2.25
V
2.55
V
AC ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = 0V, VCM = VOCM = VICM = 1.25V, VSHDN = open, RI
= 150Ω, RF = 150Ω (0.1% resistors), CF = 1.8pF, RLOAD = 400Ω (see Figure 2) unless otherwise noted. VS is defined as (V+ – V–). VICM
is defined as (V+IN + V–IN)/2. VOUTDIFF is defined as (V+OUT – V–OUT).
SYMBOL
PARAMETER
CONDITIONS
SR
Slew Rate
Differential Output
GBW
Gain-Bandwidth Product
fTEST = 30MHz
f–3dB
–3dB Frequency (See Figure 2)
50MHz Distortion
Differential Input, VOUTDIFF = 2VP-P
(Note 13)
MIN
l
VOCM = 1.25V, VS = 3V
2nd Harmonic
3rd Harmonic
l
500
TYP
MAX
UNITS
630
V/μS
3
GHz
800
MHz
–77
–65
–55
dBc
dBc
VOCM = 1.25V, VS = 3V, RLOAD = 800Ω
2nd Harmonic
3rd Harmonic
–85
–72
dBc
dBc
VOCM = 1.25V, VS = 3V, RLOAD = 800Ω,
RI = RF = 500Ω
2nd Harmonic
3rd Harmonic
–80
–69
dBc
dBc
50MHz Distortion
Single-Ended Input, VOUTDIFF = 2VP-P
(Note 13)
VOCM = 1.25V, VS = 3V, RLOAD = 800Ω,
RI = RF = 500Ω
2nd Harmonic
3rd Harmonic
–69
–73
dBc
dBc
3rd-Order IMD at 49.5MHz, 50.5MHz
VOUTDIFF = 2VP-P Envelope,
RLOAD = 800Ω
–65
dBc
OIP3 at 50MHz (Note 11)
RLOAD = 800Ω
36.5
dBm
tS
Settling Time
VOUTDIFF = 2V Step
1% Settling
0.1% Settling
NF
Noise Figure at 50MHz
Shunt-Terminated to 50Ω, RS = 50Ω
ZIN = 200Ω (RI = 100Ω, RF = 300Ω)
7
11
ns
ns
14.1
7.5
dB
dB
6406fc
4
LTC6406
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Input pins (+IN, –IN, VOCM, SHDN and VTIP) are protected by
steering diodes to either supply. If the inputs should exceed either supply
voltage, the input current should be limited to less than 10mA. In addition,
the inputs +IN, –IN are protected by a pair of back-to-back diodes. If the
differential input voltage exceeds 1.4V, the input current should be limited
to less than 10mA.
Note 3: A heat sink may be required to keep the junction temperature
below the Absolute Maximum Rating when the output is shorted
indefinitely. Long-term application of output currents in excess of the
absolute maximum ratings may impair the life of the device.
Note 4: The LTC6406C/LTC6406I are guaranteed functional over the
operating temperature range –40°C to 85°C.
Note 5: The LTC6406C is guaranteed to meet specified performance from
0°C to 70°C. The LTC6406C is designed, characterized, and expected
to meet specified performance from –40°C to 85°C but is not tested or
QA sampled at these temperatures. The LTC6406I is guaranteed to meet
specified performance from –40°C to 85°C.
Note 6: Input bias current is defined as the average of the input currents
flowing into the inputs (–IN, and +IN). Input offset current is defined as the
difference between the input currents (IOS = IB+ – IB–).
Note 7: Input common mode range is tested using the test circuit of
Figure 1 by taking three measurements of differential gain with a ±1V DC
differential output with VICM = 0V; VICM = 1.25V; VICM = 3V, verifying that
the differential gain has not deviated from the VICM = 1.25V case by more
than 0.5%, and that the common mode offset (VOSCM) has not deviated
from the common mode offset at VICM = 1.25V by more than ±20mV.
The voltage range for the output common mode range is tested using the
test circuit of Figure 1 by applying a voltage on the VOCM pin and testing at
both VOCM = 1.25V and at the Electrical Characteristics table limits to verify
that the common mode offset (VOSCM) has not deviated by more than
±10mV from the VOCM = 1.25V case.
Note 8: Input CMRR is defined as the ratio of the change in the input
common mode voltage at the pins +IN or –IN to the change in differential
input referred voltage offset. Output CMRR is defined as the ratio of
the change in the voltage at the VOCM pin to the change in differential
input referred voltage offset. This specification is strongly dependent on
feedback ratio matching between the two outputs and their respective
inputs, and it is difficult to measure actual amplifier performance (see the
Effects of Resistor Pair Mismatch in the Applications Information section
of this data sheet). For a better indicator of actual amplifier performance
independent of feedback component matching, refer to the PSRR
specification.
Note 9: Differential power supply rejection (PSRR) is defined as the ratio
of the change in supply voltage to the change in differential input referred
voltage offset. Common mode power supply rejection (PSRRCM) is
defined as the ratio of the change in supply voltage to the change in the
common mode offset, VOUTCM – VOCM.
Note 10: Extended operation with the output shorted may cause the
junction temperature to exceed the 150°C limit.
Note 11: Because the LTC6406 is a feedback amplifier with low output
impedance, a resistive load is not required when driving an ADC.
Therefore, typical output power can be very small in many applications. In
order to compare the LTC6406 with RF style amplifiers that require 50Ω
load, the output voltage swing is converted to dBm as if the outputs were
driving a 50Ω load. For example, 2VP-P output swing is equal to 10dBm
using this convention.
Note 12: Includes offset/drift induced by feedback resistors mismatch. See
the Applications Information section for more details.
Note 13: QFN package only. Refer to data sheet curves for MSOP package
numbers.
TYPICAL PERFORMANCE CHARACTERISTICS
Differential Input Referred
Offset Voltage vs Input Common
Mode Voltage
2.0
1.0
1.5
0.8
VS = 3V
VOCM = 1.25V
VICM = 1.25V
RI = RF = 150Ω
FIVE TYPICAL UNITS
0.6
0.4
0.2
0
–0.2
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
6406 G01
1.0
Common Mode Offset Voltage
vs Temperature
TA = –40°C
TA = 0°C
TA = 25°C
TA = 70°C
TA = 85°C
0.5
0
–0.5
V = 3V
–1.0 VS = 1.25V
OCM
RI = RF = 150Ω
–1.5 0.1%
FEEDBACK NETWORK RESISTORS
TYPICAL UNIT
–2.0
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
3.0
6406 G02
7
COMMON MODE OFFSET VOLTAGE (mV)
1.2
DIFFERENTIAL VOS (mV)
DIFFERENTIAL VOS (mV)
Differential Input Referred Offset
Voltage vs Temperature
6
5
4
3
2
VS = 3V
1 VOCM = 1.25V
VICM = 1.25V
FIVE TYPICAL UNITS
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
6406 G03
6406fc
5
LTC6406
TYPICAL PERFORMANCE CHARACTERISTICS
20
10
5
15
10
5
VSHDN = OPEN
0
0
0.5
1.0 1.5 2.0 2.5
SUPPLY VOLTAGE (V)
3.0
0
3.5
0.5
1.0
1.5
2.0
SHDN VOLTAGE (V)
2.5
en
1k
10k
100k
FREQUENCY (Hz)
INPUT VOLTAGE NOISE DENSITY (nV/√Hz)
in
1
100
150
100
50
VSHDN = V–
0.5
1.0 1.5 2.0 2.5
SUPPLY VOLTAGE (V)
3.0
Differential Slew Rate
vs Temperature
3
in
2
2
en
1
1
VS = 3V
NOISE MEASURED AT f = 1MHz
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
0
3.0
650
VS = 3V
630
610
590
570
550
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
6406 G09
6406 G08
CMRR vs Frequency
VS = 3V
RI = RF = 150Ω
3.5
6406 G06
3
Differential Output Impedance
vs Frequency
Differential PSRR vs Frequency
80
80
70
70
60
60
10
1
PSRR (dB)
100
CMRR (dB)
OUTPUT IMPEDANCE (Ω)
200
0
4
6406 G07
1000
250
3.0
4
0
1
10M
1M
300
0
INPUT CURRENT NOISE DENSITY (pA/√Hz)
10
INPUT CURRENT NOISE DENSITY (pA/√Hz)
INPUT VOLTAGE NOISE DENSITY (nV/√Hz)
100
10
350
Input Noise Density vs Input
Common Mode Voltage
Input Noise Density vs Frequency
VS = 3V
VICM = 1.25V
400
6406 G05
6406 G04
100
TA = –40°C
TA = 0°C
TA = 25°C
TA = 70°C
TA = 85°C
450
VS = 3V
0
SLEW RATE (V/μs)
15
500
TA = –40°C
TA = 0°C
TA = 25°C
TA = 70°C
TA = 85°C
SHUTDOWN SUPPLY CURRENT (μA)
TA = –40°C
TA = 0°C
TA = 25°C
TA = 70°C
TA = 85°C
TOTAL SUPPLY CURRENT (mA)
TOTAL SUPPLY CURRENT (mA)
20
Shutdown Supply Current
vs Supply Voltage
Supply Current vs SHDN Voltage
Supply Current vs Supply Voltage
5O
40
30
0.1
0.01
1
10
100
FREQUENCY (MHz)
1000 2000
6406 G10
5O
40
30
VS = 3V
20 VOCM = 1.25V
RI = RF = 150Ω, CF = 1.8pF
0.1% FEEDBACK NETWORK RESISTORS
10
1
10
100
1000 2000
FREQUENCY (MHz)
6406 G11
20
VS = 3V
10
1
10
100
FREQUENCY (MHz)
1000 2000
6406 G12
6406fc
6
LTC6406
TYPICAL PERFORMANCE CHARACTERISTICS
Small-Signal Step Response
(QFN Package)
Large-Signal Step Response
Output Overdrive Response
2.5
–OUT
+OUT
VOLTAGE (V)
2.0
0.2V/DIV
20mV/DIV
+OUT
6406 G13
10ns/DIV
VS = 3V
VOCM = VICM = 1.25V
RLOAD = 400Ω
RI = RF = 150Ω, CF = 1.8pF
CL = 0pF
VIN = 200mVP-P, DIFFERENTIAL
10ns/DIV
VS = 3V
RLOAD = 400Ω
VIN = 2VP-P, DIFFERENTIAL
30
40
20
30
10
0
10
GAIN (dB)
GAIN (dB)
20
0
AV = 1
AV = 2
AV = 5
AV = 10
AV = 20
AV = 100
–30
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 400Ω
–50
1
10
100
FREQUENCY (MHz)
1000 2000
Frequency Response vs Input
Common Mode Voltage
10
CL = 0pF
CL = 2pF
CL = 3pF
CL= 4.7pF
CL = 10pF
5
0
–5
–10
–20
VS = 3V
–30 VOCM = VICM = 1.25V
RLOAD = 400Ω
–40 RI = RF = 150Ω, CF = 1.8pF
CAPACITOR VALUES ARE FROM EACH
–50 OUTPUT TO GROUND.
NO SERIES RESISTORS ARE USED.
–60
1
10
100
1000 2000
FREQUENCY (MHz)
6406 G17
AV (V/V) RI (Ω)
1
2
5
10
20
100
150
150
150
150
150
150
RF (Ω)
CF (pF)
150
300
750
1.5k
3k
15k
1.8
1.8
0.7
0.3
0.2
0
6406 G15
100ns/DIV
VS = 3V
VOCM = 1.25V
RLOAD = 200Ω TO GROUND PER OUTPUT
Frequency Response
vs Load Capacitance
50
+OUT
0
6406 G14
GAIN (dB)
Frequency Response
vs Closed-Loop Gain
–20
1.0
0.5
–OUT
–10
–OUT
1.5
–10
–15
VICM = 0V
VICM = 0.5V
VICM = 1.25V
VICM = 2V
VICM = 3V
–20
–25 VS = 3V
VOCM = 1.25V
–30 RLOAD = 400Ω
RI = RF = 150Ω, CF = 1.8pF
–35
1
10
100
FREQUENCY (MHz)
1000 2000
6406 G18
6406 G16
6406fc
7
LTC6406
TYPICAL PERFORMANCE CHARACTERISTICS
Harmonic Distortion
vs Input Common Mode Voltage
–40
–60
–50
DISTORTION (dBc)
DISTORTION (dBc)
–30
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–70
–80
–90
–110
1
10
FREQUENCY (MHz)
–40
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–60
–70
–80
VS = 3V
–90 VOCM = 1.25V
VOUTDIFF = 2VP-P
fIN = 50MHz
RLOAD = 800Ω DIFFERENTIAL INPUTS
–100
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
–100
100
Harmonic Distortion
vs Input Amplitude
DISTORTION (dBc)
Harmonic Distortion vs Frequency
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 800Ω
= 2VP-P
V
–50 OUTDIFF
DIFFERENTIAL INPUTS
(QFN Package)
6406 G19
–90
–110
100
–60
VS = 3V
3RD
–80 VOCM = 1.25V
fIN = 50MHz
RLOAD = 800Ω
–90 RI = RF = 500Ω
VOUTDIFF = 2VP-P
SINGLE-ENDED INPUT
–100
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
2ND
–80
3RD
–90
–100
–4
–2
(0.4VP-P)
3.0
–90
–100
–110
100
6406 G25
10
(2VP-P)
–40
THIRD ORDER IMD (dBc)
–80
8
Intermodulation Distortion
vs Input Amplitude
–50
–70
0
2
4
6
INPUT AMPLITUDE (dBm)
6406 G24
–40
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 800Ω
RI = RF = 150Ω
–50
2 TONES, 1MHz TONE
SPACING, 2VP-P COMPOSITE
–60
DIFFERENTIAL INPUTS
THIRD ORDER IMD (dBc)
THIRD ORDER IMD (dBc)
–70
Intermodulation Distortion
vs Input Common Mode Voltage
–30
10
FREQUENCY (MHz)
VS = 3V
VOCM = VICM = 1.25V
–50 fIN = 50MHz
RLOAD = 800Ω
RI = RF = 500Ω
–60 SINGLE-ENDED INPUT
6406 G23
Intermodulation Distortion
vs Frequency
1
2ND
–70
6406 G22
10
(2VP-P)
–40
DISTORTION (dBc)
DISTORTION (dBc)
DISTORTION (dBc)
–100
10
FREQUENCY (MHz)
8
Harmonic Distortion
vs Input Amplitude
–50
–90
1
0
2
4
6
INPUT AMPLITUDE (dBm)
6406 G21
–50
–80
2ND
–100
–2
–4
(0.4VP-P)
3.0
–40
VS = 3V
VOUTDIFF = 2VP-P
–40 VOCM = VICM = 1.25V SINGLE-ENDED INPUT
RLOAD = 800Ω
–70
3RD
–80
Harmonic Distortion
vs Input Common Mode Voltage
–30
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–70
6406 G20
Harmonic Distortion vs Frequency
–60
VS = 3V
VOCM = VICM = 1.25V
–50 fIN = 50MHz
RLOAD = 800Ω
RI = RF = 150Ω
–60 DIFFERENTIAL INPUTS
–60
–70 V = 3V
S
VOCM = 1.25V
–80 fIN = 50MHz
RLOAD = 800Ω
RI = RF = 150Ω
–90 2 TONES, 1MHz TONE
SPACING, 2VP-P COMPOSITE
DIFFERENTIAL INPUTS
–100
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
VS = 3V
VOCM = VICM = 1.25V
–50 fIN = 50MHz
RLOAD = 800Ω
RI = RF = 150Ω
–60 2 TONES, 1MHz TONE
SPACING
DIFFERENTIAL INPUTS
–70
–80
–90
3.0
6406 G26
–100
–4
–2
(0.4VP-P)
0
2
4
6
INPUT AMPLITUDE (dBm)
8
10
(2VP-P)
6406 G27
6406fc
8
LTC6406
TYPICAL PERFORMANCE CHARACTERISTICS
Frequency Response
vs Load Capacitance
50
30
40
20
30
10
0
AV = 1
AV = 2
AV = 5
AV = 10
AV = 20
AV = 100
–20
–30
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 400Ω
–50
1
10
100
FREQUENCY (MHz)
1000 2000
10
CL = 0pF
CL = 2pF
CL = 3pF
CL= 4.7pF
CL = 10pF
0
10
GAIN (dB)
GAIN (dB)
20
Frequency Response vs Input
Common Mode Voltage
5
0
–10
–20
VS = 3V
–30 VOCM = VICM = 1.25V
RLOAD = 400Ω
–40 RI = RF = 150Ω, CF = 2.2pF
CAPACITOR VALUES ARE FROM
–50 EACH OUTPUT TO GROUND.
NO SERIES RESISTORS ARE USED.
–60
1
10
100
FREQUENCY (MHz)
VICM = 0V
VICM = 0.5V
VICM = 1.25V
VICM = 2V
VICM = 3V
–5
GAIN (dB)
Frequency Response
vs Closed-Loop Gain
–10
(MSOP Package)
–10
–15
–20
–25 VS = 3V
VOCM = 1.25V
–30 RLOAD = 400Ω
RI = RF = 150Ω, CF = 2.2pF
–35
1
10
100
FREQUENCY (MHz)
1000 2000
1000 2000
6406 G30
6406 G29
AV (V/V) RI (Ω)
1
2
5
10
20
100
150
150
150
150
150
150
RF (Ω)
CF (pF)
150
300
750
1.5k
3k
15k
2.2
2.2
0.9
0.4
0.2
0
6406 G28
Harmonic Distortion
vs Input Common Mode Voltage
Harmonic Distortion vs Frequency
–40
–40
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–50
–60
–70
VS = 3V
VOCM = 1.25V
fIN = 50MHz
RLOAD = 800Ω
VOUTDIFF = 2VP-P
DIFFERENTIAL INPUTS
–80
–90
–90
–100
–110
–50
DISTORTION (dBc)
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 800Ω
–50 VOUTDIFF = 2VP-P
DIFFERENTIAL INPUTS
–60
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
–70
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
–80
DISTORTION (dBc)
DISTORTION (dBc)
–30
Harmonic Distortion
vs Input Amplitude
10
FREQUENCY (MHz)
100
6406 G31
–70
2ND
3RD
–80
–90
–100
10
–60
VS = 3V
VOCM = VICM = 1.25V
fIN = 50MHz
RLOAD = 800Ω
RI = RF = 150Ω
DIFFERENTIAL INPUTS
–100
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
3.0
6406 G32
–4
–2
(0.4VP-P)
0
2
4
6
INPUT AMPLITUDE (dBm)
8
10
(2VP-P)
6406 G33
6406fc
9
LTC6406
TYPICAL PERFORMANCE CHARACTERISTICS
–40
VS = 3V
–40 VOCM = VICM = 1.25V
RLOAD = 800Ω
= 2VP-P
V
–50 OUTDIFF
SINGLE-ENDED INPUT
–70
–80
2ND, RI = RF = 150Ω
2ND, RI = RF = 500Ω
3RD, RI = RF = 150Ω
3RD, RI = RF = 500Ω
10
10
FREQUENCY (MHz)
100
–60
2ND
–70
VS = 3V
VOCM = 1.25V
fIN = 50MHz
RLOAD = 800Ω
RI = RF = 500Ω
VOUTDIFF = 2VP-P
SINGLE-ENDED INPUT
–80
–90
3RD
VS = 3V
VOCM = VICM =1.25V
–50 fIN = 50MHz
RLOAD = 800Ω
RI = RF = 500Ω
SINGLE-ENDED
INPUT
–60
–70
2ND
3RD
–80
–90
–100
–100
0
0.5
1.0
1.5
2.0
2.5
INPUT COMMON MODE VOLTAGE (V)
6406 G34
PIN FUNCTIONS
DISTORTION (dBc)
–60
–110
–40
–50
DISTORTION (dBc)
DISTORTION (dBc)
–30
–100
Harmonic Distortion
vs Input Amplitude
Harmonic Distortion
vs Input Common Mode Voltage
Harmonic Distortion vs Frequency
–90
(MSOP Package)
3.0
6406 G35
–4
–2
(0.4VP-P)
0
2
4
6
INPUT AMPLITUDE (dBm)
8
10
(2VP-P)
6406 G36
(QFN/MSOP)
SHDN (Pin 1/Pin 7): When SHDN is floating or directly
tied to V+, the LTC6406 is in the normal (active) operating mode. When the SHDN pin is connected to V–, the
LTC6406 enters into a low power shutdown state with
Hi-Z outputs.
V+, V– (Pins 2, 10, 11 and Pins 3, 9, 12/Pins 3, 6): Power
Supply Pins. It is critical that close attention be paid to
supply bypassing. For single supply applications it is
recommended that a high quality 0.1μF surface mount
ceramic bypass capacitor be placed between V+ and V– with
direct short connections. In addition, V– should be tied
directly to a low impedance ground plane with minimal
routing. For dual (split) power supplies, it is recommended
that additional high quality, 0.1μF ceramic capacitors are
used to bypass V+ to ground and V– to ground, again
with minimal routing. For driving large loads (
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