LTC6430-20 - High Linearity Differential RF/IF Amplifier/ADC Driver

LTC6430-20
High Linearity Differential
RF/IF Amplifier/ADC Driver
DESCRIPTION
FEATURES
51.0dBm OIP3 at 240MHz into a 100Ω Diff Load
n NF = 2.9dB at 240MHz
n 20MHz to 2060MHz –3dB Bandwidth
n 20.8dB Gain
n A-Grade 100% OIP3 Tested at 380MHz
n0.6nV/√Hz Total Input Noise
n S11 < –10dB Up to 1.4GHz
n S22 < –10dB Up to 1.4GHz
n>2.75V
P-P Linear Output Swing
n P1dB = 24.0dBm
n Insensitive to V
CC Variation
n100Ω Differential Gain-Block Operation
n Input/Output Internally Matched to 100Ω Diff
n Single 5V Supply
n DC Power = 850mW
n4mm × 4mm, 24-Lead QFN Package
n
The LTC®6430-20 is a differential gain block amplifier
designed to drive high resolution, high speed ADCs with
excellent linearity beyond 1000MHz and with low associated output noise. The LTC6430-20 operates from a single
5V power supply and consumes only 850mW.
In its differential configuration, the LTC6430-20 can directly
drive the differential inputs of an ADC. Using 1:2 baluns,
the device makes an excellent 50Ω wideband balanced
amplifier. While using 1:1.33 baluns, the device creates
a high fidelity 40MHz to 1000MHz 75Ω CATV amplifier.
The LTC6430-20 is designed for ease of use, requiring a
minimum of support components. The device is internally
matched to 100Ω differential source/load impedance. Onchip bias and temperature compensation ensure consistent
performance over environmental changes.
The LTC6430-20 uses a high performance SiGe BiCMOS
process for excellent repeatability compared with similar
GaAs amplifiers. All A-grade LTC6430-20 devices are tested
and guaranteed for OIP3 at 380MHz. The LTC6430-20 is
housed in a 4mm × 4mm, 24-lead, QFN package with an
exposed pad for thermal management and low inductance.
A single-ended 50Ω IF gain block with similar performance
is also available, see the related LTC6431-20.
APPLICATIONS
Differential ADC Driver
Differential IF Amplifier
n OFDM Signal Chain Amplifier
n50Ω Balanced IF Amplifier
n75Ω CATV Amplifier
n700MHz to 800MHz LTE Amplifier
n Low Phase Noise Clock or LO Amplifier
n
n
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
OIP3 vs Frequency
55
Differential 16-Bit ADC Driver
5V
VCM
1:2
BALUN
OIP3 (dBm)
RF
CHOKES
VCC = 5V
ADC
LTC6430-20
50Ω
RSOURCE = 100Ω
DIFFERENTIAL
RLOAD = 100Ω
DIFFERENTIAL
50
FILTER
643020 TA01a
45
40
V = 5V
35 PCC = 3dBm/TONE
OUT
ZIN = ZOUT = 100Ω DIFF.
TA = 25°C
30
200
400
600
0
FREQUENCY (MHz)
800
1000
643020 TA01b
643020f
For more information www.linear.com/LTC6430-20
1
LTC6430-20
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Total Supply Voltage (VCC to GND)...........................5.5V
Amplifier Output Current (+OUT)..........................120mA
Amplifier Output Current (–OUT)..........................120mA
RF Input Power, Continuous, 50Ω (Note 2)........ +15dBm
RF Input Power, 100µs Pulse, 50Ω (Note 2).......+20dBm
Operating Temperature Range (TCASE) ....–40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Junction Temperature (TJ)..................................... 150°C
DNC
DNC
DNC
VCC
GND
+IN
TOP VIEW
24 23 22 21 20 19
DNC 1
18 +OUT
DNC 2
17 GND
DNC 3
16 T_DIODE
25
GND
DNC 4
15 DNC
13 –OUT
DNC
DNC
9 10 11 12
VCC
8
DNC
7
–IN
14 GND
DNC 6
GND
DNC 5
UF PACKAGE
24-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 150°C, θJC = 40°C/W*
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
*Measured from Junction to the back of a PCB with natural convection.
ORDER INFORMATION
The LTC6430-20 is available in two grades. The A-grade guarantees a minimum OIP3 at 380MHz while the B-grade does not.
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC6430AIUF-20#PBF
LTC6430AIUF-20#TRPBF
43020
24-Lead (4mm × 4mm) Plastic QFN
–40°C to 85°C
LTC6430BIUF-20#PBF
LTC6430BIUF-20#TRPBF
43020
24-Lead (4mm × 4mm) Plastic QFN
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard 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
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω. Typical measured DC electrical
performance using Test Circuit A (Note 3).
SYMBOL PARAMETER
VS
Operating Supply Range
IS,TOT
Total Supply Current
IS,OUT
ICC
Total Supply Current to OUT Pins
Current to VCC Pin
CONDITIONS
MIN
TYP
MAX
UNITS
4.75
5.0
5.25
V
117
113
170
l
213
220
mA
mA
102.9
99
152
l
199
206
mA
mA
14.1
14.0
18
l
22.5
22.5
mA
mA
All VCC Pins Plus +OUT and –OUT
Current to +OUT and –OUT
Either VCC Pin May Be Used
643020f
2
For more information www.linear.com/LTC6430-20
LTC6430-20
AC
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3).
Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Small Signal
BW
–3dB Bandwidth
De-Embedded to Package (Low Frequency Cut-Off,
20MHz)
2060
MHz
S11
Differential Input Match
De-Embedded to Package, 25MHz to 2200MHz
–10
dB
S21
Forward Differential Power Gain
De-Embedded to Package, 100MHz to 400MHz
20.8
dB
S12
Reverse Differential Isolation
De-Embedded to Package, 25MHz to 4000MHz
–23
dB
S22
Differential Output Match
De-Embedded to Package, 25MHz to 1400MHz
–10
dB
Frequency = 50MHz
S21
Differential Power Gain
De-Embedded to Package
21.1
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
47.9
45.9
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–91.8
–87.8
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–82.6
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–93.1
dBc
P1dB
Output 1dB Compression Point
23.0
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
2.9
dB
Frequency = 140MHz
S21
Differential Power Gain
De-Embedded to Package
20.9
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
48.0
46.0
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–92.0
–88.0
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–82.1
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–94.9
dBc
P1dB
Output 1dB Compression Point
23.3
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
2.9
dB
Frequency = 240MHz
S21
Differential Power Gain
De-Embedded to Package
20.8
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 8MHz, ZO = 100Ω A-Grade
B-Grade
51.0
47.0
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 8MHz, ZO = 100Ω A-Grade
B-Grade
–98.0
–90.0
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–79.8
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–80.9
dBc
P1dB
Output 1dB Compression Point
23.9
dBm
NF
Noise Figure
2.9
dB
De-Embedded to Package for Balun Input Loss
643020f
For more information www.linear.com/LTC6430-20
3
LTC6430-20
AC
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3).
Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Frequency = 300MHz
S21
Differential Power Gain
De-Embedded to Package
20.8
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
50.1
47.1
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–96.2
–90.2
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–75.5
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–77.2
dBc
P1dB
Output 1dB Compression Point
24.7
dBm
NF
Noise Figure
3.0
dB
De-Embedded to Package for Balun Input Loss
Frequency = 380MHz
19.6
20.8
POUT = 3dBm/Tone, Δf = 8MHz, ZO = 100Ω A-Grade
B-Grade
44.8
48.3
46.3
dBm
dBm
Third-Order Intermodulation
POUT = 3dBm/Tone, Δf = 8MHz, ZO = 100Ω A-Grade
B-Grade
–83.6
–90.6
–86.6
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–70.3
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–74.3
dBc
P1dB
Output 1dB Compression Point
24.7
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
3.05
dB
S21
Differential Power Gain
De-Embedded to Package
OIP3
Output Third-Order Intercept Point
IM3
l
22.1
dB
Frequency = 500MHz
S21
Differential Power Gain
De-Embedded to Package
20.7
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
48.9
46.9
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–93.8
–89.8
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–68.9
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–82.8
dBc
P1dB
Output 1dB Compression Point
24.3
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
3.30
dB
Frequency = 600MHz
S21
Differential Power Gain
De-Embedded to Package
20.7
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
48.7
45.7
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–93.4
–87.4
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–65.9
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–73.1
dBc
P1dB
Output 1dB Compression Point
24.0
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
3.44
dB
De-Embedded to Package
20.7
dB
Frequency = 700MHz
S21
Differential Power Gain
643020f
4
For more information www.linear.com/LTC6430-20
LTC6430-20
AC
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω, unless otherwise noted (Note 3).
Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without de-embedding (Note 4).
SYMBOL PARAMETER
CONDITIONS
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
MIN
48.6
45.6
TYP
MAX
UNITS
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–93.2
–87.2
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–58.0
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–74.5
dBc
P1dB
Output 1dB Compression Point
23.6
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
3.68
dB
Frequency = 800MHz
S21
Differential Power Gain
De-Embedded to Package
20.7
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
46.5
43.5
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–89.0
–83.0
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–51.4
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–71.2
dBc
P1dB
Output 1dB Compression Point
22.9
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
3.93
dB
Frequency = 900MHz
S21
Differential Power Gain
De-Embedded to Package
20.7
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
45.1
43.1
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–86.2
–82.2
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–48.9
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–68.4
dBc
P1dB
Output 1dB Compression Point
22.3
dBm
NF
Noise Figure
De-Embedded to Package for Balun Input Loss
4.0
dB
Frequency = 1000MHz
S21
Differential Power Gain
De-Embedded to Package
20.6
dB
OIP3
Output Third-Order Intercept Point
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
43.7
41.7
dBm
dBm
IM3
Third-Order Intermodulation
POUT = 2dBm/Tone, Δf = 1MHz, ZO = 100Ω A-Grade
B-Grade
–83.4
–79.4
dBc
dBc
HD2
Second Harmonic Distortion
POUT = 8dBm
–55.2
dBc
HD3
Third Harmonic Distortion
POUT = 8dBm
–65.8
dBc
P1dB
Output 1dB Compression Point
22.5
dBm
NF
Noise Figure
4.27
dB
De-Embedded to Package for Balun Input Loss
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: Guaranteed by design and characterization. This parameter is not tested.
Note 3: The LTC6430-20 is guaranteed functional over the case operating
temperature range of –40°C to 85°C.
Note 4: Small signal parameters S and noise are de-embedded to the
package pins, while large signal parameters are measured directly from the
test circuit.
643020f
For more information www.linear.com/LTC6430-20
5
LTC6430-20
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω,
unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without
de-embedding (Note 4).
10
7
6
5
0
500
1000 1500 2000
FREQUENCY (MHz)
2500
4
3
643020 G01
0
1000
3000
4000
2000
FREQUENCY (MHz)
0
5000
50
450
850
650
FREQUENCY (MHz)
250
643020 G02
1050
1250
643020 G03
Differential Reverse Isolation
(S12DD) vs Frequency Over
Temperature
0
TCASE =
100°C
85°C
50°C
–10
30°C
0°C
–20°C
–15
–40°C
–5
–20
500
3
1
25
–15
0
4
Differential Gain (S21DD)
vs Frequency Over Temperature
MAG S21DD (dB)
–10
5
2
2
0
3000
TCASE =
100°C
85°C
50°C
30°C
0°C
–20°C
–40°C
–5
MAG S11DD (dB)
6
1
0
TCASE =
–40°C
30°C
85°C
7
NOISE FIGURE (dB)
8
Differential Input Match (S11DD)
vs Frequency Over Temperature
–25
8
TCASE =
100°C
85°C
50°C
30°C
0°C
–20°C
–40°C
9
S11
S21
S12
S22
Noise Figure vs Frequency
Over Temperature
1000
1500
FREQUENCY (MHz)
2000
643020 G04
20
TCASE =
100°C
85°C
15
50°C
30°C
0°C
–20°C
–40°C
10
1000
1500
0
500
FREQUENCY (MHz)
Differential Output Match (S22DD)
vs Frequency Over Temperature
MAG S12DD (dB)
35
30
25
20
15
10
5
0
–5
–10
–15
–20
–25
–30
Differential Stability Factor K
vs Frequency Over Temperature
STABILITY FACTOR K (UNITLESS)
MAG (dB)
Differential S Parameters
vs Frequency
–20
–25
–30
–35
2000
Common Mode Gain (S21CC)
vs Frequency Over Temperature
0
0
643020 G05
500
1000
1500
FREQUENCY (MHz)
2000
643020 G06
CM-DM Gain (S21DC)
vs Frequency Over Temperature
22
5
21
–15
–20
0
500
1000
1500
FREQUENCY (MHz)
2000
643020 G07
18
MAG S21DC (dB)
TCASE =
100°C
85°C
50°C
30°C
0°C
–20°C
–40°C
MAG S21CC (dB)
MAG S22DD (dB)
19
–10
–25
0
20
–5
17
16
TCASE =
15
100°C
85°C
14
50°C
13
30°C
12
0°C
–20°C
11
–40°C
10
1000
1500
0
500
FREQUENCY (MHz)
–5
–10
TCASE =
100°C
85°C
50°C
30°C
0°C
–20°C
–40°C
–15
–20
–25
2000
643020 G08
–30
0
500
1500
1000
FREQUENCY (MHz)
2000
643020 G09
643020f
6
For more information www.linear.com/LTC6430-20
LTC6430-20
TYPICAL
PERFORMANCE CHARACTERISTICS
TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω,
unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without
de-embedding (Note 4).
OIP3 vs Frequency
OIP3 vs RF Power Out/Tone
Over Frequency
52
55
54
VCC = 5V
50 ZIN = ZOUT = 100Ω
TA = 25°C
48
50
52
50
48
40
46
OIP3 (dBm)
OIP3 (dBm)
OIP3 (dBm)
46
45
44
42
40
V = 5V
35 PCC = 3dBm/ TONE
OUT
ZIN = ZOUT = 100Ω DIFF.
TA = 25°C
30
200
400
600
0
FREQUENCY (MHz)
50MHz
100MHz
200MHz
300MHz
36
643020 G10
OIP3 vs Tone Spacing Over
Frequency
OIP3 (dBm)
43
41
50MHz
140MHz
200MHz
240MHz
37
0
30
40
20
TONE SPACING (MHz)
VCC = 5V
ZIN = ZOUT = 100Ω
POUT = 2dBm/TONE TA = 25°C
400
600
FREQUENCY (MHz)
1000
800
643020 G12
40
TCASE =
85°C
70°C
50°C
30°C
0°C
–20°C
–40°C
35
50
20
0
200
643020 G13
POUT = 2dBm/TONE
ZIN = ZOUT = 100Ω
TA = 25°C
400
600
FREQUENCY (MHz)
OIP2 vs Frequency
0
100
–50
–60
60
–40
50
40
30
20
–80
10
–90
0
1200
643020 G15
HD3 vs Frequency Over POUT
70
–70
400
200
600
800 1000
2ND HARMONIC FREQUENCY (MHz)
1000
643020 G14
POUT = 6dBm
POUT = 8dBm
–20 VCC = 5V
ZIN = ZOUT = 100Ω
–30 TA = 25°C
80
–40
800
–10
90
OIP2 (dBm)
HD2 (dBc)
200
OIP3 vs Frequency Over
Temperature
25
10
POUT = 6dBm
POUT = 8dBm
VCC = 5V
ZIN = ZOUT = 100Ω
TA = 25°C
0
0
643020 G11
30
400MHz
600MHz
800MHz
1000MHz
HD2 vs Frequency Over POUT
–30
30
10
HD3 (dBc)
OIP3 (dBm)
45
39
–20
8
45
47
–10
32
50
49
0
POUT = 2dBm/TONE
ZIN = ZOUT = 100Ω
TA = 25°C
34
6
55
51
35
VCC = 4.5V
VCC = 4.75V
VCC = 5V
VCC = 5.25V
VCC = 5.5V
42
40
36
400MHz
600MHz
800MHz
1000MHz
34
–10 –8 –6 –4 –2 0 2 4
RF POUT (dBm/TONE)
1000
44
38
38
800
OIP3 vs Frequency Over
VCC Voltage
–60
–70
VCC = 5V
ZIN = ZOUT = 100Ω
POUT = 8dBm
TA = 25°C
0
–50
–80
–90
400
200
600
800 1000
FUNDAMENTAL FREQUENCY (MHz)
1200
643020 G22
–100
0
1000
1500
500
3RD HARMONIC FREQUENCY (MHz)
643020 G16
643020f
For more information www.linear.com/LTC6430-20
7
LTC6430-20
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VCC = 5V, ZSOURCE = ZLOAD = 100Ω,
unless otherwise noted (Note 3). Measurements are performed using Test Circuit A, measuring from 50Ω SMA to 50Ω SMA without
de-embedding (Note 4).
26
Output P1dB vs Frequency
180
25
24
22
21
20
19
8
16
10
200
0
643020 G17
150
140
130
120
VCC = 5V
ZIN = ZOUT = 100Ω
TA = 25°C
17
6
–2
0
2
4
INPUT POWER (dBm)
TCASE = 25°C
160
23
18
–4
Total Current (ITOT) vs VCC
170
ITOT (mA)
25
24
23
22
21
20
19
18
17
16
15
14
13
12
–6
OUTPUT P1dB (dBm)
OUTPUT POWER (dBm)
Output Power vs Input Power
Over Frequency
110
400
600
FREQUENCY (MHz)
800
1000
100
3
643020 G18
3.5
4
4.5
VCC (V)
5
5.5
6
643020 G19
100MHz, P1dB = 23.2dBm
200MHz, P1dB = 23.7dBm
400MHz, P1dB = 24.7dBm
600MHz, P1dB = 23.9dBm
800MHz, P1dB = 22.9dBm
1000MHz, P1dB = 22.4dBm
Total Current (ITOT)
vs Case Temperature
Total Current vs RF Input Power
190
200
180
160
150
140
ITOT (mA)
TOTAL CURRENT (mA)
170
130
110
120
100
80
60
90
70 VCC = 5V
TA = 25°C
50
0
5
10
–20 –15 –10 –5
RF INPUT POWER (dBm)
40
20
15
20
643020 G20
VCC = 5V
0
–60 –40 –20 0 20 40 60 80 100 120
CASE TEMPERATURE (°C)
643020 G21
643020f
8
For more information www.linear.com/LTC6430-20
LTC6430-20
PIN FUNCTIONS
GND (Pins 8, 14, 17, 23, Exposed Pad Pin 25): Ground.
For best RF performance, all ground pins should be connected to the printed circuit board ground plane. The
exposed pad (Pin 25) should have multiple via holes to
an underlying ground plane for low inductance and good
thermal dissipation.
+OUT (Pin 18): Positive Amplifier Output Pin. A transformer
with a center tap tied to VCC or a choke inductor tied to 5V
supply is required to provide DC current and RF isolation.
For best performance select a choke with low loss and
high self resonant frequency (SRF). See the Applications
Information section for more information.
+IN (Pin 24): Positive Signal Input Pin. This pin has an
internally generated 1.8V DC bias. A DC-blocking capacitor
is required. See the Applications Information section for
specific recommendations.
–OUT (Pin 13): Negative Amplifier Output Pin. A transformer with a center tap tied to VCC or a choke inductor is
required to provide DC current and RF isolation. For best
performance select a choke with low loss and high SRF.
–IN (Pin 7): Negative Signal Input Pin. This pin has an
internally generated 1.8V DC bias. A DC-blocking capacitor
is required. See the Applications Information section for
specific recommendations.
DNC (Pins 1 to 6, 10 to 12, 15, 19 to 21): Do Not Connect.
Do not connect these pins, allow them to float. Failure
to float these pins may impair the performance of the
LTC6430-20.
VCC (Pins 9, 22): Positive Power Supply. Either or both
VCC pins should be connected to the 5V supply. Both VCC
pins are internally connected within the package. Bypass
the VCC pin with 1000pF and 0.1µF capacitors. The 1000pF
capacitor should be physically close to a VCC pin.
T_DIODE (Pin 16): Optional. A diode which can be forward
biased to ground with up to 1mA of current. The measured
voltage will be an indicator of the chip temperature.
BLOCK DIAGRAM
VCC
9, 22
BIAS AND TEMPERATURE
COMPENSATION
24
+IN
20dB
GAIN
+OUT
T_DIODE
7
–IN
20dB
GAIN
–OUT
18
16
13
GND
8, 14, 17, 23 AND PADDLE 25
643020 BD
643020f
For more information www.linear.com/LTC6430-20
9
LTC6430-20
Differential Application Test Circuit A (Balanced Amp)
RFIN
50Ω, SMA
+OUT
DNC
GND
DNC
–OUT
DNC
DNC
VCC
GND
R2
350Ω
T2
2:1
DNC
DNC
–IN
C2
1000pF
C3
1000pF
T_DIODE
LTC6430-20
DNC
C8
60pF
DNC
DNC
DNC
DNC
BALUN_A
L1
560nH
DNC
T1
1:2
GND
PORT
INPUT
+IN
R1
350Ω
VCC
C7
60pF
DNC
C1
1000pF
GND
TEST CIRCUIT A
C5
1nF
C4
1000pF
•
•
BALUN_A
PORT
OUTPUT
RFOUT
50Ω, SMA
L2
560nH
C6
0.1µF
VCC = 5V
BALUN_A = ADT2-IT FOR 50MHz TO 300MHz
BALUN_A = ADT2-1P FOR 300MHz TO 400MHz
BALUN_A = ADTL2-18 FOR 400MHz TO 1000MHz
ALL ARE MINI-CIRCUITS CD542 FOOTPRINT
643020 F01
Figure 1. Test Circuit A
OPERATION
The LTC6430-20 is a highly linear, fixed-gain amplifier
for differential signals. It can be considered a pair of 50Ω
single-ended devices operating 180 degrees apart. Its core
signal path consists of a single amplifier stage minimizing stability issues. The input is a Darlington pair for high
input impedance and high current gain. Additional circuit
enhancements increase the output impedance commensurate with the input impedance and minimize the effects
of internal Miller capacitance.
The LTC6430-20 uses a classic RF gain block topology,
with enhancements to achieve excellent linearity. Shunt
and series feedback elements are added to lower the input/
output impedance and match them simultaneously to the
source and load. An internal bias controller optimizes the
bias point for peak linearity over environmental changes.
This circuit architecture provides low noise, good RF power
handling capability and wide bandwidth; characteristics
that are desirable for IF signal-chain applications.
643020f
10
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
The LTC6430-20 is a highly linear fixed-gain amplifier
which is designed for ease of use. Both the input and
output are internally matched to 100Ω differential source
and load impedance from 20MHz to 1400MHz. Biasing and
temperature compensation are also handled internally to
deliver optimized performance. The designer need only
supply input/output blocking capacitors, RF chokes and
decoupling capacitors for the 5V supply. However, because
the device is capable of such wideband operation, a single
application circuit will probably not result in optimized
performance across the full frequency band.
will drop the available voltage to the device. Also look for an
inductor with high self resonant frequency (SRF) as this will
limit the upper frequency where the choke is useful. Above
the SRF, the parasitic capacitance dominates and the choke’s
impedance will drop. For these reasons, wire-wound inductors are preferred, while multilayer ceramic chip inductors
should be avoided for an RF choke if possible. Since the
LTC6430-20 is capable of such wideband operation, a single
choke value will not result in optimized performance across
its full frequency band. Table 1 lists common frequency bands
and suggested corresponding inductor values.
Differential circuits minimize the common mode noise
and 2nd harmonic distortion issues that plague many
designs. Additionally, the LTC6430’s differential topology matches well with the differential inputs of an ADC.
However, evaluation of these differential circuits is difficult, as high resolution, high frequency, differential test
equipment is lacking.
Table 1. Target Frequency and Suggested Inductor Value
Our test circuit is designed for evaluation with standard
single ended 50Ω test equipment. Therefore, 1:2 balun
transformers have been added to the input and output to
transform the LTC6430-20’s 100Ω differential source/load
impedance to 50Ω single-ended impedance compatible
with most test equipment.
Other than the balun, the evaluation circuit requires a
minimum of external components. Input and output DCblocking capacitors are required as this device is internally
biased for optimal operation. A frequency appropriate
choke and de-coupling capacitors provide DC bias to the
RF ±OUT nodes. Only a single 5V supply is necessary to
either of the VCC pins on the device. Both VCC pins are
connected inside the package. Two VCC pins are provided
for the convenience of supply routing on the PCB. An optional parallel 60pF, 350Ω input network has been added
to ensure low frequency stability.
The particular element values shown in Test Circuit A are
chosen for wide bandwidth operation. Depending on the
desired frequency, performance may be improved by
custom selection of these supporting components.
Choosing the Right RF Choke
Not all choke inductors are created equal. It is always important to select an inductor with low RLOSS as resistance
FREQUENCY
BAND
(MHz)
INDUCTOR
VALUE
(nH)
SRF
(MHz)
MODEL
NUMBER
20 to 100
1500
100
0603LS
100 to 500
560
525
0603LS
500 t o 1000
100
1150
0603LS
1000 to 2000
51
1400
0603LS
MANUFACTURER
Coilcraft
www.coilcraft.com
DC-Blocking Capacitor
The role of a DC-blocking capacitor is straightforward:
block the path of DC current and allow a low series impedance path for the AC signal. Lower frequencies require a
higher value of DC-blocking capacitance. Generally, 1000pF
to 10,000pF will suffice for operation down to 20MHz.
The LTC6430-20 linearity is insensitive to the choice of
blocking capacitor.
RF Bypass Capacitor
RF bypass capacitors act to shunt the AC signals to
ground with a low impedance path. They prevent the AC
signal from getting into the DC bias supply. It is best to
place the bypass capacitor as close as possible to the DC
supply pins of the amplifier. Any extra distance translates
into additional series inductance which lowers the effectiveness of the bypass capacitor network. The suggested
bypass capacitor network consists of two capacitors:
a low value 1000pF capacitor to shunt high frequencies
and a larger 0.1µF capacitor to handle lower frequencies.
Use ceramic capacitors of appropriate physical size for
each capacitance value (e.g., 0402 for the 1000pF, 0805
for the 0.1µF) to minimize the equivalent series resistance
(ESR) of the capacitor.
643020f
For more information www.linear.com/LTC6430-20
11
LTC6430-20
APPLICATIONS INFORMATION
Low Frequency Stability
Most RF gain blocks suffer from low frequency instability. To avoid stability issues, the LTC6430-20, contains
an internal feedback network that lowers the gain and
matches the input and output impedance of the intrinsic
amplifier. This feedback network contains a series capacitor, whose value is limited by physical size. So, at some
low frequencies, this feedback capacitor looks like an open
circuit; the feedback fails, gain increases and gross impedance mismatches occur which can create instability. This
situation is easily resolved with a parallel capacitor and a
resistor network on the input. This is shown in Figure 1.
This network provides resistive loss at low frequencies
and is bypassed by the capacitor at the desired band of
operation. However, if the LTC6430-20 is preceded by
a low frequency termination, such as a choke or balun
transformer, the input stability network is not required.
A choke at the output can also terminate low frequencies
out-of-band and stabilize the device.
Exposed Pad and Ground Plane Considerations
As with any RF device, minimizing the ground inductance is
critical. Care should be taken with PC board layouts using
exposed pad packages, as the exposed pad provides the
lowest inductive path to ground. The maximum allowable
number of minimum diameter via holes should be placed
underneath the exposed pad and connected to as many
ground plane layers as possible. This will provide good RF
ground and low thermal impedance. Maximizing the copper
ground plane at the signal and microstrip ground will also
improve the heat spreading and lower inductance. It is a
good idea to cover the via holes with solder mask on the
backside of the PCB to prevent the solder from wicking
away from the critical PCB to exposed pad interface. One
to two ounces of copper plating is suggested to improve
heat spreading from the device.
Frequency Limitations
The LTC6430-20 is a wide bandwidth amplifier but it is not
intended for operation down to DC. The lower frequency
cutoff is limited by on-chip matching elements. The cutoff
may be arbitrarily pushed lower with off chip elements;
however, the translation between the low fixed DC common mode input voltage and the higher open collector
12
DC common mode output bias point make DC-coupled
operation impractical.
Using the On-Chip Diode to Sense Temperature
An on-chip temperature diode is accessible through the
T_DIODE pin. This is an optional feature to determine the
on-chip temperature. Forward bias this pin with 0.01mA
to 1mA of current and the voltage drop will indicate the
temperature on the die. With this temperature, the user can
determine the thermal impedance of the chip to PCB and
get an indicator of the exposed pad solder attach quality.
For best accuracy the user needs to perform a temperature
calibration at their desired current to accurately determine
the absolute temperature. At 1mA the diode voltage slope
is –1.2mV/°C.
Test Circuit A
Test Circuit A, shown in Figure 1, is designed to allow for
the evaluation of the LTC6430-20 with standard singleended 50Ω test equipment. This allows the designer to
verify the performance when the device is operated differentially. This evaluation circuit requires a minimum of
external components. Since the LTC6430-20 operates over
a very wide band, the evaluation test circuit is optimized for
wideband operation. Obviously, for narrowband operation,
the circuit can be further optimized.
Input and output DC-blocking capacitors are required, as
this device is internally DC biased for optimal performance.
A frequency appropriate choke and decoupling capacitors
are required to provide DC bias to the RF output nodes
(+OUT and –OUT). A 5V supply should also be applied to
one of the VCC pins on the device.
Components for a suggested parallel 60pF, 350Ω stability network have been added to ensure low frequency
stability. The 60pF capacitance can be increased to improve
low frequency (<150 MHz) performance, however the
designer needs to be sure that the impedance presented
at low frequency will not create an instability.
Balanced Amplifier Circuit, 50Ω Input and 50Ω Output
This balanced amplifier circuit is a replica of Test Circuit A.
It is useful for single-ended 50Ω amplifier requirements and
is surprisingly wideband. Using this balanced arrangement
For more information www.linear.com/LTC6430-20
643020f
LTC6430-20
APPLICATIONS INFORMATION
and the frequency appropriate baluns, one can achieve the
intermodulation and harmonic performance listed in the AC
Electrical Characteristics specifications of this data sheet.
Besides its impressive intermodulation performance, the
LTC6430-20 has impressive 2nd harmonic suppression as
well. This makes it particularly well suited for multioctave
applications where the 2nd harmonic cannot be filtered.
Please note that a number of DNC pins are connected on
the evaluation board. These connections are not necessary
for normal circuit operation.
The evaluation board also includes an optional back to
back pair of baluns so that their losses may be measured.
This allows the designer to de-embed the balun losses and
more accurately predict the LTC6430-20 performance in
a differential circuit.
This balanced circuit example uses two Mini-Circuits 1:2
baluns. The baluns were chosen for their bandwidth and
frequency options that utilize the same package footprint
(see Table 2). A pair of these baluns, back-to-back has
less than 1.5dB of loss, so the penalty for this level of
performance is minimal. Any suitable 1:2 balun may be
used to create a balanced amplifier with the LTC6430-20.
Table 2. Target Frequency and Suggested 2:1 Balun
The optional stability network is only required when the
balun’s bandwidth reaches below 20MHz. It is included in
the circuit as a comprehensive protection for any passive
element placed at the LTC6430-20 input. Its performance
degradation at low frequencies can be mitigated by increasing the 60pF capacitor’s value.
300 to 400
ADT2-1T-1P
400 to 1300
ADTL2-18
MANUFACTURER
Mini-Circuits
www.minicircuits.com
Boasting high linearity, low associated noise and wide
bandwidth, the LTC6430-20 is well suited to drive high
speed, high resolution ADCs with over a GHz of input bandwidth. To demonstrate its performance, the LTC6430-20
was used to drive an LTC2158 14-bit, 310Msps ADC with
DNC
DNC
GND
DNC
DNC
DNC
–OUT
VCC
GND
DNC
–IN
100Ω
DIFFERENTIAL
C4
• •
1000pF
BALUN_A
DNC
DNC
C3
1000pF
T2
2:1
T_DIODE
LTC6430-20
DNC
C8
60pF
DNC
+OUT
DNC
DNC
BALUN_A
VCC
+IN
100Ω
DIFFERENTIAL
L1
560nH
DNC
GND
T1
1:2
GND
R1
350Ω
C2
1000pF
ADT2-1T
C7
60pF
C1
1000pF
RFIN
50Ω, SMA
MODEL NUMBER
50 to 300
Driving the LTC2158, 14-Bit, 310Msps ADC with
1.25GHz of Bandwidth
Demo Boards 2076A-A and 2076A-B implement this balanced amplifier circuit. It is shown in Figure 18.
PORT
INPUT
FREQUENCY BAND (MHz)
PORT
OUTPUT
RFOUT
50Ω, SMA
L2
560nH
R2
350Ω
C5
1000pF
C6
0.1µF
OPTIONAL STABILITY
NETWORK
VCC = 5V
643020 F02
BALUN_A = ADT2-1T FOR 50MHz TO 300MHz
BALUN_A = ADT2-1T-1P FOR 300MHz TO 400MHz
BALUN_A = ADTL2-18 FOR 400MHz TO 1300MHz
ALL ARE MINI-CIRCUITS CD542 FOOTPRINT
Figure 2. Balanced Amplifier Circuit, 50Ω Input and 50Ω Output
643020f
For more information www.linear.com/LTC6430-20
13
LTC6430-20
APPLICATIONS INFORMATION
1.25GHz of input bandwidth in an undersampling application. Typically, a filter is used between the ADC driver
amplifier and ADC input to minimize the noise contribution from the amplifier. However, with the typical SNR of
higher sample rate ADCs, the LTC6430-20 can drive them
without any intervening filter, and with very little penalty
in SNR. This system approach has the added benefit of
allowing over two octaves of usable frequency range. The
LTC6430-20 driving the LTC2158, as shown in the circuit
of Figure 3, the bandwidth is limited only by the 1.25GHz
input BW of the ADC, still produces 57dB SNR, and offers
IM performance that varies little from 240MHz to 1GHz. At
the lower end of this frequency range, the IM contribution
of the ADC and amplifier are comparable, and the thirdorder IM products may be additive, or may see cancelation.
At 1GHz input, the ADC is dominant in terms of IM and
noise contribution, limited by internal clock jitter and high
input signal amplitude. Table 3 shows noise and linearity
performance. Example outputs at 500MHz and 1000MHz
are shown in Figure 5, Figure 6, Figure 7, and Figure 8.
The LTC6430-20 can directly drive the high speed ADC
inputs and settles quickly. Most feedback amplifiers
require protection from the sampling disturbances, the
mixing products that result from direct sampling. This is
in part due to the fact that unless the ADC input driving
circuitry offers settling in less than one-half clock cycle,
the ADC may not exhibit the expected linearity. If the ADC
samples the recovery process of an amplifier it will be seen
as distortion. If an amplifier exhibits envelope detection
VCM
5V
560nH
0603
60pF
GUANELLA
BALUN
1nF
150Ω
VCC = 5V
49.9Ω
1nF
350Ω
•
•
100nH
0402CS
LTC6430-20
LTC2158
MA/COM
ETC1-1-13
643020 F03
200ps
Figure 3. Wideband ADC Driver, LTC6430-20 Directly Driving the LTC2158 ADC
VCM
5V
560nH
0603
60pF
MINI-CIRCUITS
ADTL2-18
2:1 BALUN
1nF
VCC = 5V
49.9Ω
1nF
350Ω
•
•
LTC6430-20
100nH
0402CS
LTC2158
643020 F04
200ps
Figure 4. Wideband ADC Driver, LTC6430-20 Directly Driving the LTC2158 ADC—Alternative Using Mini-Circuits 2:1 Balun
643020f
14
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
Table 3. LTC6430-20 and LTC2158 Combined Performance
Frequency
(MHz)
Sample Rate
(Msps)
IM3
(Low, Hi)
(dBFS)
HD3
(3rd Harmonic)
(dBc)
SFDR
(dB)
SNR
(dB)
240
307.2
(–87, –87)
–79.7
77.4
58.6
380
307.2
(–86, –86)
–74.2
71.7
58.2
500
307.2
(–92, –92)
–79.7
77.4
58.6
656
307.2
(–86, –85)
–88.5
61.3
56.8
690
307.2
(–87, –87)
–73.0
68.8
57.0
842
307.2
(–84, –85)
–69.6
61.8
56.2
1000
307.2
(–83,–83)
–70.8
67.5
55.5
in the presence of multi-GHz mixing products, it will also
distort. A band limiting filter would provide suppression
from those products beyond the capability of the amplifier,
as well as limit the noise bandwidth, however the settling of
the filter can be an issue. The LTC2158, at 310Msps only
allows 1.5ns settling time for any driver that is disturbed
by these transients.
This approach of removing the filter between the ADC
and driver amplifier offers many advantages. It opens
the opportunity to precede the amplifier with switchable
bandpass filters, without any need to change the critical
network between the drive amplifier and ADC. The transmission line distances shown in the schematic are part
of the design, and are devised such that there are no
impedance discontinuities, and therefore no reflections,
in the distances between 75ps to 200ps from the ADC.
End termination can be immediately prior to, or preferably
after the ADC, and the amplifier should either be within
the 75ps inner boundary, or outside the 200ps distance.
Similarly, any shunt capacitor or resonator incorporated
into a filter, including the large pads required by some
inductors with more than a small fraction of 1pF, should
not be in this range of distances from the ADC where reflections will impair performance. Transformers with large
pads should be avoided within these distances.
A 100nH shunt inductor at the ADC input approximates
the complex conjugate of the ADC sampling circuit, and in
doing so, improves power transfer and suppresses the low
frequency difference products produced by direct sampling
ADCs. If the entire frequency range from 300MHz to 1GHz
were of interest, a 100nH inductor at the input is acceptable,
but if interest is only in higher frequencies, performance
would be better if the input inductor is reduced in value.
If lower frequencies are of interest, a higher value up to
some 200nH may be practical, but beyond that range the
SRF of the inductor becomes an issue. As this inductor
is placed at different distances either before or after the
ADC inputs, the optimal value may change. In all cases, it
should be within 50ps of the ADC inputs. End termination
may be more than 200ps distant if after the ADC. If the
end termination were perfect, it could be at any distance
after the ADC. To terminate the input path after the ADC,
place the termination resistors on the back of the PCB. If
the input signal path is buried or on the back of the PCB,
termination resistors should be placed on the top of the
PCB to properly terminate after the ADC.
Although the ADC is isolated by a driver amplifier, care
must be taken when filtering at the amplifier input. Much
like MESFETs, high frequency mixing products are handled
well by the LTC6430. However, if there is no band limiting
after the LTC6430, these mixing products, reduced by
reverse isolation but subsequently reflected from a filter
prior to the LTC6430 and reamplified, can cause distortion. In such cases, the network will then be sensitive to
transmission line lengths and impedance characteristics
of the filter prior to the LTC6430. Diplexers or absorptive
filters can produce more robust results. An absorptive
filter or diplexer-like structure after the amplifier reduces
the sensitivity to the network prior to the amplifier, but the
same constraints previously outlined apply to the filter.
643020f
For more information www.linear.com/LTC6430-20
15
LTC6430-20
APPLICATIONS INFORMATION
Figure 5. ADC Output: 1-Tone Test at 500MHz with 307.2Msps Sampling Rate Undersampled in the Fourth Nyquist Zone
Figure 6. ADC Output: 2-Tone Test at 500MHz with 307.2Msps Sampling Rate Undersampled in the Fourth Nyquist Zone
643020f
16
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
Figure 7. ADC Output: 1-Tone Test at 1000MHz with 307.2Msps Sampling Rate Undersampled in the Seventh Nyquist Zone
Figure 8. ADC Output: 2-Tone Test at 1000MHz with 307.2Msps Sampling Rate Undersampled in the Seventh Nyquist Zone
643020f
For more information www.linear.com/LTC6430-20
17
LTC6430-20
APPLICATIONS INFORMATION
Figure 9. LTC6430-20 LTC2158 Combo Board
CATV AMPLIFIER 40MHZ TO 1000MHZ
Wide bandwidth, excellent linearity and low output noise
makes the LTC6430-20 an exceptional candidate for CATV
amplifier applications.
As expected, the LTC6430-20 works well in a push-pull
circuit to cover the entire 40MHz to 1000MHz CATV band.
Using readily available SMT baluns, the LTC6430-20 offers high linearity and low noise across the whole CATV
band. Remarkably, this performance is achieved with
only 850mW of power at 5V. Its low power dissipation
greatly reduces the heat sinking requirements relative to
traditional “block” CATV amplifiers.
The native LTC6430-20 device is well matched to 100Ω
differential impedance at both the input and the output.
Therefore, we can employ 1:1.33 surface mount (SMT)
baluns to transform its native 100Ω impedance to the
standard 75Ω CATV impedance, while retaining all the
exceptional characteristics of the LTC6430-20. In addition,
the balun’s excellent phase balance and the 2nd order
linearity of the LTC6430-20 combine to further suppress
2nd order products across the entire CATV band. As with
any wide bandwidth application, care must be taken when
selecting a choke. An SMT wire wound ferrite core inductor
was chosen for its low series resistance, high self resonant frequency (SRF) and compact size. An input stability
network is not required for this application as the balun
presents a low impedance to the LTC6430-20’s input at
low frequencies. Our resulting push-pull CATV amplifier
circuit is simple, compact, completely SMT and extremely
power efficient.
The LTC6430-20 push-pull circuit has 19.2dB of gain with
±0.58dB of flatness across the entire 40MHz to 1000MHz
band. It sports an OIP3 of 46dBm. The CTB and CSO
measurements have not been taken as of this writing.
These characteristics make the LTC6430-20 an ideal
amplifier for head-end cable modem applications or CATV
distribution amplifiers. The circuit is shown in Figure 10,
with 75Ω “F” connectors at both input and output. The
evaluation board may be loaded with either 75Ω “F” connectors, or 75Ω BNC connectors, depending on the users
preference. Please note that the use of substandard connectors can limit usable bandwidth of the circuit.
643020f
18
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
T1
1:1.33
DNC
DNC
DNC
GND
DNC
T_DIODE
LTC6430-20
DNC
C3
0.047µF
T2
1.33:1
C5
1000pF
–IN
BALUN_A = TC1.33-282+ FOR 40MHz TO 1000MHz
MINI-CIRCUITS 1:1.33 BALUN
•
C4
0.047µF
DNC
–OUT
DNC
GND
DNC
C2
0.047µF
100Ω
DIFFERENTIAL
DNC
DNC
GND
BALUN_A
L1
560nH
+OUT
DNC
100Ω
DIFFERENTIAL
RFIN
75Ω,
CONNECTOR
VCC
DNC
VCC
PORT
INPUT
DNC
+IN
GND
C1
0.047µF
PORT
OUTPUT
•
BALUN_A
RFOUT
75Ω,
CONNECTOR
L2
560nH
C6
0.1µF
VCC = 5V
643020 F10
Figure 10. CATV Amplifier: 75Ω Input and 75Ω Output
–5
MAG (dB)
S22
–15
10
20
8
15
10
–20
0
200
400
600
800
FREQUENCY (MHz)
1000
0
1200
0
200
643020 F11
Figure 11. CATV Circuit, Input and
Output Return Loss vs Frequency
400
600
800
FREQUENCY (MHz)
6
4
1200
0
0
200
400
600
800
FREQUENCY (MHz)
643020 F12
1000
1200
643020 F13
Figure 13. CATV Amplifier Circuit,
Noise Figure vs Frequency
0
VCC = 5V, T = 25°C
–10 POUT = 6dBm/TONE
–20
VCC = 5V, T = 25°C
50 P
OUT = 2dBm/TONE
45
40
35
30
25
20
–30
–40
–50
HD2
–60
–70
HD3
–80
–90
15
10
1000
Figure 12. CATV Amplifier Circuit,
Gain (S21) vs Frequency
HD2 AND HD3 (dBc)
–30
VCC = 5V, T = 25°C
INCLUDES BALUN LOSS
2
5
S11
–25
OIP3 (dBm)
MAG (dB)
–10
25
NOISE FIGURE (dB)
0
–100
0
200
400
600
800
FREQUENCY (MHz)
1000
1200
643020 F14
Figure 14. CATV Amplifier Circuit,
OIP3 vs Frequency
–110
0
200
400
600
800 1000 1200
HARMONIC FREQUENCY (MHz) 643015 F15
Figure 15. HD2 and HD3 Products
vs Frequency
643020f
For more information www.linear.com/LTC6430-20
19
LTC6430-20
APPLICATIONS INFORMATION
5
4
3
2
1


D









D




































C




























































C


















 





















B
B

A















5
4



TECHNOLOGY



 


A
 

CATV AMPLIFIER



3

2






 
 
1
Figure 16. LTC6430-20 CATV Circuit Schematic
Figure 17. LTC6430-20 CATV Evaluation Board
643020f
20
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
5
4
3
2
1


































C








B



























C






































































D












































































D

 






















B








A
















5
4
3
TECHNOLOGY




 


A
 
RF/IF AMP/ADC DRIVER



2







 
 
1
Figure 18. Demo Board 2076A Schematic
A Low Phase Noise Amplifier Appropriate for Clock or
LO Amplification
Many wide band amplifiers are based on field effect devices
(FET). CMOS, MesFET, PHEMT and GaN FETs devices are
capable of wide bandwidth operation. On the other hand,
the LTC6430-20 is based on a SiGe HBT device structure.
The active junction of an HBT is sub-surface and not prone
to the surface state effects that plague Field Effect Device.
These surface charges have long lifetime and manifest
themselves as low frequency (phase) noise contributors
Great care was also taken with the bias circuitry surrounding
the LTC6430-20 as to minimize low frequency noise. As a
result the LTC6430-20 has very low residual phase noise.
We have measured our amplifiers phase noise performance
using an Agilent E5500. This noise measurement method
uses two equivalent paths to the noise detector, where they
are combined in quadrature to eliminate the noise from
the synthesizer. Thus leaving only the residual noise of
the amplifier. The residual phase noise of the LTC6430-20
is only –160dBc at 10kHz offset. See Figures 19 and 20.
643020f
For more information www.linear.com/LTC6430-20
21
LTC6430-20
APPLICATIONS INFORMATION
Figure 19. LTC6430-20 Residual Phase Noise at 380MHz and 24dBm POUT
Figure 20. LTC6430-20 Residual Phase Noise at 600MHz and 23dBm POUT
643020f
22
For more information www.linear.com/LTC6430-20
LTC6430-20
APPLICATIONS INFORMATION
Figure 21. Demo Board 2076A PCB
643020f
For more information www.linear.com/LTC6430-20
23
LTC6430-20
DIFFERENTIAL
S PARAMETERS ZDIFF = 100Ω, T = 25°C, De-Embedded to Package Pins,
5V,
DD: Differential In to Differential Out
FREQUENCY
(MHz)
S11DD
(Mag)
S11DD
(Ph)
S21DD
(Mag)
S21DD
(Ph)
S12DD
(Mag)
S12DD
(Ph)
S22DD
(Mag)
S22DD
(Ph)
GTU
(Max)
STABILITY
(K)
13
–9.26
–90.51
23.80
175.00
–32.77
38.54
–10.95
–83.37
24.72
1.22
63
–15.14
–165.61
21.00
171.00
–23.30
–0.67
–19.70
–168.07
21.18
0.99
125
–15.42
–179.50
20.89
168.00
–23.31
–6.13
–20.63
163.80
21.06
1.00
188
–15.47
173.98
20.86
164.00
–23.33
–10.22
–20.76
146.05
21.02
1.00
250
–15.53
168.66
20.82
159.00
–23.35
–14.01
–20.62
130.46
20.98
1.00
313
–15.58
163.86
20.79
154.00
–23.36
–17.68
–20.40
115.73
20.95
1.00
375
–15.66
159.47
20.76
150.00
–23.37
–21.42
–20.10
102.10
20.92
1.00
438
–15.71
155.10
20.74
145.00
–23.38
–25.16
–19.71
89.32
20.90
1.00
500
–15.80
150.93
20.72
140.00
–23.39
–28.89
–19.31
76.53
20.89
1.00
563
–15.93
146.85
20.69
135.00
–23.41
–32.65
–18.85
63.92
20.86
1.00
625
–16.09
142.84
20.68
131.00
–23.43
–36.45
–18.36
51.44
20.85
1.00
688
–16.27
138.71
20.66
126.00
–23.45
–40.31
–17.77
39.16
20.84
1.00
750
–16.51
134.71
20.66
121.00
–23.48
–44.17
–17.16
26.91
20.84
1.00
813
–16.76
131.11
20.66
116.00
–23.51
–48.08
–16.54
14.95
20.85
1.00
875
–17.06
127.47
20.66
111.00
–23.54
–52.09
–15.83
3.31
20.86
1.00
938
–17.43
124.24
20.67
106.00
–23.59
–56.11
–15.12
–8.18
20.88
1.00
1000
–17.84
121.27
20.68
101.00
–23.65
–60.15
–14.40
–19.09
20.91
1.00
1063
–18.33
118.52
20.69
95.90
–23.71
–64.29
–13.68
–29.61
20.94
1.00
1125
–18.93
116.83
20.71
90.70
–23.80
–68.44
–12.95
–39.87
20.99
0.99
1188
–19.57
116.37
20.72
85.20
–23.89
–72.62
–12.26
–49.91
21.03
0.99
1250
–20.14
117.52
20.74
79.50
–24.00
–76.89
–11.55
–59.70
21.10
0.99
1313
–20.68
120.07
20.72
73.80
–24.11
–81.21
–10.88
–69.02
21.13
0.98
1375
–21.14
124.93
20.68
67.70
–24.26
–85.55
–10.22
–78.13
21.15
0.98
1438
–21.23
131.06
20.66
61.70
–24.41
–89.92
–9.62
–87.07
21.20
0.98
1500
–20.90
138.25
20.56
55.50
–24.60
–94.32
–9.04
–95.80
21.18
0.97
1563
–19.95
144.26
20.48
48.90
–24.81
–98.64
–8.48
–104.53
21.19
0.96
1625
–18.83
147.76
20.33
42.70
–25.03
–102.91
–8.01
–113.14
21.14
0.96
1688
–17.57
149.45
20.13
35.90
–25.25
–107.24
–7.55
–121.73
21.04
0.95
1750
–16.37
149.11
19.94
29.40
–25.52
–111.45
–7.15
–130.18
20.97
0.95
1813
–15.17
147.51
19.61
23.10
–25.80
–115.57
–6.78
–138.82
20.77
0.95
1875
–14.06
144.51
19.28
16.30
–26.10
–119.65
–6.44
–147.52
20.57
0.95
1938
–13.10
140.68
18.94
10.50
–26.38
–123.43
–6.19
–155.94
20.35
0.95
2000
–12.25
136.43
18.48
4.49
–26.69
–127.22
–5.93
–164.25
20.03
0.97
2063
–11.53
131.89
18.05
–1.39
–26.99
–131.08
–5.72
–172.58
19.72
0.99
2125
–10.87
127.16
17.58
–6.43
–27.27
–134.59
–5.54
179.33
19.37
1.02
2188
–10.31
122.28
17.04
–11.60
–27.59
–138.32
–5.39
171.30
18.95
1.07
2250
–9.81
117.46
16.62
–16.20
–27.86
–141.93
–5.26
163.58
18.63
1.11
2313
–9.37
112.41
16.10
–20.00
–28.21
–145.40
–5.17
156.00
18.21
1.18
2375
–9.01
107.65
15.68
–24.30
–28.44
–149.05
–5.09
148.51
17.87
1.23
643020f
24
For more information www.linear.com/LTC6430-20
LTC6430-20
TYPICAL APPLICATIONS
50Ω Input/Output Balanced Amplifier
T1
1:2
DNC
DNC
VCC
DNC
GND
DNC
T_DIODE
LTC6430-20
DNC
BALUN_A = ADT2-1T FOR 50MHz TO 300MHz
BALUN_A = ADT2-1T-1P FOR 300MHz TO 400MHz
BALUN_A = ADTL2-18 FOR 400MHz TO 1300MHz
ALL ARE MINI-CIRCUITS CD542 FOOTPRINT
T2
2:1
GND
DNC
–OUT
R2
350Ω
100Ω
DIFFERENTIAL
C4
• •
1000pF
BALUN_A
DNC
DNC
–IN
C2
1000pF
C3
1000pF
DNC
DNC
C8
60pF
DNC
BALUN_A
L1
560nH
+OUT
VCC
100Ω
DIFFERENTIAL
RFIN
50Ω, SMA
DNC
DNC
GND
PORT
INPUT
+IN
R1
350Ω
GND
C7
60pF
C1
1000pF
PORT
OUTPUT
RFOUT
50Ω, SMA
L2
560nH
C6
0.1µF
C5
1000pF
VCC = 5V
OPTIONAL STABILITY
NETWORK
643020 TA02
16-Bit ADC Driver
T1
1:2
+OUT
GND
DNC
T_DIODE
LTC6430-20
LOWPASS
FILTER
+IN
–IN
14- TO 16-BIT
ADC
DNC
DNC
DNC
–OUT
VCC
DNC
GND
GND
C2
1000pF
100Ω
DIFFERENTIAL
C4
1000pF
DNC
DNC
ETC1-1-13
1:1 TRANSFORMER
M/A-COM
•
DNC
DNC
BALUN_A
C3
1000pF
•
RFIN
50Ω, SMA
L1
220nH
DNC
DNC
VCC
DNC
GND
DNC
–IN
PORT
INPUT
+IN
C1
1000pF
L2
220nH
BALUN_A = ADT2-1T FOR 50MHz TO 300MHz
BALUN_A = ADT2-1T-1P FOR 300MHz TO 400MHz
BALUN_A = ADTL2-18 FOR 400MHz TO 1300MHz
ALL ARE MINI-CIRCUITS CD542 FOOTPRINT
C5
1000pF
C6
0.1µF
VCC = 5V
643020 TA03
643020f
For more information www.linear.com/LTC6430-20
25
LTC6430-20
TYPICAL APPLICATIONS
75Ω 40MHz to 1000MHz CATV Amplifier
DNC
GND
DNC
T_DIODE
LTC6430-20
T2
1.33:1
C4
0.047µF
DNC
DNC
–OUT
DNC
GND
DNC
VCC
100Ω
DIFFERENTIAL
DNC
DNC
GND
C2
0.047µF
C3
0.047µF
+OUT
DNC
BALUN_A
L1
560nH
DNC
DNC
DNC
DNC
100Ω
DIFFERENTIAL
RFIN
75Ω,
CONNECTOR
VCC
+IN
T1
1:1.33
–IN
PORT
INPUT
GND
C1
0.047µF
•
•
BALUN_A
PORT
OUTPUT
RFOUT
75Ω,
CONNECTOR
L2
560nH
BALUN_A = TC1.33-282+
FOR 40MHz TO 1000MHz
C5
1000pF
C6
0.1µF
VCC = 5V
MINI-CIRCUITS 1:1.33
643020 TA04
643020f
26
For more information www.linear.com/LTC6430-20
LTC6430-20
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
UF Package
24-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1697 Rev B)
0.70 ±0.05
4.50 ±0.05
2.45 ±0.05
3.10 ±0.05 (4 SIDES)
PACKAGE OUTLINE
0.25 ±0.05
0.50 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
4.00 ±0.10
(4 SIDES)
BOTTOM VIEW—EXPOSED PAD
R = 0.115
TYP
0.75 ±0.05
PIN 1 NOTCH
R = 0.20 TYP OR
0.35 × 45° CHAMFER
23 24
PIN 1
TOP MARK
(NOTE 6)
0.40 ±0.10
1
2
2.45 ±0.10
(4-SIDES)
(UF24) QFN 0105 REV B
0.200 REF
0.00 – 0.05
0.25 ±0.05
0.50 BSC
NOTE:
1. DRAWING PROPOSED TO BE MADE A JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGD-X)—TO BE APPROVED
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
643020f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representaFor more
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tion that the interconnection
of itsinformation
circuits as described
herein will not infringe on existing patent rights.
27
LTC6430-20
TYPICAL APPLICATION
Wideband Balanced Amplifier
5V
VCC = 5V
RF
1:2
TRANSFORMER
VIN
LTC6430-20
RS
50Ω
RSOURCE = 100Ω
DIFFERENTIAL
RLOAD = 100Ω
DIFFERENTIAL
2:1
TRANSFORMER
RL
50Ω
643020 TA05
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
Fixed Gain IF Amplifiers/ADC Drivers
LTC6431-20
50Ω 20dB Gain Block IF Amplifier
Single-Ended Version of LTC6430-20, 20.8dB Gain, 46.2dBm OIP3 at
240MHz into a 50Ω Load
LTC6431-15
50Ω 15dB Gain Block IF Amplifier
Single-Ended Version of LTC6430-15, 15.5dB Gain, 47dBm OIP3 at
240MHz into a 50Ω Load
LTC6430-15
100Ω Differential 15dB Gain Block IF Amplifier
20MHz to 2GHz 3.3dB NF 15.5dB Gain, 50dBm OIP3 at 240MHz into a
100Ω Differential Load
LTC6417
1.6GHz Low Noise High Linearity Differential Buffer/ OIP3 = 41dBm at 300MHz, Can Drive 50Ω Differential Output High
ADC Driver
Speed Voltage Clamping Protects Subsequent Circuitry
LTC6400-8/LTC6400-14/
LTC6400-20/LTC6400-26
1.8GHz Low Noise, Low Distortion Differential
ADC Drivers
–71dBc IM3 at 240MHz 2VP-P Composite, IS = 90mA, AV = 8dB, 14dB,
20dB, 26dB
LTC6401-8/LTC6401-14/
LTC6401-20/LTC6401-26
1.3GHz Low Noise, Low Distortion Differential
ADC Drivers
–74dBc IM3 at 140MHz 2VP-P Composite, IS = 50mA, AV = 8dB, 14dB,
20dB, 26dB
LT6402-6/LT6402-12/
LT6402-20
300MHz Differential Amplifier/ADC Drivers
–71dBc IM3 at 20MHz 2VP-P Composite, AV = 6dB, 12dB, 20dB
LTC6410-6
1.4GHz Differential IF Amplifier with Configurable
Input Impedance
OIP3 = 36dBm at 70MHz, Flexible Interface to Mixer IF Port
LTC6420-20
Dual 1.8GHz Low Noise, Low Distortion Differential
ADC Drivers
Dual Version of the LTC6400-20, AV = 20dB
Variable Gain IF Amplifiers/ADC Drivers
LTC6412
800MHz, 31dB Range Analog-Controlled VGA
OIP3 = 35dBm at 240MHz, Continuously Adjustable Gain Control
Baseband Differential Amplifiers
LTC6409
1.1nV/√Hz Single Supply Differential Amplifier/ADC
Driver
88dB SFDR at 100MHz, AC- or DC-Coupled Inputs
LTC6406
3GHz Rail-to-Rail Input Differential Amplifier/
ADC Driver
–65dBc IM3 at 50MHz 2VP-P Composite, Rail-to-Rail Inputs,
eN = 1.6nV/√Hz, 18mA
LTC6404-1/LTC6404-2
Low Noise Rail-to-Rail Output Differential Amplifier/ 16-Bit SNR, SFDR at 10MHz, Rail-to-Rail Outputs, eN = 1.5nV/√Hz,
ADC Driver
LTC6404-1 Is Unity-Gain Stable, LTC6404-2 Is Gain-of-Two Stable
High Speed ADCs
LTC2208/LTC2209
16-Bit, 13Msps/160Msps ADC
74dBFS Noise Floor, SFDR > 89dB at 140MHz, 2.25VP-P Input
LTC2259-16
16-Bit, 80Msps ADC, Ultralow Power
72dBFS Noise Floor, SFDR > 82dB at 140MHz, 2.00VP-P Input
LTC2160-14/LTC2161-14/ 14-bit, 25Msps/40Msps/60Msps ADC Low Power
LTC2162-14
76.2 dBFS Noise Floor, SFDR > 84dB at 140MHz, 2.00VP-P Input
LTC2155-14/LTC2156-14/ 14-bit, 170Msps/210Msps/250Msps/310Msps
LTC2157-14/LTC2158-14 ADC 2-Channel
69dBFS Noise Floor, SFDR > 80dB at 140MHz, 1.50VP-P Input,
>1GHz Input BW
LTC2216
79dBFS Noise Floor, SFDR > 91dB at 140MHz, 75VP-P Input
16-Bit, 80Msps ADC
643020f
28
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC6430-20
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC6430-20
LT 1014 • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2014