DC2090A - Demo Manual

DEMO MANUAL DC2090A
LTC6430-15
50MHz to 1200MHz Parallel Connected,
Boosted OIP3, ADC/IF Amplifier
Description
Demonstration circuit 2090A features two LTC®6430-15s
differential ADC/IF Amplifier connected in parallel at the
inputs and outputs, boosting the output third order intercept point (OIP3) and the output power each by about 3dB
higher. The parallel connection reduces the differential
input and output impedance by one-half so the composite
amplifier has 50Ω differential input and output impedances,
this demo circuit uses 1:1 balun transformers to convert
the differential I/O impedances to 50Ω single-ended so
that the DC2090A can be easily evaluated with most RF
test equipment.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2090A
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.
VCC
RF CHOKE
560nH
1000pF
+
1000pF
•
3
4
–
1:1
1000pF
+
1000pF
4
3
•
6
•
1
•
RSOURCE
50Ω
1000pF
LTC6430-15
6
1
1:1
1000pF
LTC6430-15
–
RF CHOKE
560nH
VCC
RLOAD
50Ω
DC2090A F01
Figure 1. DC2090A Two LTC6430-15s in Parallel Simplified Schematic
dc2090af
1
DEMO MANUAL DC2090A
Performance Summary
Specifications are at TA = 25°C
SYMBOL
CONDITIONS
MIN
4.75
PARAMETER
TYP
MAX
UNITS
Power Supply
VCC
Operating Supply Range
All VCC Pins Plus ±OUT
ICC
Current Consumption
Total Current
FREQUENCY POWER GAIN
(MHZ)
|S21| (dB)
OUTPUT THIRD
ORDER INTERCEPT OUTPUT THIRD ORDER
POINT *
INTERMODULATION*
OIP3 (dBm)
OIM3 (dBc)
5.25
V
330
mA
SECOND
HARMONIC
DISTORTION**
HD2 (dBc)
THIRD
HARMONIC
DISTORTION **
HD3 (dBc)
OUTPUT 1DB
COMPRESSION
POINT
P1DB (dBm)
NOISE
FIGURE ‡
NF (dB)
50
13.4
49.7
–95.5
–84.6
–95.4
25.4
6.33
100
14.6
49.9
–95.7
–84.2
–96.4
25.5
4.14
200
14.8
51.0
-98.1
–84.3
–95.1
25.2
3.46
300
14.5
51.3
–98.6
–79.4
–88.0
25.7
4.10
400
14.1
50.8
–97.6
–82.7
–81.8
25.0
4.55
–79.8
–78.6 †
24.6
4.55
500
13.9
48.8
–93.6
600
13.9
45.2
–96.4
–71.7
–80.8 †
24.1
4.68
700
13.7
44.6
–85.2
–73.2 †
–78.0 †
24.0
5.05
–76.7 †
800
13.8
43.2
–82.3
–70.8 †
23.3
5.33
900
12.8
42.4
–80.8
–74.4 †
–76.4 †
23.3
5.52
–80.3
–70.2 †
–71.9 †
23.3
5.61
–68.7 †
23.5
5.77
–72.6 †
23.5
6.08
1000
12.5
42.1
1100
12.4
41.9
–79.9
–67.7 †
1200
12.5
43.8
–83.6
–65.6 †
Note: All figures are referenced to J1 (input port) and J4 (output port)
* Two-tone test conditions: Output power level = 5dBm/tone, tone spacing = 1MHz
**Single-tone test conditions: Output power level = 6dBm
† Outside of input and output transformers’ working frequency range
‡ Small signal noise figure
2
dc2090af
DEMO MANUAL DC2090A
Operation
18
4
16
0
|S21|
–4
14
|S21| (dB)
–8
|S11|
10
–12
|S22|
8
6
–16
–20
|S12|
4
–24
2
–28
0
–32
–2
0
400
800
1200
1600
FREQUENCY (MHz)
|S11|, |S12|, |S22| (dB)
12
–36
2000
DC2090A F02
Figure 2. Demo Board S-Parameters
DC2090A is a high linearity, fixed gain amplifier. It is
designed for ease of use. The demo circuit contains two
LTC6430-15s that are connecting in parallel at each pair
of inputs and outputs. Each of the individual LTC6430-15s
is internally matched to 100Ω differential source and load
impedance from 20MHz to 1400MHz. When connected in
parallel, the impedance becomes 50Ω differential. Most
test equipment have 50Ω single-ended input. To make
measurement compatible, the 1:1 balun transformers have
been added to convert the amplifier differential impedances to single-ended 50Ω. The other advantage of the
parallel connection is that it gives higher output power
and OIP3 by about 3dB each. Note that these devices
are cross connected to improve the matching of the two
180º paths. It is very important that the two paths match
to achieve the best 2nd and 3rd order harmonic suppression. The frequency range of the circuit is limited by the
balun transformers. Hence, this demo board optimizes
the amplifiers performance over the frequency range from
50MHz to 1200MHz. Figure 2 shows the DC2090A’s two
port S-Parameters.
The demo board requires a minimum of passive support
components. At the board’s input and output are the balun
transformers. Each of these transformers (T1, T2) has a
1:1 impedance transformation ratio. The shunt capacitors
(C18 and C19) help to match the input/output signals.
A pair of stability networks has been added to ensure low
frequency stability. They consist of a 120pF capacitor (C5
and C8) and 174Ω resistor (R4 and R7) in parallel at the
LTC6430-15’s input network. Note that the input stability
network does degrade performance below 150MHz. Low
frequency performance can be improved by increasing
the value of the capacitors (C5 and C8).
The input and output DC-blocking capacitors (C4, C10,
C14, C15, C16 and C17) are required because this device
is internally DC-biased for optimal operation. The frequency
appropriate RF chokes (L1 and L2) and the de-coupling
capacitors (C2, C3, C11 and C12) provide the proper DC
bias to the RF ± OUT ports. A single 5V supply is required
for the VCC pins on the device.
L3, L4, C6 and C20 are optional components. They are for
additional matching when further optimization to a lower
or wider frequency range applications is required.
The T_DIODE1 and T_DIODE2 turrets (E1 and E3) can
be forward biased to ground with 1mA of current. The
measured voltage will be an indicator of the chip junction
temperature (TJ).
Please note that a number of DNC pins are connected on
the demo board. These connections are not necessary for
normal operation, however, failure to float these pins may
impair the operation of the device.
Table 2. DC2090A Board I/O Descriptions
CONNECTOR
FUNCTION
J1 (IN)
Single-ended input. Impedance matched to 50Ω.
Drive from a 50Ω Network Analyzer or signal source.
J4 (OUT)
Single-ended output. Impedance matched to 50Ω.
Drives a 50Ω network analyzer or spectrum analyzer
E1, (T_DIODE1)
The measured voltage will be an indicator of the chip
junction temperature, U1
E3, (T_DIODE2)
The measured voltage will be an indicator of the chip
junction temperature, U2
E2 , J5 (VCC)
Positive supply voltage source
E4, J6 (GND)
Supply ground
dc2090af
3
DEMO MANUAL DC2090A
Additional Information
As with any RF device, minimizing ground inductance
is critical. Care should be taken during the board layout
when using these exposed pad packages. A maximum
of small-diameter vias should be placed underneath the
exposed ground pad. This will ensure a good RF ground
and low thermal impedance. Maximizing the copper
ground plane will also improve heat spreading and lower
the inductance to ground. It is a good idea to cover the
via holes with solder mask on the back side of the PCB to
prevent solder from wicking away from the critical PCB
to the exposed pad interface.
The DC2090A is a wide bandwidth demo board, but it is not
intended for operation down to DC. The lower frequency
cutoff is limited by on-chip matching elements.
Table 3 shows the LTC643X-YY amplifier series and its
associated demo boards. Each demo board lists the typical
working frequency range and the input and output impedance of the amplifiers.
Setup Signal Sources and Spectrum Analyzer
The LTC6430-15 is an amplifier with high linearity performance. Therefore, the output intermodulation products are
very low. Even using high dynamic range test equipment,
third-order intercept (IP3) measurements can drive test
setups to their limits. Consequently, accurate measurement of IP3 for a low distortion IC such as the LTC6430-15
requires certain precautions to be observed in the test
setup as well as the testing procedure.
Table 3. The LTC643X-YY Amplifier Family and Corresponding Application Demo Boards
DEMO BOARD
NUMBER
FREQUENCY RANGE
(MHZ)
NOTES/APPLICATIONS
BOARD’S IN/OUT
IMPEDANCE
AMPLIFIER
AMPLIFIER’S IMPEDANCE
DC1774A-A
50 to 350
Low Frequency
50Ω
LTC6430-15
Differential 100Ω
4
DC1774A-B
400 to 1000
Mid Frequency
50Ω
LTC6430-15
Differential 100Ω
DC1774A-C
100 to 1200
Wide Frequency
50Ω
LTC6431-15
Single-Ended 50Ω
DC2032A
50 to 1000
Cable Infrastructure
75Ω
LTC6430-15
Differential 100Ω
DC2077A
100 to 1200
Wide Frequency
50Ω
LTC6431-20
Single-Ended 50Ω
DC2153A
700 to 1700
High Frequency
50Ω
LTC6430-15
Differential 100Ω
DC2090A
50 to 1200
Power Doubler
50Ω
Dual LTC6430-15
Differential 50Ω
dc2090af
DEMO MANUAL DC2090A
Additional Information
Setup Signal Sources
Setup the Spectrum Analyzer
Figure 3 shows a proposed IP3 test setup. This setup has
low phase noise, good reverse isolation, high dynamic
range, sufficient harmonic filtering and wideband impedance matching. The setup is outlined below:
a. Adjust the spectrum analyzer for maximum possible
resolution of the intermodulation products’ amplitude
in dBc. A narrower resolution bandwidth will take a
longer time to sweep.
a. High performance signal generators 1 and 2 ( HP8644A)
are used. These suggested generators have low harmonic distortion and very low phase noise.
b.Optimize the dynamic range of the spectrum analyzer
by adjusting the input attenuation. First, increase the
spectrum analyzer’s input attenuation (normally in
steps of 5dB or 10dB). If the IM product levels decrease
when the input attenuation is increased, then the input
power level is too high for the spectrum analyzer to
make a valid measurement. Most likely, the spectrum
analyzer’s 1st mixer was overloaded and producing its
own IM products. If the IM reading holds constant with
increased input attenuation, then a sufficient amount
of attenuation was present. Adding too much attenuation will bury the intended IM signal in the noise floor.
Therefore, select just enough attenuation to achieve a
stable and valid measurement.
b.High linearity amplifiers are used to improve the reverse
isolation. This prevents cross talk between the two
signal generators and provides higher output power.
c. A low pass filter is used to suppress the harmonic
content from interfering with the test signal. Note that
second order inputs can “mix” with the fundamental
frequency to form intermodulation (IM) products of their
own. We suggest filtering the harmonics to –50dBc or
better.
d.The signal combiner from mini-circuits (ADP-2-9)
combines the two isolated input signals. This combiner
has a typical isolation of 27dB. For improved VSWR and
isolation, the H-9 signal combiner from MA/COM is an
alternative which features >40dB isolation and a wider
frequency range. Passive devices (e.g. combiners) with
magnetic elements can contribute nonlinearity to the
signal chain and should be used cautiously.
e. The attenuator pads on all three ports of the signal
combiner will further support isolation of the two input
signal sources. They also reduce reflections and promote
maximum power transfer with wideband impedance
matching.
c. In order to achieve this valid measurement result,
the test system must have lower total distortion than
the DUT’s intermodulation. For example, to measure
51dBm OIP3, the measured intermodulation products
will be –92dBc below a –15dBm/tone input level and
the test system must have intermodulation products
approximately –98dBc or better. For best results, the
IM products and noise floor should measure at least
–102dBc before connecting the DUT.
dc2090af
5
DEMO MANUAL DC2090A
Quick Start Procedure
DC2090A can be set up to evaluate the performance of
the LTC6430-15. Refer to Figure 3 for proper equipment
connections and follow the procedure below:
Two-Tone Measurement
Connect all test equipment as suggested in Figure 3.
4.Change the spectrum analyzer’s center frequency and
observe the two IM3 tones at 1MHz below and above
the input frequencies. The frequencies of IM3_LOW and
IM3_HIGH are 299MHz and 302MHz, respectively. The
measurement levels should be approximately –92dBc;
+51dBm is typical OIP3 performance for the demo board
DC2090A at 300MHz.
1.The power labels of VCC 4.75V to 5.25V and GND directly correspond to the power supply. Typical current
consumption for two LTC6430-15s is about 330mA.
The OIP3 calculation is:
2.Apply two independent signals f1 and f2 from signal
generator 1 and signal generator 2 at 300MHz and
301MHz, while setting the amplitude to –9dBm/tone
at the demo board input (J1).
where POUT is the lower output signal power of the
fundamental products.
3.Monitor the output tone level on the spectrum analyzer.
Adjust the signal generator levels such that the output
power measures 5dBm/tone at the amplifier output J2,
after correcting for external cable losses and attenuations.
6
OIP3 = POUT + ∆IMD3/2
∆IMD3 = POUT – PIM3; PIM3 is the higher third-order
intermodulation product.
Single-Tone Measurement
5.Continue with step 4 above, turn off one signal source
to measure gain and harmonic distortions.
dc2090af
DEMO MANUAL DC2090A
Quick Start Procedure
Signal
Generator 1
(HP8644A)
Amplifier
(Mini-Circuits,
ZHL-2 or Equivalent)
Low-Pass Filter
6dB Attenuation Pad
(Optional)
3dB
Attentuation Pad
COMBINER
MINI-CIRCUITS
ADP-2-9
20dB
Attentuation Pad
Coaxial Cable
Spectrum
Analyzer
6dB Attenuation Pad
(Optional)
Rohde & Schwarz
FSEM30
Low-Pass Filter
VCC = 4.75V to 5.25V
Amplifier
(Mini-Circuits,
ZHL-2 or Equivalent)
Signal
Generator 2
DC Power Supply
GND
V+
(HP8644A)
Figure 3. Proper Equipment Setup for IP3 Measurement
dc2090af
7
DEMO MANUAL DC2090A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
3
C1, C7, C13
CAP., X7R, 1000pF, 50V 5%, 0402
AVX, 04025C102JAT2A
2
8
C2, C4, C10, C11,
C14–C17
CAP., X7R, 1000pF, 50V 5%, 0603
AVX, 06035C102JAT2A
3
2
C3, C12
CAP., X5R, 0.1µF, 10V, 10%, 0603
AVX, 0603ZD104KAT2A
4
2
C5, C8
CAP., NPO, 120pF, 50V, 5%, 0603
AVX, 06035A121JAT
5
2
C18, C19
CAP., NPO, 2.7pF, 50V, ±0.25pF, 0603
AVX, 06035A2R7CAT1A
6
0
C6, C20
CAP., 0603, OPT
7
4
E1-E4
TESTPOINT, TURRET, .093"
MILL-MAX, 2501-2-00-80-00-00-07-0
8
2
J1, J4
CONN., SMA 50Ω EDGE-LAUNCH
E.F.JOHNSON, 142-0701-851
9
0
J2, J3
CON., OPT
10
2
J5, J6
JACK, BANANA
KEYSTONE, 575-4
11
2
L1, L2
INDUCTOR, CHIP, 560nH, 5%, 0603LS-1608
COILCRAFT, 0603LS-561XJLB
12
2
L3, L4
INDUCTOR, CHIP, 0Ω, 0805
13
2
R3, R6
RES., CHIP, 0Ω, 0603
14
0
R5, R8
RES., OPT
15
2
R4, R7
RES., CHIP, 174Ω, 1%, 0603
VISHAY, CRCW0603174RFKED
16
2
T1, T2
RF TRANSFORMER, CASE STYLE CD542
MINI-CIRCUITS, ADTL1-12+
17
2
U1, U2
BALANCED AMPLIFIER LTC6430AIUF-15, QFN24UF-4X4
LINEAR TECH., LTC6430AIUF-15
8
VISHAY, CRCW06030000Z0ED
dc2090af
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
A
B
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 
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1

TECHNOLOGY
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 
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
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
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
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



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

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
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D
5
A
B
C
D
DEMO MANUAL DC2090A
Schematic Diagram
dc2090af
9
DEMO MANUAL DC2090A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
10 Linear Technology Corporation
dc2090af
LT 0714 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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