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dc1591af
DEMO MANUAL DC1591A
DESCRIPTION
LTC6409 High Speed, Low
Noise/Distortion Differential
ADC Drivers
Demonstration circuit 1591A features the LT C
®
6409 dif-
ferential ADC driver. It incorporates a variety of passive
components to support configurations for varied applica-
tions. On this board, two amplifier circuits are provided.
One is single-ended, the other is a differential input and
output. There is also a calibration circuit to de-embed the
effects of other circuit components.
The LTC6409 is a high-speed differential amplifier with
superior distortion and low noise suitable for demanding
communications transceivers, cellular base-stations, and
other high-speed signal chain applications. These fully-
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.
QUICK START PROCEDURE
differential amplifiers accept single-ended or differential
inputs with almost no difference in distortion performance.
Each part has the ability to adjust the output common-mode
voltage without any additional components and flexible
input common-mode ranges, which enable input signal DC
coupling and level-shifting for ADC driving applications.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1591A
Table 1 shows the function of each SMA connector on the
board. Refer to Figure 1 for the connection diagram and
follow the procedure below:
1. Connect the power supply to V+ and GND as shown in
Figure 1. Typical current consumption of each LTC6409
is about 52mA. Jumper JP1 enables or shuts down
the single-ended amplifier.
2. The power supply voltage range is shown in Figure 1.
Do not exceed the maximum power supply voltage
rating for the parts.
3. Apply an input signal to J1. A low distortion, low noise
signal source with an external high order filter will
yield the best performance. The J1 input is impedance
matched to 50Ω.
4. Observe the output via J2. The output is impedance
matched to 50Ω, suitable for the input of a network or
spectrum analyzer.
Table 1: DC1591A Board I/O Descriptions
CONNECTOR FUNCTION
J1 (IN) Single-ended Input. Impedance matched to 50Ω, drive
from a 50Ω network analyzer or signal source.
J2 (OUT) Single-ended Output. Impedance matched to 50Ω, can
be used to drive a 50Ω network/spectrum analyzer input.
J3 (CAL IN) Calibration Input. Impedance matched to 50Ω, pairing
with J4 for calibration.
J4 (CAL OUT) Calibration Output. Impedance matched to 50Ω, pairing
with J3 for calibration to de-embed the effects of other
circuit components.
J5 (IN+)/
J6 (IN–)
Differential Inputs. They are impedance matched to
300Ω differentially. Signal can be driven from preceding
receiver signal chain (i.e., Mixer or I/Q Demodulator).
J7 (OUT–)/
J8 (OUT+)
Differential Outputs. They are impedance matched to
100Ω differentially.
JP1 (SHDN1) Shutdown Jumper. The lower (EN) position enables the
single-ended amplifier circuit, while the upper (DIS)
puts the amplifier into shutdown mode.
JP2 (SHDN2) Shutdown Jumper. The lower (EN) position enables the
differential amplifier circuit, while the upper (DIS) puts
the amplifier into shutdown mode.
E4 (VOCM) Output Common Mode Adjust. By default, this pin is
self-biasing within U1 and U2. Override this voltage
with other DC voltage source as required.
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dc1591af
DEMO MANUAL DC1591A
QUICK START PROCEDURE
Figure 1. Proper Measurement Equipment Setup
IMPEDANCE
MATCHED TO
50Ω
IMPEDANCE
MATCHED TO
50Ω
DC1591A F01
+ –
VCC = 2.7V TO 5.2V
POWER SUPPLY
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DEMO MANUAL DC1591A
ADDITIONAL INFORMATION
The DC1591A demo board is ready for use out of the
box. A single-ended and a differential amplifier circuit are
provided for ease of use and with minimum modification.
DEMO BOARD VERSIONS
Single-Ended Input and Output Configuration
J1: The single-ended input can be driven from a 50Ω signal
source or network analyzer (usually port 1).
J2: The single-ended output can be connected to spectrum
analyzer or network analyzer (usually port 2).
Differential Inputs and Outputs Configuration
J5 and J6: Differential inputs. Typically, signal input to
these ports are from a receiver signal chain such as a
mixer or I/Q demodulator.
J7 and J8: Differential outputs. These ports can drive
directly into the differential inputs of an ADC.
DRIVING THE INPUTS DC-COUPLED
It is possible to configure the DC1591A inputs differentially
with DC coupling. Transformer T1 should be removed,
and C23 and C24 connections should be replaced with
0Ω resistors. The inputs are now DC-coupled and can be
driven single-ended or differentially (resistor values may
be changed to balance the source impedances, et cetera.
See the product data sheet for more information. Note
input bias currents will flow through the amplifier’s input
resistors if DC1591A is driven DC-coupled.
CHANGING THE OUTPUT COMMON-MODE VOLTAGE
Turret E4 (VOCM) controls the output common mode
voltage ofU1 and U2. E4 can be used to level-shift the DC
output voltage for optimum system performance. If used
for this purpose, transformer T2 should be removed, and
C18 and C19 connections can be replaced by 0Ω resistors
to allow the DC bias to reach the output. By default, the
VOCM voltage is self-biased through resistors internal to
the IC’s (U1 and U2).
OUTPUT DRIVE
Each amplifier circuit on the demo board is designed to
have a 50Ω source impedance at its output to facilitate
direct connections to 50Ω terminated test instruments.
ENABLE (SHUTDOWN)
Jumper JP1 and JP2 control the enable function of U1
and U2, respectively, on DC1591A. When set to the EN
position, the part will be on and draws normal operating
current. In the DIS position, the part will be in shutdown
and draws a very small amount of leakage current.
GROUND AND VCC CONNECTIONS
DC1591A’s GND connector is not only connected to V– of
the LTC6409, it also serves as the demo board ground.
For best result, a low impedance return path to the power
supply from GND is recommended. Short, low impedance
wires to the V+ and GND connectors of DC1591A will yield
the best performance from the LTC6409.
SCHEMATIC NOTES
Note that transformer T2 and the series resistors at the
amplifier outputs form a 12.6dB attenuation (if the output
has a 50Ω load) that will affect the measured gain of the
demo board. This is done so that the output of DC1591A can
plug directly into a 50Ω network/spectrum analyzer input,
while the amplifier sees a higher 400Ω load impedance.
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DEMO MANUAL DC1591A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 2 C1, C5 CAP. CHIP, X7R, 100pF, 50V, 10%, 0402 AVX, 04025C101KAT
2 2 C2, C6 CAP. CHIP, X7R, 0.01μF, 16V, 10%, 0402 AVX, 0402YC103KAT
3 19 C3, C7, C11, C14, C15, C16, C18, C19, C20, C21,
C23, C24, C25, C26, C28, C29, C30, C31, C32
CAP. CHIP, X7R, 0.1μF, 16V, 10%, 0402 AVX, 0402YC104KAT
4 2 C4, C8 CAP. CHIP, X5R, 0.47µF, 10V, 10%, 0402 MURATA, GRM155R61A474KE15D
5 2 C9, C10 CAP. CHIP, X7R, 1000pF, 25V, 10%, 0402 AVX, 04023C102KAT
6 1 C12 CAP. CHIP, X5R, 10μF, 10V, 10%, 0805 AVX, 0805ZD106KAT
7 4 C13, C17, C22, C27 CAP. CHIP, X7R, 1.3pF, 25V, 10%, 0402 AVX, 04023J1R3ABWTR
8 3 E1, E3, E4 TESTPOINT, TURRET, 0.065" PBF MILL-MAX, 2308-2-00-80-00-00-07-0
9 0 E2 (OPT) TESTPOINT, TURRET, 0.065" PBF MILL-MAX, 2308-2-00-80-00-00-07-0
10 2 JP1, JP2 HEADER, 3 PINS, 2mm SAMTEC, TMM-103-02-L-S
11 2 JP1, JP2 SHUNT, 2mm CENTER SAMTEC, 2SN-BK-G
12 8 J1, J2, J3, J4, J5, J6, J7, J8 CON., SMA 50Ω EDGE-LANCH CONNEX, 132357 / 142-0701-851
13 8 R1, R7, R14, R18, R27, R31, R36, R37 RES., CHIP, 0Ω 1/16W, 1%, 0402 YAGEO, RC0402FR-070RL
14 0 R2, R6, R13, R15, R16, R19, R26, R32, R35, R38 RES., CHIP, 0402 (OPT)
15 2 R3, R4 RES., CHIP, 100Ω 1/16W, 1%, 0402 YAGEO, RC0402FR-07100RL
16 8 R5, R8, R9, R10, R28, R29, R33, R39 RES., CHIP, 150Ω 1/16W, 0.1%, 0402 YAGEO, RT0402BRE07150RL
17 6 R11, R12, R20, R22, R23, R25, RES., CHIP, 300Ω 1/16W, 1%, 0402 YAGEO, RC0402FR-07300RL
18 2 R17, R30 RES., CHIP, 10Ω 1/16W, 1%, 0402 YAGEO, RC0402FR-0710RL
19 2 R21, R24 RES., CHIP, 75Ω 1/16W, 1%, 0402 YAGEO, RC0402FR-0775RL
20 2 R34, R40 RES., CHIP, 49.9Ω, 1/16W, 1% 0402 VISHAY, CRCW040249R9FKED
21 4 T1, T2, T3, T4 TRANS., TCM4-19 SURFACE MOUNT MINI CIRCUITS, TCM4-19
22 2 U1, U2 DIFFERENTIAL AMPLIFIER/ADC DRIVER LINEAR TECH., LTC6409UDB
23 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT # DC1591A
24 2 STENCIL – TOP & BOTTOM DC1591A
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DEMO MANUAL DC1591A
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
E
E
D
D
C
C
B
B
A
A
OUT-
SMA
SMA
IN-
SMA SMA
OUT+
1:4 Xfmr by Mini-Circuits 1:4 Xfmr by Mini-Circuits
EN
DIS
VCM
VOCM
GND
V+
SMA
IN SMA
OUT
SHDN1
DIS
SHDN2
EN
IN+
CALIBRATION PATH
1:4 Xfmr by Mini-Circuits 1:4 Xfmr by Mini-Circuits
SMA
CAL IN CAL OUT
SMA
2.7V - 5.25V
2
DEMO CIRCUIT 1591A
Thursday, June 10, 2010
11
DIFFERENTIAL AMPLIFIER / ADC DRIVER
N/A
LTC6409UDB
NC
JOHN C.
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
JOHN C.PRODUCTION FAB
-206-02-10
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
VOCM
VCM
VOCM
V+
V+
V+
V+
R32
OPT
J5
1
3
2
4
5
C32
0.1uF
R21
75
R26
OPT
R17
10
R37
0 Ohm
J3
1
3
2
4
5
R10
150 0.1%
R8
150 0.1%
R6
OPT
E3
T2
TCM4-19
6
4
1
2
3Pd
P
S
CT
Sd
C6 0.01uF
R12
300
J1
1
3
2
4
5
R24
75
C28
0.1uF
T1
TCM4-19
6
4
1
2
3
Pd
P
S
CT
Sd
C14
0.1uF
C11
0.1uF
R19
OPT
R13
OPT
R27
0 Ohm
C22
1.3pF
U2
LTC6409UDB
6
2
7
1
4
9
8
10
5
3
11
-IN
+IN
+OUT
-OUT
V+
V+
V-
V-
Vocm
SHDN
V-
E1
R40
50
R39
150 0.1%
J2
1
3
2
4
5
U1
LTC6409UDB
6
2
7
1
4
9
8
10
5
3
11
-IN
+IN
+OUT
-OUT
V+
V+
V-
V-
Vocm
SHDN
V-
R16
OPT
JP1
1
3
2
R38
OPT
T3
TCM4-19
6
4
1
2
3
Pd
P
S
CT
Sd
C16
0.1uF
C7 0.1uF
J4
1
3
2
4
5
R1
0 Ohm
C30
0.1uF
J7
1
3
2
4
5
R9
150 0.1%
C1 100pF
C18
0.1uF
C9
1000pF
C26
0.1uF
R29
150 0.1%
T4
TCM4-19
6
4
1
2
3Pd
P
S
CT
Sd
C29
0.1uF
R25
300
C12
10uF
C5 100pF
R36
0 Ohm
R30
10
E4
C25
0.1uF
C8 0.47uF
C19
0.1uF
C2 0.01uF
R3
100
R34
50
C15
0.1uF
C23
0.1uF
C17
1.3pF
R22
300
R15
OPT
J6
1
3
2
4
5
R28
150 0.1%
R31
0 Ohm
R23
300
R5
150 0.1%
R35
OPT
C20
0.1uF
C13
1.3pF
C3 0.1uF
R11
300
R7
0 Ohm J8
1
3
2
4
5
E2
C21
0.1uF
C24
0.1uF
R2
OPT
C10
1000pF
R4
100
R20
300
C27
1.3pF
C4 0.47uF
C31
0.1uF
R14
0 Ohm
JP2
1
3
2
R33
150 0.1%
R18
0 Ohm
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dc1591af
DEMO MANUAL DC1591A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2015
LT 1115 • PRINTED IN USA
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.
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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.
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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.
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