DC1660B - Demo Manual

DEMO MANUAL DC1660B
LTC6417
1.6GHz Low Noise Differential
16-Bit ADC Buffer
Description
Demonstration circuit 1660B features the LTC®6417 differential 16-bit ADC buffer. The demo board incorporates a
variety of passive components to allow for direct connection to a two-port network analyzer or other single-ended
50Ω test system.
The demo board is easily configured to control commonmode voltage VCM, clamp voltage CLHI, power adjust
PWRADJ, and SHUTDOWN pins. Other simple PCB modifications can accommodate differential input/output signals.
Design files for this circuit board are available at
http://www.linear.com/demo
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
DC1660B is easy to set up to evaluate the performance of
the LTC6417. Refer to Figure 1 for proper measurement
equipment setup and follow the procedure below:
1.Connect SMA cables to IN+ and OUT+ ports.
to the positive supply V+. Table 1 shows the function of
each SMA connector on the board. Only J1, J3 and J5
are used in the default configuration. J2 and J4 provide
flexibility for differential input/output signals.
2.Apply 5.0V between V+ and GND turrets.
Table 1. DC1660B SMA Connectors
Tie PWRADJ (TURRET E4) to V+. Limit supply current
to approximately 150mA.
CONNECTOR
FUNCTION
J1 (IN+)
Differential input connected to input balun for singleended operation. Drive from a 50Ω signal source.
No external termination needed.
J2 (IN–)
Differential Input. Not connected by default. Remove
capacitor C12 to drive the input balun differentially.
J3 (OUT+)
Differential output connected to balun for single-ended
operation. Connect to a 50Ω network/spectrum
analyzer input.
J4 (OUT–)
Differential Output. Not connected by default. Remove
capacitor C11 to drive the input balun differentially.
J5 (OR)
Overrange Output. Connect to oscilloscope for
monitoring the output signal.
3.VCM , CLHI and SHDN turrets may be left floating.
This procedure contains a critical sequence. The user
must apply supply voltage before applying signal power
to the inputs or forcing a voltage to any other turrets. The
user must also remove the signal from the input ports
and voltages on any other turret before turning down
the supply voltage. This proper sequence will prevent
excessive current through the ESD diodes from any pin
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1
DEMO MANUAL DC1660B
quick start procedure
DC Power Supply
V+
GND
V + = 4.75V to 5.25V
Signal
Generator
Spectrum
Analyzer
DC1660B F01
T1
IMPEDANCE
RATIO
MABA-007159-000000
1:1
R2 = R6 =
VALUE (Ω)
24.9
POWER
GAIN (dB)
0
TMC4-19+
1:4
100
3
TC8-1G2+
1:8
200
4.5
Figure 1. Proper Measurement Equipment Setup
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2
DEMO MANUAL DC1660B
Applications Information
Input
CLHI
Demo board DC1660B’s single-ended input is AC-coupled
at port J1. The balun transformer T1 has a 1:4 impedance
ratio and it is matched to 50Ω at its input, when resistors
R2 and R6 are equal to 100Ω.
To DC-couple the inputs, replace DC blocking capacitors
C7 and C10 with 0Ω resistors.
Turret E5, labeled CLHI, controls the high side clamping
voltage of the LTC6417. If turret E5 is left floating, the
LTC6417 will self-bias the CLHI pin to 2.5V on a 5.0V
supply. The internal low side clamping voltage and CLHI
is symmetric with respect to VCM. When CLHI = 2.5V, and
VCM = 1.25V, internal low side clamp will be 0V. Either
output will be limited by these clamp voltages. See the
LTC6417 data sheet for more information.
Output
PWRADJ
The board’s output transformer T2 has a 1:1 impedance
ratio. T2 converts the LTC6417’s differential output signals
to a single-ended output.
Turret E4, labeled PWRADJ, scales the supply current of
the LTC6417. If turret E4 is left floating, the LTC6417 will
self-bias the PWRADJ pin to 1.6V on a 5.0V supply with
a supply current of approximately 115mA.
To drive the inputs differentially, remove capacitor C12.
To match T2 to 50Ω, change output series resistors R1
and R3 to 23.7Ω each.
For differential outputs, remove capacitor C11.
To DC-couple the outputs, replace DC blocking capacitors
C5 and C9 with a 0Ω resistor.
Additional Information
The demo board DC1660B is ready to use out of the box.
The demo board is shipped with the default configuration
as single ended input and output. However, it has features
that you can access by adding, removing or changing
components on the board. Refer to LTC6417 data sheet
for more information.
Output Common Mode Adjustment
Turret E1, labeled VCM, controls the output common mode
voltage of the LTC6417.
Shutdown
Turret E7, labeled SHUTDOWN, puts the LTC6417 into
sleep mode when pulled high, significantly reducing
supply current (~25mA). If turret E7 is left floating, the
LTC6417 will pull the SHUTDOWN pin to GND potential
and remain enabled.
Schematic Note
The schematic included at the end of this Quick Start Guide
includes approximate power gains at various points along
DC1660B’s signal chain. The power gains (PG1 – PG4)
assume single-ended 50Ω test system and the LTC6417
is operating in a small-signal region. If the output load is
a high-impedance load, the power gains PG3 – PG4 will
vary from the schematic.
This function can be used to set the DC output voltage for
optimum system performance.
In the default configuration, C5 and C9 block the DC output voltages. Replace these capacitors with 0Ω jumpers,
and the transmission-line type transformer T2 will couple
the DC voltages to the output port J3. If turret E1 is left
floating, the LTC6417 will self-bias the VCM pin to 1.25V
on a 5.0V supply. The VCM pin has a voltage range from
0.85V to 1.65V.
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DEMO MANUAL DC1660B
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
15
C1, C3, C4, C5, C7, C9, C10,
C13-C15, C17, C19-C21, C24
CAP., X5R, 0.1µF, 16V, 10% 0402
AVX, 0402YD104KAT2A
2
4
C2, C16, C18, C22
CAP., X7R, 680pF, 50V, 10% 0402
AVX, 04025C681KAT2A
3
2
C11, C12
CAP., X7R, 0.1µF, 25V, 20% 0603
AVX, 06033C104MAT2A
4
0
C6, C8, C23
CAP., OPT 0603
(OPT)
5
6
E1, E2, E3, E4, E5, E7
TESTPOINT TURRET, .061" PBF
MILL-MAX, 2308-2-00-80-00-00-07-0
6
5
J1, J2, J3, J4, J5
CON., SMA 50Ω EDGE-LAUNCH
E.F. JOHNSON, 142-0701-851/132357
7
2
R2, R6
RES., CHIP, 100Ω, 1/16W, 1% 0402
VISHAY CRCW0402100RFKED
8
4
R1, R3, R4, R5
RES., CHIP, 0Ω, 1/16W, 1% 0402
VISHAY, CRCW04020000Z0ED
9
0
R7, R8
RES., CHIP OPT 0402
(OPT)
10
1
T1
TRANSFORMER, TCM4-19+ SM-22
MINI-CIRCUITS TCM4-19+
11
1
T2
TRANSFORMER, ETC1-1-13, SM-22
M/A-COM, MABA-007159-000000 (PBF)
12
1
U1
I.C. LTC6417CUDC UDC 20 PIN (3×4)
LINEAR, LTC6417CUDC#PBF
13
1
FAB, PRINTED CIRCUIT BOARD
DEMO CIRCUIT 1660B
14
2
STENCILS TOP AND BOTTOM
STENCIL DC1660B
dc1660bf
4
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
C
J2
J5
C23
OPT
0603
4
5
TCM4-19+
T1
V+
C10
0.1uF
V+
C13
0.1uF
R6
100
R2
100
C4
0.1uF
PG4
10 GND
200
200
1:8
1:8
TC8-1G2+
TC8-1G2+
23.7
0
4
4.5
4.5
0
0
0
3
23.7
100
1:4
TCM4-19+
0
3
0
0
0
-3
0
0
0
0
-3
0
-3
0
0
23.7
100
1:4
TCM4-19+
24.9
1:1
MABA-007159-000000
0
1.5
4.5
0
3
-3
0
3
C21
0.1uF
R8
OPT
V+
C14
0.1uF
OUTPUT TERMINATION POWER GAIN = PG3
C22
680pF
R3
0
R7
OPT
R1
0
C3
0.1uF
C9
0.1uF
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
JOHN C.
APP ENG.
2
SCALE = NONE
LT
1
2
PCB DES.
APPROVALS
1. ALL RESISTORS AND CAPACITORS ARE 0402
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.
V+
__
ECO
2
REV
C11
0.1uF
0603
C6
OPT
0603
2ND PROTOTYPE
DESCRIPTION
DATE:
N/A
SIZE
VCM
OUT-
OUT+
GND
DATE
2-29-12
1
LTC6417CUDC
DEMO CIRCUIT 1660B
ADC BUFFER
SHEET 1
2
OF 1
REV.
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
Wednesday, February 29, 2012
IC NO.
TITLE: SCHEMATIC
TECHNOLOGY
JOHN C.
APPROVED
V+
4.75V - 5.25V
E1
J4
J3
E3
E2
1
REVISION HISTORY
OUTPUT TRANSFORMER POWER GAIN = PG4
C20
0.1uF
5
T2
C5 MABA-007159-000000
0.1uF
3
4
C2
680pF
2
NOTE: UNLESS OTHERWISE SPECIFIED
GND 21
OUT- 18
GND 17
OUT+ 19
GND 20
BUFFER POWER GAIN = PG2
PG
0
0
0
0
24.9
PG3
PG2
R1=R3
R2=R6
U1
LTC6417CUDC
Overall
PG1
C18
680pF
R5
0
9 IN-
8 IN+
7 GND
RATIO
C15
0.1uF
R4
0
C16
680pF
TRANSFORMATION
1:1
5
3
2
1
INPUT NETWORK POWER GAIN = PG1
MABA-007159-000000
T1
0.1uF
C24
C19
0.1uF
C12
0.1uF
0603
C8
OPT
0603
C7
0.1uF
V+
DEMO BOARD SIGNAL CHAIN:
PG=Power Gain (dB)
OR
SHUT E7
DOWN
IN-
IN+
J1
C1
0.1uF
V+
11
PWRADJ
12
D
V+ 6
SHUTDOWN
E4
NC 4
13
PWRADJ 5
NC
C17
0.1uF
GND 3
OR
14
CL HI
V+ 1
VCM
15
4
CL HI 2
V+
16
E5
5
A
B
C
D
DEMO MANUAL DC1660B
Schematic Diagram
dc1660bf
5
DEMO MANUAL DC1660B
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
dc1660bf
6
Linear Technology Corporation
LT 0412 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2012
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