DC1959B - Demo Manual

DEMO MANUAL DC1959B
LTC6948
Ultralow Noise and Spurious Fractional-N
Synthesizer with Integrated VCO
Description
Demonstration circuit 1959B features the LTC6948, an
Ultralow Noise and Spurious Fractional-N Synthesizer
with Integrated VCO.
A DC590 USB serial controller board is used for SPI communication with the LTC6948, controlled by the supplied
FracNWizard™ software.
There are four options of the DC1959B, one for each version of the LTC6948. Table 1 summarizes the available
DC1959B options.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1959B
The DC1959B provides 50Ω SMA connectors for the reference frequency input fREF (REF+IN) and the differential
RF output (RF+ and RF–).
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
FracNWizard is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
FREQUENCY
REFERENCE
INPUT, SMA
LOOP FILTER
COMPONENTS
RIBBON CABLE
CONNECTION
TO DC590
5V DC SUPPLY,
BANANA JACKS
3.3V DC SUPPLY,
BANANA JACKS
MUTE
JUMPER
DIFFERENTIAL
OUTPUT, SMA
Figure 1. DC1959B Connections
dc1959bfa
1
DEMO MANUAL DC1959B
Quick Start Procedure
The DC1959B is easy to set up to evaluate the performance
of the LTC6948. Follow the procedure below.
Connect the DC590 to one of your computer’s USB ports
with the included USB cable.
The DC590 and FracNWizard application are required to
control the DC1959B through a personal computer (PC).
FracNWizard Installation
JP4: EE – Must be in the EN position.
The FracNWizard software is used to communicate with
the LTC6948 synthesizer. It uses the DC590 to translate
between USB and SPI-compatible serial communications formats. It also includes advanced PLL design and
simulation capabilities. The following are the FracNWizard
system requirements:
JP5: ISO – ON must be selected.
n
DC590 Configuration
Place the DC590 jumpers in the following positions (refer
to Figure 2):
Windows Operating System: Windows XP, Windows
2003 Server, Windows Vista, Windows 7
JP5: SW – ON must be selected.
JP6: VCCIO – 3.3V must be selected. This sets the SPI
port to 3.3V operation.
Microsoft .NET 3.5 SP1 or later
n
Windows Installer 3.1 or later
n
Linear Technology’s DC590 hardware
n
J4, RIBBON
CABLE
CONNECTION
TO THE
DC1959
J3,
USB CONNECTION
TO PC
JP4
JUMPER
JP6
JUMPERS
JP5 JUMPERS
Figure 2. DC590 Jumper and Connector Locations
2
dc1959bfa
DEMO MANUAL DC1959B
Quick Start Procedure
Download the FracNWizard setup file at www.linear.com/
FracNWizard.
JP1: GND/3.3V – MUTE position. Select GND to mute
the RF output, 3.3V to un-mute.
Run the FracNWizard setup file and follow the instructions
given on the screen. The setup file will verify and/or install
Microsoft .NET and install the FracNWizard. Refer to the
Help menu for software operation.
3.Connect the GND, 3.3V, and 5V banana jacks to a power
supply and apply power (see Figure 1 and the Typical
DC1959B Requirements and Characteristics table).
DC1959B Configuration
1.Connect a 100MHz reference frequency source to REF+IN
(at J1) and signal analyzers to RF+ and/or RF– (at J5
and/or J4) using the SMA connectors (see Figure 1 and
the Typical DC1959B Requirements and Characteristics
table).
Be sure to terminate any unused RF output with 50Ω,
or poor spurious performance may result.
2.Choose the MUTE jumper setting:
4.Connect the DC590 to the DC1959B with the provided
ribbon cable.
5.Run the FracNWizard application.
6.In FracNWizard, click File -> Load Settings and point to
the LTC6948-1_100MHz.fracnset file in case of evaluating the LTC6948-1, for instance, or load the appropriate
file depending on which option of the LTC6948 you are
evaluating.
The red LED on the DC1959B should turn on indicating
that the loop is locked and the output is at 907MHz.
Figure 3. FracNWizard Screenshot
dc1959bfa
3
DEMO MANUAL DC1959B
Quick Start Procedure
Troubleshooting
If the red LED is on but you cannot detect an RF output,
make sure jumper JP1 is at the 3.3V position. Run Help ->
Troubleshoot in FracNWizard if the problem is not resolved.
If the red LED does not illuminate, follow the instructions
below:
1.Verify that you are able to communicate with the
DC1959B. The bottom status line in FracNWizard should
read LTC6948 and Comm Enabled as shown in Figure 3.
Refer to FracNWizard’s Troubleshoot and Help if not.
DC1959B Reconfiguration
You can redesign the frequency plan of the DC1959B using
FracNWizard. You can change the loop filter as found using FracNWizard by reinstalling the loop filter components
shown in Figure 1.
2.Verify that the 3.3V and 5V have the correct voltages
on them and that the reference frequency is applied to
the REF+IN SMA input.
Assembly Options
Table 1. DC1959B Options and Frequency Ranges
ASSEMBLY VERSION
PART NUMBER
VCO FREQUENCY RANGE (GHz)
OUTPUT DIVIDER SETTINGS
DC1959B-A
LTC6948IUFD-1
2.240 to 3.740
Integers 1 through 6
DC1959B-B
LTC6948IUFD-2
3.080 to 4.910
Integers 1 through 6
DC1959B-C
LTC6948IUFD-3
3.840 to 5.790
Integers 1 through 6
DC1959B-D
LTC6948IUFD-4
4.200 to 6.390
Integers 1 through 6
Typical DC1959B Requirements and Characteristics
PARAMETER
INPUT OR OUTPUT PHYSICAL LOCATION
DETAILS
3.3V Power Supply
Input
J6 and J7 Banana Jacks
Low-Noise and Spur-Free 3.3V, 130mA
5V Power Supply
Input
J8 and J9 Banana Jacks
Low-Noise and Spur-Free 5V, 33mA
REF+ IN, Reference Frequency Input
J1 SMA Connector
Low-Noise 100MHz*, 6dBm to 10dBm into 50Ω, See Note
Below
RF+ and RF–
Two Outputs
J4 and J5 SMA Connectors**
Frequency: 907MHz*, Power: 0dBm, Frequency Range:
Depends on the Version of the LTC6948 Device – Refer to
Table 1
Loop Bandwidth
–
Set by Loop Filter Component Values Approximately 160kHz* Depending on the DC1959B Version
*These frequencies are for the DC1959B fracnset files included with FracNWizard.
**Any unused RF output must be terminated with 50Ω, or poor spurious performance may result.
Note: A low noise 100MHz reference frequency, such as the Wenzel 501-04516D OCXO, is recommended. If using a different frequency, make sure to
update the Fref and R_DIV boxes under the System tab in FracNWizard so that Fpfd is still 50MHz. For example, if a 250MHz clock is used, Fref should be
changed to 250MHz and R_DIV to 5. Ref BST and FILT under the System tab in FracNWizard might need to be changed if the reference frequency and/or
power is different than what is recommended in the table above. More information can be found in the LTC6948 data sheet.
4
dc1959bfa
DEMO MANUAL DC1959B
PCB Layout
The top metal layer of the DC1959B is shown here as an example of good PCB layout for the LTC6948.
dc1959bfa
5
DEMO MANUAL DC1959B
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
Required Circuit Components
1
0
CI2
CAP., 0805
OPT
2
5
C1, C8, C9, C15, C18
CAP., X7R, 1.0µF, 16V, 10%, 0603
TDK, C1608X7R1C105K
3
2
C2, C10
CAP., TANT., 330µF, 10V, 10%, 7343
AVX, TPME337K010R0035
4
9
C3, C7, C17, C22-C27
CAP., X7R, 0.1µF, 10V, 10%, 0402
TDK, C1005X7R1A104K
5
2
C6, C11
CAP., X5R, 1.0µF, 16V, 10%, 0402
TDK, C1005X5R1C105K
6
3
C12, C13, C19
CAP., X7R, 0.01µF, 16V, 10%, 0402
AVX, 0402YC103KAT2A
7
1
C16
CAP., X5R, 2.2µF, 16V, 10%, 0603
TDK, C1608X5R1C225K
8
0
C2_F2, C28
CAP., 0603
OPT
9
2
C20, C21
CAP., X7R, 100pF, 50V, 10%, 0402
AVX, 04025C101KAT2A
10
1
D1
LED, RED
PANASONIC, LN1251C-TR
11
1
E3
TURRET, TESTPOINT, 2501
MILL-MAX, 2501-2-00-80-00-00-07-0
12
1
JP1
HEADERS, 3 PINS 2mm CTRS.
SAMTEC, TMM-103-02-L-S
13
3
J1, J4, J5
CON., SMA 50Ω EDGE-LAUNCH
E.F. JOHNSON, 142-0701-851
14
1
J2
CON., HEADER, 14 PIN, 2mm
MOLEX, 87831-1420
15
4
J6, J7, J8, J9
JACK, BANANA
KEYSTONE, 575-4
16
2
L1, L2
IND., 68nH 5%, 0402
COILCRAFT, 0402HPH-68NXJLW
17
1
L1_F1
IND., 10µH, 0805
TDK, MLF2012E100K
18
0
L1_F2
IND., 0805
OPT
19
1
R1
RES., CHIP, 51.1Ω, 1/16W, 1%, 0402
NIC, NRC04F51R1TRF
20
0
R1_F2
RES., 0603
OPT
21
4
R2, R18, R19, R20
RES., CHIP, 0Ω, 0402
NIC, NRC04Z0TRF
22
1
R3
RES., CHIP, 330Ω, 1/16W, 1%, 0402
NIC, NRC04F3300TRF
23
1
R4
RES., CHIP, 15Ω, 1/16W, 1%, 0402
NIC, NRC04F15R0TRF
24
4
R5, R6, R7, R13
RES., CHIP, 200k, 1/16W, 1%, 0402
NIC, NRC04F2003TRF
25
3
R8, R9, R14
RES., CHIP, 4.99k, 1/16W, 1%, 0402
NIC, NRC04F4991TRF
26
3
R10, R11, R12, R21
RES., CHIP, 100Ω 1/16W, 5%, 0402
NIC, NRC04J101TRF
27
1
R15
RES., CHIP, 0Ω, 0603
NIC, NRC06Z0TRF
28
2
U2, U3
I.C., DUAL BUFFER, SC70-6
FAIRCHILD SEMI., NC7WZ17P6X
29
1
U4
I.C., DUAL TRANSCEIVER, SOT363
NXP, 74LVC1T45GW+125
30
1
U5
I.C., SERIAL EEPROM, TSSOP8
MICROCHIP, 24LC025-I /ST
31
1
SHUNT ON JP1
SHUNT, 2mm CTRS.
SAMTEC 2SN-BK-G
6
dc1959bfa
DEMO MANUAL DC1959B
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
DC1959B-A Required Circuit Components
1
1
2
1
C2_F1
DC1959B GENERAL BOM
CAP., C0G, 2.4nF, 50V, 5%, 0603
MURATA, GRM1885C1H242JA01D
3
1
CI1
CAP., X7R, 82nF, 50V, 10%, 0603
MURATA, GRM188R71H823KA93D
4
1
CP
CAP., C0G, 3.6nF, 50V, 5%, 0603
MURATA, GRM1885C1H362JA01D
5
2
R1_F1, RZ
RES., CHIP, 57.6Ω, 1/16W, 1%, 0603
NIC, NRC06F57R6TRF
6
1
U1
I.C. SYNTHESIZER, QFN28UFD-4X5
LINEAR TECH., LTC6948IUFD-1
DC1959B-B Required Circuit Components
1
1
2
1
C2_F1
DC1959B GENERAL BOM
CAP., C0G, 2nF, 50V, 5%, 0603
MURATA, GRM1885C1H202JA01D
3
1
CI1
CAP., X7R, 68nF, 50V, 10%, 0603
MURATA, GRM188R71H683KA93D
4
1
CP
CAP., C0G, 3nF, 50V, 5%, 0603
MURATA, GRM1885C1H302JA01D
5
2
R1_F1, RZ
RES., CHIP, 63.4Ω, 1/16W, 1%, 0603
NIC, NRC06F63R4TRF
6
1
U1
I.C. SYNTHESIZER, QFN28UFD-4X5
LINEAR TECH., LTC6948IUFD-2
DC1959B-C Required Circuit Components
1
1
DC1959B GENERAL BOM
2
1
C2_F1
CAP., X7R, 1.8nF, 50V, 10%, 0603
MURATA, GRM188R71H182KA01D
3
1
CI1
CAP., X7R, 56nF, 50V, 10%, 0603
MURATA, GRM188R71H563KA93D
4
1
CP
CAP., C0G, 2.4nF, 50V, 5%, 0603
MURATA, GRM1885C1H242JA01D
5
2
R1_F1, RZ
RES., CHIP, 75Ω, 1/16W, 5%, 0603
VISHAY, CRCW060375R0JNEA
6
1
U1
I.C. SYNTHESIZER, QFN28UFD-4X5
LINEAR TECH., LTC6948IUFD-3
DC1959B-D Required Circuit Components
1
1
DC1959B GENERAL BOM
2
1
C2_F1
CAP., C0G, 1.6nF, 50V, 5%, 0603
MURATA, GRM1885C1H162JA01D
3
1
CI1
CAP., X7R, 56nF, 50V, 10%, 0603
MURATA, GRM188R71H563KA93D
4
1
CP
CAP., C0G, 2.4nF, 50V, 5%, 0603
MURATA, GRM1885C1H242JA01D
5
2
R1_F1, RZ
RES., CHIP, 76.8Ω, 1/16W, 1%, 0603
NIC, NRC06F76R8TRF
6
1
U1
I.C. SYNTHESIZER, QFN28UFD-4X5
LINEAR TECH., LTC6948IUFD-4
dc1959bfa
7
A
B
C
*
SMA-R
J1
J9
J8
J7
J6
STATUS
C9
1uF
0603
C1
1uF
0603
E3
330uF
10V
7343
+ C10
5V
330uF
10V
7343
+ C2
A
B
C
D
ASSY
5
LTC6948-1
LTC6948-2
LTC6948-3
LTC6948-4
U1
1
2
3
4
SUFFIX
2.24 TO 3.74 GHz
3.08 TO 4.91 GHz
3.84 TO 5.79 GHz
4.20 TO 6.39 GHz
VCO
1. ALL RESISTORS ARE IN OHMS, 0402
2. ALL CAPACITORS ARE IN MICROFARADS, 0402
4
2.4nF
2nF
1.8nF
1.6nF
C2_F1
D1
LN1251C
R3
330
NOTE: UNLESS OTHERWISE SPECIFIED
REF+
IN
GND
5V
GND
3.3V
82nF
68nF
56nF
56nF
CI1
GND
3.3V
1
C27
0.1uF 3.3V
57.6
63.4
75
76.8
R1_F1, RZ
3.3V
3.6nF
3nF
2.4nF
2.4nF
CP
JP1
2
3
C28
OPT
0603
MUTE
SDO
SDI
SCLK
CS
R1
51.1
C6
1uF
3.3V
R20
0
V+D
LDO
SDO
SDI
SCLK
CS
STAT
REF+
R2
0
3.3V
*
0603
C2_F1
*
C12
0.01uF
C8
1uF 0603
R4
15
C21
100pF
RF+
J5
SMA-R
C13
0.01uF
R18
0
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
RF-
C20
100pF
3.3V
15
16
17
18
19
20
21
22
*
CP
0603
L2
3.3V
68nH
0402HPH-68NXJL
C19
0.01uF
R19
0
TUNE
TB
GNDB
CMC
CMB
CMA
GNDC
BVCO
5V
0805
L1_F1
10uH
0805
0603
CI2
OPT
*
CI1
2
2
SCALE = NONE
__
ECO
DATE:
N/A
SIZE
CHRIS P.
APPROVED
DATE
09-21-15
IC NO.
Monday, September 21, 2015
1
DEMO CIRCUIT 1959B
SHEET
1
OF
ULTRALOW NOISE & SPURIOUS FRACTIONAL-N
SYNTHESIZER WITH INTEGRATED VCO
LTC6948IUFD-1/2/3/4
TECHNOLOGY
TUNE
C2_F2
OPT
0603
R1_F2
OPT
0603
1
2
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
REBUILD WITH CHANGE
1
L1_F2
OPT
0805
DESCRIPTION
REVISION HISTORY
REV
TITLE: SCHEMATIC
*0603
RZ
CHRIS P.
KIM T.
APPROVALS
C22
0.1uF
C18
1uF
0603
0603
C16
2.2uF
C15
1uF 0603
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
J4
SMA-R
U1
*
0603
R1_F1
QFN28UFD-4X5
L1
68nH
0402HPH-68NXJL
C17
0.1uF
8
7
6
5
4
3
2
1
C11
1uF
C7
0.1uF
3
24
3.3V
4
29
GND
28
REF-
27
GNDA
10
RF-
11
BB
1
2
CP
26
V+REF
25
V+CP
RF+
12
MUTE
9
V+VCO
23
GNDD
V+RF
13
8
14
D
5
A
B
C
D
DEMO MANUAL DC1959B
Schematic Diagram
dc1959bfa
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
D
5
1
V+ 2
5V
6
CS 4
SCK/SCL 7
MOSI/SDA 5
MISO
10
EEVCC 9
EESDA 11
EESCL 12
EEGND 14
AUX
J2
HD2X7-079-MOLEX
WP
R8
4.99K
6
5
7
3
2
1
SCL
SDA
WP
A2
A1
A0
U5
24LC025-I /ST
R9
4.99K
3
R15
0
0603
C3
0.1uF
4
3
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
R21
100
C26
0.1uF
R6
200K
R5
200K
R7
200K
3
2
1
5
2
SCALE = NONE
DATE:
N/A
SIZE
VCC
DIR
VCC(B)
5
4
5
6
C25
0.1uF
1
SDO
SDI
SCLK
CS
IC NO.
2
Monday, September 21, 2015
DEMO CIRCUIT 1959B
1
SHEET
2
OF
ULTRALOW NOISE & SPURIOUS FRACTIONAL-N
SYNTHESIZER WITH INTEGRATED VCO
LTC6948IUFD-1/2/3/4
2
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
R13
200K
3.3V
C24
0.1uF
R12
100
0.1uF
R11 100
R10
100
C23
3.3V
3.3V
TECHNOLOGY
GND
VCC(A)
U4
74LVC1T45GW
GND
4
3
2
6
1
U3
NC7WZ17P6X
4
3
VCC
6
GND
U2
NC7WZ17P6X
1
2
CHRIS P. TITLE: SCHEMATIC
KIM T.
APPROVALS
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
APP ENG.
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
CUSTOMER NOTICE
3.3V
DC590 SPI INTERFACE
NOTE: EEPROM FOR BOARD IDENTIFICATION
EEGND
R14
4.99K
V+DIG CS SCLK SDI SDO
ARRAY
GND
GND
GND
13
8
3
4
EEPROM
8
VCC
GND
4
5
A
B
C
D
DEMO MANUAL DC1959B
Schematic Diagram
Note: The buffers shown on sheet 2 of 2 of the schematic are used to protect the LTC6948 when connected to the DC590 before the LTC6948 is powered up. There is no
need for such circuitry if the SPI bus is not active before powering up the LTC6948. The EEPROM is for identification and is not needed to program the LTC6948.
dc1959bfa
9
DEMO MANUAL DC1959B
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
dc1959bfa
LT 0915 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014