Linear Technology DC1705C Quick setup guide

1
dc1705cfa
DEMO MANUAL DC1705C
Description
LTC6946
Ultralow Noise and Spurious Integer-N
Frequency Synthesizer with Integrated VCO
DC1705C features the LTC
®
6946, an ultralow noise and
spurious integer-N frequency synthesizer with integrated
VCO. The VCO uses no external components and is inter-
nally calibrated without external system support.
There are three versions of the DC1705C, one for each
version of the LTC6946. The DC1705C-A contains the
LTC6946-1, the DC1705C-B incorporates the LTC6946-2
and DC1705C-C uses the LTC6946-3.
Each DC1705C provides 50Ω SMA connectors for the
reference frequency input, fREF (REF+ IN), the reference
output buffer (REF OUT), and the differential RF output
(RF+and RF–). A DC590 USB serial controller board is
used for SPI communication with the LTC6946, controlled
by the supplied PLLWizard™ software.
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 and
PLLWizard and QuikEval are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Figure 1. Proper Measurement Equipment Setup

2
dc1705cfa
DEMO MANUAL DC1705C
PARAMETER INPUT OR OUTPUT PHYSICAL LOCATION DETAILS
3.3V Power Supply Input 3.3V and GND Banana Jacks Low Noise and Spur-Free 3.3V, 115mA
5V Power Supply Input 5V and GND Banana Jacks Low Noise and Spur-Free 5V, 45mA
REF+IN, Reference Frequency Input J1 SMA Connector Low Noise 10MHz or 100MHz*, 6dBm into 50Ω
(Note 1)
REF OUT, Buffered Reference Output J3 SMA Connector Frequency = fREF, 0dBm
RF+and RF–Two Outputs J4 and J5 SMA Connectors Frequency: 900MHz*, Power: 0dBm, Frequency
Range: Depends on the version of the LTC6946
device – refer to Table 1, Step Size: 200kHz*
Loop Bandwidth – Set by Loop Filter Component Values 47kHz*
* These frequencies are for the DC1705C pllset files included with PLLWizard.
Note 1: A low noise 10MHz or 100MHz reference frequency, such as the Wenzel 501-04608A or 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 PLLWizard so that fPFD is still 1MHz. For example, if a 20MHz clock is
used, fREF should be changed to 20MHz and R_DIV to 20. REF BST and FILT under the System tab in PLLWizard 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 LTC6946 data sheet.
Table 1. DC1705C Options and Frequency Ranges
ASSEMBLY VERSION PART NUMBER VCO FREQUENCY RANGE (GHz) OUTPUT DIVIDER SETTINGS
DC1705C-A LTC6946IUFD-1 2.240 to 3.740 Integers 1 through 6
DC1705C-B LTC6946IUFD-2 3.080 to 4.910 Integers 1 through 6
DC1705C-C LTC6946IUFD-3 3.840 to 5.790 Integers 1 through 6
typical Dc1705c requirements anD characteristics
quick start proceDure
The DC590 and PLLWizard application are required to
control the DC1705C through a personal computer (PC).
DC590 Configuration
The DC590’s QuikEval™ drivers must be installed before
the DC590 will be able to communicate with the LTC6946.
To configure the DC590, follow the procedure below, start-
ing with step 1. If you have already installed the DC590
software previously, skip to step 5.
Note: Once the QuikEval software is installed, the applica-
tion does not need to be executed to run PLLWizard or to
control the DC1705C.
1. Do Not plug in the DC590 before running the installation
program.
2. Download the QuikEval installation program from
http://www.linear.com/software.
3. Run the QuikEval installation program and follow the
on-screen instructions. More detailed installation infor-
mation may be found in the DC590’s Quick Start guide.
4. Exit the QuikEval program once the installation is com-
plete, as it is not needed to run the PLLWizard software.
5. Place the DC590 jumpers in the following positions:
JP4 EE Must be in the “EN” position.
JP5 ISO “ON” must be selected.
JP5 SW “ON” must be selected.
JP6 VCCIO “3.3V” must be selected. This sets the SPI
port to 3.3V operation.
6. Connect the DC590 to one of your computer’s USB
ports with the included USB cable.

3
dc1705cfa
DEMO MANUAL DC1705C
Figure 2. DC590 Jumper Locations
quick start proceDure
PLLWizard Installation
The PLLWizard software is used to communicate with
the LTC6946 synthesizer. It uses the DC590 to translate
between USB and SPI-compatible serial communications
formats. It also includes advanced PLL design and simula-
tion capabilities. The following are the PLLWizard system
requirements:
• WindowsOperatingSystem:WindowsXP,
Windows 2003 Server, Windows Vista, Windows 7
• Microsoft.NET2.0orlater
• WindowsInstaller3.1orlater
• LinearTechnology’sQuikEvalandDC590hardware
Microsoft .NET
You must have Microsoft .NET 2.0 or later installed on
your computer. PLLWizard will not run without it. Note that
with Windows Vista and Windows 7, you should have at
least version 3.5 pre-installed.
To manually determine your version of .NET using Win-
dows XP, click Start Menu →Settings →Control Panel
→Add or Remove Programs.
Depending upon your .NET version, choose one of
two PLLWizard setup programs, downloaded from
http://www.linear.com/software.

4
dc1705cfa
DEMO MANUAL DC1705C
quick start proceDure
Figure 3. PLLWizard Screenshot
Either setup program will automatically install Microsoft
.NET if a compatible .NET version is not found. But, the
installation source depends upon which file you down-
loaded from Linear Technology’s website. You should pick
one of the following two choices, depending upon your
version of .NET.
Table 2. PLLWizard Installation File
FILE .NET 2.0 SOURCE
PLLWizardSetup.exe Latest Version Downloaded from Microsoft
PLLWizardSetup_net20.exe 2.0 SP2 Included (Much Larger File Size)
• ChoosePLLWizardSetup if you have .NET 2.0 or later,
have Windows Vista or Windows 7, or if you have less
than .NET 2.0 but want the latest .NET installed.
• ChoosePLLWizardSetup_net20 if you have less than
.NET 2.0, and want faster installation (no additional
Microsoft downloads are needed, but the file size is
much larger).
The setup file will verify and/or install Microsoft .NET and
install PLLWizard. Refer to the Help menu for software
operation.

5
dc1705cfa
DEMO MANUAL DC1705C
quick start proceDure
DC1705C Configuration
1. Connect an appropriate reference frequency source (at
J1) and signal analyzers (at J4 and/or J5) using the
SMA connectors (see Figure 1 and the Typical DC1705C
Requirements and Characteristics table).
2. Choose theMUTE jumpersetting:JP1 - GND/3.3VMUTE
position. Select GND to mute the RF output, 3.3V to
un-mute.
3. Connect the GND, 3.3V and 5V banana jacks to a power
supply and apply power (see Figure 1 and the Typical
DC1705C Requirements and Characteristics table).
4. Connect the DC590 to the DC1705C with the provided
ribbon cable.
5. Run the PLLWizard application.
6. In PLLWizard, click File →Load Settings and point
to the appropriate pllset file. For example, if you are
using a 10MHz reference with a DC1705C-B to evalu-
ate the LTC6946-2, load the “DC1705-B (LTC6946-2)
10MHz.pllset” file found in the PLLWizard installation
directory (typically Program Files →LTC →PLLWizard
→ Set Files).
The red LED on DC1705C should turn on indicating that
the loop is locked at 900MHz.
You can then change the values of N_DIV and/or O_DIV
in PLLWizard to change the output frequency.
Troubleshooting
If the red LED does not illuminate, follow the instructions
below:
1. Verify that you are able to communicate with the
DC1705C. The bottom status line in PLLWizard should
read “LTC6946” and “Comm Enabled.” Refer to PLL-
Wizard’s Troubleshoot and Help if not.
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.
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 PLLWizard if the problem is not resolved.
DC1705C Reconfiguration
You can redesign the frequency plan of the DC1705C us-
ing PLLWizard. You can change the loop filter as found
using PLLWizard by reinstalling the loop filter components
shown in Figure 4.

6
dc1705cfa
DEMO MANUAL DC1705C
Figure 4. DC1705C Components and Connections
quick start proceDure

7
dc1705cfa
DEMO MANUAL DC1705C
parts list
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
DC1705C General BOM
1 1 CI1 CAP., X7R 0.022µF 50V 5%, 0603 AVX, 06035C223JAT2A
2 1 CI2 CAP., COG 6800pF 50V 5%, 0805 MURATA, GRM2195C1H682JA01D
3 1 CP CAP., COG 2700pF 50V 5%, 0603 MURATA, GRM1885C1H272JA01D
4 4 C1, C8, C9, C18 CAP., X7R, 1.0µF, 16V, 10%, 0805 TDK, C2012X7R1C105K
5 2 C2, C10 CAP., Tantalum, 330µF,10V, 10%, 7343 AVX, TPME337K010R0035
6 8 C3, C13, C17, C22-C26 CAP., X5R, 0.1µF, 10V, 10%, 0402 TDK, C1005X5R1A104K
7 2 C6, C11 CAP., X5R, 1µF, 16V, 10%, 0402 TDK, C1005X5R1C105K
8 4 C7, C12, C15, C19 CAP., X7R, 0.01µF, 16V, 10%, 0402 AVX, 0402YC103KAT2A
9 1 C14 CAP., X7R 0.022µF 16V, 10%, 0402 AVX, 0402YC223KAT2A
10 1 C16 CAP., X7R, 2.2µF, 16V, 10%, 0805 TDK, C2012X7R1C225K
11 2 C20, C21 CAP., NPO, 100pF, 50V, 5%, 0402 TDK, C1005C0G1H101J
12 1 D1 LED, RED ROHM, SML-010VTT86L
13 1 E3 TURRET, Testpoint, 2501 MILL-MAX, 2501-2-00-80-00-00-07-0
14 1 JP1 HEADERS, 3 Pins 2mm Ctrs. SAMTEC, TMM-103-02-L-S
15 4 J1, J3, J4, J5 CON., SMA 50-OHM EDGE-LAUNCH E.F. JOHNSON, 142-0701-851
16 1 J2 CON., Header, 14 Pin, 2mm MOLEX, 87831-1420
17 4 J6, J7, J8, J9 JACK, BANANA KEYSTONE, 575-4
18 2 L1, L2 IND, 68nH 5%, 0402 COILCRAFT, 0402HPH-68NXJLW
19 1 RZ RES., CHIP, 453Ω, 1/10W 1%, 0603 NIC, NRC06F4530TRF
20 1 R1 RES., CHIP, 51.1Ω, 1/16W, 1%, 0402 NIC, NRC04F51R1TRF
21 1 R3 RES., CHIP, 330Ω, 1/16W, 1%, 0402 NIC, NRC04F3300TRF
22 1 R4 RES., CHIP, 15Ω, 1/16W, 1%, 0402 NIC, NRC04F15R0TRF
23 4 R5, R6, R7, R13 RES., CHIP, 200K, 1/16W, 1%, 0402 NIC, NRC04F2003TRF
24 3 R8, R9, R14 RES., CHIP, 4.99K, 1/16W, 1%, 0402 NIC, NRC04F4991TRF
25 4 R10, R11, R12, R16 RES., CHIP, 100Ω 1/16W, 5%, 0402 NIC, NRC04J101TRF
26 1 R15 RES., CHIP, 0Ω, 0603 VISHAY, CRCW06030000Z0EA
27 2 U2, U3 I.C., Dual Buffer, SC70 FAIRCHILD SEMI., NC7WZ17P6X
28 1 U4 I.C., Dual Transceiver, SOT363 NXP, 74LVC1T45GW
29 1 U5 I.C., Serial EEPROM, TSSOP8 MICROCHIP, 24LC025-I/ST
30 1 SHUNT ON JP1 (2&3) SHUNT, 2mm Ctrs. SAMTEC, 2SN-BK-G
31 4 MH1-MH4 STANDOFF, NYLON, 0.5, 1/2" KEYSTONE, 8833 (SNAP ON)
32 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 1705C
DC1705C-A
1 1 GENERAL BOM DC1705C
2 1 U1 I.C. Synthesizer, QFN28UFD-4X5 LINEAR TECH., LTC6946IUFD-1#PBF
DC1705C-B
1 1 GENERAL BOM DC1705C
2 1 U1 I.C. Synthesizer, QFN28UFD-4X5 LINEAR TECH., LTC6946IUFD-2#PBF
DC1705C-C
1 1 GENERAL BOM DC1705C
2 1 U1 I.C. Synthesizer, QFN28UFD-4X5 LINEAR TECH., LTC6946IUFD-3#PBF

8
dc1705cfa
DEMO MANUAL DC1705C
schematic Diagram
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
VCO
2.24 TO 3.74 GHz 3.08 TO 4.91 GHz 3.84 TO 5.79 GHz
ASSY U1
*-A LTC6946IUFD-1
-B LTC6946IUFD-2 -C LTC6946IUFD-3
NOTE: UNLESS OTHERWISE SPECIFIED 1. ALL RESISTORS ARE IN OHMS, 0402
ALL CAPACITORS ARE IN MICROFARADS, 0402.
3.3V
5V
3.3V
3.3V
3.3V
3.3V
3.3V
3.3V
CS
SCLK
SDO
SDI
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.REBUILD WITH CHANGE
__
101-22-13
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.REBUILD WITH CHANGE
__
101-22-13
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
MICHEL A.REBUILD WITH CHANGE
__
101-22-13
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
12
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
12
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
12
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
C6 1uF C6 1uF
L2
68nH
0402HPH-68NXJL
5%
L2
68nH
0402HPH-68NXJL
5%
C12
0.01uF
C12
0.01uF
C8
1uF 16V
0805C8
1uF 16V
0805
J3
SMA-R
REF OUT
J3
SMA-R
REF OUT
JP1
GND
3.3V
MUTE
JP1
GND
3.3V
MUTE
1 3 2
C20 100pF 5% C20 100pF 5%
J1
SMA-R
REF+
IN
J1
SMA-R
REF+
IN
+
C2 330uF 10V 7343
+
C2 330uF 10V 7343
C9 1uF 16V 0805 C9 1uF 16V 0805
C16
2.2uF
16V
0805 C16
2.2uF
16V
0805
L1
68nH
0402HPH-68NXJL
5%
L1
68nH
0402HPH-68NXJL
5%
J5 SMA-R
RF+
J5 SMA-R
RF+
J7
GND
J7
GND
C21
100pF
5% C21
100pF
5%
R3 330 R3 330
J9
GND
J9
GND
J8
5V
J8
5V
C22
0.1uF
C22
0.1uF
TUNETUNE
C13 0.1uF C13 0.1uF
J6
3.3V
J6
3.3V
E3
STATUS
E3
STATUS
R4 15 R4 15
C19 0.01uF C19 0.01uF
U1 * U1 *
REFO
2
TUNE 15
STAT
3
MUTE
9
SCLK
5
V+D
8
SDO
7
RF+
12
RF-
11
GNDB
10
CS
4
TB 16
GNDC 17
V+RF
13
V+REFO
1
BB
14
SDI
6
CMc 18
CMb 19
CMa 20
GNDA 21
V+VCO 22
GNDD 23
V+CP 24
CP 25
V+REF 26
REF+ 27
REF- 28
GND 29
C7
0.01uF
C7
0.01uF
CI2
6800pF
0805
CI2
6800pF
0805
CP
2700pF
0603
CP
2700pF
0603
C15
0.01uF
C15
0.01uF
C14
0.022uF
C14
0.022uF
J4
SMA-R
RF-
J4
SMA-R
RF-
CI1
0.022uF
0603
CI1
0.022uF
0603
R1 51.1 1% R1 51.1 1%
C17 0.1uF C17 0.1uF
+
C10 330uF 10V 7343
+
C10 330uF 10V 7343
D1
SML-010VT
RED
D1
SML-010VT
RED
2 1
C11
1uF
C11
1uF
C18 1uF 16V 0805 C18 1uF 16V 0805
RZ 453 1% 0603 RZ 453 1% 0603
C1 1uF 16V 0805 C1 1uF 16V 0805

9
dc1705cfa
DEMO MANUAL DC1705C
schematic Diagram
Note: The buffers shown on sheet 2 of 2 of the schematic are used to protect the LTC6946 when communicating to it starts before powering it up. There is no
need for such circuitry if the SPI bus is not active before powering up the LTC6946. The EEPROM is for identification and is not needed to program the LTC6946.
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
0603
NOTE: EEPROM FOR BOARD IDENTIFICATION
DC590 SPI INTERFACE
3.3V
3.3V
3.3V
3.3V
CS
SCLK
SDI
SDO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
22
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
22
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
DEMO CIRCUIT 1705C
01/22/2013, 12:44 PM
22
ULTRALOW NOISE & SPURIOUS INTEGER-N
N/A LTC6946IUFD-1/-2/-3
KIM T.
MICHEL A.
SYNTHESIZER WITH INTEGRATED VCO
R11 100R11 100
C23 0.1uFC23 0.1uF
CSCS
C3
0.1uF
C3
0.1uF
R12
100
R12
100
R10
100
R10
100
V+DIGV+DIG
R7
200K
R7
200K
SDOSDO
J2
HD2X7-079-MOLEX
J2
HD2X7-079-MOLEX
MOSI/SDA 7
EESDA 9
V+ 1
5V 2
CS 6
SCK/SCL 4
EEVCC 10
MISO 5
EESCL 11
EEGND 12
AUX 14
GND
3
GND
13
GND
8
R6
200K
R6
200K
R15
0
R15
0
EEPROM
ARRAY
U5
24LC025-I /ST
EEPROM
ARRAY
U5
24LC025-I /ST
SDA
5
VCC 8
A0
1A1 2A2 3
GND
4
WP
7
SCL
6
R5
200K
R5
200K
C24 0.1uF C24 0.1uF
WPWP R13
200K
R13
200K
EEGNDEEGND
GND
DIR
VCC(A) VCC(B)
U4 74LVC1T45GW
GND
DIR
VCC(A) VCC(B)
U4 74LVC1T45GW
1 6
43 52
R8
4.99K
R8
4.99K
SDISDI
C25
0.1uF
C25
0.1uF
R16 100 R16 100
GND VCC
U3
NC7WZ17P6X
GND VCC
U3
NC7WZ17P6X
1 6
43 52
R9
4.99K
R9
4.99K
C26
0.1uF
C26
0.1uF
R14
4.99K
R14
4.99K
SCLKSCLK
GND VCC
U2
NC7WZ17P6X
GND VCC
U2
NC7WZ17P6X
1 6
43 52

10
dc1705cfa
DEMO MANUAL DC1705C
layout
The top metal layer of the DC1705C is shown here as an example of good PCB layout for the LTC6946.

11
dc1705cfa
DEMO MANUAL DC1705C
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.
revision history
BOARD REV DATE DESCRIPTION
Original Design
B 03/12 Added EEPROM for identification purposes.
C 05/13 Added support for 5V SPI in addition to the default 3.3V.

12
dc1705cfa
DEMO MANUAL DC1705C
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2012
LT REV A 0613 • 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.
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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation