DC1705A-B - LINEAR TECHNOLOGY

dc1705afa

DEMO MANUAL DC1705A

DESCRIPTION

LTC6946

Ultralow Noise and Spurious Integer-N

Frequency Synthesizer with Integrated VCO

DC1705A 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 DC1705A, one for each

version of the LTC6946. The DC1705A-A contains the

LTC6946-1, the DC1705A-B incorporates the LTC6946-2

and DC1705A-C uses the LTC6946-3.

Each DC1705A provides 50Ω SMA connectors for the

reference frequency input, fREF, the reference output buffer

(REF OUT), and the differential RF output (RF+ and RF–).

A DC590 USB serial controller board is used for SPI com-

munication 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

dc1705afa

DEMO MANUAL DC1705A

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 DC1705A 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. DC1705A Options and Frequency Ranges

ASSEMBLY VERSION PART NUMBER VCO FREQUENCY RANGE (GHz) OUTPUT DIVIDER SETTINGS

DC1705A-A LTC6946IUFD-1 2.240 to 3.740 Integers 1 through 6

DC1705A-B LTC6946IUFD-2 3.080 to 4.910 Integers 1 through 6

DC1705A-C LTC6946IUFD-3 3.840 to 5.790 Integers 1 through 6

TYPICAL DC1705A REQUIREMENTS AND CHARACTERISTICS

QUICK START PROCEDURE

The DC590 and PLLWizard application are required to

control the DC1705A 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 DC1705A.

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.

dc1705afa

DEMO MANUAL DC1705A

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 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.

dc1705afa

DEMO MANUAL DC1705A

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.

dc1705afa

DEMO MANUAL DC1705A

QUICK START PROCEDURE

DC1705A 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 DC1705A

Requirements and Characteristics table).

2. Choose the MUTE jumper setting: JP1 - GND/3.3V MUTE

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

DC1705A Requirements and Characteristics table).

4. Connect the DC590 to the DC1705A 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 DC1705A-B to evaluate the

LTC6946-2, load the “DC1705A-B (LTC6946-2) 10MHz

Ref.pllset” file found in the PLLWizard installation direc-

tory (typically Program Files → LTC → PLLWizard →

Set Files).

The red LED on DC1705A 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

DC1705A. 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.

DC1705A Reconfiguration

You can redesign the frequency plan of the DC1705A using

PLLWizard. You can change the loop filter components

as found using PLLWizard by reinstalling the loop filter

components shown in Figure 4.

Figure 4. DC1705A Components and Connections

dc1705afa

DEMO MANUAL DC1705A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

DC1705A General BOM

1 1 CI1 Capacitor, X7R 0.022μF 50V 5% 0603 AVX 06035C223JAT2A

2 1 CI2 Capacitor, COG 6800pF 50V 5% 0805 Murata GRM2195C1H682JA01D

3 1 CP Capacitor, COG 2700pF 50V 5% 0603 Murata GRM1885C1H272JA01D

4 4 C1, C8, C9, C18 Capacitor, X7R, 1μF, 16V, 10%, 0805 TDK, C2012X7R1C105K

5 2 C2, C10 Capacitor, Tantalum, 330μF, 10V, 10%, 7343 AVX, TPME337K010R0035

6 2 C6, C11 Capacitor, X7R, 470pF, 50V, 10%, 0402 AVX, 04025C471KAT2A

7 4 C7, C12, C15,

C19

Capacitor, X7R, 0.01μF, 16V, 10%, 0402 AVX, 0402YC103KAT2A

8 C13, C14, C17,

C22, C23,

Capacitor, X5R, 0.1μF, 10V, 10%, 0402 TDK, C1005X5R1A104K

8 C24, C25, C26

9 1 C16 Capacitor, X7R, 2.2μF, 16V, 10%, 0805 TDK, C2012X7R1C225K

10 2 C20, C21 Capacitor, NPO, 100pF, 50V, 5%, 0402 TDK, C1005C0G1H101J

11 1 D1 LED, Red Panasonic, LN1251CTR

12 4 E1, E2, E5, E8 Jack, Banana Keystone, 575-4

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 1 XJP1 Shunt, 2mm Ctrs. Samtec 2SN-BK-G

16 4 J1, J3, J4, J5 Connector, SMA 50Ω EDGE-LAUNCH E. F. Johnson, 142-0701-851

17 1 J2 Connector, Header, 14-Pin, 2mm Molex, 87831-1420

18 2 L1, L2 Inductor, Chip, 68nH, ±5%, 0402 Coilcraft, 0402 HPH-68NXJL

19 1 RZ Resistor, Chip, 453 1/10W 1% 0603 NIC, NRC06F4530TRF

20 1 R1 Resistor, Chip, 51.1Ω, 1/16W, 1% 0402 NIC, NRC04F51R1TRF

21 1 R3 Resistor, Chip, 330Ω, 1/16W, 1% 0402 NIC, NRC04F3300TRF

22 1 R4 Resistor, Chip, 15Ω, 1/16W, 1% 0402 NIC, NRC04F15R0TRF

23 4 R5, R6, R7, R13 Resistor, Chip, 200k, 1/16W, 1% 0402 NIC, NRC04F2003TRF

24 2 R8, R9 Resistor, Chip, 4.99k, 1/16W, 1% 0402 NIC, NRC04F4991TRF

25 3 R10, R11, R12 Resistor, Chip, 100Ω 1/16W, 5%, 0402 NIC, NRC04J101TRF

26 2 U2, U3 IC, Dual Buffer SC-70 6-Lead Fairchild Semi. NC7WZ17P6X

27 1 U4 IC, Dual Transceiver SC-70 6-Lead NXP 74LVC1T45GW

28 4 4 Corners Standoff, Nylon, 0.5, 1/2" Keystone, 8833 (SNAP ON)

DC1705A-A

1 1 DC1705A General BOM DC1705A

21U1 IC Synthesizer QFN-28 4mm × 5mm Linear Technology Corporation, LTC6946IUFD-1

DC1705A-B

1 1 DC1705A General BOM DC1705A

21U1 IC Synthesizer QFN-28 4mm × 5mm Linear Technology Corporation, LTC6946IUFD-2

DC1705A-C

1 1 DC1705A General BOM DC1705A

21U1 IC Synthesizer QFN-28 4mm × 5mm Linear Technology Corporation, LTC6946IUFD-3

dc1705afa

DEMO MANUAL DC1705A

SCHEMATIC DIAGRAM

dc1705afa

DEMO MANUAL DC1705A

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.

dc1705afa

DEMO MANUAL DC1705A

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.

LAYOUT

The top metal layer of the DC1705A is shown here as an example of good PCB layout for the LTC6946.

dc1705afa

DEMO MANUAL DC1705A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com

LT 1211 REV A • 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