DC1846A-A - LINEAR TECHNOLOGY

dc1846af

DEMO MANUAL DC1846A

DESCRIPTION

LTC6947

Ultralow Noise and Spurious

Fractional-N Synthesizer

Demonstration circuit 1846A features the LT C

6947, an

Ultralow Noise and Spurious Fractional-N Synthesizer.

DC1846A provides 50Ω SMA connectors for the reference

frequency (REF+) and the two single-ended RF outputs

(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.

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

munication with the LTC6947, controlled by the supplied

FracNWizard™ software.

Design files for this circuit board are available at

http://www.linear.com/demo

Figure 1. DC1846A Connections



Frequency

referenceinput,

SMA

ExternalVCO

input,SMA

Differential

outputofVCO

buffer,SMA

3.3VDCsupply,

bananajacks

5VDCsupply,

bananajacks

Ribbon

cable

connection

toDC590

Activeloopfilterop‐

ampDCsupply,turret

U3(VCO)DC

supply,turret

U4(VCOorVCXO)

DCsupply,turret

Enable(pin2)

ofU4(VCOor

VCXO),turret

dc1846af

DEMO MANUAL DC1846A

QUICK START PROCEDURE

The DC1846A is easy to set up to evaluate the performance

of the LTC6947. Follow the procedure below.

The DC590 and FracNWizard application are required to

control the DC1846A through a personal computer (PC).

DC590 Configuration

Place the DC590 jumpers in the following positions (refer

to Figure 2):

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.

Connect the DC590 to one of your computer’s USB ports

with the included USB cable.

FracNWizard Installation

The FracNWizard software is used to communicate with

the LTC6947 synthesizer. It uses the DC590 to translate

between USB and SPI-compatible serial communica-

tions formats. It also includes advanced PLL design and

simulation capabilities. The following are the FracNWizard

system requirements:

• Windows Operating System: Windows XP, Windows

2003 Server, Windows Vista, Windows 7

• Microsoft .NET 3.5 SP1 or later

• Windows Installer 3.1 or later

• Linear Technology’s DC590 hardware

Figure 2. DC590 Jumper and Connector Locations



JP6

jumpers

J4,ribbon

cable

connection

tothe

DC1846

JP5jumpers

JP4

jumper

J3,USB

connection

toPC

dc1846af

DEMO MANUAL DC1846A

QUICK START PROCEDURE

Download the FracNWizard setup file at:

www.linear.com/FracNWizard

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.

DC1846A Configuration

1. Connect a 100MHz reference frequency source (at J2)

and signal analyzers to RF+ and/or RF– (at J6 and/or

J7) using the SMA connectors (see Figure 1 and the

Typical DC1846A 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:

JP1: GND/3.3V - MUTE position. Select GND to mute

the RF output, 3.3V to unmute.

3. Connect the GND, 3.3V, 5V banana jacks and the

V+VCO turret to a power supply and apply power (see

Figure 1 and the Typical DC1846A Requirements and

Characteristics table).

4. Connect the DC590 to the DC1846A with the provided

ribbon cable.

5. Run the FracNWizard application.

6. In FracNWizard, click File -> Load Settings and point

to the “LTC6947_100MHz.fracnset” file.

The red LED on the DC1846A should turn on indicating

that the loop is locked at 2415MHz.

Figure 3. FracNWizard Screenshot

dc1846af

DEMO MANUAL DC1846A

QUICK START PROCEDURE

DC1846A RECONFIGURATION

Troubleshooting

If the red LED does not illuminate, follow the instructions

below:

1. Verify that you are able to communicate with the

DC1846A. The bottom status line in FracNWizard

should read “LTC6947” and “Comm Enabled”. Refer

to FracNWizard’s Troubleshoot and Help if not.

2. Verify that the 3.3V, 5V and V+VCO have the correct

voltages on them and that the reference frequency is

applied to the REF+ SMA input.

If the red LED is on but you cannot detect an RF output,

make sure the DC1846A jumper JP1 is at the 3.3V position.

Run Help -> Troubleshoot in FracNWizard if the problem

is not resolved.

The DC1846A is flexible and allows the use of a variety of

VCOs and the choice to employ either an active or pas-

sive loop filter. The following covers the hardware recon-

figuration of the DC1846A. Refer to FracNWizard’s Help

and the LTC6947 data sheet to better understand how to

change programmed parameters on the DC1846A.

Installing Different Tunable Devices

The DC1846A permits the use of different tunable oscil-

lators, such as VCOs and VCXOs. There are two different

oscillator footprints on the board: U3, which accommodates

the popular 0.5 × 0.5 in. package, and U4, which accom-

modates another common 14mm × 9 mm package with

four or six pins. An external connectorized VCO can also

drive the LTC6947 through J5. Table 1 gives options to

customize the DC1846’s VCOs. When using an active loop

filter, an additional pole is required in the loop filter to limit

the op amp’s noise contribution to the VCO phase noise.

Selecting Loop Filter Type

The DC1846A can use either an active or a passive loop

filter, depending upon the application. Some VCO tuning

voltage ranges are greater than the LTC6947 charge pump

voltage range (refer to the LTC6947 data sheet). In such

cases, an active loop filter using an op amp can deliver

the required tuning voltage. Table 2 summarizes these

options. FracNWizard helps determine the component

values listed in this table.

Table 1. Oscillator Options

TUNABLE

DEVICE

SELECTION

COMPONENTS

RESISTOR FOR

ADDITIONAL POLE

CAPACITOR FOR

ADDITIONAL POLE POWER

ENABLE PIN OR

REMARKS

U3* C26 ≅ 100pF, depopulate

R2_F3, C25 and C28*

R2_F2 = 0Ω for passive

loop filter*

R2_F2 = 75Ω for active

loop filter

C3_F2 = Open for passive

loop filter*

Pick C3_F2 such that

1/(2π × R2_F2 × C3_F2) ≅

15 × the loop bandwidth in

Hz for active loop filter

Determined by U3

device power supply

specification, up to 24V

applied to V+VCO turret

U4 C28 ≅ 100pF, depopulate

R2_F2, C25 and C26

R2_F3 = 0Ω for passive

loop filter

R2_F3 ≅ 75Ω for active

loop filter

C3_F3 = Open for passive

loop filter

Pick C3_F3 such that

1/(2π × R2_F3 × C3_F3) ≅

15 × the loop bandwidth in

Hz for active loop filter

Determined by U4

device power supply

specification, up to 24V

applied to V+VCXO turret

Use EN turret to control

pin 2 of U4 if needed

External C25 ≅ 100pF, R15 = 0Ω

Ohms, depopulate R13,

C26 and C28

- - - Selection components

are for an active loop

filter. Connect the

external VCO output to

J5. Use CPGAIN to tune

the external device.

*These are the default installation options. For the DC1846A-A, U3 is populated with CVCO55CC-2328-2536 from Crystek

dc1846af

DEMO MANUAL DC1846A

TYPICAL DC1846A REQUIREMENTS AND CHARACTERISTICS

DC1846A RECONFIGURATION

Table 2. Loop Filter Options

LOOP FILTER

TYPE

SELECTION

RESISTORS

RZ FROM

FRACNWIZARD

CI FROM

FRACNWIZARD

CP FROM

FRACNWIZARD POWER

CPINV BOX,

SYSTEM TAB IN

FRACNWIZARD

Passive R14 and R16 = 0Ω,

depopulate R13 and

R15

RZ_P CI1_P in parallel

with CI2_P

CP_P None Unchecked

Active R13 (except when

using an external

VCO) and R15 = 0Ω,

depopulate R14 and

R16

RZ_A CI1_A in parallel

with CI2_A

CP_A Determined by the

maximum allowed

tune voltage of the

populated VCO (U3

or U4), up to 24V

applied to V+OA

turret

Checked

PARAMETER INPUT OR OUTPUT PHYSICAL LOCATION DETAILS

3.3V Power Supply Input J9 and J10 banana jacks Low noise and spur-free 3.3V,

103mA**

5V Charge Pump Power Supply Input J11 and J12 banana jacks Low noise and spur-free 5V,

22mA**

5V VCO Power Supply Input V+VCO turret Low noise and spur-free 5V,

30mA**

REF+, Reference Frequency Input J2 SMA connector Low noise 100MHz**, 6 to 10dBm

into 50Ω, see Note

RF+ and RF– Tw o Outputs J6 and J7 SMA connectors*** 2328 to 2536MHz** in 190.7Hz**

steps, 0dBm

Loop Bandwidth – Set by loop filter component values 30.7kHz**

**These values are for the “DC1846A_100MHz.fracnset” file and included VCO.

***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 LTC6947 data sheet.

dc1846af

DEMO MANUAL DC1846A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

1 0 CI1_A, C3_F2, C3_F3, CP_A, C14 CAP, 0603 OPT

2 6 CI1_P, C5, C12, C13, C18, C31 CAP, 0603 1.0µF 10% 10V X7R TAIYO YUDEN, LMK107B7105KA-T

3 0 CI2_P, CI2_A CAP, 1206 OPT

4 1 CP_P CAP, 0603 47nF 10% 50V X7R AVX 06035C473KAT2A

5 3 C1, C19, C33 CAP, 7361 47µF 10% 35V, 7361 AVX TAJV476K035RNJ

6 3 C2, C21, C35 CAP, 0805 0.1µF 10% 50V X7R AVX 08055C104KAT2A

7 2 C3, C16 CAP, 7343 330µF 10% 10V TANT AVX TPME337K010R0035

8 9 C4, C6, C11, C30, C36, C39, C41, C43, C44 CAP, 0402 0.1µF 10% 10V X7R TAIYO YUDEN, LMK105B7104KV-F

9 1 C7 CAP, 7343 47µF 10% 20V TANT AVX TAJD476K020RNJ

10 2 C8, C15 CAP, 0402 1µF 10% 16V X5R TDK C1005X5R1C105K

11 4 C17, C23, C34, C45 CAP, 0402 0.01µF 10% 16V X7R AVX 0402YC103KAT2A

12 1 C2_F1 CAP, 0603 33nF 10% 50V X7R AVX 06035C333KAT2A

13 0 C25, C28 CAP, 0402 OPT

14 4 C26, C29, C37, C38 CAP, 0402 100pF 10% 16V NPO AVX 0402YA101KAT2A

15 1 D1 LED, RED PANASONIC LN1251CTR

16 10 E3, E6, E11-E18 TURRET MILL-MAX 2501-2-00-80-00-00-07-0

17 1 JP1 HEADER, 3-PIN 2mm SAMTEC TMM-103-02-L-S

18 4 J2, J5, J6, J7 CONN, SMA 50Ω EDGE-LAUNCH E.F. JOHNSON, 142-0701-851

19 0 J3, J4 CONN, SMA 50Ω Straight OPT

20 4 J9, J10, J11, J12 JACK, BANANA KEYSTONE 575-4

21 1 J13 HEADER, 7 DUAL PIN, 2mm MOLEX 87831-1420

22 0 L1 IND, 0402 OPT

23 2 L2, L3 IND, 0402 68nH 5% COILCRAFT 0402HPH-68NXJLW

24 1 L1_F1 RES, 0805, 0Ω JUMPER VISHAY CRCW08050000Z0EA

25 0 L1_F2, L1_F3 IND, 0805 OPT

26 2 R1_F1, RZ_P RES, 0603 21Ω 1% 1/10W VISHAY CRCW060321R0FKED

27 5 R1, R2, R11, R20, R26 RES, 0402 4.99kΩ 1% 1/16W VISHAY CRCW04024K99FKED

28 1 R4 RES, 0402 330Ω 1% 1/16W NIC NRC04F3300TRF

29 1 R5 RES, 0402 51.1Ω 1% 1/10W VISHAY CRCW040251R1FKED

30 4 R7, R8, R18, R19 RES, 0402 200kΩ 1% 1/16W VISHAY CRCW0402200KFKED

31 4 R9, R14, R16, R2_F2 RES, 0603 0Ω JUMPER VISHAY CRCW06030000Z0EA

32 3 R12, R21, R22 RES, 0402 100Ω 5% 1/16W VISHAY CRCW0402101RJKED

33 0 R13, R15, R2_F3, RZ_A, R31 RES, 0603 OPT

34 0 R23, R24 RES, 0402 OPT

35 5 R25, R27, R28, R29, R30 RES, 0402 0Ω JUMPER VISHAY CRCW04020000Z0EA

36 1 U1 IC, QFN28IUFD-4X5 LINEAR TECH. LTC6947IUFD

37 1 U2 IC, LOW NOISE AMP, SO8 LINEAR TECH. LT1678IS8#PBF

38 1 U3 IC, VCO CRYSTEK, CVCO55CC-2328-2536

39 0 U4 IC, CRYSTAL OSCILLATOR OPT

40 2 U5, U10 IC, DUAL BUFFER, SC70 FAIRCHILD SEMI NC7WZ17P6X

41 1 U8 I.C., Serial EEPROM, TSSOP8 MICROCHIP, 24LC025-I /ST

42 1 U11 IC, DUAL TRANSCEIVER, SOT363 NXP 74LVC 1T45GW

43 1 SHUNT ON JP1 (2&3) SHUNT, 2mm CTRS SAMTEC 2SN-BK-G

dc1846af

DEMO MANUAL DC1846A

SCHEMATIC DIAGRAM

A A

B B

C C

D D

3.3V

GND

MUTE

VCO

2328 - 2536 MHz

ASSY U3

-A CVCO55CC-2328-2536

NOTE: UNLESS OTHERWISE SPECIFIED

1. ALL RESISTORS ARE IN OHMS, 0402

2. ALL CAPACITORS ARE IN MICROFARADS, 0402.

SCLK

SDI

SDO

3.3V

3.3V 3.3V

V+VCO

V+VCXO

3.3V

V+VCO

3.3V

V+OA

3.3V

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

MICHEL A.PRODUCTION2 01-28-14

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

MICHEL A.PRODUCTION2 01-28-14

REVISION HISTORY

DESCRIPTION DATEAPPROVEDECO REV

MICHEL A.PRODUCTION2 01-28-14

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

01/28/2014, 12:25 PM

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

MICHEL A.

KIM T.

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

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

01/28/2014, 12:25 PM

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

MICHEL A.

KIM T.

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

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

01/28/2014, 12:25 PM

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

MICHEL A.

KIM T.

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

C16

330uF

7343

10V

C16

330uF

7343

10V

C3_F2

OPT

0603

C3_F2

OPT

0603

C3_F3

OPT

0603

C3_F3

OPT

0603

C18

1uF

0603

C18

1uF

0603

E18

C15

1uF

C15

1uF

C23

0.01uF

C23

0.01uF

J12 GND

C31 1uF

0603

C31 1uF

0603

E12

CPGAIN

E12

CPGAIN

R16 0

0603

R16 0

0603

JP1JP1

R14 0

0603

R14 0

0603

C17

0.01uF

C17

0.01uF

1uF

OPT J3

OPT

R25

RZ_P

0603

RZ_P

0603

C33

35V

47uF

7361

C33

35V

47uF

7361

RF-

E13 V+VCO

C45

0.01uF

C45

0.01uF

0.1uF

35V

0805

0.1uF

35V

0805

4.99K

L1_F3

OPT

0805

L1_F3

OPT

0805

R2_F3

OPT

0603

R2_F3

OPT

0603

EXT VCO IN

CI2_A

OPT 1206

CI2_A

OPT 1206

CPGAIN

OPTJ4

CPGAIN

OPT

C11

0.1uF

C11

0.1uF

C12

1uF

0603

C12

1uF

0603

R29

4.99K

C6 0.1uFC6 0.1uF

CP E3

3.3V J9

3.3V

R31

OPT

0603

R31

OPT

0603

51.1

C38

100pF

C38

100pF

R30

E15 V+VCXO

35V

47uF

7361

35V

47uF

7361

CP_A

OPT 0603

CP_A

OPT 0603

R23

OPT

R23

OPT

C21 0.1uF

35V 0805

C21 0.1uF

35V 0805

LN1251CTR

RED

LN1251CTR

RED

C29

100pF

C29

100pF

0.1uF

1uF

0603

1uF

0603

CI2_P

OPT 1206

CI2_P

OPT 1206

LT1678IS8

OUTA

-INA

+INA

V-

4+INB 5

-INB 6

OUTB 7

V+ 8

C25

OPT

C25

OPT

CI1_A

OPT 0603

CI1_A

OPT 0603

R27

C30

0.1uF

C30

0.1uF

E11

V+OA

E11

V+OA

CI1_P

1uF 0603

CI1_P

1uF 0603

C2_F1

33nF

0603

C2_F1

33nF

0603

R15

OPT

0603

R15

OPT

0603

E17

GND

E17

GND

J11 5V

U4 OPTU4 OPT

VTUNE

GND

3RFOUT 4

NC 5

VCC 6

RF+

R24

OPT

R24

OPT

68nH

0402HPH-68NXJL

68nH

0402HPH-68NXJL

LTC6947IUFD

QFN28UFD-4X5

LTC6947IUFD

QFN28UFD-4X5

STAT

VCO- 15

MUTE

SDI

V+D

LDO

RF+

RF-

GNDA

SCLK

VCO+ 16

GNDB 17

V+RF

REF+

SDO

GNDC 18

GNDD 19

GNDE 20

GNDF 21

GNDG 22

V+VCO 23

GNDH 24

V+CP 25

CP 26

V+REF 27

REF- 28

GND 29

R13 OPT

0603

R13 OPT

0603

GND 1

VTUNE 2

GND 3

GND 4

GND

RFOUT

GND

GND 13

VCC 14

GND 15

GND 16

C35

0.1uF

35V 0805

C35

0.1uF

35V 0805

C28

OPT

C28

OPT

330uF

7343

10V

330uF

7343

10V

C34

0.01uF

C34

0.01uF

L1_F1

0805

L1_F1

0805

STATUS E6

STATUS

L1_F2

OPT

0805

L1_F2

OPT

0805

C14

OPT

0603

C14

OPT

0603

REF+

E14 GND

OPT

CP_P

47nF

0603

CP_P

47nF

0603

C26

100pF

C26

100pF

C19

35V

47uF

7361

C19

35V

47uF

7361

68nH

0402HPH-68NXJL

68nH

0402HPH-68NXJL

330

20V

47uF

7343

20V

47uF

7343

RZ_A OPT

0603

RZ_A OPT

0603

J10

GND J10

GND

C13

1uF

0603

C13

1uF

0603

R1_F1

0603

R1_F1

0603

R28

E16 GND

C37

100pF

C37

100pF

R2_F2

0603

R2_F2

0603

dc1846af

DEMO MANUAL DC1846A

SCHEMATIC DIAGRAM

Note: The buffers shown on sheet 2 of 2 of the schematic are used to protect the LTC6947 when connected to the DC590 before the LTC6947 is powered

up. There is no need for such circuitry if the SPI bus is not powered before powering up the LTC6947. The EEPROM is for identification and is not needed

to program the LTC6947.

4 4

3 3

2 2

1 1

0603

DC590B SPI INTERFACE

NOTE: EEPROM FOR BOARD IDENTIFICATION

SCLK

SDI

SDO

3.3V

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

01/28/2014, 12:25 PM

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

MICHEL A.

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

KIM T.

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

01/28/2014, 12:25 PM

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

MICHEL A.

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

KIM T.

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

01/28/2014, 12:25 PM

ULTRALOW NOISE AND SPURIOUS FRACTIONAL-N SYNTHESIZER

MICHEL A.

N/A

LTC6947IUFD

DEMO CIRCUIT 1846A

KIM T.

200K

WPWP

GND VCC

U10

NC7WZ17P6X

GND VCC

U10

NC7WZ17P6X

1 6

200K

SDOSDOSCLKSCLKV+DIGV+DIG

R12

100

R12

100

R19

200K

R19

200K

R22 100R22 100

C44

0.1uF

C44

0.1uF

GND

DIR

VCC(A) VCC(B)

U11

74LVC1T45GW

GND

DIR

VCC(A) VCC(B)

U11

74LVC1T45GW

1 6

R18

200K

R18

200K

R26

4.99K

R26

4.99K

GND VCC

NC7WZ17P6X

GND VCC

NC7WZ17P6X

1 6

R21

100

R21

100

J13

HD2X7-079-MOLEX

J13

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

C36

0.1uF

C36

0.1uF

CSCS

EEGNDEEGND

SDISDI

EEPROM

ARRAY

24LC025-I /ST

EEPROM

ARRAY

24LC025-I /ST

SDA

VCC 8

1A1

2A2

GND

SCL

R11

4.99K

R11

4.99K C43

0.1uF

C43

0.1uF

C39

0.1uF

C39

0.1uF

C41 0.1uFC41 0.1uF

R20

4.99K

R20

4.99K

dc1846af

DEMO MANUAL DC1846A

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 TOP LAYER

dc1846af

DEMO MANUAL DC1846A

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

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

 LINEAR TECHNOLOGY CORPORATION 2014

LT 0514 • PRINTED IN USA

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,

customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.

LT C 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 LT C applica-

tion engineer.

Mailing Address:

Linear Technology

1630 McCarthy Blvd.

Milpitas, CA 95035