DC1795A - Demo Manual

DEMO MANUAL DC1795A
LTC6950
1.4GHz Low Phase Noise, Low Jitter PLL
with Clock Distribution
Description
Demonstration circuit 1795A features the LTC®6950, a
1.4GHz low phase noise, low jitter PLL with clock distribution.
For ease of use, the DC1795A comes installed with a
100MHz reference and a 1GHz VCSO, voltage controlled
SAW oscillator with sine wave output. All differential
inputs and outputs have 0.5" spaced SMA connectors.
The DC1795A has four AC coupled LVPECL outputs with
50Ω transmission lines making them suitable to drive
50Ω impedance instruments. The LVDS/CMOS output is
DC coupled. The LTC6950’s EZSync™ function is made
available via a turret and an SMA connector.
Ribbon
cable
connection
to DC590
LVDS/CMOS
DC-coupled
Outputs, SMA
Stat Outputs,
turrets
For the evaluation of the LTC6950 with other VCOs and
references, the DC1795A can be modified to accommodate
different on-board or external components. It also allows
the user the option of a passive or active loop filter.
A DC590 USB serial controller board is used for SPI communication with the LTC6950, controlled by the supplied
ClockWizard™ software.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1795A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and EZSync
and ClockWizard are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
EZSyncTM
SYNC Input,
SMA & turret
PECL0
AC Coupled
Outputs, SMA
PECL1
AC Coupled
Outputs, SMA
3.3V DC Supply,
BNC & turret
5V U4 (VCXO) DC
Supply, turret
External VCO
Input, SMA
PECL2
AC Coupled
Outputs, SMA
U3 (VCO) DC
Supply, turret
5V DC Supply,
BNC & turret
External VCO Charge
Pump Output, SMA
and turret
Active Loop Filter
Op-amp (U2) DC
Supply, turret
Frequency Reference
Input, SMA
PECL3
AC Coupled
Outputs, SMA
Figure 1. DC1795A Connections
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1
DEMO MANUAL DC1795A
Quick Start Procedure
The DC1795A is easy to set up to evaluate the performance
of the LTC6950. Follow the procedure below.
Connect the DC590 to one of your computer’s USB ports
with the included USB cable.
The DC590 and ClockWizard application are required to
control the DC1795A through a personal computer (PC).
ClockWizard Installation
DC590 Configuration
Place the DC590 jumpers in the following positions (refer
to Figure 2):
JP4: EE - Must be in the EN position.
The ClockWizard software is used to communicate with
the LTC6950. 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 ClockWizard system requirements:
JP5: ISO - ON must be selected.
• Windows Operating System: Windows XP, Windows
2003 Server, Windows Vista, Windows 7
JP5: SW - ON must be selected.
• Microsoft .NET 3.5 SP1 or later
JP6: VCCIO - 3.3V or 5V must be selected. This sets
the SPI port to 3.3V or 5V operation. 3.3V operation is
recommended.
• Windows Installer 3.1 or later
• Linear Technology’s DC590 hardware
J4, ribbon cable connection to the DC1795 J3, USB connection to PC JP4 jumper JP6 jumpers JP5 jumpers Figure 2. DC590 Jumper and Connector Locations
2
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DEMO MANUAL DC1795A
Quick Start Procedure
Download the ClockWizard setup file at www.linear.com/
ClockWizard.
2.Connect the DC590 to the DC1795A with the provided
ribbon cable.
Run the ClockWizard setup file and follow the instructions
given on the screen. The setup file will verify and/or install
Microsoft .NET and install the ClockWizard. Refer to the
Help menu for software operation.
3.Run the ClockWizard application.
DC1795A Configuration
1.Connect the GND, V+ = 3.15V to 3.45V, V+ to 5.25V and
V+ VCXO turrets to a power supply and apply power
(see Figure 1 and the Typical DC1795A Requirements
and Characteristics table).
4.In ClockWizard, click File > Load Settings and point to
the “LTC6950_PECL0_250MHz.clkset” file.
The green “STAT1” LED on the DC1795A should turn on
and the “STAT2” LED should turn off indicating that the
loop is locked at 1000MHz. A 250MHz signal should be
present on the PECL0 outputs.
Be sure to power down or terminate any unused RF output
with 50Ω, or poor spurious performance may result.
Figure 3. ClockWizard Screenshot
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3
DEMO MANUAL DC1795A
Quick Start Procedure
Troubleshooting
If the green LED does not illuminate, follow the instructions below:
1.Verify that you are able to communicate with the
DC1795A. The bottom status line in ClockWizard should
read “LTC6950” and “Comm Enabled.”
2.Verify that V+ = 3.15V to 3.45V, V+ to 5.25V and V+
VCXO turrets have the correct voltages on them (see
the Typical DC1795A Requirements and Characteristics
table).
3.Select “Status” Output = 2 in ClockWizard’s System
Tab. Click “Read All.” See if the NO_VCO or NO_REF
boxes in the second column are checked.
a. If NO_REF is checked, verify the “V+ XO” test point
voltage is set to 3.3V. Verify R73 is installed (0 ohm)
b.IF NO_VCO is checked, verify the components between
U4 and U1 match the default BOM.
Contact the factory for further troubleshooting.
DC1795A Reconfiguration
The DC1795A allows the use of a variety of references,
VCOs and active or passive loop filters. The following
covers the hardware reconfiguration of the DC1795A.
Refer to ClockWizard and the LTC6950 data sheet to better understand how to change programmed parameters
on the DC1795A.
LTC6950 CLKSET Files
The ClockWizard provides three different clkset files for
evaluation purposes. These files were made for the default
bill of materials. If board modifications are made, these
files or the loop filter may need to be modified for the
LTC6950 to lock correctly.
1.LTC6950_PECL0_250MHz.clkset: Produces a 250MHz
output on PECL0. All other outputs are powered down.
2.LTC6950_Figure16_250MHZ.clkset: Matches Figure
16 of the LTC6950 data sheet. To sync outputs, refer
to the EZSync Function section.
3.LTC6950_ALL_CHAN_250MHz.clkset: Produces a
250MHz output on all five outputs. To sync outputs,
refer to the EZSync Function section.
4
EZSync Function
Apply a 1ms or longer high pulse to the SYNC SMA connector to take advantage of the EZSync function. Refer
to the LTC6950 data sheet for SYNC timing and level
requirements.
LVPECL Output Options
The DC1795A has four AC coupled LVPECL outputs.
Internal biasing (IBIASx = H) is required with this default
termination network. The DC1795A has options for pull
down or series resistors to accommodate the other LVPECL
termination networks described in the data sheet.
LVDS/CMOS Output Options
The LVDS/CMOS output is DC coupled without on-board
termination by default. The DC1795A provides pull down,
series and a differential termination resistor options to
accommodate other termination networks described in
the data sheet.
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DEMO MANUAL DC1795A
DC1795A Reconfiguration
Reference Options
Clock Follower
Table 1 details the available reference options and board
modifications for each available option. The CLKSET files
described above assume the noise profile of the default
reference. If a different reference is used, change the
reference noise profile in ClockWizard before simulating
the LTC6950 under the Loop Design tab.
When using the LTC6950 as a clock follower the LTC6950’s
PLL circuitry can be powered down by setting the PDPLL
bit in ClockWizard. This will reduce the LTC6950’s overall
power consumption. Table 2 describes how to reconfigure
the board for a differential external input when using the
LTC6950 as a clock follower. Refer to the EZSync Function
section and to the data sheet for more details on using
the LTC6950 as a clock follower.
VCO Input Options
Table 2 describes the available VCO input options. Board
modifications and power requirements for each option are
also provided in Table 2. There are two different oscillator
footprints on the board: U3, which accommodates the
popular 0.5" × 0.5" package, and U4, which accommodates
another common 14mm × 9mm package with four or six
pins. U4 also accommodates the smaller 5mm × 7.5mm
package. An external connectorized VCO can also drive the
LTC6950 through SMA connector J15. The CLKSET files
described above assume the noise profile for the default
VCO. If a different VCO is used, change the VCO noise
profile in ClockWizard before simulating the LTC6950
under the Loop Design tab.
Loop Filter Design and Installation
Tables 3, 4 and 5 cross reference the loop filter options
shown in ClockWizard’s Loop Design tab with the DC1795A
component reference designators. Table 3 is dedicated to
the default oscillator, component U4. Table 4 is dedicated to
another common oscillator footprint, component U3. Table 5
can be used with external oscillators. Use ClockWizard to
select, design and simulate different loop filters.
Some VCO tuning voltage ranges are greater than the
LTC6950 charge pump voltage range (refer to the LTC6950
data sheet). In such cases, an active loop filter using an
op amp can deliver the required tuning voltage. When
satisfied with the loop filter design, use Tables 3, 4 and 5
to help identify which components should be modified.
The loop filter components are located on the bottom side
of the DC1795A.
Table 1. Reference Options and Board Modifications
DEFAULT
OPTION
l
REFERENCE
OPTION
INSTALL
DEPOPULATE
LTC6950 PERFORMANCE
U9 can accommodate any 5mm × 7.5mm or
9mm × 14mm oscillator package
For improved performance connect J4 to a very low
noise reference, such as the Wenzel 501-04517D
On-Board
NA
NA
Limited by on board reference at
frequency offsets <10kHz
External
C67
0402 0.1µF
R73, C71
Best performance when using an
ultralow noise external reference
COMMENTS
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DEMO MANUAL DC1795A
DC1795A Reconfiguration
Table 2. VCO Input Options: Power Settings and Board Modifications
BOARD MODIFICATIONS
DEFAULT
OPTION OSCILLATOR
l
OSCILLATOR POWER SETTINGS
V+ OA
V+ VXCO
TURRET
V+ VCO
TURRET
EN
TURRET
-
Connects to
pin 2 of U4.
Not used with
Default U4
Refer to Table 3: loop
filter component
selections for U4
INSTALL
DEPOPULATE
U4
NA
(Default)
NA
(Default)
U3
U3, *C38
0402 0Ω
*R43
[For Active Filters
Only] Determined by
U3 VTUNE specification.
Must be less than 24V
-
Determined
by U3 VCC
specification.
Must be less
than 24V
-
Refer to Table 4: loop
filter component
selections for U3
Single-Ended
External
*C25
0402 0Ω
*R25, R40,
R41
[For Active Filters
Only] Determined by
External Oscillator
VTUNE specification,
must be less than 24V
-
-
-
Connect signal to
J15. Refer to Table 5:
loop filter component
selections.
Differential
External
*C25, C26
0402 0Ω
C69 0402
~100pF
*R25, R40,
R41
[For Active Filters
Only] Determined by
External Oscillator
VTUNE specification,
must be less than 24V
-
-
-
Connect signals to J14
and J15. [For External
Oscillator Only] Refer
to Table 5: loop filter
component selections.
TURRET
Determined
[For Active Filters
by U4 VCC
Only] Determined by
U4 VTUNE specification. specification.
5V for Default
5V for Default U4.
Must be less than 24V U4. Must be
less than 24V
COMMENTS
*General Recommendations: There are several termination and common mode options on the DC1795A for different input signal types. Refer to the
DC1795A schematic, the LTC6950 data sheet and the data sheet for the VCO or clock distribution component used for an optimum termination network.
Table 3. Loop Filter Selection for U4 Oscillator (Refer to ClockWizard’s Loop Design Tab)
CLOCKWIZARD AND BOM CROSS REFERENCE
OTHER MODIFICATIONS
DEFAULT
OPTION
LOOP FILTER
TYPE
RZ
CI
CP
R1
C2
L1
INSTALL
DEPOPULATE
COMMENTS
l
Filter 1 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
-
-
-
-
-
RZ_P, CI1_P, CI2_P, CP_P
populated with default values
Filter 2 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
R12
C22
-
-
-
Filter 3 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
R72
C22
R12
-
-
Filter 4 (Active)
RZ_A
CI1_A + CI2_A
CP_A
R12
C22
-
R69, R71
(0402 0Ω)
R70, R72
Select CPINV under the
ClockWizard System tab
Table 4. Loop Filter Selection for U3 Oscillator (Refer to ClockWizard’s Loop Design Tab)
CLOCKWIZARD AND BOM CROSS REFERENCE
DEFAULT
OPTION LOOP FILTER TYPE
RZ
CI
CP
R1
6
OTHER MODIFICATIONS
C2
L1
INSTALL
DEPOPULATE
Filter 1 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
-
-
-
R18
(0402 0Ω)
R12
Filter 2 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
R18
C29
-
Filter 3 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
R72
C29
R18
-
R12
Filter 4 (Active)
RZ_A
CI1_A + CI2_A
CP_A
R18
C29
-
R69, R71
(0402 0Ω)
R12, R70,
R72
COMMENTS
R12
Select CPINV under the
ClockWizard System tab
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DEMO MANUAL DC1795A
DC1795A Reconfiguration
Table 5. Loop Filter Selection for External Oscillator (Refer to ClockWizard’s Loop Design Tab)
DEFAULT
OPTION
CLOCKWIZARD AND BOM CROSS REFERENCE
OTHER MODIFICATIONS
LOOP FILTER TYPE
RZ
CI
CP
INSTALL
DEPOPULATE
COMMENTS
Filter 1 (Passive)
RZ_P
CI1_P + CI2_P
CP_P
R68
(0402 0Ω)
R72
Connect CPOUT turret to VTUNE of
external oscillator
Filter 4 (Active)
RZ_A
CI1_A + CI2_A
CP_A
R67, R69
(0402 0Ω)
R70, R72
Select CPINV under the ClockWizard
System tab. Connect CPOUT turret to
VTUNE of external oscillator
Typical DC1795A Requirements and Characteristics
PARAMETER
INPUT OR OUTPUT
PHYSICAL LOCATION
3.3V Power Supply
Input
J2 BNC connector, or
V+ = 3.15V to 3.45V turret
Charge Pump Power Supply
Input
J1 BNC connector, or
V+ to 5.25V turret
VCXO/VCSO Power Supply
Input
V+ VCXO turret
LVDS/CMOS+, LVDS/CMOS–
Two Outputs
J19 and J18 SMA connectors**
DC coupled, 250MHz, (if enabled)*.
Refer to LTC6950 data sheet for output levels for LVDS and
CMOS option.
PECL0+, PECL0–
Two Outputs
J17 and J16 SMA connectors**
AC coupled, 250MHz, 800mVP differential*.
Must have LTC6950’s IBIAS0 = H with default BOM. DC1795A
has options for an external pull down resistor if IBIAS0 = L.
PECL1+, PECL1–
Two Outputs
J13 and J12 SMA connectors**
PECL2+, PECL2–
Two Outputs
J8 and J7 SMA connectors**
PECL3+, PECL3–
AC coupled, 250MHz, 800mVP differential (if enabled)*. Must
have LTC6950’s IBIASX = H with default BOM. DC1795A has
options for an external pull down resistor if IBIASX = L.
Two Outputs
J11 and J10 SMA connectors**
SYNC
Input
SYNC turret or J9 SMA connector
STAT1, STAT2
Output
STAT1 and STAT2 turret
Loop Bandwidth
VCO Power Supply
Active Loop Filter Supply
-
DETAILS
Low-noise and spur-free 3.3V,
500mA default (200mA configured*).
Powers LTC6950, U6, U7, U8 and U9
Low-noise and spur-free 5V, 35mA*.
Powers LTC6950 and provides common mode to U2
Low-noise and spur-free 5V, 20mA*. Powers U4
EZSync, 0V to 3.3V control signal, refer to the data sheet
STAT1 GREEN LED, if ON LTC6950 is locked*.
STAT2 RED LED, if ON indicates issue*.
Refer to the troubleshooting section and data sheet
Set by loop filter component values 4.2kHz*
Input
V+ VCO turret
Board Modifications required for use, see Table 2
Input
V+ OA turret
Board Modifications required for use, see Table 2
REF, External Reference
Input
J4 SMA connector
VCO+, VCO–, External VCO or
Input for clock distribution
Input
J14 and J15 SMA connectors
CPOUT
Output
CPOUT Turret
Board Modifications required for use, see Table 1
Board Modifications required to use External VCO.
See Tables 2 and 5. Clock Distribution, see Table 2 only
Used with External VCO, connect to external VCO’s VTUNE
voltage
* These values are for the “LTC6950_PECL0_250MHz” file and the default on board VCO and Reference.
** Any unused RF output must be powered down or terminated with 50Ω, or poor spurious performance may result.
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DEMO MANUAL DC1795A
Layout Top Layer
8
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DEMO MANUAL DC1795A
Parts List
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1
2
0
CI1_A, C22, C29, CP_A
CAP., 0603
OPT
1
CI1_P
CAP., X7R, 0.1µF, 25V, 10%, 0603
AVX, 06033C104KAT2A
3
0
CI2_A
CAP., 1206
OPT
4
1
CI2_P
CAP., X7R, 0.56µF, 25V, 10%, 1206
AVX, 12063C564KAT2A
5
1
CP_P
CAP., X7R, 0.056µF, 16V, 10%, 0603
AVX, 0603YC563KAT2A
6
3
C1, C3, C7
CAP., TANT, 47µF, 20V, 20%, 7343
AVX, TAJD476M020HNJ
7
2
C2, C8
CAP., X7R, 1µF, 10V, 10%, 0603
AVX, 0603ZC105KAT2A
8
20
C4, C9-C19, C42-C48, C60
CAP., X7R, 0.01µF, 6.3V, 10%, 0201
AVX, 02016C103KAT2A
9
3
C5, C24, C32
CAP., X7R, 0.1µF, 50V, 10%, 0805
AVX, 08055C104KAT2A
10
29
C6, C28, C31, C33-C36, C39-C41, C49-C58,
C61-C66, C71, C73, C74
CAP., X7R, 0.1µF, 10V, 10%, 0402
AVX, 0402ZC104KAT2A
11
3
C23, C30, C59
CAP., TANT, 47µF, 35V, 10%, 7361
AVX, TAJV476K035RNJ
12
0
C25-C27, C38, C67, C69, C70
CAP., 0402
OPT
13
2
C68, C72
CAP., NPO, 100pF, 25V, 10%, 0402
AVX, 04023A101KAT2A
14
1
D1
LED, GREEN, LED-ROHM-SML-010FT
ROHM, SML-010FTT86L
15
1
D2
LED, RED, LED-ROHM-SML-010VT
ROHM, SML-010VTT86L
16
15
E1-E11, E16, E17, E20, E21
TURRET, TESTPOINT 0.064"
MILL-MAX, 2308-2-00-80-00-00-07-0
17
2
J1, J2
CONN, BNC, 5 PINS
CONNEX, 112404
18
2
J3, J9
CONN., SMA 50Ω STRAIGHT MOUNT
CONNEX, 132134
19
13
J4, J7, J8, J10-J19
CONN., SMA 50Ω EDGE-LAUNCH
EMERSON, 142-0701-851
20
1
J5
CONN., HEADER, 14 PIN, 2mm
MOLEX, 87831-1420
21
1
RZ_P
RES., CHIP, 196Ω, 1/16W, 1%, 0603
VISHAY, CRCW0603196RFKEA
22
5
R1, R2, R4, R5, R10
RES., CHIP, 4.99k, 1/16W, 1% 0402
VISHAY, CRCW04024K99FKED
23
0
R6, R9, R17, R19, R21-R24, R26, R30-R33,
R36, R38, R42, R46, R52, R57, R60, R61
RES., 0402
OPT
24
4
R7, R16, R28, R29
RES., CHIP, 49.9, 1/16W, 1% 0402
VISHAY, CRCW040249R9FKED
25
15
R8, R43, R44, R55, R56, R62-R66, R74-R78
RES., CHIP, 0Ω, 0402
VISHAY, CRCW04020000Z0ED
26
5
R11, R12, R70, R72, R73
RES., CHIP, 0Ω, 0603
YAGEO, RC0603JR-070RL
27
5
R13-R15, R35, R58
RES., CHIP, 200K, 1/16W, 1% 0402
VISHAY, CRCW0402200KFKED 2rls
28
0
R18, R67-R69, R71, RZ_A, R53
RES., 0603
OPT
29
5
R20, R51, R54, R59, R79
RES., CHIP, 100, 1/16W, 1% 0402
NIC, NRC04F1000TRF
30
2
R25, R40
RES., CHIP, 150, 1/16W, 1% 0402
VISHAY, CRCW0402150RFKED
31
2
R37, R39
RES., CHIP, 330, 1/16W, 1% 0402
VISHAY, CRCW0402330RFKED
32
1
R41
RES., CHIP, 37.4, 1/16W, 1% 0402
VISHAY, CRCW040237R4FKED
33
1
U1
I.C. LTC6950IUHH, QFN48UHH-5X9
LINEAR TECH., LTC6950IUHH#PBF
34
1
U2
I.C. LT1678IS8, SO8
LINEAR TECH., LT1678IS8#PBF
35
0
U3
VCO, 0.5" × 0.5"
OPT
36
1
U4
VCSO, 1GHz 5V
CRYSTEK, CVCSO-914-1000.000
37
1
U5
I.C., SERIAL EEPROM, TSSOP8
MICROCHIP, 24LC025-I /ST
38
2
U6, U7
I.C., DUAL BUFFER, SC70-6
FAIRCHILD SEMI., NC7WZ17P6X
39
1
U8
I.C., DUAL TRANSCEIVER, SOT363
NXP, 74LVC1T45GW
40
1
U9
CLOCK OSCILLATOR, 100MHz, 3.3V
CRYSTEK, CCHD-575-25-100.000
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9
1
2
3
E2
E7
J3
E4
E16
E17
J15
E8
E5
E6
J14
J9
E9
E10
V+OA
V+VCO
V+VCXO
OPT
R30
3
2
1
0805
OPT
R32
GND
GND
RFOUT
GND
0.1uF
12
11
10
9
C38
C22
OPT
C30
35V
7361
47uF
0805
C5
0.1uF
0603
+
1. ALL RESISTORS ARE IN OHMS, 0402
2. ALL CAPACITORS ARE IN MICROFARADS, 0402
A
R43
OPT
4
5
6
OPT
0
V+VCXO
R44
OPT
0805
C23
47uF
35V
7361
C24
C25
OUT+
OUT-
VCC
47uF
7361
0.1uF
CVCSO-914-1000
GND
EN
VTUNE
U4
C59
35V
C32
C26
0
U3
OPT
OUTB
-INB
U2
V+
B
A
1
2
3
4
OUTA
-INA
+INA
V-
B
*
1
2
3
4
0603
R12
GND
VTUNE
GND
GND
LT1678IS8
OPT
0603
+INB
V+OA
8
7
6
5
R67
150
R25
R36
OPT
37.4
OPT
R41
OPT
0603
R68
V+VCO
OPT
R26
C27
B
0
R72
0
0603
100pF
OPT
C3
20V
R1
C6
47uF
7343
4.99K
0.1uF
0603
1206
CI1_A
OPT
CI2_A
R71
OPT
0603
R18
OPT
0603
C29
OPT
0603
R29
49.9
R28
49.9
R37
330
CS
SDO
SCLK
SDI
0.1uF
C28
C40
R69
OPT
0603
R70
0
0603
CP_P
0.056uF
0603
0.1uF
R2
4.99K
V+CP
0603
0603
CP_A
OPT
RZ_A OPT
RZ_P
196
0603
0603
CI1_P 0.1uF
1206
CI2_P 0.56uF
R35
200K
SML-010MT SML-010VT
D1
GRN
D2
RED
R39
330
C
CP
V+CP
V+
C
THE LAYOUT FOOTPRINT FOR U4 AND U9 ACCEPTS
MOST OSCILLATORS IN 9mm X 14mm OR 5mm X
7.5mm PACKAGES WITH EITHER FOUR OR SIX PINS.
R40
150
C68
100pF
C72
R38
OPT
C69
OPT
+
NOTE: UNLESS OTHERWISE SPECIFIED
V+OA
GND
CPOUT
CPOUT
V+VCO
GND
VCO-
EN
V+VCXO
GND
VCO+
SYNC
SYNC
STAT1 (LOK)
STAT2 (ERR)
8
1
2
4
6
1
2
E11
7
GND
GND
13
GND
5
GND
GND
15
VCC
14
GND
GND
16
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
CP
V+CP
GND
V+
V+VCO
VCO-
VCO+
V+VCO
V+
GND
SYNC
STAT1
STAT2
SDI
SCLK
V+
21
R56
0
U1
LTC6950IUHH
V+
V+P3
PECL3-
PECL3+
V+P3
V+P2
PECL2-
PECL2+
V+P2
V+P1
PECL1-
PECL1+
V+P1
V+P0
PECL0-
PECL0+
V+P0
OPT
R53
CUSTOMER NOTICE
0.1uF
C57
0.1uF
C58
V+
OPT
R42
OPT
R46
OPT
1
2
3
4
D
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
OPT
R19
OPT
100
OPT
OPT
OPT
SCALE = NONE
6
5
4
R17
OPT
APPROVED
J12
J13
J16
J17
J18
J19
VTUNE
1
2
3
EN-XO
DATE:
N/A
SIZE
LTC6950IUHH
E
DEMO CIRCUIT 1795A
03/24/2014, 05:07 PM
IC NO.
SHEET 1
2
OF 2
REV.
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C66
0.1uF
CCHD-575-25-100
VCC
GND
REF
PECL3-
PECL3+
PECL2-
PECL2+
PECL1-
PECL1+
PECL0-
PECL0+
LVDS/CMOS-
LVDS/CMOS+
EN
J4
J10
J11
J7
J8
DATE
MICHEL A. 03-24-14
OUT-
OUT+
U9
0
TECHNOLOGY
0603
R73 0
V+XO
R9
R23
R33
R20
KIM T.
MICHEL A. TITLE: SCHEMATIC
APPROVALS
R7
49.9
C70
R16 0.1uF
49.9
OPT
C71
R8
0
R21
OPT
C49
0.1uF
R64
OPT
C50
0.1uF
R65
0.1uF
C51
0
R66
0
R22
OPT
R24
0.1uF
C52
0.1uF
0
R74
0
C53
0
R75
C54
0.1uF
R76
0.1uF
0
R52
0.1uF
C56
C55
0
R78
PRODUCTION
R77
OPT
5
6
8
E
DESCRIPTION
REVISION HISTORY
OPT
R57
OPT
R60
OPT
R61
2
7
C67
__
REV
R31
R6
OPT
R55
0
0
0
R62
R63
ECO
9
10
11
12
13
14
15
16
D
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
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
42
V+REF
43
REF44
SDO
23
CS
22
LV/CM+
20
LV/CM-
19
V+
REF+
45
GND
41
V+
17
GND
18
V+
V+REF
46
V+
47
GND
48
GND
49
+
+
*
10
*
A
1
2
3
4
DEMO MANUAL DC1795A
Schematic Diagram
dc1795af
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.
1
2
3
A
GND
V+ = 3.15V - 3.45V
GND
20V +
7343
V+
20V +
7343
1
V+ 2
5V
6
CS 4
SCK/SCL 7
MOSI/SDA 5
MISO
10
EEVCC 9
EESDA 11
EESCL 12
EEGND 14
AUX
J5
HD2X7-079-MOLEX
E20
J2
BNC
E3
E21
J1
BNC
C8
1.0uF
0603
C2
1.0uF
0603
C4
0.01uF
0201
C9
0.01uF
0201
WP
R5
4.99K
EEGND
R4
4.99K
SDO
6
5
7
3
2
1
SCL
SDA
WP
A2
A1
A0
U5
24LC025-I /ST
R10
4.99K
V+DIG CS SCLK SDI
DC590 SPI INTERFACE
C7
47uF
C1
47uF
V+CP
B
NOTE: EEPROM FOR BOARD IDENTIFICATION
13
8 GND
3 GND
GND
4
E1
ARRAY
V+ TO 5.25V
R11
0
0603
C31
0.1uF
C10
0.01uF
0201
LTC6950 BYPASS AND BULK CAPACITORS
B
EEPROM
8
VCC
GND
4
A
R14
200K
C13
0.01uF
0201
C43
0.01uF
0201
C41
0.1uF
3
2
1
5
2
C
5
GND
DIR
VCC(B)
4
5
6
V+
0.1uF
R15
200K
C34
C35 0.1uF
D
SCALE = NONE
SDO
SDI
SCLK
CS
C18
0.01uF
0201
C48
0.01uF
0201
C65
0.1uF
C74
0.1uF
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
C19
0.01uF
0201
C60
0.01uF
0201
C73
0.1uF
E
DATE:
N/A
SIZE
LTC6950IUHH
E
DEMO CIRCUIT 1795A
03/24/2014, 05:07 PM
IC NO.
SHEET 2
2
OF 2
REV.
1.4 GHZ LOW PHASE NOISE, LOW JITTER PLL WITH CLOCK DISTRIBUTION
TECHNOLOGY
C17
0.01uF
0201
C47
0.01uF
0201
C64
0.1uF
0.1uF
R59 100
C36
R54 100
R51 100
C16
0.01uF
0201
C46
0.01uF
0201
C63
0.1uF
MICHEL A. TITLE: SCHEMATIC
KIM T.
APPROVALS
VCC(A)
U8
74LVC1T45GW V+
VCC
4
GND
3
2
6
1
U7
NC7WZ17P6X
4
3
VCC
6
V+
C15
0.01uF
0201
1
GND
D
C45
0.01uF
0201
C62
0.1uF
U6
NC7WZ17P6X
C14
0.01uF
0201
C44
0.01uF
0201
C61
0.1uF
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
CUSTOMER NOTICE
C33
0.1uF
R13
200K
R58
200K
C12
0.01uF
0201
C42
0.01uF
0201
C39
0.1uF
R79
100
V+
V+
V+
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
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
C11
0.01uF
0201
C
1
2
3
4
DEMO MANUAL DC1795A
Schematic Diagram
Note: The buffers shown on sheet 2 of 2 of the schematic are used to protect the LTC6950 when connected to the DC590 before the
LTC6950 is powered up. There is no need for such circuitry if the SPI bus is not active before powering up the LTC6950. The EEPROM
is for identification and is not needed to program the LTC6950.
dc1795af
11
DEMO MANUAL DC1795A
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
12 Linear Technology Corporation
dc1795af
LT 0714 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2014
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