SHF Communication Technologies AG
Wilhelm-von-Siemens-Str. 23D • 12277 Berlin • Germany
Phone +49 30 772051-0 • Fax +49 30 7531078
E-Mail: sales@shf-communication.com • Web: www.shf-communication.com

Datasheet
SHF C651 B
67 GHz Clock Buffer

SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 1/6

Description
The SHF C651 B Clock Buffer operates at frequencies up to 67 GHz and can be used in broadband test
setups and telecom transmission systems. The AC-coupled differential inputs can also be driven singleended by terminating the unused input. This renders the device perfectly suited to generate two copies of
the input clock signal (with one output being 180° shifted). This way the Buffer can be used as a clock
signal splitter which does not add 6 dB attenuation like a passive splitter.
For single ended input signals >150 mV the output voltage will be clipped to ~500 mV. All RF in- andoutput ports are AC-coupled and internally terminated with 50 Ohm to GND. Unused in- or output ports
should be terminated with 50 Ohm.

Features

Broadband operation up to 67 GHz
One differential output port
500 mVpp single ended output swing
Single ended or differential operation (either In or In! or both can be used)

Applications





Clock signal amplification
Splitting one clock signal into 2 single ended output signals
100G Ethernet development and prototyping
OC-768 / STM-256 applications
Telecom transmission
Fibre Channel®
Broadband test and measurement equipment

Block Diagram
SHF
C651 BInOutClockBufferInOutMini-USB(Service only)+5VFE

Accessories1 +5V power supply desktop adapter
 Functional earth cable  Connection to test setup ground has to be set up first before any otherconnection to prevent instrument damage!
®
1Fibre Channel is a registered trademark of the Fibre Channel Industry Association
Mini-USB port is only for service purposes, no USB cable will be provided

SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 2/6

Absolute Maximum Ratings
Parameter

UnitSymbol

Clock Input VoltagemVVclk inExternal DC Voltage onRF Input Ports

VVDCinExternal DC Voltage on
RF Output PortsV

DC Supply Voltage

Min.

Typ.

Max.

Comment900

Peak-to-Peak-6+6AC coupled input

VDCout-6+6AC coupled output

VVcc

0+6Unit

SymbolMin.

Minimum Input FrequencyMHz

fin minMaximum Input Frequency

GHz

fin max

67

Clock Input VoltagemVpp

Vclk in150

Input Parameters

Specifications
Parameter

Typ.

Max.

Comment

Input Parameters
12850

Peak-to-Peak;Single-ended

Output Parameters

Clock Output Voltage≤ 50 GHz> 50 GHz
Peak-to-Peak;Single-ended;
See page 4450300

6004504.85.05.2350mVppVout

Supply Voltage

VVcc

Supply Current

mAIee320

Power Dissipation

WPd

1.6@ VCC = +5V50

1.85 mm (V) female

Power Requirements
2.5 x 0.7 mm
DC Power Jack

Mechanical CharacteristicConnectors

ΩDimensionsmm

Weightgsee page 690Conditions
Operating Temperature

2°C

Tambient

1535

Small signal bandwidth of the module is ~30 GHz

SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 3/6

Typical Output Voltage

Fig.1: Output voltage @ Pin = 200 mVpp

Typical S-Parameters

Fig.2: S-Parameter measurements @ Pin = -30 dBm
SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 4/6

Typical Output Waveform
The measurements below had been performed using an Agilent 86100B DCA with Precision Time Base
Module (86107A) and 70 GHz Sampling Head (86118A). The outputs of the clock buffer module had beenconnected by 6 dB attenuators to the DCA input.

Output Signal @ fin= 70 GHz

Output Signal @ fin= 67 GHz

Output Signal @ fin= 60 GHz

Output Signal @ fin= 50 GHz

Output Signal @ fin= 32 GHz

Output Signal @ fin= 10 GHz

SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 5/6

Outline Drawing – Moduleb ca

52.7

4x

40
28

13.6

InØ2.7
13.6

Out

SHF C651 B
InOut514535

XXXXX

3SHF Communication
Technologies AG+5 V DC

PortConnector

In

1.85mm (V) female

In1.85mm (V) female

Out1.85mm (V) femaleOut

1.85mm (V) female

13.63413.623.5USB354554ClockBuffer

all dimensions immPortConnectoraMini-USBbPowerc

Functional earth (FE)SHF reserves the right to change specifications and design without notice – SHF C651 B - V001 – November 30, 2020 Page 6/6