Sundance Multiprocessor Technology Limited
SMT399-F Clock Distribution
Module User Manual
Unit / Module Description:
Unit / Module Number: SMT399-F
Document Issue Number: 1.1
Issue Date: 6/9/2006
Original Author: G Parker
SMT399-F Clock
Distribution Module
Form : QCF42
Date : 6 July 2006
User Manual
Sundance Multiprocessor Technology Ltd, Chiltern House,
Waterside, Chesham, Bucks. HP5 1PS.
This document is the property of Sundance and may not be copied
nor communicated to a third party without prior written
permission.
© Sundance Multiprocessor Technology Limited 2006
SMT399-F Clock Distribution Module User Manual
Revision History
Issue Changes Made Date Initials
1.0 First draft 12/7/06 GKP
1.1 Added phase diagram 6/9/06 GKP
SMT399-F Clock Distribution Module User Manual Page 2 of 11
Table of Contents
1 Introduction....................................................................................................................... 4
2 Related Documents.......................................................................................................... 4
3 Acronyms and Abbreviations....................................................................................... 4
4 Functional Description ................................................................................................... 5
4.1 Block Diagram.............................................................................................................. 5
4.2 Module Options........................................................................................................... 6
4.3 Module Adjustments.................................................................................................. 7
4.3.1 Phase Adjustment...............................................................................................7
4.4 Module Component Selection................................................................................... 8
5 Footprint............................................................................................................................. 9
5.1 Top View....................................................................................................................... 9
6 Circuit Diagram ..............................................................................................................10
7 Physical Properties........................................................................................................ 11
8 Safety.................................................................................................................................11
9 EMC.................................................................................................................................... 11
SMT399-F Clock Distribution Module User Manual Page 3 of 11
1 Introduction
The SMT399-F is a single width TIM designed to distribute a clock signal to four
devices.
It can produce a local clock using an OCXO, or receive an external clock on an MMBX
or MMCX style connector.
The clock signal is split into 4 via a power splitter.
2 Related Documents
TIM-40 Specification.
OCXO Datasheet
PSC Datasheet
3 Acronyms and Abbreviations
OCXO Oven controlled Crystal Oscillator
TIM Texas Instruments Module
LED Light Emitting Diode
SMT399-F Clock Distribution Module User Manual Page 4 of 11
4 Functional Description
The output of the OCXO is a +7dBm sinewave. This is split via a 4-way power
splitter and feeds the four outputs.
A minimum input voltage of 0.4Vp-p is required if the external clock is to be used.
4.1 Block Diagram
Oven Controlled
Crystal Oscillator
(OCXO)
VFTC Series, Valpey Fisher
Select
Output
MMBX/
MMCX
Input
MMBX/
MMCX
Phase
Adjust
Variable Gain Amplifier
(VGA)
Analog Devices AD8367
Gain
Adjust
Output
Tuning
Circuit
SMT399-F Clock Distribution Module User Manual Page 5 of 11
4.2 Module Options
Although the module is fully assembled, there are several surface mount selector
pads that are user adjustable.
The selector pads are labelled S1 thru S9, and consist of 3 pads in an ‘L’ shape. The
pad spacing allows for surface mount 0805 packaged devices to be fitted; typical ly
zero-Ohm resistors.
The following table details all of the selector pad functions;
Selector Position Function
S1 1 Enable VGA. Leaves OCXO powered down.
2 Enable OCXO. Leaves VGA powered down.
S2 1 Enable J1 output, MMBX.
2 Enable J2 output, MMCX.
S3 1 Enable J3 output, MMBX.
2 Enable J4 output, MMCX.
S4 1 VFTCR thru-hole OCXO. Factory fitted, do not alter.
2 VFTCS surface mount OCXO. Factory fitted, do not alter.
S5 1 Enable OCXO. Can fit capacitor for AC coupling.
2 Enable VGA.
S6 1 Enable J5 output, MMBX.
2 Enable J6 output, MMCX.
S7 1 Enable J7 output, MMBX.
2 Enable J8 output, MMCX.
S8 1 Enable J9 clock input, MMCX.
2 Enable J10 clock input, MMBX.
S9 1 Routes VGA output to J11, SMA. Used for output LC filter
adjustment.
2 Normal operation.
SMT399-F Clock Distribution Module User Manual Page 6 of 11
4.3 Module Adjustments
Several trimmer capacitors and multi-turn potentiometers are provided. The
following table describes their use;
Adjustment Function
VC1 Phase adjust COARSE.
VC2 Phase adjust FINE.
VC3 Output tuning COARSE.
VC4 Output tuning FINE.
R13 VGA gain adjust.
R4 OCXO frequency trim.
4.3.1 Phase Adjustment
When using an external clock input, the phase relationship between the input and
output can be adjusted. This is implemented using the LC tuned circuit consisting
of L1 and VC1&2.
Set VC1 and VC2 to their centre positions. Whilst monitoring the input and an
output on an oscilloscope, adjust VC1 for the correct phase delay. VC2 may be used
to make fine adjustments.
The diagram below shows a typical input-output phase relationshi p.
+90
125mVp-p
+155°
310mVp-p
+177°
180
190mVp-p
-105°
22° range extension using
output tuned circuit too, VC3
78° range using input tuned
circuit only, VC1
0
-90
SMT399-F
Input to Output phase delay.
Input: 100MHz, +7dBm
SMT399-F Clock Distribution Module User Manual Page 7 of 11
4.4 Module Component Selection
Some component values may be replaced if different operating frequencies are
required. The following table lists these components;
Component Function
L1 Input phase adjustment.
100nH fitted for frequencies of 100MHz.
L2 Output tuning.
100nH fitted for frequencies of 100MHz.
SMT399-F Clock Distribution Module User Manual Page 8 of 11
5 Footprint
5.1 Top View
SMT399-F Clock Distribution Module User Manual Page 9 of 11
6 Circuit Diagram
SMT399-F Clock Distribution Module User Manual Page 10 of 11
7 Physical Properties
Dimensions 4.2” x 2.5”
Weight
Supply Current +5V @ 1.1A
MTBF
8 Safety
This module presents no hazard to the user when in normal use.
9 EMC
This module is designed to operate from within an enclosed host system, which is
built to provide EMC shielding. Operation within the EU EMC guidelines is not
guaranteed unless it is installed within an adequate host system.
This module is protected from damage by fast voltage transients originating from
outside the host system which may be introduced through the output cables.
Short circuiting any output to ground does not cause the host system to lock up or
reboot.
SMT399-F Clock Distribution Module User Manual Page 11 of 11
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