SCG2500
Synchronous Clock
Generators
2111 Comprehensive Drive
Aurora, Illinois 60505
Phone: 630- 851- 4722
Fax: 630- 851- 5040
www.conwin.com
US Headquarters:
630-851-4722
European Headquarters:
+353-61-472221
General Description
Features
The SCG2500 is a mixed-signal phase lock loop
generating CMOS outputs from an intrinsically low jitter
voltage controlled crystal oscillator.
The SCG2500 can lock to one of two possible input
reference frequencies at 8 kHz which is selectable using
one input select pin.
Further features include an alarm output to indicate
Loss of Reference, LOR, or Loss of Lock, LOL. If only
one of the references is lost, the unit will disable its
phase detector and will signal an alarm, but will not
switch reference automatically. If both references are
lost, the SCG2500 will enter a Free Run state which will
guarantee a 20 ppm accurate output. Additionally, the
Free Run mode may be entered manually by applying a
high signal to the Force Free Run pin. If the unit is in
Free Run mode, the Free Run status pin will be high.
All outputs, except the Oscillator Output, may be put
into the tri-state high impedance condition for external
testing purposes by applying a high signal to the Reset/
Tri-State pin.
The filtered 8 kHz is derived from the oscillator
output. The offset between the filtered output and the
reference input will change with each reference
rearrangement.
The package maximum dimensions are .780” x .830”
x .35” on a six layer FR4 board with surface mount pins.
Parts are assembled using high temperature solder to
withstand surface mount reflow process.
• Phase Locked Output
Frequency Control
• Intrinsically Low Jitter Crystal
Oscillator
• Two Selectable References @ 8
kHz
• Alarm Output
• Tri-Statable Alarm Outputs and
Reference Output
• Force Free Run Function
• Automatic Free Run Operation
upon loss of both references
• Input Duty Cycle Tolerant
• 3.3 Volt Power Supply
• Small Size: 0.78” x 0.83” x 0.35”
maximum
• Surface Mount, DIL Package
Absolute Maximum Rating
Table 1
Symbol
Parameter
Minimum
Nominal
Maximum
Units
VCC
Power Supply Voltage
-0.5
-
+4.0
Volts
VI
Input Voltage
-0.5
-
+5.5
Volts
TS
Storage Temperature
-65.0
-
+150.0
°C
Notes
Operating Specifications
Table 2
Parameter
Specifications
Notes
Voltage
3.3V ±5%
1.0
Current
150 mA @ 3.46V
Oscillator Output Frequencies
1.544, 2.048, 19.44, 20.48, 44.736, 51.84, and 77.76 MHz
Temperature Range
0 to 70°C
Input Frequency Ref 1 and Ref 2
8 kHz
Input Jitter Tolerance
≥ 31.25us Typical
2.0
(Jitter Frequencies > 10 Hz)
Jitter Bandwidth
< 10 Hz
Acquisition Time
Approximately 1 second
3.0
Capture/Pull-In Range
± 25 ppm Minimum
Output Duty Cycle
40/60 % Min/Max @ 50% Level
Output Rise and Fall Time
3 nS @ 20% to 80% output level
Output Load
30 pF
Alarm
LOR/LOL Status Signal Output
Free Run Accuracy
±20 ppm
Package
Fr4 SM 0.78” x 0.83” x 0.350” (Maximum)
MTIE @ Synchronization Rearrangement
GR-253-CORE, 1999 R5-136
4.0, 4.1
Input and Output Characteristics
Table 3
Symbol
Parameter
Minimum
Nominal
VIH
High level input voltage
2.0
-
5.5
V
VIL
Low level input voltage
0
-
0.8
V
TIO
I/O to output valid
-
-
10
nS
COUT
Output capacitance
-
-
10
pF
VHO
High level output voltage loh = -4mA
2.40
-
-
-
Vcc Min
VIO
Low Level output voltage lo1 = 8mA
-
-
0.4
-
Vcc Max
TIR
Input reference signal pulse width
30
-
-
nS
Preliminary Data Sheet #: SG027
Maximum
Page 2 of 10
Units
Rev: 02
Notes
Date: 03/15/02
© Copyright 2002 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Output Jitter Specifications
Table 4
All SCG2500 Models (Ver. 2)
Jitter BW 10 Hz - 1 MHz
pS (RMS)
m UI
Frequency (MHz)
SONET Jitter BW 12 kHz - 20 MHz
pS (RMS)
m UI
1.544
30 Typ.
0.046 Typ.
4 Typ.
0.006 Typ.
2.048
30 Typ.
0.061 Typ.
4 Typ.
0.008 Typ.
19.44
10 Typ.
0.194 Typ.
1 Max., 0.5 Typ.
0.019 Max.
20.48
10 Typ.
0.205 Typ.
1 Max., 0.5 Typ.
0.020 Max.
34.368
10 Typ.
0.344Typ.
1 Max., 0.5 Typ.
0.034Max.
44.736
10 Typ.
0.447Typ.
1 Max., 0.5 Typ.
0.045 Max.
51.84
10 Typ.
0.518 Typ.
1 Max., 0.5 Typ.
0.052 Max.
77.76
10 Typ.
0.778Typ.
1 Max., 0.5 Typ.
0.078 Max.
Input Selection / Output Response
Table 5
All SCG2500 Models
INPUTS
OUPUTS
Reset/
Tri-State
SELAB
REFA
REFB
FR
FRstatus
Alarm
Oscillator 8 kHz
Output
Output
1
X
X
X
X
TS
TS
FR
TS
0
X
X
X
1
1
1
FR
FR
0
0
A
A
0
0
0
LRA
LRAD
0
1
NA
A
0
0
0
LRB
LRBD
0
0
NA
A
0
0
1
U
U
5.0
0
1
A
NA
0
0
1
U
U
5.0
0
0
A
NA
0
0
0
LRA
LRAD
0
X
NA
NA
0
1
1
FR
FR
TS = Tri-State
FR = Free Run
LRA = Locked to Ref A
LRB = Locked to Reb B
Notes
U = Unstable
LRAD = Locked to Ref A and divided down
LRAB = Locked to ref B and divided down
X = Don’t care
NOTES:
1.0 Requires external regulation
2.0 Externally selectable via Input Select AB
3.0 From a 20 ppm offset in reference frequency
4.0 Entry into Free Run doesn’t meet requirement for initial 2.33 seconds of self-timing
4.1 If the selected reference is removed, system response to the ALARM must be less than 10µs
5.0 On alarm assertion, switch references. If alarm is still active, force Free Run
Preliminary Data Sheet #: SG027
© Copyright 2002 The Connor-Winfield Corp.
Page 3 of 10
Rev: 02
Date: 03/15/02
All Rights Reserved Specifications subject to change without notice
Circuit Board Footprint
Pin Connections
Figure 1
Table 6
Pin
0.800 (20.32mm)
0.640
0.080
(16.26mm)
(2.03mm)
0.050 TYP
(1.27mm)
0.100
TYP
(2.54mm)
0.050 TYP
(1.27mm)
0.650
(16.51mm)
Connection
1
Filtered 8 kHz Output
2
TCK
3
TMS
4
Ground
5
Force Free Run / TDI (1 = Free Run)
6
Alarm Output (1 = Alarm)
7
REF B
8
REF A
9
Oscillator Output
10
Free Run Status Output (FR = 1)
11
Vcc
12
TDO
13
Reset / Tri-State
14
Input Reference Select AB (A = 0, B = 1)
Block Diagram
Figure 2
FREE RUN STATUS
OUTPUT
FORCE
FREE RUN
ALARM OUTPUT
REFA
REFB
SELECT
AB
8 kHz PHASE
ALIGNER
DPFD
ANALOG
FILTER
LOW JITTER
VCXO
OSCILLATOR
OUTPUT
1/N
8 kHz
OUTPUT
TRI-STATE/
RESET
Preliminary Data Sheet #: SG027
Page 4 of 10
Rev: 02
Date: 03/15/02
© Copyright 2002 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Package Maximum Dimensions
Figure 3
Preliminary Data Sheet #: SG027
© Copyright 2002 The Connor-Winfield Corp.
Page 5 of 10
Rev: 02
Date: 03/15/02
All Rights Reserved Specifications subject to change without notice
Loss of Reference Condition Alarm Timing
Figure 4
Start-up
Region
Alarm Output
(LOR + LOL)
LOR
(Internal Signal)
4
LOL
(Internal Signal)
2
1
Phase Detector
(Internal Signal)
3
1
External Reference
(Selected Input A or B)
Internal Reference
(Internal Signal)
2
2
2
2
2
2
2
2
2
2
2
2
2
2
AlarmTiming Legend
Use for all alarm timing diagrams
Table 7
19.44 MHz Reference Input Units
1
2
3
4
5
Start-up Region
8 kHz Reference Input Units
< 1 µsec
< 31.25 µsec
1 µsec
31.25 µsec
> 1 µsec
LOR is active when LOL is active
Minimum pulse width = 2 µsec
> 31.25 µsec
125 µsec wide range
Minimum pulse width = 62.5 µsec
During Start-up, The LOL Alaram will pulse
during the few seconds of operation
Preliminary Data Sheet #: SG027
Page 6 of 10
Rev: 02
Date: 03/15/02
© Copyright 2002 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Loss of Lock Condition Alarm Timing
Figure 5
Alarm Output
(LOR + LOL)
LOR
(Internal Signal)
LOL
(Internal Signal)
Phase Detector
(Internal Signal)
5
1
1
1
3
1
1
3
External Reference
(Selected Input A or B)
Internal Reference
(Internal Signal)
2
2
2
2
2
2
2
2
Preliminary Data Sheet #: SG027
© Copyright 2002 The Connor-Winfield Corp.
2
2
Page 7 of 10
2
2
Rev: 02
2
2
Date: 03/15/02
All Rights Reserved Specifications subject to change without notice
Tape and Reel Packaging
Figure 6
1.31
(33.27mm)
.08
8.45 DIA
.08
(2.0mm)
(2.0mm)
(214.6mm) DIA
13.00
(330.2mm)
.08
3.15
(2.0mm)
(80mm)
1.00 DIA
(25.4mm)
POCKET SIZE
MEETS EIA-481A AND EIAJ-1009B
250 PCS/REEL MAXIMUM
DIRECTION OF FEED (CUSTOMER)
.157
.079
21.17mm (.833")
(Ko)
9.49mm (.374")
(KI)
6.99mm (.275")
32mm (1.26") PITCH
3°
.069
(2mm)
20.92mm (.824")
(Bo)
32mm (1.26") WIDTH
.063 (1.6mm) DIA.
.059 (1.5mm) DIA.
(4mm)
(Ao)
BD
(1.75mm)
.138
(3.51mm)
.559
1.26
(14.2mm)
(32.0mm)
1.118
(28.4mm)
.072
.065
.236
(6.0mm)
.063
.059
(1.85mm)
(1.65mm)
1.260
P
.079
(1.6mm)
W
.383
.236
(9.74mm)
(6.00mm)
(2mm) DIA. MIN.
.833
(Bo)
(21.17mm)
.014
(.36mm)
(1.5mm)
.118
(32.0mm)
(3.00mm)
3°
AD
45°
.275
19.4°
(6.99mm)
.374
(9.49mm)
(Ko)
.076
(1.93mm)
.824
(20.92mm)
Preliminary Data Sheet #: SG027
Page 8 of 10
Rev: 02
Date: 03/15/02
© Copyright 2002 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice
Solder Profile
Figure 7
250
200
Temp
(Deg C)
150
100
50
0
1
2
3
4
5
6
7
8
Time (minutes)
Recommended Reflow Profile
Peak Temp:
217 Deg C
Max Rise Slope:
1.5 Deg
C/Sec
Time Above 150 C: 100 Sec
Ordering Information
SCG{XXXX}-{FFF.FFF}{M}
XXXX equals a specific model (2500)
FFF.FFF equals the Oscillator Output frequency (001.544, 002.048, 019.44, 020.48, 034.368,
044.736, 051.84, 077.76)
M equals MHZ and is added to all part numbers
Example: To order an SCG2500 with an Oscillator Output of 77.76 MHz,
Order part number SCG2500-077.76M
Please contact Connor-Winfield for other frequencies that may be available.
Preliminary Data Sheet #: SG027
© Copyright 2002 The Connor-Winfield Corp.
Page 9 of 10
Rev: 02
Date: 03/15/02
All Rights Reserved Specifications subject to change without notice
Revision
Revision Date
Note
00
4/24/01
Product Release
01
7/24/01
Reformatted to new Style
02
3/15/02
Updated Jitter Table