SCG2500A Datasheet, PDF (1/12 Pages) Connor-Winfield Corporation – Synchronous Clock Generator

2111 Comprehensive Drive
Aurora, Illinois 60505
Phone: [phone]
Fax: [phone]
www.conwin.com
SCG2500A
Synchronous Clock
Generator
US Headquarters:
630-851-4722
European Headquarters:
[phone]
General Description
The SCG2500A is a mixed-signal phase lock loop
generating CMOS outputs from an intrinsically low jitter
voltage controlled crystal oscillator. The SCG2500A is
based on Connor-Winfield’s SCG2500 series product line.
The SCG2500A can lock to one of two possible
reference inputs at 8 kHz that are selectable using one
input select pin. The SCG2500A has an improved filter
compared to the SCG2500. The new filter allows the
SCG2500A to more closely track the selected input
reference and lowers switching MTIEs.
The SCG2500A provides 3 alarm outputs, Loss of
Reference A, (LOR A) Loss of Reference B, (LOR B), and
Loss of Lock, (LOL) as compared to the SCG2500’s
combined alarms. In the event of a LOL condition, the LOL
alarm will activate in 1us of the next rising edge of the
internal, 8 kHz reference. Switching references within 100
ns will then comply with GR-253-CORE requirements.
LOR A and LOR B independently monitor the input
references. If Both references are lost the unit will go into
Free Run automatically. When both references are lost,
the unit should be forced into Free Run (pin 5 = 1). LOR A
and LOR B can then be monitored until the references
return. Refer to Table 6 for more operational details.
The reference output at 8 kHz is derived from the
oscillator output. Note that 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
.350” on a six layer FR4 board with surface mount pins.
Parts are assembled using high temperature solder to
withstand surface mount reflow processes.
Tri-State is not available with this model.
Features
• Phase Locked Output Frequency
Control
• Intrinsically Low Jitter Crystal
Oscillator
• Two Selectable References @ 8 kHz
• Hitless Reference Switching
• 2 Independent Reference Monitors
• LOL Alarm 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
Quick Overview
Ref_In
Osc_Out
8 kHz
2.048 MHz
8 kHz
19.44 MHz
8 kHz
51.84 MHz
8 kHz
77.76 MHz
Ref_Out
8 kHz
8 kHz
8 kHz
8 kHz