SONET OC-12/OC-3
CLOCK SYNTHESIZER
FEATURES
s
Single chip source for 622.08MHz and 155.52MHz
clocks
s
622.08MHz output is differential PECL, 155.52MHz
output is single-ended PECL
s
TTL/CMOS compatible inputs and reference output
s
SONET compliant jitter performance (
≤
0.01UI)
s
Choice of three reference frequencies
s
Only 395mW (typ)
s
Complies with Bellcore, CCITT and ANSI standards
s
Single +5 volt power supply
s
Fully compatible with industry standard 10KH I/O
levels
s
Available in 28-pin PLCC package
ClockWorks™
SY89426
DESCRIPTION
Micrel-Synergy's SY89426 Multi-Output Phase Locked
Loop (PLL) is a SONET compliant clock generator providing
622.08MHz, 155.52MHz and retimed reference clock
outputs. The PLL produces low jitter OC-12/STS-12 and
OC-3/STS-3 rate clocks from an input reference clock of
38.88, 51.84, or 77.76MHz. Additionally, the input reference
clock is retimed and provided as a TTL/CMOS compatible
output, which may be disabled to minimize switching noise.
The SY89426 operates from a single +5 volt supply, and
requires only a simple series RC loop filter.
Coupling Micrel-Synergy's advanced PLL technology
with our proprietary ASSET™ bipolar process has produced
a clock generator IC which exceeds applicable Bellcore
and ANSI specifications, while setting a new standard for
performance and flexibility.
TYPICAL APPLICATION
PIN CONFIGURATION
RETRFCK
+3V
VCC
VCCO
CK622P
(PECL)
CK622N
2X 50Ω
622.08MHz
CLOCK OUT
+3V
25 24 23 22 21 20 19
CLOCK
IN
0.1uF
RFCK
(TTL)
GND
GND
SEL39
SEL78
RFCK
V
CC
DISC
V
CC
RST
V
CC
+5V
+5V
FLTRP
FLTRN
26
27
28
1
2
3
4
5
6
7
8
9
10 11
18
17
V
CC
V
CC
CK622P
CK622N
V
CCO
CK155
GND
FLTRN
FLTRP
SY89426
CK155
(PECL)
RETRFCK
(TTL)
GND
RST DISC
(TTL) (TTL)
PLCC
TOP VIEW
J28-1
16
15
14
13
12
1000Ω
SEL39
(TTL)
SEL78
(TTL)
50Ω
155.52MHz
CLOCK OUT
RETIMED
REFOUT
NC
NC
GND
NC
GND
GND
GND
Rev.: F
NC
Amendment: /0
1
Issue Date: July, 1999
Micrel
ClockWorks™
SY89426
FUNCTIONAL BLOCK DIAGRAM
V
CCA
GND
5
7
FLTRP/N
V
CCO
RST
(TTL)
RFCK
(TTL)
Φ/f
CHG
PUMP
622MHz
VCO
FEEDBACK
÷ 2/3/4
SEL39
(TTL)
SEL78
(TTL)
DIVIDER
÷4
CK622P
(PECL)
CK622N
CK155
(PECL)
RETRFCK
(TTL)
DISC
(TTL)
PIN DESCRIPTION
INPUTS
RFCK [Reference Clock]
TTL
Reference clock IN. (38.88, 51.84 or 77.76MHz).
SEL39 [38.88MHz Select]
TTL
Logic HIGH on this pin denotes a 38.88MHz input reference
clock. Tie to logic LOW if input is not 38.88MHz.
SEL78 [77.76MHz Select]
TTL
Logic HIGH on this pin denotes a 77.76MHz input reference
clock. Tie to logic LOW if input is not 77.76MHz.
RST [Reset]
TTL
Tie to logic LOW for normal operation; logic HIGH forces reset
of internal Phase Detector & feedback dividers.
FLTRP, FLTRN [Loop Filter, Pos & Neg]
Analog
Connect a series RC loop filter between these pins. The
suggested RC values are 500Ω and 0.1µF, as shown in the
Typical Application.
DISC [Disable Clock]
TTL
Logic HIGH on this pin disables the Retimed Reference Clock
output RETRFCK); if this output is not required, it is
recommended that it be disabled to reduce switching noise. A
logic LOW enables the output.
OUTPUTS
CK622P, CK622N [622 Clock Output]
Differential PECL.
622.08MHz output clock from PLL B.
CK155 [155 Clock Out]
Single-ended PECL
155.52MHz output clock.
RETRFCK [Retimed Reference Clock Out]
TTL
An output clock with the same frequency as the input Reference
Clock (RFCK) and a 45-55% duty cycle. This output is derived
by dividing the 622.08MHz output by the appropriate factor
(e.g., divide by 16 for a 38.88MHz inout reference; divide by
12 for 51.84Mhz in; or divide by 8 for 77.76MHz in).
POWER & GROUND
V
CC
V
CCO
GND
+5V for internal circuits.
+5V for PECL outputs.
Ground (0 volts).
2
Micrel
ClockWorks™
SY89426
REFERENCE FREQUENCY SELECTION
(1)
SEL39
0
0
1
1
SEL78
0
1
0
1
fRFCK
51.84
77.76
38.88
77.76
NOTE:
1. Airflow greater than 500lfpm is maintained.
ABSOLUTE MAXIMUM RATINGS
(1), (2)
Symbol
V
CC
V
I
I
OUT
T
A
T
store
Power Supply
Input Voltage
Output Current
Operating Temperature Range
Storage Temperature Range
–Continuous
–Surge
Parameter
Rating
0 to +7
0 to V
CC
50
100
–40 to +85
–65 to +150
Unit
V
V
mA
°C
°C
NOTES:
1. Permanent device damage may occur if ABSOLUTE MAXIMUM RATINGS are exceeded. This is a stress rating only and functional operation is not
implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to ABSOLUTE MAXIMUM RATING conditions
for extended periods may affect device reliability.
2. Airflow greater than 500lfpm is maintained.
PECL DC ELECTRICAL CHARACTERISTIC
(1), (2)
V
CC
= V
CCO
= +5V
±
5%; GND = 0V; T
A
= –40°C to 85°C
T
A
= –40
°
C
Symbol
V
OH
V
OL
V
IH
V
IL
I
IL
Parameter
Output HIGH Voltage
Output LOW Voltage
Input HIGH Voltage
(1)
Input LOW Voltage
(1)
Input LOW Current
Min.
V
CC
-1130
Max.
V
CC
-840
T
A
= 0
°
C
Min.
V
CC
-1070
Max.
V
CC
-790
T
A
= +25
°
C
Min.
V
CC
-1030
Max.
V
CC
-760
T
A
= +85
°
C
Min.
V
CC
-960
Max.
V
CC
-670
Unit
mV
mV
mV
mV
µA
V
CC
-2000
V
CC
-1600
V
CC
-2000
V
CC
-1230
V
CC
-890
V
CC
-1170
V
CC
-1580
V
CC
-2000
V
CC
-1580
V
CC
-2000
V
CC
-1545
V
CC
-840
V
CC
-1130
V
CC
-810
V
CC
-1060
V
CC
-720
V
CC
-1950
V
CC
-1500
V
CC
-1950
0.5
—
0.5
V
CC
-1480
V
CC
-1950
V
CC
-1480
V
CC
-1950
V
CC
-1445
—
0.5
—
0.3
—
NOTES:
1. Forcing one input at a time. Apply V
IH
(Max) or V
IL
(Min) to all other inputs.
2. Airflow greater than 500lfpm is maintained.
TTL DC ELECTRICAL CHARACTERISTICS
(1)
V
CC
= V
CCO
= +5V
±
5%; GND = 0V; T
A
= –40°C to 85°C
Symbol
V
OH
V
OL
I
OS
V
IH
V
IL
Parameter
Output HIGH Voltage
Output LOW Voltage
Output Short Circuit Current
Input HIGH Voltage
Input LOW Voltage
Min.
2.4
—
–150
2.0
—
Max.
—
0.5
–60
—
0.8
Unit
V
V
mA
V
V
Condition
I
OH
= –2mA
I
OL
= 4mA
V
OUT
= 0
—
—
NOTE:
1. Airflow greater than 500lfpm is maintained.
3
Micrel
ClockWorks™
SY89426
DC ELECTRICAL CHARACTERISTICS
(1)
— TTL
DC ELECTRICAL CHARACTERISTICS
V
CC
= V
CCO
= +5V
±
5%; GND = 0V; T
A
= –40°C to 85°C
Symbol
I
EE
I
OUT
Parameter
Internal Operating Current
Termination Output Current
Min.
—
—
Typ.
79
11
Max.
120
—
Unit
mA
mA
50Ω to Vcc -2, 50% duty cycle
Condition
NOTE:
1. Airflow greater than 500lfpm is maintained.
AC ELECTRICAL CHARACTERISTICS
(1)
V
CC
= V
CCO
= +5V
±
5%; GND = 0V; T
A
= –40°C to 85°C
Parameter
VCO Center Frequency
Reference Clock (RFCK)
Frequency Tolerance
Reference Clock (RFCK) Input Duty Cycle
Reference Clock (RETRFCK) Output Duty Cycle
Acquisition Lock Time
TTL Output Rise/Fall Time
PECL Output Rise/Fall Time
CK622 Output Duty Cycle
CK155 Output Duty Cycle
tRST – RST pulse width
tp622 Static Phase Offset of CK622
tp155 Static Phase Offset of CK155
tpREF Static Phase Offset of RETRFCK
NOTE:
1. Airflow greater than 500lfpm is maintained.
Min.
—
—
—
45
40
—
—
—
45
45
1
190
–250
—
Typ.
±20
±20
±10
—
—
—
—
—
—
—
—
400
–400
+3.5
Max.
—
—
—
55
60
15
2
500
55
55
—
600
–750
—
Units
MHz
ppm
ppm
ppm
% of UI
% of UI
µsec
ns
ps
% of UI
% of UI
µsec
ps
ps
ns
15pF load
Nominal
77.76MHz
51.84MHz
38.88MHz
Condition
622.08
±1%
10% to 90% of amplitude, 15pF load
10% to 90%, 50Ω load, 5pF cap
DC ELECTRICAL CHARACTERISTICS — TTL
TIMING WAVEFORM
RFCK
Input
tp 622
CK622
Output
tp REF
RETRFCK
Output
tp 155
(1)
CK155
Output
NOTE:
1.
Does not apply to 52MHz reference
4
Micrel
ClockWorks™
SY89426
JITTER GENERATION
Jitter Generation Definition
Bellcore TR-NWT-000499 (Issue 4), section 7.3.3 "Jitter
generation is the process whereby jitter appears at the output
port of an individual unit of digital equipment in the absence of
applied input jitter."
Jitter Generation Requirement
Bellcore TA-NWT-000253 (Issue 2), section 5.6.5.2 "For
Category II interfaces, jitter generation shall not exceed 0.01
UI rms. For OC-N and STSX-N interfaces, a high-pass
measurement filter with a 12kHz cutoff frequency shall be
used." The low-pass cutoff frequency of the measurement
filter shall be higher than 5MHz.
The characteristic of the measurement filter is shown
below.
SONET OC-12 Category II Jitter Generation Measurement Filter Characteristics
UI (rms)
0.01
+20dB/decade
12kHz
Figure 1
Frequency
5MHz
(minimum)
PRODUCT ORDERING CODE
Ordering
Code
SY89426JC
SY89426JCTR
SY89426JI
SY89426JITR
Package
Type
J28-1
J28-1
J28-1
J28-1
Operating
Range
Commercial
Commercial
Industrial
Industrial
5
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