s
Two independently-powered 622.08MHz clock
sources one chip
s
Differential PECL outputs
s
TTL/CMOS compatible inputs
s
SONET compliant jitter performance (
0.01UI)
s
Choice of three reference frequencies for each PLL
s
Only 395mW per PLL (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
Rev.: E
Amendment: /0
Issue Date: August, 1998
TYPICAL APPLICATION
ClockWorksTM
SY89425
FEATURES
DESCRIPTION
Micrel-Synergy's SY89425 Dual Phase Locked Loop
(PLL) consists of two totally separate, SONET compliant
622.08MHz clock generators on one chip. The user may
select to power both PLLs or PLL A only. Each PLL
produces a low-jitter OC-12/STS-12 clock rate from an
input reference clock of 38.88, 51.84, or 77.76MHz. When
using both PLLs, it is not necessary that they share a
common reference clock (e.g., PLL A may operate from an
STS-1 reference of 51.84MHz, while PLL B operates from
an OC-3/STS-3 reference of 77.76MHz).
The SY89425 operates from a single +5 volt supply, and
requires only a simple series RC loop filter for each PLL.
Coupling Micrel-Synergy's advanced PLL technology
with our proprietary ASSETTM bipolar process has produced
a clock generator IC which exceeds applicable Bellcore
and ANSI specifications, while setting a new standard for
performance and flexibility.
PIN CONFIGURATION
DUAL SONET OC-12
CLOCK SYNTHESIZER
26
27
28
1
2
3
4
18
17
16
15
14
13
12
25 24 23 22
21 20 19
5
6
7
8
9
10 11
SEL78A
GND
V
CCB
FLTRBP
FLTRBN
V
CCB
GND
RSTB
CK622AP
GND
GND
V
CCA
FLTRAP
FLTRAN
V
CCA
RSTA
PLCC
TOP VIEW
CK622AN
V
CCOA
GND
V
CCOB
CK622BN
CK622BP
SEL39A
RFCKA
V
CCA
RFCKB
SEL39B
SEL78B
0.1uF
GND
AGND
FLTRAN
RFCKA
(TTL)
SEL39A
(TTL)
SEL78A
(TTL)
RSTA
(TTL)
500
CK622AP
(PECL)
CK622AN
622.08MHz
PLL A
VCCA
VCCOA
+5V
+5V
FLTRAP
PLL B
(SAME AS PLL A)
2X 50
+3V
GND
CLOCK IN
1
2
ClockWorksTM
SY89425
Micrel
FUNCTIONAL BLOCK DIAGRAM
V
CCA
GND
FLTRAP/N
V
CCOA
2
3
/f
CHG
PUMP
622MHz
VCO
/f
CHG
PUMP
622MHz
VCO
FEEDBACK
DIVIDER
(8/12/16)
PLL A
PLL B
V
CCB
GND
FLTRBP/N
V
CCOB
3
2
RFCKA (TTL)
SEL39A (TTL)
RFCKB (TTL)
SEL78A (TTL)
SEL78B (TTL)
SEL39B (TTL)
RSTA (TTL)
CK622AP
CK622AN
(PECL)
CK622BP
CK622BN
(PECL)
RSTB (TTL)
FEEDBACK
DIVIDER
(8/12/16)
3
ClockWorksTM
SY89425
Micrel
INPUTS
RFCKB [Reference Clock B] TTL
Reference clock in for PLL B. (38.88, 51.84 or 77.76MHz).
SEL39B [38.88MHz Select B] TTL
Logic HIGH on this pin denotes a 38.88MHz input reference
clock for PLL B. Tie to logic LOW if input is not 38.88MHz.
SEL78B [77.76MHz Select B] TTL
Logic HIGH on this pin denotes a 77.76MHz input reference
clock for PLL A. Tie to logic LOW if input is not 77.76MHz.
RSTB [Reset B] TTL
Tie to logic LOW for normal operation; logic HIGH forces reset
of internal Phase Detector & feedback dividers on PLL B.
FLTRBP, FLTRBN (Loop Filter B, Pos & Neg) Analog.
Connect a series RC loop filter between these pins. The
suggested loop filter is 0.1
F and 500 ohms, as shown in the
typical application on page 3-9.
RSTA (Reset A) TTL
Tie to logic LOW for normal operation; logic HIGH forces reset
of internal Phase Detector & feedback dividers on PLL A.
SEL78A [77.76MHz Select A] TTL
Logic HIGH on this pin denotes a 77.76MHz input reference
clock for PLL A. Tie to logic LOW if input is not 77.76MHz.
SEL39A [38.88MHz Select A] TTL
Logic HIGH on this pin denotes a 38.88MHz input reference
clock for PLL A. Tie to logic LOW if input is not 38.88MHz.
PIN DESCRIPTION
REFCKA [Reference Clock A] TTL
Reference clock in for PLL A.
FLTRAP, FLTRAN (Loop Filter A, Pos & Neg) Analog.
Connect a series RC loop filter between these pins. The
suggested loop filter is 0.1
F and 500 ohms, as shown in the
typical application on page 5-527.
OUTPUTS
CK622BP, CK622BN (Clock Out B) Differential PECL
622.08MHz output clock from PLL B.
CK622AP, CK622AN (Clock Out A) Differential PECL
622.08MHz output clock from PLL A.
POWER & GROUND
V
CCA
+5V for PLL A.
V
CCB
+5V for PLL B.
V
CCOA
+5V for PLL A PECL outputs.
V
CCOB
+5V for PLL B PECL outputs.
GND
Ground (0 volts)
REFERENCE FREQUENCY SELECTION
SEL39
SEL78
fRFCK
0
0
51.84
0
1
77.76
1
0
38.88
1
1
77.76
Symbol
Parameter
Rating
Unit
V
CC
Power Supply
0 to +7
V
V
I
Input Voltage
0 to V
CC
V
I
OUT
Output Current
Continuous
50
mA
Surge
100
T
A
Operatimg Temperature Range
0 to +85
C
T
store
Storage Temperature Range
65 to +150
C
NOTE:
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.
ABSOLUTE MAXIMUM RATINGS
(1)
4
ClockWorksTM
SY89425
Micrel
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
I
EE
Internal Operating Current
--
157
204
mA
Both PLLs powered
I
OUT
Termination Output Current
--
11
--
mA
50
to Vcc -2, 50% duty cycle
DC ELECTRICAL CHARACTERISTICS -- TTL
V
CCA
= V
CCB
= V
CCOA
=V
CCOB
= +5V
5%; GND = 0V; T
A
= 0
C to 85
C
DC ELECTRICAL CHARACTERISTICS
(1), (2), (3)
NOTES:
1. To calculate total power supply current into the V
CC
pins: I
CC
= (n * I
OUT
); where n = number of ECL output pins used (ie, terminated).
2. To calculate total device power dissipation; P
D
= [I
EE
* (V
CC
- V
EE
)] + [n * I
OUT
* 1.33]
(3)
.
3. Average ECL output voltage is calculated as V
OAVG
= (V
OH(MAX)
+ V
OH(MIN)
+ V
OL(MAX)
+ V
OL(MIN)
) /4 = 1.33V.
V
CCA
= V
CCB
= V
CCOA
=V
CCOB
= +5V
5%; GND = 0V; T
A
= 0
C to 85
C
Symbol
Parameter
Min.
Max.
Unit
Condition
V
OH
Output HIGH Voltage
2.4
--
V
I
OH
= 2mA
V
OL
Output LOW Voltage
--
0.5
V
I
OL
= 4mA
I
OS
Output Short Circuit Current
150
60
mA
V
OUT
= 0V
V
IH
Input HIGH Voltage
2.0
--
--
--
V
IL
Input LOW Voltage
--
0.8
V
--
TTL DC ELECTRICAL CHARACTERISTICS
PECL DC ELECTRICAL CHARACTERISTIC
(1), (2)
T
A
= 40
C
T
A
= 0
C
T
A
= +25
C
T
A
= +85
C
Symbol
Parameter
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Unit
V
OH
Output HIGH Voltage
V
CC
-1130
V
CC
-840
V
CC
-1070
V
CC
-790
V
CC
-1030
V
CC
-760
V
CC
-960
V
CC
-670
mV
V
OL
Output LOW Voltage
V
CC
-2000
V
CC
-1600
V
CC
-2000
V
CC
-1580
V
CC
-2000
V
CC
-1580
V
CC
-2000
V
CC
-1545
mV
V
IH
Input HIGH Voltage
(1)
V
CC
-1230
V
CC
-890
V
CC
-1170
V
CC
-840
V
CC
-1130
V
CC
-810
V
CC
-1060
V
CC
-720
mV
V
IL
Input LOW Voltage
(1)
V
CC
-1950
V
CC
-1500
V
CC
-1950
V
CC
-1480
V
CC
-1950
V
CC
-1480
V
CC
-1950
V
CC
-1445
mV
I
IL
Input LOW Current
0.5
--
0.5
--
0.5
--
0.3
--
A
V
CCA
= V
CCB
= V
CCOA
=V
CCOB
= +5V
5%; GND = 0V; T
A
= 0
C to 85
C
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.
5
ClockWorksTM
SY89425
Micrel
DC ELECTRICAL CHARACTERISTICS -- TTL
TIMING WAVEFORMS
RFCK
Input
CK622
Output
tp 622
Parameter
Min.
Typ.
Max.
Units
Condition
VCO Center Frequency
622.08
1%
MHz
Nominal
--
20
--
ppm
77.76MHz
--
20
--
ppm
51.84MHz
--
10
--
ppm
38.88MHz
Reference Clock (RFCK) Input Duty Cycle
45
--
55
% of UI
Acquisition Lock Time
--
--
15
sec
TTL Output Rise/Fall Time
--
--
2
ns
10% to 90% of amplitude, 15pF load
PECL Output Rise/Fall Time
--
--
500
ps
10% to 90%, 50
load, 5pF cap
CK622 Output Duty Cycle
45
--
55
% of UI
tRST RST pulse width
1
--
--
sec
tp622 Static Phase Offset of CK622
--
0.7
--
ns
AC ELECTRICAL CHARACTERISTICS
V
CCA
= V
CCB
= V
CCOA
=V
CCOB
= +5V
5%; GND = 0V; T
A
= 0
C to 85
C
Reference Clock (RFCK)
Frequency Tolerance
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