The SY89421V is a digital Phase Locked Loop based on
Micrel-Synergy's differential PLL technology. It is capable
of operating in the 30MHz to 560MHz reference input
frequency range, and up to 2000MHz with the HFIN input
and an external VCO. Use of a phase-frequency detector
results in excellent PLL locking and tracking characteristics.
Error correction voltages are generated by the detector if
either phase or frequency deviations occur. The VCO has
a frequency range covering more than a 2:1 ratio from
480MHz to 1120MHz.
Feedback for the loop is realized by connecting FOUT,
FOUT to FIN, FIN by means of external circuitry. This
allows the flexibility of inserting additional circuitry off-chip
in the feedback paths, such as an additional divider and/or
buffer. Pulldown resistors are required for the FOUT and
FOUT pins. High frequency inputs HFIN, HFIN and
corresponding outputs HFOUT, HFOUT are featured for
use with external components such as an active loop filter
and a high frequency VCO.
Select pins S1 and S2 are used to program the N divider
for optimum VCO operation, in other words with the VCO in
the center of its range. Select pin S3 allows bypassing the
N divider enabling the PLL to output the VCO directly.
Select pin S4 is used to select off-chip or on-chip VCO.
Select pin S5 enables the divide-by-two prescaler, which is
useful in frequency doubling applications. All Select pins
are TTL compatible.
FEATURES
s
3.3V and 5V power supply options
s
1.12GHz maximum VCO frequency
s
30MHz to 560MHz reference input operating
frequency
s
External 2.0GHz VCO capability
s
Low jitter differential design
s
Frequency doubler mode
s
PECL Differential output
s
External loop filter optimizes performance/cost
s
Available in 20-pin SOIC package
DESCRIPTION
ClockWorksTM
SY89421V
5V/3.3V
HIGH-PERFORMANCE
PHASE LOCKED LOOP
APPLICATIONS
s
Workstations
s
Advanced communications
s
High-performance computing
PIN CONFIGURATION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
20
19
18
17
16
15
TOP VIEW
SOIC
Z20-1
S1
FIN
FIN
V
EE
F1
F2
S5
HFIN
HFIN
S4
HFOUT
HFOUT
V
CCO
FOUT
FOUT
V
CC
S3
RIN
RIN
S2
1
Rev.: F
Amendment: /0
Issue Date:
May 2000
2
ClockWorksTM
SY89421V
Micrel
BLOCK DIAGRAM
LOOP FILTER COMPONENT SELECTION
C
= 1.0
F
10% (X7R dielectric)
R
= 560
10%
R
C
F1
F2
S1
S2
S3
RIN
RIN
F1
F2
VCO
FIN
FIN
FOUT
FOUT
P
(1, 2)
S5
D
HFOUT
HFOUT
HFIN
HFIN
S4
2
MUX
0
1
LOOP
FILTER
PHASE-FREQUENCY
DETECTOR
N
(1,2,4,8,10,12,16,20)
3
ClockWorksTM
SY89421V
Micrel
Pin
Function
I/O
F1
Filter Pin 1
I/O
F2
Filter Pin 2
I/O
RIN
Reference Input
I
RIN
Inverted Reference Input
I
FIN
Feedback Input
I
FIN
Inverted Feeback Input
I
HFIN
High Frequency Input
I
HFIN
Inverted High Frequency Input
I
HFOUT
High Frequency Output
O
HFOUT
Inverted High Frequency Output
O
FOUT
Frequency Output
O
FOUT
Inverted Frequency Output
O
V
CC
V
CC
--
V
CCO
Output V
CC
--
V
EE
V
EE
(0V)
--
S1
Select Input 1 (TTL)
I
S2
Select Input 2 (TTL)
I
S3
Select Input 3 (TTL)
I
S4
Select Input 4 (TTL)
I
S5
Select Input 5 (TTL)
I
RIN, RIN
Reference frequency inputs. These are differential signal
pairs and may be driven differentially or single-ended.
FIN, FIN
Feedback frequency inputs. These are a differential signal
pair and may be driven differentially or single-ended.
HFIN, HFIN
High frequency feedback inputs. These are a differential
signal pair. Differential drive is recommended.
F1, F2
These pins are connection points for the loop filter, which is to
be provided off-chip. F1 is the high impedance side, F2 is the
reference side. The loop filter should be a first order, low pass
with a DC block. The difference voltage on these pins will be
a dc level, which is controlled by the loop feedback and
determined by the required VCO frequency.
FOUT, FOUT
Frequency outputs for the loops. These are differential, positive
referenced, emitter-follower signals and must be terminated
off chip. Termination in 50 ohms is recommended.
HFOUT, HFOUT
High frequency output. These are a differential signal pair.
Termination in 50 ohms is recommended.
S1, S2, S3, S4, S5
These are the frequency select inputs, and are used to
configure the PLL. They are compatible with standard TTL
signal levels. See the Frequency Selection Table for details
of the logic.
V
CC
This is the positive supply for the chip. It should be decoupled
and should present a very low impedance in order to assure
low-jitter operation.
V
CCO
This is the positive supply for the output buffer. It is constrained
to be equal to or less than the value of V
CC
. It should be
decoupled and should present a very low impedance for low-
jitter.
V
EE
This pin is the negative supply for the chip and is normally
connected to ground (0V).
PIN NAMES
PIN DESCRIPTION
4
ClockWorksTM
SY89421V
Micrel
FREQUENCY SELECTION TABLE
FOUT
HFOUT
S4
S3
S2
S1
N
Freq. Range MHz
Freq. Range MHz
0
0
0
0
2
240 560
480 1120
0
0
0
1
4
120 280
480 1120
0
0
1
0
8
60 140
480 1120
0
0
1
1
16
30 70
480 1120
0
1
0
0
1
480 1120
480 1120
0
1
0
1
10
48 112
480 1120
0
1
1
0
12
40 93.3
480 1120
0
1
1
1
20
20 56
480 1120
1
0
0
0
2
HFIN divide by 4
HFIN divide by 2
1
0
0
1
4
HFIN divide by 8
HFIN divide by 2
1
0
1
0
8
HFIN divide by 16
HFIN divide by 2
1
0
1
1
16
HFIN divide by 32
HFIN divide by 2
1
1
0
0
1
HFIN divide by 2
HFIN divide by 2
1
1
0
1
10
HFIN divide by 20
HFIN divide by 2
1
1
1
0
12
HFIN divide by 24
HFIN divide by 2
1
1
1
1
20
HFIN divide by 40
HFIN divide by 2
Maximum Feedback
S5
Divide-by-P
Frequency (MHz)
0
P = 1
560
1
P = 2
1120
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
Parameter
Value
Unit
V
CC
Power Supply Voltage
0.5 to +7.0
V
V
I
TTL Input Voltage
(2)
0.5 to 6.0
V
I
I
TTL Input Current
(2)
30 to +5.0
mA
I
OUT
ECL Output Current
mA
-- Continuous
50
-- Surge
100
T
store
Storage Temperature
65 to +150
C
T
A
Operating Temperature Range
(3)
0 to +85
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. Either voltage limit or current limit is sufficient to protect input.
3. All DC and AC electrical characteristics are specified over the operating termperature range.
5
ClockWorksTM
SY89421V
Micrel
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
V
OH
Output HIGH Voltage
V
CC
1.025
--
V
CC
0.780
V
V
OL
Output LOW Voltage
V
CC
1.810
--
V
CC
1.520
V
V
IH
Input HIGH Voltage
V
CC
1.165
--
V
CC
0.780
V
V
IL
Input LOW Voltage
V
CC
1.810
--
V
CC
1.475
V
PECL DC ELECTRICAL CHARACTERISTICS
V
CC
= V
CCO
= 3.3V or 5.0V
5%
TTL DC ELECTRICAL CHARACTERISTICS
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
V
IH
Input HIGH Voltage
2.0
--
--
V
V
IL
Input LOW Voltage
--
--
0.8
V
I
IH
Input HIGH Current
--
--
20
A
V
IN
= 2.7V
100
V
IN
= V
CC
I
IL
Input LOW Current
--
--
0.3
mA
V
IN
= 0.5V
V
IK
Input Clamp Voltage
--
--
1.2
V
I
IN
= 12mA
V
CC
= V
CCO
= 3.3V or 5.0V
5%
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
V
CC
Power Supply Voltage
4.75
--
5.25
V
V
CC
= V
CCO
I
CC
Power Supply Current (V
CC
)
--
--
100
mA
I
CCO
Power Supply Current (V
CCO
)
--
--
28
mA
PECL outputs are open
5V DC ELECTRICAL CHARACTERISTICS
V
CC
= V
CCO
= 5.0V
5%
Symbol
Parameter
Min.
Typ.
Max.
Unit
Condition
V
CC
Power Supply Voltage
3.135
--
3.465
V
V
CC
= V
CCO
I
CC
Power Supply Current (V
CC
)
--
--
100
mA
I
CCO
Power Supply Current (V
CCO
)
--
--
28
mA
PECL outputs are open
3.3V DC ELECTRICAL CHARACTERISTICS
V
CC
= V
CCO
= 3.3V
5%
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