The SY89420V device consists of two identical, low

jitter, digital Phase Locked Loops based on Micrel-Synergy's
differential PLL technology. Each of the PLLs (PLLA and
PLLB) is capable of operating in the 30MHz to 560MHz
input reference frequency range independently of the other
and is configurable separately. The PLLs can be configured
to be matched in all regards, or can be configured so that
PLLB is used as a frequency doubler, while PLLA is used
to regenerate the undoubled frequency.

Two reference inputs (RINX and RINX), two feedback

inputs (FINX and FINX), two filter pins (F1X and F2X) and
two differential outputs (FOUTX and FOUTX) are provided
for each of the two PLLs. The reference and feedback
inputs can be used as either differential or single-ended
inputs. In single-ended mode RINX and FINX can be
connected to either V

for normal 100K PECL levels or

for normal TTL levels.

Feedback for the loops is realized by connecting FOUTX,

FOUTX to FINX, FINX by means of external circuitry. This
allows the user the flexibility of inserting additional circuitry
off-chip in the feedback paths, such as a divider. Pulldown
resistors are required for the FOUTX and FOUTX pins.

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.

Select pins S1X and S2X are used to program the N

dividers for optimum VCO operation, in other words with
the VCO in the center of its range. Additional select pins,
S3B and S4B, are provided for PLLB. When both S3B and
S4B are low, PLLB is identical to PLLA. When S3B is high,
N

can be set to 1, 10, 18, or 20. When S4B is high, the

frequency doubler option is enabled (P = 2). All Select pins
are TTL compatible.

FEATURES

3.3V and 5V power supply options

1.12GHz maximum VCO frequency

30MHz to 560MHz reference input operating
frequency

Frequency doubler mode

Low jitter design

PECL differential outputs

PECL and TTL reference voltages available

External loop filter optimizes performance/cost

Available in 28-pin PLCC package

DESCRIPTION

ClockWorksTM

SY89420V

5V/3.3V DUAL
PHASE LOCKED LOOP

APPLICATIONS

Workstations

Advanced communications

High-end consumer

High-performance computing

PIN CONFIGURATION

S2A

F1A

F2A

FOUTB

25 24 23 22 21 20 19

10 11

TOP VIEW

PLCC

J28-1

S1B

S2B

F1B

F2B

S3B

FINB

S4B

RINB

RINA

S1A

FINA

CCOB

FOUTB

FOUTA

CCOA

FINA

FINB

RINB

Rev.: K

Amendment: /0

Issue Date:

May 2000

ClockWorksTM

SY89420V

Micrel

PIN DESCRIPTION

RINA, RINA, RINB, RINB

Reference frequency inputs for loop A and B. These are
differential signal pairs and may be driven differentially or
single-ended.

FINA, FINA, FINB, FINB

Feedback frequency inputs for loop A and B. These are
differential signal pairs and may be driven differentially or
single-ended.

, V

These are the reference voltages for use as bias for the
frequency inputs. The references are generated on-chip. V

is PECL compatible, while V

is TTL compatible.

F1A, F2A, F1B, F2B

These pins are connection points for the loop filters, which are
to be provided off-chip. F1X is the high impedance side, F2X
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.

FOUTA, FOUTA, FOUTB, FOUTB

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.

S1A, S2A, S1B, S2B, S3B, S4B

These inputs are used to select the configuration for PLLA and
PLLB. They are compatible with standard TTL signal levels.
See the Frequency Selection Table for details of the logic.

This is the positive supply for the entire chip excluding output
buffers. It should be decoupled and present a very low
impedance in order to assure low-jitter operation.

CCOA

, V

CCOB

These are the positive supplies for the output buffers. They
are constrained to be equal to the value of V

. They should

be decoupled and present a very low impedance in order to
assure low-jitter operation.

This pin is the negative supply for the chip and is normally
connected to ground (0V).

1.0

�

10% (X7R dielectric)

560

�

10%

LOOP FILTER COMPONENT SELECTION

Pin

Function

I/O

F1A

Filter Pin 1A

I/O

F2A

Filter Pin 2A

I/O

RINA

Reference Input A

RINA

Inverted Reference Input A

FINA

Feedback Input A

FINA

Inverted Feedback Input A

FOUTA

Frequency Output A

FOUTA

Inverted Frequency Output A

F1B

Filter Pin 1B

I/O

F2B

Filter Pin 2B

I/O

RINB

Reference Input B

RINB

Inverted Reference Input B

FINB

Feedback Input B

FINB

Inverted Feedback Input B

FOUTB

Frequency Output B

FOUTB

Inverted Frequency Output B

CCOA

Output A V

CCOB

Output B V

(0V)

PECL Threshold Voltage

TTL Threshold Voltage

S1A

Select Input 1A (TTL)

S2A

Select Input 2A (TTL)

S1B

Select Input 1B (TTL)

S2B

Select Input 2B (TTL)

S3B

Select Input 3B (TTL)

S4B

Select Input 4B (TTL)

PIN NAMES

F2X

F1X

ClockWorksTM

SY89420V

Micrel

S3B

S2B

S1B

Divide-by-N

Output Frequency Range (MHz)

N =2

240 � 560

N = 4

120 � 280

N = 8

60 � 140

N = 16

30� 70

N = 1

480 � 1120

N = 10

48 � 112

N = 12

40 � 93.3

N = 20

24 � 56

S2A

S1A

Divide-by-N

Output Frequency Range (MHz)

N = 2

240 � 560

N = 4

120 � 280

N = 8

60 � 140

N = 16

30 � 70

FREQUENCY SELECTION TABLE

PLLA

PLLB

S4B

Divide-by-P

Max. Feedback Frequency (MHz)

P =1

560

P = 2

1120

Symbol

Parameter

Value

Unit

Power Supply Voltage

�0.5 to +7.0

TTL Input Voltage

(2)

�0.5 to 6.0

TTL Input Current

(2)

�30 to +5.0

OUT

ECL Output Current

-- Continuous

-- Surge

100

store

Storage Temperature

�65 to +150

�

Operating Temperature Range

(3)

0 to +85

�

ABSOLUTE MAXIMUM RATINGS

(1)

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 temperature range.

ClockWorksTM

SY89420V

Micrel

Symbol

Parameter

Min.

Typ.

Max.

Unit

Condition

Power Supply Voltage

4.75

5.25

CCO

Power Supply Current (V

)

200

CCO

Power Supply Current (V

CCO

)

PECL outputs are open

5V DC ELECTRICAL CHARACTERISTICS

= V

CCOA

= V

CCOB

= 5.0V

�

Symbol

Parameter

Min.

Typ.

Max.

Unit

Condition

Power Supply Voltage

3.135

3.465

CCO

Power Supply Current (V

)

200

CCO

Power Supply Current (V

CCO

)

PECL outputs are open

3.3V DC ELECTRICAL CHARACTERISTICS

= V

CCOA

= V

CCOB

= 3.3V

�

PECL DC ELECTRICAL CHARACTERISTICS

Symbol

Parameter

Min.

Typ.

Max.

Unit

Condition

Output HIGH Voltage

� 1.025

� 0.780

Output LOW Voltage

� 1.810

� 1.520

Input HIGH Voltage

� 1.165

� 0.780

Input LOW Voltage

� 1.810

� 1.475

PECL Threshold

� 1.35

= V

CCOA

= V

CCOB

= 3.3V or 5.0V

�

Symbol

Parameter

Min.

Typ.

Max.

Unit

Condition

Input HIGH Voltage

2.0

Input LOW Voltage

0.8

Input HIGH Current

�

= 2.7V

100

= V

Input LOW Current

�0.3

= 0.5V

Input Clamp Voltage

� 1.2

= �12mA

TTL Threshold

1.5

TTL DC ELECTRICAL CHARACTERISTICS

= V

CCOA

= V

CCOB

= 3.3V or 5.0V

�

ClockWorksTM

SY89420V

Micrel

Ordering

Package

Operating

Code

Type

Range

SY89420VJC

J28-1

Commercial

SY89420VJCTR

J28-1

Commercial

APPLICATION

PRODUCT ORDERING CODE

50MHz Low Skew Clock System with 100MHz Clock to CPU

Symbol

Parameter

Min.

Typ.

Max.

Unit

Condition

Output Period Jitter

ps rms

Output Duty Cycle

Output Rise/Fall Time

300

550

(20% to 80%)

300

550

FOUTA

Output Frequency PLLA

560

MHz

FOUTB

Output Frequency PLLB

1120

MHz

S4B=1

RINA, B

Input Frequency PLLA, B

560

MHz

AC ELECTRICAL CHARACTERISTICS

= V

CCOA

= V

CCOB

= 3.3V or 5.0V

�

RINA

FINA

RINB

FINB

PLLA

PLLB

OUTA

OUTB

SY100H641

SY100H842

50MHz

100MHz

SY89429A

16MHz

SY89420V

S2A = 1

S1A = 1

S4B = 1

S3B = 1

S2B = 0

S1B = 1

50MHz

Clock

Электронный компонент: SY89420VJCTR