DESCRIPTION
I Integrated programmable clock divider and 1:2
fanout buffer
I Guaranteed AC performance over temperature and
voltage:
> 2.0GHz f
MAX
< 200ps t
r
/t
f
< 15ps within device skew
I Low jitter design:
< 10ps (pk-pk) total jitter
< 1ps (rms) cycle-to-cycle jitter
I Unique input termination and V
T
Pin for DC-coupled
and AC-coupled Inputs; CML, PECL, LVDS and
HSTL
I LVDS compatible outputs
I TTL/CMOS inputs for select and reset
I Parallel programming capability
I Programmable divider ratios of 1, 2, 4, 8 and 16
I Low voltage operation 2.5V
I Output disable function
I 40
C to 85
C temperature range
I Available in 16-pin (3mm 3mm) MLFTM package
FEATURES
2.5V, 2.0GHz ANY DIFF. IN-TO-LVDS
PROGRAMMABLE CLOCK DIVIDER AND 1:2
FANOUT BUFFER W/ INTERNAL TERMINATION
Precision EdgeTM
SY89875U
FINAL
APPLICATIONS
I SONET/SDH line cards
I Transponders
I High-end, multiprocessor servers
1
Rev.: A
Amendment: /1
Issue Date:
February 2003
This low-skew, low-jitter device is capable of accepting a
high-speed (e.g., 622MHz or higher) CML, LVPECL, LVDS
or HSTL clock input signal and dividing down the frequency
using a programmable divider to create a lower speed
version of the input clock. Available divider ratios are 2, 4, 8
and 16, or straight pass-through.
The differential input buffer has a unique internal
termination design that allows access to the termination
network through a V
T
pin. This feature allows the device to
easily interface to different logic standards. A V
REF-AC
reference is included for AC-coupled applications.
The /RESET input asynchronously resets the divider. In
the pass-through function (divide by 1) the /RESET
synchronously enables or disables the outputs on the next
falling edge of IN (rising edge of /IN).
FUNCTIONAL BLOCK DIAGRAM
TYPICAL PERFORMANCE
Precision Edge is a trademark of Micrel, Inc.
MicroLeadFrame and MLF are trademarks of Amkor Technology, Inc.
IN
/IN
S1
S0
Q1
/Q1
Q0
/Q0
509
509
/RESET
V
T
V
REF_AC
S2
Divided
by
2, 4, 8
or 16
Enable
MUX
MUX
Enable
FF
Decoder
Divide-by-4
CML/LVPECL/LVDS
622MHz
Clock In
OC-12 to OC-3
Translator/Divider
LVDS
155.5MHz
Clock Out
622MHz In
/Q0
Q0
/IN
IN
155.5MHz Out
2
Precision EdgeTM
SY89875U
Micrel
PACKAGE/ORDERING INFORMATION
Ordering Information
Package
Operating
Package
Part Number
Type
Range
Marking
SY89875UMI
MLF-16
Industrial
875U
SY89875UMITR*
MLF-16
Industrial
875U
*Tape and Reel
Pin Number
Pin Name
Pin Function
12, 9
IN, /IN
Differential Input: Internal 50
termination resistors to V
T
input. Flexible input accepts any
differential input. See
"Input Interface Applications" section.
1, 2, 3, 4
Q0, /Q0
Differential Buffered LVDS Outputs: Divided by 1, 2, 4, 8 or 16. See
"Truth Table."
Q1, /Q1
Unused output pairs must be terminated with 100
across the different pair.
16, 15, 5
S0, S1, S2
Select Pins: See
"Truth Table." LVTTL/CMOS logic levels. Internal 25k
pull-up resistor.
Logic HIGH if left unconnected (divided by 16 mode.) Input threshold is V
CC
/2.
6
NC
No Connect.
8
/RESET,
LVTTL/CMOS Logic Levels: Internal 25k
pull-up resistor. Logic HIGH if left unconnected.
/DISABLE
Apply LOW to reset the divider (divided by 2, 4, 8 or 16 mode). Also acts as a disable/enable
function. The reset and disable function occurs on the next high-to-low clock input transition.
Input threshold is V
CC
/2.
10
VREF-AC
Reference Voltage: Equal to V
CC
1.4V (approx.). Used for AC-coupled applications only.
Decouple the V
REFAC
pin with a 0.01
F capacitor. See "Input Interface Applications" section.
11
VT
Termination Center-Tap: For CML or LVDS inputs, leave this pin floating. Otherwise, See
Figures 4a to 4f,
"Input Interface Applications" section.
7, 14
VCC
Positive Power Supply: Bypass with 0.1
F//0.01F low ESR capacitor.
13
GND
Ground. Exposed pad must be connected to the same potential as the GND pin.
Exposed
PIN DESCRIPTION
1
2
3
4
12
11
10
9
16 15 14 13
5
6
7
8
Q0
/Q0
Q1
/Q1
IN
VT
VREF-AC
/IN
GND
VCC
S1
S0
/
RESET
VCC
NC
S2
16-Pin MLFTM (MLF-16)
/RESET
(1)
S2
S1
S0
Outputs
1
0
X
X
Reference Clock (pass through)
1
1
0
0
Reference Clock
2
1
1
0
1
Reference Clock
4
1
1
1
0
Reference Clock
8
1
1
1
1
Reference Clock
16
0
(1)
X
X
X
Q = LOW, /Q = HIGH
Clock Disable
Note 1.
Reset/Disable function is asserted on the next clock input
(IN, /IN) high-to-low transition.
TRUTH TABLE
3
Precision EdgeTM
SY89875U
Micrel
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 RATlNG
conditions for extended periods may affect device reliability.
Note 2.
The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.
Note 3.
Due to the limited drive capability use for input of the same package only.
Note 4.
Junction-to-board resistance assumes exposed pad is soldered (or equivalent) to the device's most negative potential on the PCB.
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
CC
) .................................. 0.5V to +4.0V
Input Voltage (V
IN
) .................................. 0.5V to V
CC
+0.3
ECL Output Current (I
OUT
)
Continuous ......................................................... 50mA
Surge ................................................................ 100mA
Input Current IN,
/IN (I
IN
) ..........................................
50mA
V
T
Current (I
VT
) ......................................................
100mA
V
REF-AC
Sink/Source Current (I
VREF-AC
), Note 3 .......
2mA
Lead Temperature (soldering 10 sec.) ...................... 220
C
Storage Temperature (T
S
) ....................... 65
C to +150C
Operating Ratings
(Note 2)
Supply Voltage (V
CC
) ........................................ +2.5V
5%
Ambient Temperature (T
A
) ......................... 40
C to +85C
Package Thermal Resistance
MLFTM
(
JA
)
Still-Air ............................................................. 60
C/W
500lfpm ............................................................ 54
C/W
MLFTM
(
JB
), Note 4
Junction-to-Board ............................................ 32
C/W
T
A
= 40
C to +85C; Unless otherwise stated.
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
CC
Power Supply
2.375
2.625
V
I
CC
Power Supply Current
No load, max. V
CC
70
95
mA
R
IN
Differential Input Resistance (IN, /IN)
80
100
120
V
IH
Input High Voltage (IN, /IN)
Note 3
0.1
V
CC
+0.3
V
V
IL
Input Low Voltage (IN, /IN)
Note 3
0.3
V
CC
+0.2
V
V
IN
Input Voltage Swing
Note 4
1.8
V
V
DIFF_IN
Differential Input Voltage Swing
Note 5
0.1
3.6
V
|I
IN
|
Input Current (IN, /IN)
Note 3
45
mA
V
REFAC
Reference Voltage
Note 6
V
CC
1.525 V
CC
1.425 V
CC
1.325
V
Note 1.
The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.
Note 2.
Specification for packaged product only.
Note 3.
Due to the internal termination (see Figure 2a) the input current depends on the applied voltages at IN, /IN and V
T
inputs. Do not apply a combination
of voltages that causes the input current to exceed the maximum limit!
Note 4.
See
"Timing Diagram" for V
IN
definition. V
IN
(Max) is specified when V
T
is floating.
Note 5.
See
"Typical Operating Characteristics" section for V
DIFF
definition.
Note 6.
Operating using V
IN
is limited to AC-coupled PECL or CML applications only. Connect directly to V
T
pin.
DC ELECTRICAL CHARACTERISTICS
(Notes 1, 2)
4
Precision EdgeTM
SY89875U
Micrel
V
CC
= 2.5V
5%; T
A
= 40
C to +85C; Unless otherwise stated.
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
IH
Input HIGH Voltage
2.0
V
V
IL
Input LOW Voltage
0.8
V
I
IH
Input HIGH Current
125
20
A
I
IL
Input LOW Current
300
A
Note 1.
The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.
Note 2.
Specification for packaged product only.
LVTTL/CMOS DC ELECTRICAL CHARACTERISTICS
(Notes 1, 2)
V
CC
= 2.5V
5%; T
A
= 40
C to +85C; Unless otherwise stated.
Symbol
Parameter
Condition
Min
Typ
Max
Units
V
OUT
Output Voltage Swing
Note 3, 4
250
350
400
mV
V
OH
Output High Voltage
Note 3
1.475
V
V
OL
Output Low Voltage
Note 3
0.925
V
V
OCM
Output Common Mode Voltage
Note 4
1.125
1.375
V
V
OCM
Change in Common Mode Voltage
50
50
mV
Note 1.
The circuit is designed to meet the DC specifications shown in the above table after thermal equilibrium has been established.
Note 2.
Specification for packaged product only.
Note 3.
Measured as per Figure 2a, 100
across Q and /Q outputs.
Note 4.
Measured as per Figure 2b.
LVDS DC ELECTRICAL CHARACTERISTICS
(Notes 1, 2)
5
Precision EdgeTM
SY89875U
Micrel
V
CC
= 2.5V
5%; T
A
= 40
C to +85C; Unless otherwise stated.
Symbol
Parameter
Condition
Min
Typ
Max
Units
f
MAX
Maximum Input Frequency
Output Swing
200mV
2.0
2.5
GHz
t
PLH
Differential Propagation Delay
Input Swing < 400mV
590
690
870
ps
t
PHL
IN to Q
Input Swing
400mV
540
690
820
ps
t
SKEW
Within-Device Skew (diff.)
Note 3
5
15
ps
Part-to-Part Skew (diff.)
Note 3
280
ps
t
RR
Reset Recovery Time
Note 4
600
ps
t
JITTER
Cycle-to-Cycle Jitter
Note 5
1
ps(rms)
Total Jitter
Note 6
10
ps(pk-pk)
t
r
,t
f
Rise/Fall Time (20% to 80%)
70
120
200
ps
Note 1.
Measured with 400mV input signal, 50% duty cycle, all outputs loaded with 100
across each output pair, unless otherwise stated.
Note 2.
Specification for packaged product only.
Note 3.
Skew is measured between outputs under identical transitions.
Note 4.
See "
Timing Diagram."
Note 5.
Cycle-to-cycle jitter definition: the variation in period between adjacent cycles over a random sample of adjacent cycle pairs. T
jitter_cc
= T
n
T
n+1
,
where T is the time between rising edges of the output signal.
Note 6.
Total jitter definition: with an ideal clock input of frequency
f
MAX
, no more than one output edge in 10
12
output edges will deviate by more than
the specified peak-to-peak jitter value.
AC ELECTRICAL CHARACTERISTICS
(Notes 1, 2)
TIMING DIAGRAM
V
ID
/RESET
IN
/IN
/Q
Q
t
PD
t
RR
V
CC/2
V
IN
Swing
V
OUT
Swing
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