DATA
SHEET
Document Number:
MC88LV926
Rev. 7, 4/2006
Freescale Semiconductor
Technical Data
MC88LV926
Low Skew CMOS PLL 68060 Clock
Low Skew CMOS PLL 68060
Driver
MC88LV926
Clock Driver
The MC88LV926 Clock Driver utilizes phase-locked loop technology to lock its
low skew outputs' frequency and phase onto an input reference clock. It is
designed to provide clock distribution for CISC microprocessor or single
processor RISC systems. The RST_IN/RST_OUT(LOCK) pins provide a
processor reset function designed specifically for the MC68/EC/LC030/040/060
microprocessor family. To support the 68060 processor, the 88LV926 operates
from a 3.3 V supply.
The PLL allows the high current, low skew outputs to lock onto a single clock
input and distribute it to multiple locations on a board. The PLL also allows the
MC88LV926 to multiply a low frequency input clock and distribute it locally at a
higher (2X) system frequency.
LOW SKEW CMOS PLL
68080 CLOCK DRIVER
Features
•
•
•
•
•
•
•
•
•
•
2X_Q Output Meets All Requirements of the 50 and 66 MHz 68060
Microprocessor PCLK Input Specifications
Low Voltage 3.3 V VCC
Three Outputs (Q0–Q2) with Output–Output Skew 1500
V
ESD
Parameter
Table 4. DC Characteristics (TA = 0°C to 70°C; VCC = 3.3 V ± 0.3 V)(1)
Symbol
VCC
Parameter
Guaranteed Limits
Unit
Condition
3.0
3.3
2.0
2.0
V
VOUT = 0.1V or
VCC – 0.1V
Minimum Low Level Input Voltage
3.0
3.3
0.8
0.8
V
VOUT = 0.1V or
VCC – 0.1V
VOH
Minimum High Level Output Voltage
3.0
3.3
2.2
2.5
V
VIN = VIH or
VIL = –24mA
IOH = –24mA
VOL
Minimum Low Level Output Voltage
3.0
3.3
0.55
0.55
V
VIN = VIH or
IIN
Maximum Input Leakage Current
3.3
±1.0
μA
VI = VCC, GND
ICCT
Maximum ICC/Input
3.3
2.0 (3)
mA
VI = VCC – 2.1V
IOLD
Minimum Dynamic(4) Output Current
3.3
50
mA
VOLD = 1.25V Max
3.3
–50
mA
VOHD = 2.35 Min
3.3
750
μA
VI = VCC, GND
VIH
Minimum High Level Input
VIL
Voltage(1)
IOHD
ICC
Maximum Quiescent Supply Current
VIL = +24mA(2)
IOH = +24mA
1. The MC88LV926 can also be operated from a 3.3V supply. VOH output levels will vary 1:1 with VCC, input levels and current specs will be
unchanged, except VIH; when VCC > 4.0 volts, VIH minimum level is 2.7 volts.
2. IOL is +12mA for the RST_OUT output.
3. Maximum test duration 2.0ms, one output loaded at a time.
4. The PLL_EN input pin is not guaranteed to meet this specification.
IDT™ Low Skew CMOS PLL 68060 Clock Driver
Advanced
Clock Drivers
Device Data
Freescale
Timing Solutions
Organization
has been acquired by Integrated Device Technology, Inc
Freescale Semiconductor
3
MC88LV926
MC88LV926
3
MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
RST_OUT
RST_IN
Lock Indicator
RESET_OUT
2X_Q
Q
÷2
R
SYNC1
CH
PUMP
PFD
VCO
Q
Q0
÷4
R
PLL_EN
0
Q
1
Q1
÷4
R
÷8
Q
Q2
÷4
R
Q3
Q
÷4
R
Power–On
Reset
CLKEN
Delay
÷4
R
MR
Figure 2. MC88LV926 Logic Block Diagram
Table 5. Sync Input Timing Requirements
Symbol
Parameter
tRISE/FALL
SYNC Input
Rise/Fall Time, SYNC Input
From 0.8V to 2.0V
tCYCLE,
SYNC Input
Input Clock Period
Duty Cycle
Duty Cycle, SYNC Input
SYNC Input(1)
Minimum
Maximum
Unit
–
5.0
ns
1
f2X_Q/4
200(1)
ns
50% ± 25%
1. When VCC > 4.0 volts, Maximum SYNC Input Period is 125 ns.
MC88LV926
IDT™ Low
Skew CMOS PLL 68060 Clock Driver
MC88LV926
Freescale Timing Solutions Organization has been acquired by Integrated Device Technology, Inc Advanced Clock Drivers Device Data
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MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
Table 6. Frequency Specifications (TA = 0°C to 70°C; VCC = 3.3 V ± 0.3 V
Symbol
Parameter
Guaranteed Minimum
Unit
Fmax (2X_Q)
Maximum Operating Frequency, 2X_Q Output
66
MHz
Fmax (‘Q')
Maximum Operating Frequency,
Q0–Q3 Outputs
33
MHz
NOTE: Maximum Operating Frequency is guaranteed with the 88LV926 in a phase-locked condition.
Table 7. AC Characteristics (TA = 0°C to 70°C; VCC = 3.3V ± 0.3V
Symbol
Parameter
Minimum
Maximum
Unit
Condition
tRISE/FALL
All Outputs
Rise/Fall Time, into 50Ω Load
0.3
1.6
ns
tRISE – 0.8 V to 2.0 V
tFALL – 2.0 V to 0.8 V
tRISE/FALL
2X_Q Output
Rise/Fall Time into a 50Ω Load
0.5
1.6
ns
tRISE – 0.8 V to 2.0 V
tFALL – 2.0 V to 0.8 V
tpulse width(a)(1)
(Q0, Q1, Q2, Q3)
Output Pulse Width
Q0, Q1, Q2, Q3 at 1.65V
0.5tcycle – 0.5
0.5tcycle + 0.5
ns
50 Ω Load Terminated to VCC/
2 (See Application Note 3)
tpulse width(b)(1)
(2X_Q Output)
Output Pulse Width
2X_Q at 1.65V
0.5tcycle – 0.5
0.5tcycle + 0.5
ns
50 Ω Load Terminated to VCC/
2 (See Application Note 3)
tSKEWr(2)
(Rising)
Output–to–Output Skew
Between Outputs Q0–Q2
(Rising Edge Only)
–
500
ps
Into a 50Ω Load Terminated to
VCC/2 (See Timing Diagram in
Figure 6)
tSKEWf(2)
(Falling)
Output–to–Output Skew
Between Outputs Q0–Q2
(Falling Edge Only)
–
1.0
ns
Into a 50 Ω Load Terminated to
VCC/2 (See Timing Diagram in
Figure 6)
tSKEWall(2)
Output–to–Output Skew
2X_Q, Q0–Q2, Q3
–
750
ps
Into a 50 Ω Load Terminated to
VCC/2 (See Timing Diagram in
Figure 6)
tSKEW QCLKEN(1)
Output–to–Output Skew
QCLKEN to 2X_Q
2X_Q = 50 MHz
2X_Q = 66 MHz
ns
9.7(3)
–
Into a 50 Ω Load Terminated to
VCC/2 (See Timing Diagram in
Figure 6)
(2)
7.0(3)
tLOCK(4)
Phase–Lock Acquisition Time,
All Outputs to SYNC Input
1
10
ms
tPHL MR – Q(1)
Propagation Delay,
MR to Any Output (High–Low)
1.5
13.5
ns
9
–
ns
Into a 50 Ω Load
Terminated to VCC/2
tREC, MR to
Reset Recovery Time rising MR edge to
SYNC(1)(5)
falling SYNC edge(6)
tW, MR LOW(1) (5)
Minimum Pulse Width, MR input Low
5
–
ns
tW, RST_IN
Minimum Pulse Width, RST_IN Low
10
–
ns
When in Phase–Lock
tPZL(1)
Output Enable Time
RST_IN Low to RST_OUT Low
1.5
16.5
ns
See Application Notes, Note 5
tPLZ(1)
Output Enable Time
RST_IN High to RST_OUT High Z
1016 ‘Q' Cycles
(508 Q/2 Cycles)
1024 ‘Q' Cycles
(512 Q/2 Cycles)
ns
See Application Notes, Note 5
LOW(1)
1. These specifications are not tested, they are guaranteed by statistical characterization. See Application Note 1 for a discussion of this
methodology.
2. Under equally loaded conditions and at a fixed temperature and voltage.
3. Guaranteed that QCLKEN will meet the setup and hold time requirement of the 68060.
4. With VCC fully powered–on: tCLOCK Max is with C1 = 0.1 μF; tLOCK Min is with C1 = 0.01 μF.
5. Specification is valid only when the PLL_EN pin is low.
6. See Application Notes, Note 4 for the distribution in time of each output referenced to SYNC.
IDT™ Low Skew CMOS PLL 68060 Clock Driver
Advanced
Clock Drivers
Device Data
Freescale
Timing Solutions
Organization
has been acquired by Integrated Device Technology, Inc
Freescale Semiconductor
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MC88LV926
MC88LV926
5
MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
APPLICATION NOTES
1.
2.
Statistical characterization techniques were used to
guarantee those specifications which cannot be
measured on the ATE. MC88LV926 units were
fabricated with key transistor properties intentionally
varied to create a 14 cell designed experimental matrix.
IC performance was characterized over a range of
transistor properties (represented by the 14 cells) in
excess of the expected process variation of the wafer
fabrication area. IC performance to each specification
and fab variation were used to set performance limits of
ATE testable specifications within those which are to be
guaranteed by statistical characterization. In this way, all
units passing the ATE test will meet or exceed the nontested specifications limits.
A 470 KΩ or 1 MΩ resistor tied to either Analog VCC or
Analog GND, as shown in Figure 3, is required to
3.
ensure no jitter is present on the MC88LV926 outputs.
This technique causes a phase offset between the
SYNC input and the Q0 output, measured at the pins.
The tPD spec describes how this offset varies with
process, temperature, and voltage. The specs were
arrived at by measuring the phase relationship for the
14 lots described in note 1 while the part was in phaselocked operation. The actual measurements were made
with a 10 MHz SYNC input (1.0 ns edge rate from 0.8 V
to 2.0 V). The phase measurements were made at
1.5 V. See Figure 3 for a graphical description.
Two specs (tRISE/FALL and tPULSE Width 2X_Q output,
see AC Specifications) guarantee that the MC88LV926
meets the 33 MHz and 66 MHz 68060 P-Clock input
specification.
RC1
External
Loop Filter
330 Ω
0.1 μF
Analog VCC
1 MΩ or 470 KΩ
Reference
Resistor
R2
C1
1 MΩ or 470 K Ω
Reference
Resistor
RC1
330 Ω
0.1 μF
Analog GND
C1
Analog GND
With the 470 KΩ resistor tied in this fashion, the TPD specification
measured at the input pins is:
With the 470 KΩ resistor tied in this fashion, the TPD specification
measured at the input pin is:
tPD = 2.25 ns ± 1.0 ns (Typical Values)
tPD = –0.80 ns ± 0.30 ns
3V
SYNC InputT
R2
3V
SYNC Input
2.25 ns
Offset
–0.8 ns
Offset
5V
5V
Q0 OutputT
Q0 Output
Figure 3. Depiction of the Fixed SYNC to Q0 Offset (tPD) Which Is Present
When a 470 KΩ Resistor Is Tied to VCC or Ground
RST_OUT Pin
VCC
1K
Internal
Logic
CL
Analog GND
Figure 4. RST_OUT Test Circuit
MC88LV926
IDT™ Low
Skew CMOS PLL 68060 Clock Driver
MC88LV926
Freescale Timing Solutions Organization has been acquired by Integrated Device Technology, Inc Advanced Clock Drivers Device Data
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Freescale Semiconductor
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MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
2X_Q
12.5 MHz
Crystal
Oscillator
Q0
Q1
Q2
SYNC
MR
PLL_EN
RST_IN
66 MHz P–Clock
Output
33 MHz
B–Clock
and System
Outputs
Q3
QCLKEN
RST_OUT
Delay 33 MHz CLKEN Output
Figure 5. Logical Representation of the MC88LV926 With Input/Output Frequency Relationships
SYNC Input
tCYCLE SYNC Input
tSKEWall
tSKEWf
tSKEWr
tSKEWf
tSKEWr
Q0–Q3 Outputs
tCYCLE ‘Q' Outputs
2X_Q Output
QCLKEN
tSKEWQCLKEN
tSKEWQCLKEN
NOTES:
1. The MC88LV926 aligns rising edges of the outputs and the SYNC input, therefore the SYNC input does not require a
50% duty cycle.
2. All skew specs are measured between the VCC/2 crossing point of the appropriate output edges. All skews are specified
as “windows”, not as a ± deviation around a center point.
Figure 6. Output/Input Switching Waveforms and Timing Relationships
4.
The tPD spec includes the full temperature range from
0°C to 70°C and the full VCC range from 3.0 V to 3.3 V. If
the ΔT and ΔVCC is a given system are less than the
specification limits, the tPD spec window will be reduced.
5.
The RST_OUT pin is an open drain N–Channel output.
Therefore an external pull–up resistor must be provide
to pull up the RST_OUT pin when it goes into the high
impedance state (after the MC88LV926 is phase-locked
to the reference input with RST_IN held high or 1024 ‘Q'
cycles after the RST_IN pin goes high when the part is
locked). In the tPLZ and tPZL specifications, a 1 KΩ
resistor is used as a pull-up as shown in Figure 3.
IDT™ Low Skew CMOS PLL 68060 Clock Driver
Advanced
Clock Drivers
Device Data
Freescale
Timing Solutions
Organization
has been acquired by Integrated Device Technology, Inc
Freescale Semiconductor
7
MC88LV926
MC88LV926
7
MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
NOTES CONCERNING LOOP FILTER AND
BOARD LAYOUT ISSUES
1.
Figure 7 shows a loop filter and analog isolation
scheme which will be effective in most applications. The
following guidelines should be followed to ensure stable
and jitter-free operation:
1a. All loop filter and analog isolation components should
be tied as close to the package as possible. Stray
current passing through the parasitics of long traces can
cause undesirable voltage transients at the RC1 pin.
1b. The 47 Ω resistors, the 10 μF low frequency bypass
capacitor, and the 0.1 μF high frequency bypass
capacitor form a wide bandwidth filter that will make the
88LV926 PLL insensitive to voltage transients from the
system digital VCC supply and ground planes. This filter
will typically ensure that a 100mV step deviation on the
digital VCC supply will cause no more than a 100 ps
phase deviation on the 88LV926 outputs. A 250 mV
step deviation on VCC using the recommended filter
values will cause no more than a 250 ps phase
deviation; if a 25 μF bypass capacitor is used (instead of
10 μF) a 250 mV VCC step will cause no more than a
100 ps phase deviation.
If good bypass techniques are used on a board design
near components which may cause digital VCC and
ground noise, the above described VCC step deviations
should not occur at the 88LV926's digital VCC supply.
The purpose of the bypass filtering scheme shown in
Figure 6 is to give the 88LV926 additional protection
from the power supply and ground plane transients that
can occur in a high frequency, high speed digital system.
1c. There are no special requirements set forth for the loop
filter resistors (470 K and 33 0Ω). The loop filter
capacitor (0.1uF) can be a ceramic chip capacitor, the
same as a standard bypass capacitor.
1d. The 470 K reference resistor injects current into the
internal charge pump of the PLL, causing a fixed offset
between the outputs and the SYNC input. This also
prevents excessive jitter caused by inherent PLL dead–
band. If the VCO (2X_Q output) is running above
40 MHz, the 470 K resistor provides the correct amount
of current injection into the charge pump (2–3 μA). If the
VCO is running below 40 MHz, a 1 MΩ reference
resistor should be used (instead of 470 K).
2. In addition to the bypass capacitors used in the analog
filter of Figure 7, there should be a 0.1 μF bypass
capacitor between each of the other (digital) four VCC
pins and the board ground plane. This will reduce output
switching noise caused by the 88LV926 outputs, in
addition to reducing potential for noise in the ‘analog'
section of the chip. These bypass capacitors should
also be tied as close to the 88LV926 package as
possible.
Board VCC
NOTE: Further loop optimization may occur.
47 Ω
5
10 μF Low
Freq Bias
0.1 μF High
Freq Bias
470 KΩ or
Analog VCC
330 Ω
1 MΩ
6
RC1
7
Analog GND
0.1 μF (Loop Filter
Cap)
Analog Loop Filter/VCO Section
of the MC88LV926 20-Pin SOIC
Package (not drawn to scale)
47 Ω
Board GND
A separate Analog power suppy is not necessary and should not be used.
Following these prescribed guidelines is all that is necessary to use the
MC88LV926 in a normal digital environment.
Figure 7. Recommended Loop Filter and Analog Isolation Scheme for the MC88LV926
MC88LV926
IDT™ Low
Skew CMOS PLL 68060 Clock Driver
MC88LV926
Freescale Timing Solutions Organization has been acquired by Integrated Device Technology, Inc Advanced Clock Drivers Device Data
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Freescale Semiconductor
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MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
MC68060
16.67 MHz
X–TAL
Oscillator
SYNC
System Reset
RST_IN
2X_Q
QCLKEN
Q0
Q1
Q2
Q3
66MHz
ASIC
PCLK
CLKEN
Reset
ASIC
33MHz
RST_OUT
Memory Module
Figure 8. Typical MC88LV926/MC68060 System Configuration
IDT™ Low Skew CMOS PLL 68060 Clock Driver
Advanced
Clock Drivers
Device Data
Freescale
Timing Solutions
Organization
has been acquired by Integrated Device Technology, Inc
Freescale Semiconductor
9
MC88LV926
MC88LV926
9
MC88LV926
Low Skew CMOS PLL 68060 Clock Driver
NETCOM
PACKAGE DIMENSIONS
10X
PIN
NUMBER
10.55
10.05
0.25 M B
2.65
2.35
0.25
0.10
A
20X
1
20
PIN 1 INDEX
0.49
0.35
0.25
6
M
T A B
18X
1.27
A
10
4 12.95
12.65
A
11
T
SEATING PLANE
20X
7.6
7.4
0.1 T
B
5
0.75 X45˚
0.25
0.32
0.23
1.0
0.4
7˚
0˚
NOTES:
1. DIMENSIONS ARE IN MILLIMETERS.
2. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
3. DATUMS A AND B TO BE DETERMINED AT THE
PLANE WHERE THE BOTTOM OF THE LEADS
EXIT THE PLASTIC BODY.
4. THIS DIMENSION DOES NOT INCLUDE MOLD
FLASH, PROTRUSION OR GATE BURRS. MOLD
FLASH, PROTRUSION OR GATE BURRS SHALL
NOT EXCEED 0.15 MM PER SIDE. THIS DIMENSION
IS DETERMINED AT THE PLANE WHERE THE
BOTTOM OF THE LEADS EXIT THE PLASTIC BODY.
5. THIS DIMENSION DOES NOT INCLUDE INTER-LEAD
FLASH OR PROTRUSIONS. INTER-LEAD FLASH
AND PROTRUSIONS SHALL NOT EXCEED 0.25 MM
PER SIDE. THIS DIMENSION IS DETERMINED AT
THE PLANE WHERE THE BOTTOM OF THE LEADS
EXIT THE PLASTIC BODY.
6. THIS DIMENSION DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR PROTRUSION
SHALL NOT CAUSE WIDTH TO EXCEED 0.62 MM.
SECTION A-A
CASE 751D-06
ISSUE H
20-LEAD SOIC PACKAGE
MC88LV926
IDT™ Low
Skew CMOS PLL 68060 Clock Driver
Freescale Timing Solutions Organization has been acquired by Integrated Device Technology, Inc
10
10
MC88LV926
Advanced Clock Drivers Devices
Freescale Semiconductor
MC88LV926
MPC92459
PART NUMBERS
900
Low
MHz
Skew
Low
CMOS
Voltage
PLL
LVDS
68060
Clock
Clock
Synthesizer
Driver TITLE
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