MK1432/MK1434
Green PC and Local Bus Clock Source
MDS 1432 G
1
Revision 060101
Integrated Circuit Systems, Inc. 525 Race Street San Jose CA 95126 (408)295-9800 www.icst.com
The MK1432 and MK1434 are low cost, high
performance triple clock synthesizers for green PC and
local bus desktop and notebook applications. Using
analog Phase-Locked Loop (PLL) techniques, the
devices accept a 14.318 MHz crystal input to produce
multiple output clocks up to 100 MHz. They provide
selectable 2XCPU and CPU, selectable local bus clock,
ISA clock, and one fixed peripheral clock. The chips
support PCI and VL buses. The fixed clock is either
24MHz or 40MHz. The devices can operate at 5V or
3.3V up to and including 80MHz on the 2XCPU clock.
The Power Saving pin causes the CPU clocks to
smoothly transition to 33.33 MHz for Pentiums, and
16.67 MHz for 486DX4. In addition, a single pin can be
made to slow DX2s to 8 MHz.
Crystal
Oscillator
VDD
GND
X1
X2
CPU
Clocks
2XCPU
BCLK
Output
Buffer
FS0
FS1
14.318 MHz
crystal
Block Diagram
Description
Features
Output
Buffer
Output
Buffer
Output
Buffer
Output
Buffer
2
CPU
40.00 (MK1434)
or 24.00 MHz
(MK1432)
Packaged in 16 pin narrow (150 mil) SOIC
Supports all PentiumTM Processor timing specs
Supports synchronous and asynchronous local bus
Selectable local bus frequencies of 25, 33, or
50MHz
SCSI or VL bus 40MHz clock on MK1434
Floppy or super I/O clock on MK1432
Single Power Saving pin switches to low power
mode (for 486 and Pentium)
5V or 3.3V (up to 80MHz) operation
Smooth transitions for Pentium and 486 based
Green PC
Low skew (<250ps) Pentium compatible
2X and 1X outputs
Duty cycle of 45/55 up to 100 MHz
25mA output drive capability at TTL levels
Compatible with all popular microprocessors
Packaged in 16 pin narrow SOIC
For Early Clock support, consult MicroClock
FS2
14.318 MHz
Fixed
Clock
PS
BCLKS
Local
Bus
Clock
MK1432/MK1434
Green PC and Local Bus Clock Source
MDS 1432 G
2
Revision 060101
Integrated Circuit Systems, Inc. 525 Race Street San Jose CA 95126 (408)295-9800 www.icst.com
1 4 3 2
1 4 3 4
Name
Type
Description
1
1
FS2
I
Select 2 for 2XCPU and CPU frequencies. See table above. Internal Pull-Up.
2
2
X2
O
Crystal connection. Connect to 14.31818 MHz crystal.
3
3
X1
I
Crystal connection. Connect to 14.31818 MHz crystal or clock.
4
4
VDD
P
Connect to +5V or 3.3V. Must be same voltage as pin 13.
5
5
GND
P
Connect to ground.
6
6
BCLK
O
Local Bus Clock output. See table above.
7
-
24M
O
24.00 MHz clock output (MK1432 only).
-
7
40M
O
40.00 MHz clock output (MK1434 only).
8
8
PS
I
Power Saving pin. Smoothly changes CPU to/from 33.33 and 16.67 MHz. IPU.
9
9
BCLKS
TI
Local Bus Clock Select pin. See table above.
10
10
FS0
I
Select 0 for 2XCPU and CPU frequencies. See table above. Internal Pull-Up.
11
11
14.3M
O
14.318 MHz Reference Clock Output.
12
12
GND
P
Connect to ground.
13
13
VDD
P
Connect to +5V or 3.3V. Must be same voltage as pin 4.
14
14
CPU
O
CPU Clock output. See table above for frequencies.
15
15
2XCPU
O
2X CPU Clock output. See table above for frequencies.
16
16
FS1
I
Select 1 for 2XCPU and CPU frequencies. See table above. Internal Pull-Up.
Pin Descriptions
P S
F S 2 F S 1 F S 0
2 X C P U
C P U
1
0
0
0
16.00
8.00
1
0
0
1 100.00 note 350.00 note3
1
0
1
0
80.00
40.00
1
0
1
1
75.00
37.50
1
1
0
0
40.00
20.00
1
1
0
1
50.00
25.00
1
1
1
0
66.66
33.33
1
1
1
1
60.00
30.00
0
X
X
X
33.33
16.67
CPU Clock Decoding Table (in MHz)
Notes:
1. Actual frequencies are within 0.05% of those shown.
2. Transitions between mean frequencies on any CPU pin are
smooth, and do not violate Intel's 0.1% per cycle specification.
3. These selections are not guaranteed to operate at 3V.
4. M = mid level. Leave pin tri-stated, unconnected, or floating to
select this level.
5. X = don't care (either 0 or 1).
Key: TI = Tri-level Input, I = Input, O = output, P = power supply connection
Pin Assignment
1
8
9
16
2
3
4
5
6
7
10
11
12
13
14
15
FS2
X2
24M
BCLK
VDD
GND
X1
PS
FS1
14.3M
CPU
2XCPU
VDD
GND
BCLKS
FS0
BCLKS
BCLK (MHz)
0
25.00
M
33.33
1
50.00
1
8
9
16
2
3
4
5
6
7
10
11
12
13
14
15
FS2
X2
40M
BCLK
VDD
GND
X1
PS
FS1
14.3M
CPU
2XCPU
VDD
GND
BCLKS
FS0
Local Bus Clock Decoding Table (in MHz)
MK1432/MK1434
Green PC and Local Bus Clock Source
MDS 1432 G
3
Revision 060101
Integrated Circuit Systems, Inc. 525 Race Street San Jose CA 95126 (408)295-9800 www.icst.com
Electrical Specifications
Notes: 1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the
device. Prolonged exposure to levels above the operating limits but below the Absolute Maximums may
affect device reliability.
2. With 2XCPU clock at 66.66MHz, and BCLK at 33.33MHz
Parameter
Conditions
Minimum
Typical
Maximum
Units
ABSOLUTE MAXIMUM RATINGS (note 1)
ABSOLUTE MAXIMUM RATINGS (note 1)
Supply voltage, VDD
Referenced to GND
7
V
Inputs and Clock Outputs
Referenced to GND
-0.5
VDD+0.5
V
Ambient Operating Temperature
0
70
C
Soldering Temperature
Max of 20 seconds
260
C
Storage temperature
-65
150
C
DC CHARACTERISTICS (VDD = 5V unless noted)
DC CHARACTERISTICS (VDD = 5V unless noted)
Operating Voltage, VDD
3.0
5.5
V
Input High Voltage, VIH
2
V
Input Low Voltage, VIL
0.8
V
Mid-level pin Input High Voltage, VIH
Pin 9 only
VDD-0.5
V
Mid-level pin Input Low Voltage, VIL
Pin 9 only
0.5
V
Output High Voltage, VOH
IOH=-25mA
2.4
V
Output Low Voltage, VOL
IOL=25mA
0.4
V
Output High Voltage, VOH
VDD=3.3V, IOH=-8mA
2.4
V
Output Low Voltage, VOL
VDD=3.3V, IOL=8mA
0.4
V
Operating Supply Current, IDD
No Load, note 2
40
mA
Operating Supply Current, IDDPS
No Load, PS=0
27
mA
Short Circuit Current
Each output (except X2)
100
mA
On-Chip Pull-up Resistor
Pins 1, 8, 10, 16
250
k
Input Capacitance
7
pF
AC CHARACTERISTICS (VDD = 5V unless noted)
AC CHARACTERISTICS (VDD = 5V unless noted)
Input Frequency
14.31818
MHz
Output Clock Rise Time
0.8 to 2.0V
1.5
ns
Output Clock Fall Time
2.0 to 0.8V
1.5
ns
Output Clock Duty Cycle
At VDD/2
45
49 to 51
55
%
Cycle to Cycle Jitter, CPU Clocks
1000
ps
Absolute Clock Period Jitter
14-40 MHz clocks
-500
500
ps
Skew of 2XCPU with respect to CPU
Rising edges at 1.5V
-250
0
250
ps
Transition time, 33.3MHz to 66.6MHz
VDD=3.3 or 5V
3
ms
Transition time, 66.6MHz to 33.3MHz
VDD=3.3 or 5V
2
ms
External Components
The MK1432/4 requires a minimum number of external components for proper operation. Decoupling capacitors of
0.1F should be connected between VDD and GND, as close to the MK1432/4 as possible. A series termination
resistor of 33
may be used for each clock output. The device does not require (nor do we recommend) capacitors
connected to the crystal pins. The 14.31818 MHz crystal must be connected as close to the chip as possible.
Recommended load capacitance for the crystal is 12pF.
MK1432/MK1434
Green PC and Local Bus Clock Source
MDS 1432 G
4
Revision 060101
Integrated Circuit Systems, Inc. 525 Race Street San Jose CA 95126 (408)295-9800 www.icst.com
While the information presented herein has been checked for both accuracy and reliability, MicroClock Incorporated assumes no responsibility for either
its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are
implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature
range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by MicroClock.
MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not authorize or warrant any MicroClock
product for use in life support devices or critical medical instruments.
b
D
E
H
e
Q
c
A
h x 45
Package Outline and Package Dimensions
Ordering Information
Part/Order Number
Marking
Fixed Output Clock Frequency
Package
Temperature
MK1432S
MK1432S
24 MHz
16 pin SOIC
0-70C
MK1434S
MK1434S
40 MHz
16 pin SOIC
0-70C
MK1432STR
MK1432S
-
Add Tape & Reel
-
MK1434STR
MK1434S
-
Add Tape & Reel
-
16 pin SOIC narrow
Inches
Inches
Millimeters
Millimeters
Symbol
Min
Max
Min
Max
A
0.055
0.070
1.397
1.778
b
0.013
0.019
0.330
0.483
c
0.007
0.010
0.191
0.254
D
0.385
0.400
9.779 10.160
E
0.150
0.160
3.810
4.064
H
0.225
0.245
5.715
6.223
e .050 BSC
.050 BSC 1.27 BSC
1.27 BSC
h
0.016
0.406
Q
0.004
0.01
0.102
0.254
PentiumTM is a registered trademark of Intel Corporation
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