DATASHEET
AMD GEODE™ CLOCK SOURCE MK1491-06
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 1
MK1491-06 REV J 110204
Description
The MK1491-06 is a low-cost, low-jitter, high-perf ormance
clock synthesizer for AMD’s Geode-based computer and
portable appliance applications. Using patented analog
Phased-Loc k ed Loop (PLL) techniqu es, t he de vice acce pts
a 14.318 MHz crystal input to produce multiple output
clocks . It provid es selectable PCI local bus and A C97 audio
clocks, 24 MHz and 4 8 MHz clocks for Super I/O and USB,
as well as mu ltiple Reference outputs.
The device has multiple power-down modes to reduce
power consumption.
Features
•Packaged in 28-pin SOIC or in 28-pin SSOP
•Availab le in Pb (lead) free
•Provides all critical ti ming for t he AMD Geode companion
chip
•Four PCI clocks
•Selectable PCIF on up to 2 outputs
•Early PCI clock selectability
•Up to 4 Reference clocks
•48 MHz USB and 24MHz SIO support
•AC97 audio clock
•Multiple power down modes
•Low EMI Enab le pin redu ces EMI radiation o n PCI clocks
(patented)
•Operating voltage of 3.3 V ±5%
Block Diagram
Crystal
Oscillator
Fixed
Clocks
Audio
Clock
PCI
Clocks
MUX
PCI Frequency Select
Low EMI Enable
PCIF Function Enable
Early PCI Enable
SLOW#
PCISTP#
PWRDWN#
Audio Select
VDD GND
2
5
6
3
3PCI
EPCI/PCI
48 MHz
14.318 MHz or
24 MHz
14.318 MHz
16.394 MHz or
24.576 MHz or
49.152 MHz
14.31818 MHz
crystal
XI
XO
14.3M/24M Select
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 2
MK1491-06 REV J 110204
Pin Assignment
Early PCI Control Table
EMI Control
Spread direction is DOWN.
PCI Frequency Select Table
24M/14.3M Frequency Select Table
PCIF Enable Control
PCIF continues to run in PCI STOP mode. See table on page 4.
AC97 Audio Frequency Select
Pin Descriptions
EPCI# PCI (Pin 22)
0 1 ns early
1Normal
LE# PCI Low EMI
0ON
1OFF
18
7
17
8
16
9
15
GND
10
14.3M (SEL AUDIO)
11
VDD
12
48M (LE#)
13
SLOW#
14
GND
VDD
24M/14.3M
VDD
FS GND
PWRDWN#
SEL24 PCISTP#
22
21
20
19
VDD
PCI (EPCI#)
5
6
14.3M (TS)
14.3M GND
24
23
PCI
3
4
XO
GND PCI
26
25
VDD
1
2
VDD
XI PCI
28
27
AC97 AUDIO (PEN)
TS FS PCI
0 0 Tristate all clocks
01 Reserved
M 0 30 MHz
M 1 33.3 MHz
1 0 25 MHz
1 1 37.5 MHz
SEL24 24M/14.3M
0 14.31818 MHz
1 24.0 MHz
PEN Pin 25 Pin 24
0PCI PCI
MPCI PCIF
1 PCIF PCIF
SEL AUDIO AC97 AUDIO
0 16.9344 MHz
M 24.576 MHz
1 49.152 MHz
Pin
Number Pin
Name Pin
Type Pin Description
1, 9, 14 VDD P Connect to +3.3 V. Must be same voltage on all pins.
2 XI I Crystal connection. Connect to a 14.31818 MHz crystal or input clock.
3 XO O Crystal connection. Connect to a 14.31818 MHz crystal, or leave
unconnecte d for clock.
4, 7, 11,
17, 23 GND P Connect to Ground.
5 14.3M (TS) TI/O 14.318 MHz output. Input control for all clocks per table above.
6 14.3M O 14.318 MHz buffered reference clock output.
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 3
MK1491-06 REV J 110204
KEY:
I = Input
TI = Tri-le vel
O = Output
P = Power supply connection
(T)I/O = Input on power up, becomes an Output after 10 ms
W eak internal pull-up resistor s are p resent on SEL24, EPCI #, FS, LE#, PCISTP#, and SL OW#. These pins should
be tied to VDD or GND, and not be left floating. In ternal resistors on PEN, SEL AUDIO , and TS p ull to mid-le v el (M ).
8 14.3M (SEL
AUDIO) TI/O 14.318 MHz output and audio frequency select input per table above.
10 SLOW# I PCI normal or slow mode select input per table on page 4.
12 FS I Frequency Select for PCI clocks per table above.
13 SEL24 I Fixed freque ncy select input per tab le ab o ve. Selects frequency on pin
19.
15 PWRDWN# I Power down control; defined in table on page 4.
16 PCISTP# I PCI Stop power down control; defined in table on pa ge 4.
18, 20, 26 VDD P Connect to +3.3 V. Must be same voltage on all pins.
19 24M/14.3M O Fix ed frequency clock output per table above.
21 48 (LE#) I/O Fixed frequency clock output and low EMI (spread spectrum) enable
input per table above.
22 PCI (EPCI#) I/O PCI Output clock that can be early. Input control f or Early PCI per table
above.
24 PCI O PCI Output clock. PCI/PCIF control set by PEN per table above.
25 PCI O PCI Output clock. PCI/PCIF control set by PEN per table above.
27 PCI O PCI Output clock.
28 AC97 AUDIO
(PEN) TI/O Audio clock output and PCIF Function Enable per table above.
Pin
Number Pin
Name Pin
Type Pin Description
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 4
MK1491-06 REV J 110204
Power Down Control Table
Key: 1 = connected to VDD, 0 = connected to ground, X = any valid logic level, combination inputs/outputs should
be connected to VDD or ground through a 10 kΩ resistor as shown below.
Power-on Default Conditions
PCISTP# PWRDWN# SLOW# MODE PCI PCIF 24/14.3 14.3 Description
X 0 X Power down LOW LOW LOW LOW All outputs low. PLL’s
and oscillators off.
0 1 X PCI STOP LO W ON ON ON PCI clocks
synchronously enter
and leave low state.
1 1 X ON ON ON ON ON All clocks on.
Pin # Function Default Condition
5 TS M All outputs enabled.
8 SEL AUDIO M Audio clock (pin 28) set to 24.576 MHz
10 SLOW# 1 PCI clocks set to 33.3 MHz. Refer to Power Down Control Table above.
12 FS 1 PCI frequency = 33.3 MHz.
13 SEL 24 1 24M/14.3M (pin 19) set to 24 MHz.
15 PWRDWN# 1 All clocks running.
16 PCISTP# 1 PCI clocks running.
21 LE# 1 Low EMI function OFF
22 EPCI# 1 Pin 22 set to normal PCI signal (not early).
28 PEN M PCI (pin 25) set to PCI clock (33.33 MHz). PCI (pin 24) set to PCIF clock
(33.33 MHz).
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 5
MK1491-06 REV J 110204
External Components
The MK1491-06 requires some inexpensive external
components f o r proper operat ion. Deco upling capacitors of
0.1µF should be connect ed on each VDD pi n to g ro und, as
close to the MK1491-06 as possible. A series termination
resistor of 33Ω ma y be used for each clock output . See t he
discussion below for other e xternal resistors required for
proper I/O operation. The 14.3 MHz oscillator has internal
caps that provide the proper load for a parallel resonant
crystal with CL=18 pF. For tuning with other values of CL, the
formula 2*(CL-18) gives the value of each capa cito r th at
should be connected between X1 and ground and X2 and
ground.
I/O Structure
The MK1491-06 provides more functionality in a 28-pin
package by using a unique I/O technique. The device
chec ks the status of all I /O pins during pow er-up and at e xit
from the P ower Do wn state. This status (pulled high, low, or
mid-level) then determines the frequency selections and
power down modes (see the tables on pages 2 and 4).
Within 10ms after power up, the inputs change to outputs
and the clocks start up. In the diagrams to the right, the 33Ω
resistors are the normal output termination resistors. The
10kΩ resistor pulls low to generate a logic zero. Weak
internal pull-up resistors ar e present on SEL24, EPCI# , FS,
LE#, PCISTP#, and SLOW#. These pins should be
connected directly to VDD or GND if not under active
control. Internal resistors on PEN, SEL A UDIO, and TS pull
to a mid-lev el (M).
*Note: Do not use a TTL load. This will ov ercome the 10 kΩ
pull-down and force the input to a logic 1.
33
To load*
10 k
I/O
For select
= 0 (low) Do not stuff for
“1” selection
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 6
MK1491-06 REV J 110204
Absolute Maximum Ratings
Stresses abo v e the rat ings listed belo w can cause permanent damage to the MK1491- 06. These r atings, which are
standard values for ICS commercially rated parts, are stress r atings only. Functional ope ration of the device at
these or any other conditions above those indicated in the operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical
parameters are guaranteed only over the recommended operating temperat ure range.
Recommended Operation Conditions
DC Electrical Characteristics
Unless stated otherwise, VDD = 3.3 V ±5%, Ambient Temperature 0 to +70°C
Item Rating
Supply Voltage, VDD 7 V
All Inputs and Outputs -0.5 V to VDD+0.5 V
Ambient Operating Temperature 0 to +70°C
Storage Temperature -65 to +150°C
Junction Temperature 125°C
Soldering Temperature 260°C
Parameter Min. Typ. Max. Units
Ambient Operating Temperature 0 +70 °C
Power Supply Voltage (measured in respect to GND) +3.15 +3.3 +3.45 V
Parameter Symbol Conditions Min. Typ. Max. Units
Operating Voltage VDD 3.15 3.3 3.45 V
Input High Voltage VIH 2V
Input Mid-level Voltage VIM 1.2 1.4 1.6 V
Input Low Voltage VIL 0.8 V
Output High Voltage VOH IOH = -8 mA 2.4 V
Output Low Voltage VOL IOL = 8 mA 0.4 V
Output High Voltage VOH IOH = -8 mA VDD-0.4 V
Operating Supply Current IDD 33 MHz, no load 30 mA
Power Down Mode Supply
Current 15 µA
Short Circuit Current,
SIngle Output Driver VDD = 3.3 V ±60 mA
Input Capacitance CIN 7pF
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 7
MK1491-06 REV J 110204
AC Electrical Characteristics
Unless stated otherwise, VDD = 3.3 V ±5%, Ambient Temperature 0 to +70° C
Thermal Characteristics
Parameter Symbol Conditions Min. Typ. Max. Units
Input Frequency FIN 14.31818 MHz
Output Clock Rise Time tOR 20% to 80% 1.5 ns
Output Clock Fall Time tOF 80% to 20% 1.5 ns
Output Clock Duty Cycle, all
MHz Clocks tOD At 1.5 V 45 49 to 51 55 %
PCI Output to Output Skew Rising edges at 1.5 V 500 ps
Skew of EPCI with respect to
PCI 1ns
Cycle-to-Cycle Jitter , PCI clocks 250 ps
EMI Reduction, peaks of 5th -
19th odd harmonics 33.3 MHz PCI Clock 6 11 dB
Power-up Time, PWRDWN#
High to all Clocks Stable 820ms
P o wer-on Time , applied VDD to
all Clocks Stable 12 25 ms
Parameter Symbol Conditions Min. Typ. Max. Units
Thermal Resistance Junction to
Ambient θJA Still air 100 °C/W
θJA 1 m/s air flow 80 °C/W
θJA 3 m/s air flow 67 °C/W
Thermal Resistance J unction to Case θJC 60 °C/W
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 8
MK1491-06 REV J 110204
Marking Diagram
Notes:
1. ###### is the lot code.
2. YYWW is the last two digits of the year, and the week number that the part was assembled.
3. Bottom marking: country of origin.
14
28 15
######
YYWW
MK1491-06R
ICS
1
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 9
MK1491-06 REV J 110204
Package Outline and Package Dimensions (28-pin SOIC, 150 mil Body)
Package dimensions are kept current with JEDEC Publication No. 95, MO-153
h x 45°
α
L
C
SEATING
PLANE
A1
B
A
e
.10 (.004)
INDEX
AREA
1 2
N
D
EH
Millimeters Inches
Symbol Min Max Min Max
A 2.65 0.104
A1 0.10 .0040
B 0.33 0.51 .013 .020
C 0.18 0.32 .007 .013
D 17.70 18.40 .697 .724
E 7.40 7.60 .291 .299
e 1.27 Basic 0.050 Basic
H 10.00 10.65 .394 .419
h 0.25 0.75 .010 .029
L 0.40 1.27 .016 .050
α0°8°0°8°
MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
IDT™ / ICS™
AMD GEODE™ CLOCK SOURCE 10
MK1491-06 REV J 110204
Package Outline and Package Dimensions (28-pin SSOP, 150 mil Body, 0.025 mm Pitch)
Package dimensions are kept current with JEDEC Publication No. 95, MO-153
Ordering Information
“LF” denotes Pb (lead) free package.
While the information presented herein has been checked f or both accuracy and reliability, Integrated Circuit Systems (ICS) assumes no
responsibility for either its use or for the infr ingement 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 requir ing extended temperature range, high reliability, or other extraordinary environmental requirements are not
recommended without additional processin g by ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS
does not authorize or warrant any ICS product for use in lif e support de vices or critical medical instruments.
Part / Order Number Marking Shipping Packaging Package Temperature
MK1491-06R MK1491-06R Tubes 28-pin SSOP 0 to +70°C
MK1491-06RTR MK1491-06R Tape and Reel 28-pin SSOP 0 to +70°C
MK1491-06RLF MK1491-06RLF Tubes 28-pin SSOP 0 to +70°C
MK1491-06RLFTR MK1491-06RLF Tape and Reel 28-pin SSOP 0 to +70°C
MK1491-06S MK1491-06S Tubes 28-pin SOIC 0 to +70°C
MK1491-06STR MK1491-06S Tape and Reel 28-pin SOIC 0 to +70°C
MK1491-06SLF MK1491-06SLF Tubes 28-pin SOIC 0 to +70°C
MK1491-06SLFTR MK1491-06SLF Tape and Reel 28-pin SOIC 0 to +70°C
INDEX
AREA
1 2
28
D
E1 E
SEATING
PLANE
A
1
A
A
2
e
- C -
b
aaa C
c
L
Millimeters Inches
Symbol Min Max Min Max
A 1.351.75.053.069
A1 0.10 0.25 .0040 .010
A2 -- 1.50 -- .059
b 0.200.30.008.012
C 0.180.25.007.010
D 9.80 10.00 .386 .394
E 5.806.20.228.244
E1 3.80 4.00 .150 .157
e 0.635 Basic 0.025 Basic
L 0.401.27.016.050
α0°8°0°8°
aaa -- 0.10 -- 0.004
© 2006 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT and the IDT logo are trademarks of Integrated Device
Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered
trademarks used to identify products or services of their respective owners.
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Reg. No. 199707558G
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MK1491-06
AMD GEODE™ CLOCK SOURCE CLOCK SYNTHESIZER
