
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
Description Features
ICS650-12
 MPEG Clock Synthesizer
The ICS650-12 is a low cost, low jitter, high 
performance clock synthesizer designed to 
produce fixed clock outputs of 13.5 MHz and 
27.0 MHz and four selectable clock outputs of two 
Processor Clocks (PCLK1 and PCLK2), Audio 
Clock (ACLK), and Communications Clock 
(CCLK). Using our patented analog PhaseLocked Loop (PLL) techniques, the device uses a 
27.0 MHz clock or fundamental crystal input to 
produce clocks ideal for Digital Video/MPEGbased applications.
Block Diagram
PS2:0
Synthesis 
AS2:0
Control
Circuitry
CS1:0
• Packaged in 20 pin tiny SSOP (QSOP)
• Input Frequency of 27.0 MHz
• Zero ppm synthesis error in output clocks
• Provides fixed 13.5 MHz and 27.0 MHz.  
  Also provides two selectable Processor Clocks, 
  one Audio Clock, and one Communications Clock 
• Ideal for Digital Video/MPEG-based applications
• 3.3 V or 5.0 V operating voltage
• Entire chip powers down (when CS1=CS0=0)
Clock 
and
Output
Buffer
Output
Buffer
Output
Buffer
Output
Buffer
PCLK1
PCLK2
ACLK
CCLK
Output
Buffer
÷ 2
Input 
27.0 MHz 
crystal or 
clock
MDS 650-12 A   1      Revision 113000  
Buffer/Crystal
Oscillator
Output
Buffer
13.5 MHz 
27.0 MHz

ICS650-12
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
 MPEG Clock Synthesizer
Pin Assignment
PS2
X2 
X1
VDD
CS1
GND
ACLK
PCLK1
CS0 
AS2
1
2
3 
4
5 
6
7 
8
9
20 pin SSOP (QSOP)
20 
19
18 
17
16 
15
14 
13
12 
1110
PS1 
PS0
CCLK 
PCLK2
VDD
AS1 
GND
13.5M 
27M
AS0
PCLK1 and PCLK2 Select Table (in MHz)
PS2 PS1 PS0 PCLK1 PCLK2
0 0 0 108.00 54.00 
0 0 1 55.00 27.5 
0 1 0 66.67 33.33 
0 1 1 80.00 40.00 
1 0 0 54.00 27.00 
1 0 1 81.00 40.5 
1 1 0 50.00 25.00 
1 1 1 60.00 30.00
ACLK Select Table (in MHz)
AS2 AS1 AS0 ACLK
0 0 0 12.288 
0 0 1 11.2896 
0 1 0 8.192 
0 1 1 24.576
CCLK Select Table (in MHz)
CS1 CS0 CCLK
0 0 All off* 
0 1 20.00 
1 0 66.6666 
1 1 24.576
1 0 0 8.192 
1 0 1 16.9344 
1 1 0 18.432 
1 1 1 11.2896
*Note: Entire chip powers 
down (outputs stop low) 
when CS1 = CS0 = 0.
Pin Descriptions
Pin # Name  Type Description
1 PS2 I Processor Clock Select Pin 2. See above table. 
2 X2 XO Crystal connection to a 27.0 MHz crystal or leave unconnected for clock input 
3 X1 XI Crystal connection. Connect to a 27.0 MHz fundamental mode crystal or clock input.
4, 16 VDD P Connect to +3.3 V or +5.0 V. 
5 CS1 I Communications Clock Select Pin 1. See above table.
6, 14 GND P Connect to ground.
7 ACLK O Audio Clock Output. See above table. 
8 PCLK1 O Processor Clock Output 1. See above table.
9 CS0 I Communications Clock Select 0. See above table. 
10 AS2 I Audio Clock Select Pin 2. See above table. 
11 AS0 I Audio Clock Select Pin 0. See above table. 
12 27M O 27 MHz buffered clock output. 
13 13.5M O 13.5 MHz clock output. 
15 AS1 I Audio Clock Select Pin 1. See above table. 
17 PCLK2 O Processor Clock Output 2. See above table. 
18 CCLK O Communications Clock Output. See above table. 
19 PS0 I Processor Clock Select Pin 0. See above table. 
20 PS1 I Prcoessor Clock Select Pin 1. See above table. 
Key: I = Input with internal pull-up; O = output; P = power supply connection; XI, XO = crystal 
connections
MDS 650-12 A   2      Revision 113000  

ICS650-12
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
ABSOLUTE MAXIMUM RATINGS (note 1) 
DC CHARACTERISTICS (VDD = 3.3V or 5V unless noted)
AC CHARACTERISTICS (VDD = 3.3V or 5V unless noted)
  exposure to levels above the operating limits but below the Absolute Maximums may affect device reliability.
 MPEG Clock Synthesizer
Electrical Specifications
Parameter Conditions Minimum Typical Maximum Units
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 
Soldering Temperature Max of 10 seconds 260 
Storage temperature -65 150
Operating Voltage, VDD  3.0 5.5 V 
Input High Voltage, VIH 2 V 
Input Low Voltage, VIL 0.8 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 
Output High Voltage, VOH, VDD = 3.3 or 5V IOH=-8mA VDD-0.4 V 
Operating Supply Current, IDD, at 5V  No Load 39 mA 
Operating Supply Current, IDD, at 3.3V No Load 22 mA 
Short Circuit Current, VDD = 3.3 V Each output   ±50 mA 
Input Capacitance Except X1 7 pF
°C 
°C 
°C
Input Crystal or Clock Frequency 27 MHz 
Output Clocks Accuracy (synthesis error) All clocks 0 1 ppm 
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 40 50 60 % 
One Sigma Jitter, ACLK                 VDD=3.3 V 100   ps 
                                         VDD=5.0 V 40 ps 
Absolute Clock Period Jitter VDD=3.3 V, Except CCLK=20 MHz ±300 ps
VDD=5.0 V, Except CCLK=20 MHz ±200 ps
Notes: 1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the device. Prolonged 
External Components
A minimum number of external components are required for proper operation. A decoupling capacitor of 
0.01 µF should be connected between VDD and GND on pins 4 and 6, and 16 and 14, and a 33 Ω 
terminating resistor may be used on each clock output if the trace is longer than 1 inch.
MDS 650-12 A   3      Revision 113000  

 MPEG Clock Synthesizer
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
Package Outline and Package Dimensions 
(For current dimensional specifications, see JEDEC Publication No. 95.)
20 pin SSOP
Symbol Min Max Min Max
A 0.053 0.069 1.35 1.75
A1 0.004 0.010 0.10 0.25
E1 E
INDEX
1 2
D
b 0.008 0.012 0.20 0.30
c 0.007 0.010 0.18 0.25
D 0.337 0.344 8.55 8.75
e
E 0.228 0.244 5.80 6.20
E1 0.150 0.157 3.80 4.00
L 0.016 0.050 0.40 1.27
ICS650-12
A1 c
A
e
b
L
Ordering Information
Part/Order Number Marking Package Shipping Temperature
ICS650R-12 ICS650R-12 20 pin SSOP Tubes 0 to 70 °C
ICS650R-12T ICS650R-12 20 pin SSOP Tape and Reel 0 to 70 °C
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (ICS) 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 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 life support devices or critical medical instruments.
MDS 650-12 A   4      Revision 113000