PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 1
FEATURES
Advanced programmable PLL with Spread Spectrum
Reference Clock input
o 1MHz to 200MHz
Output Frequency
o <200MHz
Two programmable I/O pins
o PDB for Power Down function
o CSEL for Configuration Select
o CLK1/CLK2 additional clock outputs
Programmable Output Drive
Low Cycle to Cycle jitter
Single 2.5V or 3.3V ± 10% power supply
Available in 6-pin SOT23 or Thin SOT (TSOT)
GREEN/RoHS compliant packaging.
PIN CONFIGURATION
Note: ^ Denotes 60kΩ Pull-up resistor
DESCRIPTION
The PL671-02 is an advanced Spread Spectrum clock generator (SSCG), and a member of PicoPLL™
Programmable Clock family.
The PL671-02 offers up to three 200MHz outputs, and allows for pr ogramming the modulation type (Center or
Down Spread) as well as 16 modulation magnitudes (±0.125% to ±2.0% or -0.25% to -4.0%). In addition, the
CSEL pin can be used to toggle the device between 2 pre-programmed configurations. The option of being able
to turn ‘ON/OFF’ the Spread Spectrum modulation allows for completing a design with PL671 -02 and having the
assurance of turning ‘ON’ the EMI modulation, if EMI becomes an issue. The PL671-02’s frequency modulation
greatly reduces the fundamental and harmonic frequencies’ peak magnitude , therefore reducing the system level
Electro Magnetic Interference (EMI), by as much as 20dB
BLOCK DIAGRAM
M-Counter
11-bits
Programming
Logic
FIN
P-Counter
6-bits
Odd/Even
R-Counter
9-bits
Programmable Function
CLK0
SST
Modulation
* Optional Pre-defined
Modulation Magnitude Control /1, /2
FREF
FVCO = FREF * (M/R)
Phase
Detector
Charge
Pump
Loop
Filter VCO
÷8
÷8
FOUT = FVCO / P
CSEL
PDB
Modulation Magnitude*
CLK[0:2]
CLK1/PDB
CLK2/CSEL
/1, /2, /4
PL671-02
1
2
3 4
5
6
PDB^, CLK1
GND
FIN
CLK0
VDD
CSEL^, CLK2
SOT23-6L
TSOT-6L
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 2
KEY PROGRAMMING PARAMETERS
CLK[ 0:2 ]
Output Frequency
SST Modulation Magnitude
(Spread Percentage)
Programmable
Input/Output
Output Drive
Strength
FOUT = FREF * M / (R * P)
where M =11 bit
R = 9 bit
P = 6 bit
CLK0= FREF, FREF/2 or FVCO/P*
CLK1= FREF, FREF/2 or FVCO/P*
CLK2= FREF, CLK0, CLK0/2 or CLK0/4
* ‘P’ is a 6-bit Odd/Even divider.
16 programmable modulation
magnitudes to choose from:
Center Spread: ±0.125%
to ±2.0% in ±0.125%
steps
Down Spread: -0.25% to -
4.0% in 0.25% steps
SST On/Off Control.
Programmable I/O’s
include:
PDB – input
CSEL Configuration
Selection - input
CLK[0:2] - output
Three optional
drive strengths
to choose from:
Low: 4mA
Std: 8mA
(default)
High: 16mA
PACKAGE PIN ASSIGNMENT
Name
(T)SOT23-6L
Pin #
Description
PDB, CLK1
1
This pin can be programmed as PDB (input) or CLK1 (output).
Power Down (PDB) input. This pin has an internal 60KΩ pull up
resistor and turns off the oscillator and the output when pulled to
logic “0”.
PDB Logic
Osc
PLL
Output
0
Off
Off
Hi Z (Default)
1
Normal Operation (Default)
Clock1 (CLK1) output. This optional clock can be set to F REF,
FREF/2 or FOUT (Programmable PLL output).
GND
2
GND connection
FIN
3
Reference input pin
VDD
4
VDD connection
CSEL, CLK2
5
This pin can be programmed as CSEL (input ) or CLK2 (output).
CSEL input. Selector pin used to toggle between two pre-
programmed configurations.
CLK2 output. This optional clock can be set to F R EF, CLK0, CLK0/2
or CLK0/4.
CLK0
6
Programmable Clock Output
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 3
FUNCTIONAL DESCRIPTION
PL671-02 is a highly featured, very flexible, advanced programmable PLL design for hi gh performance, low-power
Spread Spectrum modulation applications. The PL671-02 accepts a reference clock input of 1MHz to 200MHz and
is capable of producing three SST modulated outputs up to 200MHz. This flexible design allows the PL671 -02 to
deliver any PLL generated frequency, FREF (Ref Clk) frequency or FREF /2 to CLK0, CLK1 and/or CLK2. Alternate
programming using CSEL allows the device to choose from 2 different pre -programmed settings providing a range
of spread settings and outputs to choose from. Some of the design features of the PL671-02 are mentioned below.
PLL Programming
The PLL in the PL671-02 is fully programmable. The
PLL is equipped with a 9-bit input frequency divider
(R-Counter), and an 11-bit VCO frequency feedback
loop divider (M-Counter). The output of the PLL is
transferred to a 6-bit post VCO Odd/Even divider (P -
Counter). The output frequency is determined by the
following formula [FOUT = (FREF * M)/(R*P).
Modulation Magnitude and Type
The PL671-02 provides the following programmable
capabilities for Modulation Type and Modulation
Magnitude (Spread Percentage):
Modulation
Type
Modulation
Magnitude
Programming
Steps
Center Spread
±0.125% thru ±2.00%
±0.125%
Down Spread
-0.25% thru -4.00%
0.25%
Modulation Rate
The PL671-02 modulation rate is defined as FREF (Ref
Clk Frequency) divided by 8 times the R-counter, i.e.
Modulation Rate = (FREF / 8R). The rate can be
changed by choosing alternate R-Counter settings.
Clock Outputs (CLK[0:2])
CLK0 is the main clock output. The PL671-02 can
also be programmed with additional clock outputs
CLK1 and CLK2. The outputs of CLK[0:2] can be
configured as described below:
CLK0= FREF, FREF/2 or FVCO/P*
CLK1= FREF, FREF/2 or FVCO/P*
CLK2= FREF, CLK0, CLK0/2 or CLK0/4
Where
FREF - Reference (Ref Clk) Frequency
FOUT = FREF * M / (R * P)
The output drive level of each output can be
independently programmed to Low Drive (4mA),
Standard Drive (8mA) or High Drive (16mA). The
output frequency can be programmed up to 200MHz
at 3.3V (166MHz at 2.5V).
Power-Down Control (PDB)
When activated (logic ‘0’), PDB ‘Disables the PLL,
the oscillator circuitry, counters, and all other active
circuitry. In Power Down mode the IC consumes
<10µA of power. The PDB input incorporates a
60kΩ pull up resistor giving a default condition of
logic “1”.
Configuration Select (CSEL)
The PL671-02 has the capability to be programmed
with 2 distinct configurations and to toggle “On the
Fly” between these configurations using the selector
pin CSEL. CSEL incorporates a 60kΩ pull up
resistor giving a default condition of logic “1”.
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 4
LAYOUT RECOMMENDATIONS
The following guidelines are to assist you with a performance optimized PCB design:
Signal Integrity and Termination
Considerations
- Keep traces short!
- Trace = Inductor. With a capacitive load this
equals ringing!
- Long trace = Transmission Line. Without proper
termination this will cause reflections (looks like
ringing ).
- Design long traces (> 1 inch) as “striplines” or
“microstrips” with defined impedance.
- Match trace at one side to avoid reflections
bouncing back and forth.
Decoupling and Power Supply
Considerations
- Place decoupling capacitors as close as possible to
the VDD pin(s) to limit noise from the power supply
- Multiple VDD pins should be decoupled separately
for best performance.
- Addition of a ferrite bead in series with VDD can
help prevent noise from other board sources
- Value of decoupling capacitor is frequency
dependant. Typical values to use are 0.1F for
designs using frequencies < 50MHz and 0.01F for
designs using frequencies > 50MHz.
Typical CMOS termination
Place Series Resistor as close as possible to CMOS output
CMOS Output Buffer
( Typical buffer impedance 20  To CMOS Input
Series Resistor
Use value to match output
buffer impedance to 50
trace. Typical value 30
50 line
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 5
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
PARAMETERS
SYMBOL
MIN
MAX
UNITS
Supply Voltage Range
VDD
-0.5
4.6
V
Input Voltage Range
VI
-0.5
VDD+0.5
V
Output Voltage Range
VO
-0.5
VDD+0.5
V
Soldering Temperature (Green package)
260
C
Data Retention @ 85C
10
Year
Storage Temperature
TS
-65
150
C
Ambient Operating Temperature*
-40
85
C
Exposure of the device under conditions beyond the limits specified by Maximum Ratings for extended periods may cause permanent damage to the device
and affect product reliability. These conditions represent a stress rating only, and functional operations of the device at these or any other conditions above
the operational limits noted in this specification is not implied. *Operating temperature is guaranteed by design. Parts are tested to commercial grade only.
AC SPECIFICATIONS
PARAMETERS
CONDITIONS
MIN
TYP
MAX
UNITS
Input (FIN) Frequency
@ VDD =3.3V
1
200
MHz
@ VDD =2.5V
166
Input (FIN) Signal Amplitude
Internally AC coupled (High Frequency)
0.9
VDD
Vpp
Input (FIN) Signal Amplitude
Internally AC coupled (Low Frequency)
3.3V <50MHz, 2.5V <40MHz
0.1
VDD
Vpp
Output Frequency
@ VDD =3.3V
200
MHz
@ VDD =2.5V
166
Settling Time
At power-up (after VDD increases over 2.25V)
2
ms
Output Enable Time
PDB Function; Ta=25º C, 15pF Load
2
ms
Output Rise Time
15pF Load, 10/90% VDD, Standard Drive
2.0
3.0
ns
15pF Load, 10/90% VDD, High Drive
1.2
1.7
Output Fall Time
15pF Load, 90/10% VDD, Standard Drive
1.7
2.5
ns
15pF Load, 90/10% VDD, High Drive
1.2
1.7
Duty Cycle
At VDD /2
45
50
55
%
Cycle to Cycle Jitter*
TCYC-C YC Over output frequency range @ 3.3V
100
ps
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 6
DC SPECIFICATIONS
PARAMETERS
CONDITIONS
MIN.
UNITS
Supply Current, Dynamic, with
Loaded Outputs
At 27MHz, 3.3V,
load=15pF, (PDB=1)
mA
PDB=0 [with reference
input pin (FIN) pulled down]
A
Operating Voltage
VDD
2.25
3.63
V
Power Supply Ramp
tPU
Time for VDD to reach
90% VDD. Power ramp
must be monotonic.
100
ms
Output Low Voltage
VOL
IOL = +4mA (Std. Drive)
0.4
V
Output High Voltage
VOH
IOH = -4mA (Std. Drive)
VDD – 0.4
V
Output Current, Low Drive
IOS D
VOL = 0.4V, VOH = 2.4V
4
mA
Output Current, Standard Drive
IOS D
VOL = 0.4V, VOH = 2.4V
8
mA
Output Current, High Drive
IOH D
VOL = 0.4V, VOH = 2.4V
16
mA
PACKAGE DRAWINGS (GREEN PACKAGE COMPLIANT)
SOT23-6L
TSOT-6L
Symbol
Dimension in MM
Min.
Max.
A
1.05
1.35
A1
0.05
0.15
A2
1.00
1.20
b
0.30
0.50
c
0.08
0.20
D
2.80
3.00
E
1.50
1.70
H
2.60
3.00
L
0.35
0.55
e
0.95 BSC
Symbol
Dimension in MM
Min.
Max.
A
1.00
A1
0.00
0.10
A2
0.84
0.90
b
0.30
0.50
c
0.127 w/o plating
D
2.90 BSC
E
1.60 BSC
H
2.80 BSC
L
0.30
0.50
e
0.95 TYP
C
L
A2
EH
D
A1
eb
A
Pin1 Dot
C
L
A2
EH
D
A1
eb
A
Pin1 Dot
PL671-02
PicoEMITM Spread Spectrum Clock Generator
Micrel Inc. • 2180 Fortune Dr ive • San Jose, CA 95131 • USA • tel +1(408) 944 -0800 • fax +1(408) 474-1000 • www.micrel.com Rev 07/24/09 Page 7
ORDERING INFORMATION (GREEN PACKAGE COMPLIANT)
Micrel Inc., reserves the right to make changes in its products or specifications, or both at any time without notice. The information furnished by Micrel is believed to be accurate
and reliable. However, Micrel makes no guarantee or warranty concerning the accuracy of said information and shall not be responsible for any loss or damage of whatever
nature resulting from the use of, or reliance upon this product.
LIFE SUPPORT POL ICY: Micrel’s products are not authoriz ed for use as critical components in life support devices or systems wi thout the express
written approval of the President of Micrel Inc.
For part ordering, please contact our Sales Department:
2180 Fortune Drive, San Jose, CA 95131, USA
Tel: (408) 944 492-0800 • Fax: (408) 474-1000
PART NUMBER
The order number for this device is a combination of the following:
Part Number, Package Type and Operating Temperature Range
PL671-02-xxx T C - R
Part Number
Package Type
R = TSOT-6L
T = SOT23-6L
Shipping Option
R = Tape & Reel
None = Tube
Temperature Range
C = Commercial (0°C to 70°C)
3 Digit ID Code*
* Micrel will assign a unique 3-digit ID code for each approved programmed part number.
Part/Order Number
Marking
Package Option
PL671-02-xxxRC-R
F2xxx
6-Pin TSOT (Tape and Reel)
PL671-02-xxxTC-R
F2xxx
6-Pin SOT23 (Tape and Reel)