19-5214; Rev 0; 4/10
Spread-Spectrum Clock Generators
General Description
The MAX31C80/MAX31D80 are spread-spectrum clock
generators that contain a phase-locked loop (PLL)
that generates a 2MHz to 134MHz clock from an input
clock or crystal. The PLL can provide a spread-spec-
trum down-dithered (MAX31D80) or center-dithered
(MAX31C80) frequency-modulated clock. The devices
also buffer the incoming clock and provide this output
on a separate pin.
The MAX31C80/MAX31D80 are provided in a 10-pin
TDFN package and operate over a full -40NC to +125NC
automotive temperature range. Devices can be factory
programmed for multiple combinations of input and out-
put frequencies (see the
Ordering Information
table). A
low-cost, low-frequency crystal can be used at the input
to generate frequencies up to 134MHz.
Generator
S
Input_Can_Be_Either_an_8MHz_to_34MHz_Crystal_or_
Features
S
2MHz_to_134MHz_Spread-Spectrum_Clock_
MAX31C80/MAX31D80
8MHz_to_134MHz_Clock
S
Factory-Programmable_Output_Frequencies_in_
2MHz_to_134MHz_Range
S
Low-Cost_Crystal_at_Low_Frequency_Used_to_
Generate_High_Frequencies
S
On-Board_PLL_is_Capable_of_Spread-Spectrum_
Frequency_Modulation
S
Down-_or_Center-Dither_Spread-Spectrum_
Frequency_Modulation
S
User-Configurable_Spread-Spectrum_Dither_
Typical Application Circuit
f
IN
= 27MHz
Magnitude
S
Low_Cycle-to-Cycle_Jitter
S
3.3V_Supply_Voltage
S
Temperature_Range:_-40NC_to_+125NC
S
Small_Package:_10-Pin_TDFN_(3mm_x_3mm_x_
0.8mm)
f
IN
= 27MHz
X1
MAX31D80
V
CC
SMSEL1
SMSEL0
GND
X2
Applications
27MHz CLOCK
f
CLKOUT
= 100MHz
1.5% DOWN DITHERED
V
CC
XOUT
CLKOUT
Graphics Cards
Set-Top Boxes
Automotive Infotainment
Printers
V
CC
DECOUPLING
CAPACITOR
Ordering Information
PART
MAX31C80T-xxx+
MAX31C80T-xxx+T
MAX31D80T-xxx+
MAX31D80T-xxx+T
TEMP_RANGE
-40NC to +125NC
-40NC to +125NC
-40NC to +125NC
-40NC to +125NC
DITHER_MODE
Center
Center
Down
Down
PIN-PACKAGE
10 TDFN-EP*
10 TDFN-EP*
10 TDFN-EP*
10 TDFN-EP*
xxx = Factory-programmable output frequency and dither rate (see the Selector Guide table).
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP
= Exposed pad.
Selector Guide appears at end of data sheet.
________________________________________________________________ _Maxim
Integrated Products_
_ 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Spread-Spectrum Clock Generators
MAX31C80/MAX31D80
ABSOLUTE_MAXIMUM_RATINGS
Voltage Range on V
CC
Relative to GND..............-0.3V to +4.3V
Voltage Range on Any Other Pin
Relative to GND .................................... -0.3V to (V
CC
+ 0.3V)*
Continuous Power Dissipation (T
A
= +70°C)
10-Pin TDFN (derate 24.4mW/°C above +70°C) .....1951.2mW
*Not
to exceed +4.3V.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Storage Temperature Range............................ -55NC to +135NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
RECOMMENDED_OPERATING_CONDITIONS
(T
A
= -40NC to +125NC.)
PARAMETER
Supply Voltage
Input Logic 0
(SMSEL0 and SMSEL1)
Input Logic 1
(SMSEL0 and SMSEL1)
Input Logic Unconnected
(SMSEL0 and SMSEL1)
Input Logic 0 for X1
Input Logic 1 for X1
XOUT Load
CLKOUT Load
Crystal Frequency
Clock Input Frequency
Crystal ESR
Clock Input Duty Cycle
Crystal Parallel Load
Capacitance
SYMBOL
V
CC
V
IL
V
IH
V
IF
V
IL:X1
V
IH:X1
C
L:XOUT
2MHz
P
f
CLKOUT
< 67MHz
C
L:CLKOUT
f
IN
f
IN
X
ESR
f
INDC
C
CL
40
67MHz
P
f
CLKOUT
< 101MHz
101MHz
P
f
CLKOUT
P
134MHz
8
8
Limits are in case user wants to force
voltage instead of unconnecting this pin
CONDITIONS
MIN
3.0
-0.3
0.75 x
V
CC
0.4 x
V
CC
-0.3
0.7 x
V
CC
TYP
3.3
MAX
3.6
0.25 x
V
CC
V
CC
+
0.3
0.55 x
V
CC
0.3 x
V
CC
V
CC
+
0.3
15
15
10
7
34
134
90
60
18
MHz
MHz
I
%
pF
pF
UNITS
V
V
V
V
V
V
pF
2_ _ _______________________________________________________________________________________
Spread-Spectrum Clock Generators
DC_ELECTRICAL_CHARACTERISTICS
(3.0V
P
V
CC
P
3.6V, T
A
= -40NC to +125NC, unless otherwise noted.)
PARAMETER
Supply Current
Input Leakage
(SMSEL0 and SMSEL1)
Low-Level Output Voltage
(XOUT and CLKOUT)
High-Level Output Voltage
(XOUT and CLKOUT)
Input Capacitance
(X1 and X2)
SYMBOL
I
DD
I
IL
V
OL
V
OH
C
IN
CONDITIONS
f
IN
= 27MHz, f
CLKOUT
= 100MHz, down
dithered, C
L
= 10pF
SMSEL_ = GND or V
CC
I
OL
= 10mA
I
OH
= -10mA
V
CC
-
0.2
5
MIN
TYP
22
Q15
0.2
MAX
UNITS
mA
FA
V
V
pF
MAX31C80/MAX31D80
AC_ELECTRICAL_CHARACTERISTICS
(3.0V
P
V
CC
P
3.6V, T
A
= -40NC to +125NC, unless otherwise noted.)
PARAMETER
CLKOUT Duty Cycle
XOUT Duty Cycle
Rise Time
Fall Time
Dither Rate Range
Dither Rate Accuracy
Peak Cycle-to-Cycle Jitter
Power-Up Time
t
J
t
PUP
CLKOUT = 100MHz, 10,000 cycles,
T
A
= +25NC
V
CC
valid to output active, T
A
= +25NC,
V
CC
= 3.3V
SYMBOL
f
CLKOUT:DC
f
XOUT:DC
t
R
t
F
f
DR
CONDITIONS
C
L:CLKOUT
= 7pF
C
L:XOUT
= 7pF, T
A
= +25NC,
V
CC
= 3.3V
C
L:CLKOUT
= 7pF
C
L:CLKOUT
= 7pF
Factory programmable
20
-4
75
1
MIN
40
40
1.6
1.6
40
+4
TYP
MAX
60
60
%
ns
ns
kHz
%
ps
ms
UNITS
________________________________________________________________________________________ _ 3
Spread-Spectrum Clock Generators
MAX31C80/MAX31D80
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX31C80 toc01
SUPPLY CURRENT
vs. TEMPERATURE
MAX31C80 toc02
SUPPLY CURRENT
vs. OUTPUT FREQUENCY
V
CC
= 3.3V
MAX31C80 toc03
27
25
SUPPLY CURRENT (mA)
23
21
19
17
15
f
IN
= 27MHz
f
CLKOUT
= 100MHz
29
27
SUPPLY CURRENT (mA)
25
23
21
19
17
15
f
IN
= 27MHz
f
CLKOUT
= 100MHz
25
20
SUPPLY CURRENT (mA)
15
10
5
0
V
CC
= 3.6V
T
A
= +125°C
T
A
= +25°C
T
A
= -40°C
V
CC
= 3.3V
V
CC
= 3.0V
-40
-15
10
35
60
85
110
3.0
3.2
3.4
3.6
8
32
56
80
104
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
OUTPUT FREQUENCY (MHz)
DUTY CYCLE
vs. SUPPLY VOLTAGE
MAX31C80 toc04
DUTY CYCLE
vs. TEMPERATURE
58
56
DUTY CYCLE (%)
54
52
50
48
46
44
42
40
58
56
DUTY CYCLE (%)
54
52
50
48
46
44
42
40
f
CLKOUT
= 100MHz
f
CLKOUT
= 100MHz
T
A
= +125°C
T
A
= +25°C
V
CC
= 3.6V
V
CC
= 3.3V
T
A
= -40°C
V
CC
= 3.0V
3.0
3.2
3.4
3.6
-40
10
60
110
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
FREQUENCY SPECTRUM AT 122MHz
WITH CENTER SPREAD
MAX31C80 toc06
FREQUENCY SPECTRUM AT 100MHz
WITH DOWN DITHER
f
CLKOUT
= 100MHz
CENTER DITHER = -3%
-16.56dB
MAX31C80 toc07
0
-10
ATTENUATION (dB)
-20
-30
-40
-50
f
CLKOUT
= 122MHz
CENTER DITHER = ±1.5%
-14.23dB
0
-10
ATTENUATION (dB)
-20
-30
-40
-50
-60
-60
119.2
121.2
123.2
96
98
FREQUENCY (MHz)
100
FREQUENCY (MHz)
4_ _ _______________________________________________________________________________________
MAX31C80 toc05
60
60
Spread-Spectrum Clock Generators
Block Diagram
8MHz TO 134MHz CLOCK
OR
8MHz TO 34MHz CRYSTAL
f
IN
MAX31C80
MAX31D80
X1
X2
CRYSTAL
OSCILLATOR
PROGRAMMABLE
PLL WITH SPREAD
SPECTRUM
V
CC
V
CC
CLKOUT
(f
CLKOUT
= 2MHz TO 134MHz)
XOUT
(f
XOUT
= f
IN
)
GND
MAX31C80/MAX31D80
SMSEL0
SMSEL1
SPREAD-SPECTRUM
MAGNITUDE CONTROL
Pin Configuration
XOUT
6
EP
2
SMSEL0
3
V
CC
4
GND
5
CLKOUT
GND
7
V
CC
8
MAX31C80
MAX31D80
TOP VIEW
X2
10
X1
+
1
SMSEL1
9
TDFN
Pin Description
PIN
NAME
FUNCTION
Crystal Drive/Clock Input. A crystal with
the proper loading is connected across
X1 and X2. Instead of a crystal, a clock
can be applied at the X1 input. If no
clock or crystal is present, then no clock
is output at either XOUT or CLKOUT.
Spread-Spectrum Magnitude Select.
These are three-state digital inputs
to determine the spread-spectrum
magnitude. Tables 1 and 2 provide
details for configuration of these pins for
down and center dither, respectively.
PIN
3, 8
4, 7
5
6
NAME
V
CC
GND
CLKOUT
XOUT
Ground
Clock Output. Spread-spectrum-capable
digital output clock from the PLL.
Crystal Buffered Output. Buffered digital
output of the input crystal or clock.
Crystal Drive Output. A crystal with the
proper loading is connected across X1
and X2. If a clock is applied at the X1
input, then X2 should be left open circuit.
Exposed Pad. Connect to GND.
FUNCTION
Supply Voltage
1
X1
2, 9
SMSEL0,
SMSEL1
10
X2
—
EP
________________________________________________________________________________________ _ 5
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