General Description
The DS1080L is a low-jitter, crystal-based clock gener-
ator with an integrated phase-locked loop (PLL) to gen-
erate spread-spectrum clock outputs from 16MHz to
134MHz. The device is pin-programmable to select the
clock multiplier rate as well as the dither magnitude.
The DS1080L has a spread-spectrum disable mode
and a power-down mode to conserve power.
Applications
Automotive
Cable Modems
Cell Phones
Computer Peripherals
Copiers
Infotainment
PCs
Printers
Features
oGenerates Spread-Spectrum Clocks from 16MHz
to 134MHz
oSelectable Clock Multiplier Rates of 1x, 2x, and 4x
oCenter Spread-Spectrum Dithering
oSelectable Spread-Spectrum Modulation
Magnitudes of ±0.5%, ±1.0%, and ±1.5%
oSpread-Spectrum Disable Mode
oLow Cycle-to-Cycle Jitter
oPower-Down Mode with High-Impedance Output
oLow Power Consumption
o3.0V to 3.6V Single-Supply Operation
o-40°C to +125°C Temperature Operation
oSmall 8-Lead µSOP Package
DS1080L
Spread-Spectrum Crystal Multiplier
SSO
PDNSMSEL
1
+
2
8
7
X2
VCC
GND
CMSEL
X1
μSOP
TOP VIEW
3
4
6
5
DS1080L
Pin Configuration
19-4997; Rev 4; 5/12
+
Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
T = Tape and reel.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
DS1080LU+ -40°C to +125°C 8 μSOP
DS1080LU/V+ -40°C to +125°C 8 μSOP
DS1080LU/V+T -40°C to +125°C 8 μSOP
DS1080LU+T -40°C to +125°C 8 μSOP
________________________________________________________________
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.
DS1080L
Spread-Spectrum Crystal Multiplier
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED OPERATING CONDITIONS
(TA= -40°C to +125°C, unless otherwise noted.)
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.
Voltage on VCC Relative to GND.........................-0.5V to +3.63V
Voltage on Any Lead Relative
to GND ...............-0.5V to (VCC + 0.5V), not to exceed +3.63V
Continuous Power Dissipation (TA= +70°C)
μSOP (derate 4.5mW/°C above +70°C).......................362mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-55°C to +125°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage VCC (Note 1) 3.0 3.6 V
Input Logic 1 VIH 0.8 x
VCC
VCC +
0.3 V
Input Logic 0 VIL VGND -
0.3
0.2 x
VCC V
Input Logic Open IIF 0V < VIN < VCC (Note 2) ±1 μA
Input Leakage IIL 0V < VIN < VCC (Note 3) ±80 μA
fSSO < 67MHz 15
67MHz fSSO < 101MHz 10
SSO Load CSSO
101MHz fSSO < 134MHz 7
pF
Crystal or Clock Input
Frequency fIN 16.0 33.4 MHz
Crystal ESR XESR 90
Clock Input Duty Cycle FINDC 40 60 %
Crystal Parallel Load
Capacitance CL (Note 4) 18 pF
DC ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, TA= -40°C to +125°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Current ICC1 C
SSO = 15pF, SSO = 16MHz 13 mA
Power-Down Current ICCQ PDN = GND, all input pins open 200 μA
Output Leakage (SSO) IOZ PDN = GND -1 +1 μA
Low-Level Output Voltage
(SSO) VOL I
OL = 4mA 0.4 V
High-Level Output Voltage
(SSO) VOH I
OH = -4mA 2.4 V
Input Capacitance (X1/X2) CIN (Note 5) 5 pF
DS1080L
Spread-Spectrum Crystal Multiplier
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS
(VCC = +3.0 to +3.6V, TA= -40°C to +125°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Measured at VCC/2, CMSEL = 0 or open 40 60
SSO Duty Cycle SSODC Measured at VCC/2, CMSEL = 1 30 70 %
Rise Time tR(Note 6) 1.6 ns
Fall Time tF(Note 6) 1.6 ns
Peak Cycle-to-Cycle Jitter tJfSSO = 16MHz, TA = -40 to +85°C,
10,000 cycles (Note 5) 75 ps
16MHz 20
Power-Up Time tPOR PDN pin (Note 7) 33.4MHz 11 ms
Power-Down Time tPDN PDN pin (Notes 8 and 9) 100 ns
Dither Rate fDITHER fIN/1024
Note 1: All voltages referenced to ground.
Note 2: Maximum source/sink current applied to input to be considered an open.
Note 3: Applicable to pins CMSEL, SMSEL, and PDN.
Note 4: See information about CL1 and CL2 in the
Applications Information
section at the end of the data sheet.
Note 5: Not production tested.
Note 6: For 7pF load.
Note 7: Time between PDN deasserted to output active.
Note 8: Time between PDN asserted to output high impedance.
Note 9: Guaranteed by design.
DS1080L
Spread-Spectrum Crystal Multiplier
Typical Operating Characteristics
(VCC = 3.3V, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
DS1080L toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
3.35 3.45 3.55 3.653.253.05 3.15
2
4
6
8
10
12
0
2.95
AT 16MHz
CMSEL = 4x AT 16MHz
CMSEL = 2x AT 16MHz
CMSEL = 1x AT 16MHz
SUPPLY CURRENT vs. TEMPERATURE
DS1080L toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
11010 60
2
4
6
8
10
12
0
-40
AT 16MHz
CMSEL = 2x AT 16MHz
CMSEL = 4x AT 16MHz
CMSEL = 1x AT 16MHz
SUPPLY CURRENT vs. FREQUENCY
DS1080L toc03
FREQUENCY (MHz)
SUPPLY CURRENT (mA)
3121 26
2
4
6
8
12
10
16
14
0
16
AT 16MHz
CMSEL = 2x AT 16MHz
CMSEL = 4x AT 16MHz
CMSEL = 1x AT 16MHz
PDN SUPPLY CURRENT vs. TEMPERATURE
DS1080L toc04
TEMPERATURE (°C)
PDN SUPPLY CURRENT (mA)
11010 60
0.05
0.10
0.15
0.20
0.25
0
-40
AT 16MHz
CMSEL = 1x AT 16MHz
CMSEL = 4x AT 16MHz
CMSEL = 2x AT 16MHz
DUTY CYCLE vs. TEMPERATURE
DS1080L toc05
TEMPERATURE (°C)
DUTY CYCLE (%)
11010 60
44
42
48
52
56
46
50
54
58
60
40
-40
AT 16MHz
DUTY CYCLE vs. SUPPLY VOLTAGE
DS1080L toc06
SUPPLY VOLTAGE (V)
DUTY CYCLE (%)
3.55 3.653.15 3.35 3.453.05 3.25
44
42
48
52
56
46
50
54
58
60
40
2.95
AT 16MHz
OUTPUT DURING
POWER-UP AND POWER-DOWN
DS1080L toc07
SSO AND PDN
TIME (μs)
POWER-
DOWN
tPDN tPOR
POWER-
UP
4 _______________________________________________________________________________________
DS1080L
Spread-Spectrum Crystal Multiplier
CRYSTAL
OSCILLATOR
1x/2x/4x CLOCK MULTIPLYING
PLL WITH SPREAD SPECTRUM
CONFIGURATION DECODE
AND CONTROL
VCC
VCC
GND
NOTE: SEE INFORMATION ABOUT CL1 AND CL2 IN THE APPLICATIONS INFORMATION SECTION AT THE END OF THE DATA SHEET.
PDN
SSO
CMSEL
SMSEL
X1
X2
16MHz
TO
33.4MHz
fSSO = 16MHz
TO
134MHz
CL1 CL2
fIN
fSSO
DS1080L
Block Diagram
Pin Description
PIN NAME FUNCTION
1 X1
Crystal Drive/Clock Input. A crystal with the proper loading capacitors is connected across X1 and X2.
Instead of a crystal, a clock can be applied at the X1 input.
2 GND Signal Ground
3 CMSEL
Clock Multiplier Select. Tri-level digital input.
0 = 1x
Open = 2x
1 = 4x
4 SMSEL
Spread-Spectrum Magnitude Select. Tri-level digital input.
0 = ±0.5%
Open = ±1.0%
1 = ±1.5%
5PDN
Power-Down/Spread-Spectrum Disable. Tri-level digital input.
0 = Power-Down/SSO Three-Stated
Open = Power-Up/Spread Spectrum Disabled
1 = Power-Up/Spread Spectrum Enabled
6 SSO
Spread-Spectrum Clock Multiplier Output. Outputs a 1x, 2x, or 4x spread-spectrum version of the crystal
or clock applied at the X1/X2 pins.
7 VCC Supply Voltage
8 X2
Crystal Drive Output. A crystal with the proper loading capacitors is connected across X1 and X2.
If a clock is connected to X1, then X2 should be left open circuit.
_______________________________________________________________________________________ 5
DS1080L
Spread-Spectrum Crystal Multiplier
6 _______________________________________________________________________________________
Detailed Description
The DS1080L is a crystal multiplier with center spread-
spectrum capability. A 16MHz to 33.4MHz crystal is
connected to the X1 and X2 pins. Alternately, a 16MHz
to 33.4MHz clock can be applied to X1 in place of the
crystal. In such applications, X2 would be left open cir-
cuit. Using the CMSEL input, the user selects whether
the attached crystal or input clock is multiplied by 1, 2,
or 4. The DS1080L is capable of generating spread-
spectrum clocks from 16MHz to 134MHz.
The PLL can dither the output clock about its center fre-
quency at a user-selectable magnitude. Using the
SMSEL input, the user selects the dither magnitude.
The PDN input can be used to place the device into a
low-power standby mode where the SSO output is tri-
stated. If the PDN pin is open, the SSO output is active
but the spread-spectrum dithering is disabled. The
spread-spectrum dither rate is fixed at fIN / 1024 to
keep the dither rate above the audio frequency range.
On power-up, the output clock (SSO) remains three-
stated until the PLL reaches a stable frequency (fSSO)
and dither (fDITHER).
Applications Information
Crystal Selection
The DS1080L requires a parallel resonating crystal
operating in the fundamental mode, with an ESR of less
than 90Ω. The crystal should be placed very close to
the device to minimize excessive loading due to para-
sitic capacitances.
Oscillator Input
When driving the DS1080L using an external oscillator
clock, consider the input (X1) to be high impedance.
Crystal Capacitor Selection
The load capacitors CL1 and CL2 are selected based
on the crystal specifications (from the data sheet of the
crystal used). The crystal parallel load capacitance is
calculated as follows:
For the DS1080L use CL1 = CL2 = CLX.
In this case, the equation then reduces to:
where CL1 = CL2 = CLX.
Equation 2 is used to calculate the values of CL1 and
CL2 based on values on CLand CIN noted in the data
sheet electrical specifications.
Power-Supply Decoupling
To achieve best results, it is highly recommended that
a decoupling capacitor is used on the IC power-supply
pins. Typical values of decoupling capacitors are
0.001μF and 0.1μF. Use a high-quality, ceramic, sur-
face-mount capacitor, and mount it as close as possi-
ble to the VCC and GND pins of the IC to minimize lead
inductance.
CCC
LLX IN Equati
=+
2oon
CCxC
CCC
LLL
LLIN
=++
12
12
Equation1
+1.5%
+1.0%
+0.5%
-0.5%
f0
-1.0%
-1.5%
DITHER CYCLE RATE = fDITHER = fIN/1024
fSSO
t
Figure 1. Spread-Spectrum Frequency Modulation
DS1080L
Spread-Spectrum Crystal Multiplier
_______________________________________________________________________________________ 7
Layout Considerations
As noted earlier, the crystal should be placed very
close to the device to minimize excessive loading due
to parasitic capacitances. Care should also be taken to
minimize loading on pins that could be open as a pro-
gramming option (SMSEL and CMSEL). Coupling on
inputs due to clocks should be minimized.
X2
NOTE: IN THE ABOVE CONFIGURATION WITH PDN CONNECTED TO VCC, SMSEL CONNECTED TO GND
AND CMSEL OPEN, THE DEVICE IS IN NORMAL OPERATION WITH 2x CLOCK MULTIPLICATION, AND
SPREAD-SPECTRUM MAGNITUDE OF ±0.5%.
fSSO
VCC
VCC
VCC
SSO
PDN
X1
CRYSTAL
CL1 CL2
DECOUPLING
CAPACITOR
GND
CMSEL
SMSEL
8
7
6
5
1
2
3
4
DS1080L
Typical Operating Circuit
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
8 μSOP U8+1 21-0036 90-0092
DS1080L
Spread-Spectrum Crystal Multiplier
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
8
_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2012 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 11/05 Initial release —
1 3/06 Changed VIHMIN from 0.7V x VCC to 0.08V x VCC and VILMAX from 0.3 x VCC to 0.2V x VCC
in the Recommended Operating Conditions table 2
2 10/09 Changed the part number in the Ordering Information table 1
3 10/11 Updated the Ordering Information table and Absolute Maximum Ratings section; added the
land pattern no. to the Package Information table 1, 2, 7
4 5/12 Clarified SSODC conditions and split limits based upon CMSEL input state 3