DS1081L
20MHz to 134MHz Spread-Spectrum
Clock Modulator for LCD Panels
_______________________________________________________________________________________ 5
Spread-Spectrum Enable
On power-up, the output clock (SSO) remains three-stat-
ed until the internal PLL reaches a stable frequency. The
SSEN input can be used to disable the spread-spec-
trum modulation and to three-state the SSO output. If the
SSEN pin is pulled high, the spread-spectrum modula-
tion is turned off, but the device still uses the internal
PLL to generate the clock signal at SSO. If the SSEN pin
is open, the output is three-stated.
Applications Information
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 0.01µF
and 0.1µF. Use a high-quality, ceramic, surface-mount
capacitor, and mount it as close as possible to the V
CC
and GND pins of the IC to minimize lead inductance.
f
IN
+ (0.5%, 1.0%, 1.5%, OR 2.0% OF f
IN
)
f
IN
f
IN
- (0.5%, 1.0%, 1.5%, OR 2.0% OF f
IN
)
f
SSO
TIME
1
DITHER CYCLE
RATE
DITHER AMOUNT
(±0.5%, ±1.0%, ±1.5%, OR ±2.0%)
CLKIN RANGE (MHz) DITHER RATE
66 TO 134 f
IN
/2048
33 TO 80 f
IN
/1024
20 TO 38 f
IN
/512
IF SSEN = 1
Figure 1. Spread-Spectrum Frequency Modulation
CLKIN
SMSEL1
SMSEL2
GND
CRSEL
V
CC
DECOUPLING
CAPACITOR
V
CC
SSO
f
IN
= 20MHz TO
134MHz
NOTE: IN THE ABOVE CONFIGURATION WITH SMSEL1, SMSEL2, AND SSEN CONNECTED TO GND AS WELL AS
CRSEL CONNECTED TO V
CC
AND SSEN CONNECTED TO GND, THE DEVICE IS CONFIGURED WITH A
SPREAD-SPECTRUM MAGNITUDE OF ±2.0%, AND ALLOWS A CLKIN BETWEEN 20MHz and 38MHz.
f
SSO
DITHERED
SSEN
DS1081L
Typical Operating Circuit
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
8 TSSOP H8+3
21-0175 90-0248
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.
