Application information, Typical operating circuit package information, Spread-spectrum enable – Rainbow Electronics DS1081L User Manual
Page 5: Power-supply decoupling
DS1081L
20MHz to 134MHz Spread-Spectrum
Clock Modulator for LCD Panels
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is a registered trademark of Dallas Semiconductor Corporation.
Spread-Spectrum Enable
On power-up, the output clock (SSO) remains tri-stated
until the internal PLL reaches a stable frequency. The
SSEN input can be used to disable the spread-spec-
trum modulation and to tri-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 floated, the output will be tri-stated.
Application 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. DS1081L 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.
DS1081L
f
SSO
DITHERED
SSEN
Typical Operating Circuit
Package Information
For the latest package outline information, go to www.maxim-ic.com/DallasPackInfo.