DS1081L Ver la hoja de datos (PDF) - Maxim Integrated
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DS1081L Datasheet PDF : 6 Pages
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20MHz to 134MHz Spread-Spectrum
Clock Modulator for LCD Panels
Pin Description
PIN
NAME
FUNCTION
1
CLKIN Clock Input. 20MHz to 134MHz clock input (fIN).
Spread-Spectrum Magnitude Select Inputs. These digital inputs select the desired spread-spectrum
2
SMSEL1 magnitude as shown in the table below.
SMSEL2
SMSEL1
MAGNITUDE SELECTED
0
0
±2.0%
0
3
SMSEL2
1
1
±1.5%
0
±1.0%
1
1
±0.5%
4
GND Ground
Spread-Spectrum Enable. Three-level input to enable/disable spread-spectrum and to three-state the
output.
5
SSEN 0 = Power-up/spread-spectrum enabled.
Open = SSO three-stated.
1 = Power-up/spread-spectrum disabled (not a bypass mode).
6
SSO
Spread-Spectrum Clock Output. Outputs a center-dithered spread-spectrum version of the clock input at
CLKIN.
Clock Range and Dither Rate Select. Three-level input that determines the dither rate. See the Detailed
Description section for details.
7
CRSEL
CRSEL
0
Open
1
8
VCC Supply Voltage
CLKIN RANGE
66MHz to 134MHz
33MHz to 80MHz
20MHz to 38MHz
DITHER RATE
fIN/2048
fIN/1024
fIN/512
Detailed Description
The DS1081L modulates an input clock to generate a
center-dithered spread-spectrum output. A 20MHz to
134MHz clock is applied to the CLKIN pin. An internal
PLL dithers the output clock about its center frequency
at a user-selectable magnitude.
Spread-Spectrum Dither Magnitude
The DS1081L can generate dither magnitudes up to
±2%. The desired magnitude is selected using input pins
SMSEL1 and SMSEL2 as shown in Table 1.
Table 1. Spread-Spectrum Dither Magnitude
SMSEL2
0
0
1
1
SMSEL1
0
1
0
1
MAGNITUDE
±2.0%
±1.5%
±1.0%
±0.5%
Spread-Spectrum Dither Rate
The output spread-spectrum dither rate is determined
by the input frequency to maximize EMI reduction and
to ensure that the dither rate is always above the audio
frequency range. The user must configure CRSEL,
based on Table 2, depending on the input frequency
(fIN) so that the appropriate dither rate is programmed.
Table 2. Spread-Spectrum Dither Rate
CRSEL
0
Open
1
CLKIN RANGE
66MHz to 134MHz
33MHz to 80MHz
20MHz to 38MHz
DITHER RATE
fIN/2048
fIN/1024
fIN/512
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