SM8761 Datasheet, PDF (1/11 Pages) Nippon Precision Circuits Inc – Spread Spectrum Clock Generator

SM8761 series
Spread Spectrum Clock Generator
OVERVIEW
The SM8761 series are compact clock generator ICs that have a spread spectrum (SS) function to reduce unde-
sirable EMI radiation. They have a built-in crystal oscillator circuit, PLL, and loop filter. They accept an input
clock signal, generated using an external crystal or direct external clock input, and output an SS-modulated
clock signal. In addition, versions are available for center spread and down spread modulation mode, and all
have a mode control pin to select the SS modulation function.
FEATURES
I Spread spectrum clock output to reduce EMI
I Correspond to wide range of output frequency
I Low jitter
I Operating supply voltage: 3.3 ± 0.3V
I Multiplication: 1-time multiplication
I Package: 8-pin SOP
Spectrum modulation mode
Spectrum modulation rate^*1
Crystal element connection
Input frequency
External input clock
Output frequency
Multiplication
Jitter (Cycle-to-Cycle)
SM8761AA
Down spread
– 1.0% to – 3.8%
20MHz to 40MHz
20MHz to 108MHz
20MHz to 108MHz
1-time multiplication
200ps (typ) @33MHz
120ps (typ) @75MHz
SM8761AB
Center spread
± 0.75% to ± 2.25%
12MHz to 32MHz
12MHz to 32MHz
12MHz to 32MHz
1-time multiplication
200ps (typ) @16MHz
*1. The modulation rate that can be selected varies with the input frequency.
PINOUT
(Top view)
PACKAGE DIMENSIONS
(Unit: mm)
XT 1
VDD 2
VSS 3
CLKOUT 4
8 XTN
7 MSEL1
6 MSEL0
5 TSTN
0.695typ
5.2 ± 0.3
0.15
+
−
0.1
0.05
APPLICATIONS
I Printer (laser/inkjet)
I Photocopiers, scanners
I LCD/PDP displays
I Projectors
I Miscellaneous electronic equipment
1.27
0.10
0.4 ± 0.1 _{0.12 M}
0 to 10°
ORDERING INFORMATION
Device
SM8761AAS
SM8761ABS
Package
8-pin SOP
NIPPON PRECISION CIRCUITS INC.—1