SM8761 Datasheet, PDF (8/11 Pages) Nippon Precision Circuits Inc – Spread Spectrum Clock Generator

SM8761 series
Function Controls
The SM8761 series power-down and SS modulation ON/OFF functions are controlled using the MSEL0 and
MSEL1 input pins as shown in Table 1.
SM8761AA
MSEL1 (Pin 7)
MSEL0 (Pin 6)
Input/Output
frequency range [MHz]
SS mode
SS modulation^*1 [%]
L
L
–2.3
L
M
–3.2
L
H
20 to 54
(Low range)
Down spread
−2.8
M
L
–1.9
M
M
–3.8
M
H
–2.5
H
H
L
M
50 to 108
(High range)
Down spread
–1.9
–1.0
H
H
–1.2
*1. The modulation rates in the table above are reference values at 30MHz to 40MHz (Low range) and 70MHz to 80MHz (High
range). The modulation rate varies with the input/output frequency.
Note. Signal level “H” represents V_DD level, “L” represents V_SS level, and “M” represents 1/2V_DD.
SM8761AB
MSEL1 (Pin 7)
MSEL0 (Pin 6)
Input/Output
frequency range [MHz]
SS mode
SS modulation^*1 [%]
L
L
± 1.25
L
L
M
H
12 to 18
(Low range)
Center spread
± 0.75
± 1.75
M
L
M
M
(reserved)^*2
± 2.25
M
H
± 2.25
H
H
L
M
18 to 32
(High range)
Center spread
± 1.25
± 0.75
H
H
± 1.75
*1. The modulation rates in the table above are reference values at 12MHz (Low range) and 24MHz (High range). The modula-
tion rate varies with the input/output frequency.
*2. If MSEL1 (pin 7) and MSEL0 (pin 6) are both simultaneously "M" level, then SM8761AB operation cannot be guaranteed.
Note. Signal level “H” represents V_DD level, “L” represents V_SS level, and “M” represents 1/2V_DD.
NIPPON PRECISION CIRCUITS INC.—8