CY25245
Document #: 38-07124 Rev. *B
Page 2 of 11
Pin Definitions
Pin Name Pin No. Pin Type
Pin Description
SSOUT
15
O
Output Modulated Frequency. Frequency modulated copy of the input clock (SSON# asserted).
REFOUT
20
O
Non-modulated Output. This pin provides a copy of the reference frequency. This output will
not have the Spread Spectrum feature enabled regardless of the state of logic input SSON#.
X1
1
I
Crystal Connection or External Reference Frequency Input. This pin has dual functions. It
may either be connected to an external crystal, or to an external reference clock.
X2
2
I
Crystal Connection. Input connection for an external crystal. If using an external reference, this
pin must be left unconnected.
SSON#
10
I
Spread Spectrum Control (Active LOW). Asserting this signal (active LOW) turns the internal
modulation waveform on. This pin has an internal pull-down resistor.
MW0:2
4, 11, 14
I
Modulation Width Selection. When Spread Spectrum feature is turned on, these pins are used
to select the amount of variation and peak EMI reduction that is desired on the output signal.
MW0:Down, MW1:Up, MW2:Down (see Table 2).
IR1:2
17, 16
I
Reference Frequency Selection. The logic level provided at this input indicates to the internal
logic what range the reference frequency is in and determines the factor by which the device
multiplies the input frequency. Refer to Table 3. These pins have internal pull-up resistors.
OR1:2
6, 9
I
Output Frequency Selection Bits. These pins select the frequency operation for the output.
Refer to Table 1. The OR2 pin has an internal pull-up resistor. The OR1 pin has internal pull-down
resistors.
SCLK
7
I
Clock Pin for SMBus Circuitry.
SData
5
I/O
Data Pin for SMBus Circuitry.
VDD
12, 19
P
Power Connection. Connected to 3.3V or 5V power supply.
AVDD
3
P
Analog Power Connection. Connected to 3.3V or 5V power supply.
GND
8, 13, 18
G
Ground Connection. Connect all ground pins to the common ground plane.
Table 1. Frequency Configuration (Frequencies in MHz)
Range of Fin Frequency
Multiplier
Settings
Output/
Input
Range of Fout Required R Settings
Modulation and
Power-down Settings
Min.
Max.
OR2
OR1
Min.
Max.
IR2
IR1
MW2
MW1
14
41.7
0
1
1
14
41.7
0
1
Table 2
14
41.7
1
0
2
28
83.3
0
1
Table 2
14
41.7
1
1
4
56
166
0
1
Table 2
25
83.3
0
1
0.5
13
41.7
1
0
Table 2
25
83.3
1
0
1
25
83.3
1
0
Table 2
25
83.3
1
1
2
50
166
1
0
Table 2
50
166
0
1
0.25
13
41.7
1
1
Table 2
50
166
1
0
0.5
25
83.3
1
1
Table 2
50
166
1
1
1
50
166
1
1
Table 2
Reserved
0
0
N/A
N/A
N/A
As Set
As Set
1
0
Power-down Hi-Z
0
0
N/A
N/A
N/A
As Set
As Set
1
1
Power-down 0
0
0
N/A
N/A
N/A
As Set
As Set
0
0
Power-down 1
0
0
N/A
N/A
N/A
As Set
As Set
0
1
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