
CY25245
Document #: 38-07124 Rev. *A
Page 2 of 11
Pin Definitions
Pin Name Pin No. Pin Type
SSOUT
15
REFOUT
20
Pin Description
O
O
Output Modulated Frequency
. Frequency modulated copy of the input clock (SSON# asserted).
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#.
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.
Crystal Connection
. Input connection for an external crystal. If using an external reference, this
pin must be left unconnected.
Spread Spectrum Control (Active LOW)
. Asserting this signal (active LOW) turns the internal
modulation waveform on. This pin has an internal pull-down resistor.
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
).
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.
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 an internal
pull-down resistors.
Clock Pin for SMBus Circuitry
.
Data Pin for SMBus Circuitry
.
Power Connection
. Connected to 3.3V or 5V power supply.
Analog Power Connection
. Connected to 3.3V or 5V power supply.
Ground Connection
. Connect all ground pins to the common ground plane.
X1
1
I
X2
2
I
SSON#
10
I
MW0:2
4, 11, 14
I
IR1:2
17, 16
I
OR1:2
6, 9
I
SCLK
SData
VDD
AVDD
GND
7
5
I
I/O
P
P
G
12, 19
3
8, 13, 18
Table 1. Frequency Configuration (Frequencies in MHz)
Range of Fin Frequency
Min.
14
14
14
25
25
25
50
50
50
Reserved
Power-down Hi-Z
Power-down 0
Power-down 1
Multiplier
Settings
OR2
0
1
1
0
1
1
0
1
1
0
0
0
0
Output/
Input
Range of Fout
Min.
14
28
56
13
25
50
13
25
50
N/A
N/A
N/A
N/A
Required R Settings
IR2
0
0
0
1
1
1
1
1
1
As Set
As Set
As Set
As Set
Modulation and
Power-down Settings
MW2
Table 2
Table 2
Table 2
Table 2
Table 2
Table 2
Table 2
Table 2
Table 2
1
1
0
0
Max.
41.7
41.7
41.7
83.3
83.3
83.3
166
166
166
OR1
1
0
1
1
0
1
1
0
1
0
0
0
0
Max.
41.7
83.3
166
41.7
83.3
166
41.7
83.3
166
N/A
N/A
N/A
N/A
IR1
1
1
1
0
0
0
1
1
1
As Set
As Set
As Set
As Set
MW1
1
2
4
0.5
1
2
0.25
0.5
1
N/A
N/A
N/A
N/A
0
1
0
1