CY24242 Datasheet, PDF (1/10 Pages) Cypress Semiconductor – Laser Printer System Frequency Synthesizer

CY24242
Laser Printer System Frequency Synthesizer
Features
• Maximized EMI suppression using Cypress’s Spread
Spectrum technology
• Reduces measured EMI by as much as 10 dB
• Four skew-controlled copies of CPU output
• Four skew-controlled copies of SDRAM output
• One copy of 14.31818-MHz Reference output
• One copy of 48-MHz USB clock (not spread)
• Selectable SSFTG modulation width
• Available in 28-pin SSOP (209 mil)
Key Specifications
Supply Voltage:
VDDCORE: ........................................................... 3.3V±10%
VDDC: ............................................... 3.3V±10% or 2.5V±5%
VDDS: ............................................... 3.3V±10% or 2.5V±5%
VDDU: ............................................... 3.3V±10% or 2.5V±5%
CPU Clock Cycle to Cycle Jitter: ................................ 250 ps
USBCLK Long term Jitter: ....................................... ± 500 ps
CPU0:3 Clock Skew: .................................................. 250 ps
CPU, SDRAM Output on Resistance: ............................. 15Ω
Logic inputs have 250K-ohm pull-up resistors
Block Diagram
Table 1. Pin Selectable Frequency^[1]
FS1 FS0
CPU(0:3),
SDRAM(0:3)
00
133.3 MHz
01
100 MHz
10
66.6 MHz
11
50 MHz
USBCLK
48 MHz
48 MHz
48 MHz
48 MHz
Table 2. Spread Characteristics.
SSON#
0
0
0
0
1
1
1
1
SS%1
0
0
1
1
0
0
1
1
SS%0
0
1
0
1
0
1
0
1
CPU(0:3),
SDRAM(0:3)
–0.5%
–1.0%
–2.5%
–3.75%
0 (off)\
0 (off)
0 (off)
0 (off)
Pin Configuration ^{[2, 3]}
X1
X2
SSON#
SS%1
SS%0
XTAL
OSC
PLL Ref Freq
PLL 1
FS0
FS1
SDEN
USBCLKEN
REF
CPU0:3
SDRAM0:3
VDDCORE 1
REF 2
GND 3
X1 4
X2 5
SDRAM3 6
SDRAM2 7
VDDS 8
SDRAM1 9
SDRAM0 10
GND 11
VDDCORE 12
*SDEN 13
*SS%0 14
28 USBCLKEN
27 GND
26 USBCLK
25 VDDU
24 CPU0
23 CPU1
22 VDDC
21 _CPU2
20 _CPU3
19 _GND
18 _SS%1*
17 _SSON#^
16 _FS1*
15 _FS0*
PLL 2
USBCLK
Notes:
1. All clock output loaded with maximum lump capacitance test load specified in AC Electrical Characteristics section.
2. Signals marked with [*] have internal pull-up resistors
3. Signal marked with[^] has internal pull-down resistors.
Cypress Semiconductor Corporation • 3901 North First Street • San Jose, CA 95134 • 408-943-2600
Document #: 38-07268 Rev. *B
Revised January 19, 2005