900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




Cypress Semiconductor Electronic Components Datasheet

W42C32-05 Datasheet

Spread Spectrum Frequency Timing Generator

No Preview Available !

W42C32-05
Spread Spectrum Frequency Timing Generator
Features
• Maximized EMI suppression using Cypress’s Spread
Spectrum technology
• Generates a spread spectrum timing signal
• Reduces measured EMI by as much as 12 dB
• Integrated loop filter components
• Requires a single low-cost fundamental crystal (or
other frequency reference) for proper operation
• Special spread spectrum control functions
• Low-power CMOS design
• Available in 16-pin SOIC package, (300 mil)
Overview
The W42C32 modulates the output of a single PLL in order to
‘spread’ the bandwidth of a synthesized clock and, more im-
portantly, decrease the peak amplitudes of its fundamental
harmonics. Since peak amplitudes are reduced, the radiated
electromagnetic emissions of the W42C32-05 are significantly
lower than the typical narrow band signal produced by oscilla-
tors and most frequency generators. Lowering a signal’s am-
plitude by increasing its bandwidth is a method of reducing
EMI called ‘spread spectrum frequency timing generation’.
This patented technique not only reduces the emissions of the
primary clock, but also impacts every signal synchronized to it.
Key Specifications
Cycle-to-Cycle Jitter .................................................... 250 ps
45/55 Duty Cycle .................................... approximately 1.4V
Selectable Frequency spread
2 ns rise/fall time 0.4V to 2.0V, 3.3V supply
2 ns rise/fall time 0.8V to 2.4V, 5.0V supply
Table 1. Frequency Spread Selection
W42C32-05
REFOUT
FS2 FS1 FS0 (MHz)
CLKOUT
(MHz)
VDD
(V)
00
0 22.1148
44.2296 ±
2.5%
5.0
0 0 1 22.1148
44.2296
±1.5%
5.0
01
0 14.7456
29.4912 ±
2.5%
5.0
0 1 1 18.432 18.432 ± 2.5% 5.0
1 0 0 14.318 66.66 – 2% 3.3
101
Reserved
3.3
1 1 0 14.318
100 – 2%
3.3
111
Reserved
3.3
Pin Configuration
PD#
X1
X2
GND
AGND
FS0
TEST
CLKOUT
SOIC
1 16
2 15
3 14
4 13
5 12
6 11
7 10
89
REFOUT
FS2
FS1
SSON#
RESET
VDD
AVDD
REFEN#
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
September 28, 1999, rev. **


Cypress Semiconductor Electronic Components Datasheet

W42C32-05 Datasheet

Spread Spectrum Frequency Timing Generator

No Preview Available !

W42C32-05
Pin Definitions[1]
Pin Name Pin No.
Pin
Type
Pin Description
CLKOUT
8
O Output Modulated Frequency: Frequency is set using FS0:2 (refer to Table 1).
REFOUT
16
O Reference Output: A buffered version of the input frequency.
X1 2 I Crystal Connection or External Reference Frequency Input: This pin has dual func-
tions. It can be used as either an external crystal connection, or as an external reference
frequency input.
X2 3 I Crystal Connection: If using an external reference, this pin must be left unconnected.
SSON#
13 I Spread Spectrum Control (active LOW): Pulling this input signal HIGH turns the internal
modulating waveform off. This pin has an internal pull-down resistor.
FS0 6 I Frequency Selection Bit 0: This pin selects the frequency and spreading characteristics.
Refer to Table 1. This pin has an internal pull-up resistor.
FS1 14 I Frequency Selection Bit 1: This pin selects the frequency and spreading characteristics.
Refer to Table 1. This pin has an internal pull-up resistor.
FS2
PD#
15 I Frequency Selection Bit 2: This pin selects the frequency and spreading characteristics.
Refer to Table 1 (note the VDD specification). This pin has an internal pull-up resistor.
1 I Power-down (active LOW): Enabling power-down reduces current consumption and
disables the clock outputs. This pin has an internal pull-up resistor.
REFEN#
9
I Reference Clock Selection Input: Pulling this signal LOW turns the REFOUT clock
output on. This pin has an internal pull-up resistor.
RESET
12 I Reset: A reset starts the spread spectrum modulating frequency at the beginning point
of the modulation profile. This pin has an internal pull-down resistor. To reset the spread
spectrum modulating frequency, pull this pin from LOW to HIGH.
VDD
11 P Power Connection: Connected to either 3.3V or 5.0V power supply. VDD and AVDD must
be the same voltage level.
AVDD
GND
10 P Analog Power Connection: Connected to either 3.3V or 5.0V power supply. VDD and
AVDD must be the same voltage level.
4 G Ground Connection: Connect to the common system ground plane.
AGND
5 G Analog Ground Connection: Connect to the common system ground plane.
TEST
7 I Three-state Input: Pulling this input pin and REFEN# pin HIGH, CLKOUT will be
three-stated. This pin has an internal pull-down resistor.[2]
Notes:
1. Pull-up resistors not CMOS level.
2. Pulling PD# and REFEN# input pins HIGH, REFOUT will be three-stated.
2


Part Number W42C32-05
Description Spread Spectrum Frequency Timing Generator
Maker Cypress Semiconductor
PDF Download

W42C32-05 Datasheet PDF






Similar Datasheet

1 W42C32-05 Spread Spectrum Frequency Timing Generator
Cypress Semiconductor





Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z

Site map

Webmaste! click here

Contact us

Buy Components

Privacy Policy