The ASM3P2762A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all digital method.
The ASM3P2762A modulates the output of a single PLL
in order to “spread” the bandwidth of a synthesized clock,
and more importantly, decreases the peak amplitudes of
its harmonics. This results in significantly lower system
EMI compared to the typical narrow band signal produced
by oscillators and most frequency generators. Lowering
EMI by increasing a signal’s bandwidth is called ‘spread
spectrum clock generation’.
Applications
The ASM3P2762A is targeted towards all portable
devices with very low power requirements like MP3
players and digital still cameras.
Product Description
The ASM3P2762A is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. The ASM3P2762A reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of
all clock
dependent signals. The ASM3P2762A allows significant
system cost savings by reducing the number of circuit
board layers ferrite beads, shielding that are traditionally
required to pass EMI regulations.
Key Specifications
Description
Supply voltages
Cycle-to-Cycle Jitter
Output Duty Cycle
Modulation Rate Equation
Frequency Deviation
Specification
V
DD
= 3.3V /2.5V
200pS (Max)
45/55%
F
IN
/256
-1.25% (Typ) @ 10MHz
Block Diagram
V
DD
PD
XIN
Crystal
Oscillator
Frequency
Divider
Feedback
Divider
Modulation
PLL
XOUT
Phase
Detector
Loop
Filter
VCO
Output
Divider
ModOUT
V
SS
Alliance Semiconductor
2575 Augustine Drive
•
Santa Clara, CA
•
Tel: 408.855.4900
•
Fax: 408.855.4999
•
www.alsc.com
Notice: The information in this document is subject to change without notice.
September 2005
rev 1.6
Pin Configuration (6-pin TSOT-23 Package)
ASM3P2762A
PD
1
XOUT
2
XIN/CLKIN
3
6
V
SS
ModOUT
V
DD
ASM3P2762A
5
4
Pin Description
Pin#
1
2
3
4
5
6
Pin Name
PD
XOUT
XIN/CLKIN
V
DD
ModOUT
V
SS
Type
I
O
I
P
O
P
Description
Power-down control pin. Pull low to enable power-down mode. Connect to VDD if not
used.
Crystal connection. If using an external reference, this pin must be left unconnected.
Crystal connection or external reference frequency input. This pin has dual functions. It
can be connected either to an external crystal or an external reference clock.
Power supply for the entire chip
Spread spectrum clock output.
Ground connection.
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
2 of 12
September 2005
rev 1.6
Pin Configuration (8-pin SOIC and TSSOP Packages)
ASM3P2762A
XIN/CLKIN
1
XOUT
2
PD
3
NC
4
8
7
6
5
V
DD
NC
ModOUT
V
SS
ASM3P2762A
Pin Description
Pin#
1
2
3
4
5
6
7
8
Pin Name
XIN/CLKIN
XOUT
PD
NC
V
SS
ModOUT
NC
V
DD
Type
I
O
I
-
P
O
-
P
Description
Crystal connection or external reference frequency input. This pin has dual functions. It
can be connected either to an external crystal or an external reference clock.
Crystal connection. If using an external reference, this pin must be left unconnected.
Power-down control pin. Pull low to enable power-down mode. Connect to VDD if not
used.
No connect.
Ground connection.
Spread spectrum clock output.
No connect.
Power supply for the entire chip
Modulation Profile
Specifications
Description
Frequency Range
For 2.5V Supply
For 3.3V Supply
Modulation Equation
Specification
6MHz < CLKIN < 12MHz
6MHz < CLKIN < 13MHz
F
IN
/256
-1.25% (Typ) @10MHz
Frequency Deviation
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
3 of 12
September 2005
rev 1.6
Absolute Maximum Ratings
Symbol
V
DD
, V
IN
T
STG
T
A
T
s
T
J
T
DV
Storage temperature
Operating temperature
Max. Soldering Temperature (10 sec)
Junction Temperature
Static Discharge Voltage
(As per JEDEC STD 22- A114-B)
ASM3P2762A
Parameter
Rating
-0.5 to +7.0
-65 to +125
0 to 70
260
150
2
Unit
V
°C
°C
°C
°C
KV
Voltage on any pin with respect to Ground
Note: These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect
device reliability.
DC Electrical Characteristics for 2.5V Supply
(Test condition: All parameters are measured at room temperature (+25°C) unless otherwise stated)
Symbol
V
IL
V
IH
I
IL
I
IH
I
XOL
I
XOH
V
OL
V
OH
I
DD
I
CC
V
DD
t
ON
Z
OUT
Input low voltage
Input high voltage
Input low current
Input high current
Parameter
Min
V
SS
- 0.3
2.0
-
-
-
-
-
1.8
-
-
2.375
-
-
Typ
-
-
-
-
3
3
-
-
-
2
2.5
-
50
Max
0.8
V
DD
+ 0.3
-35
35
-
-
0.6
-
10
-
2.625
5
-
Unit
V
V
µA
µA
mA
mA
V
V
uA
mA
V
mS
Ω
XOUT output low current (@0.5V, V
DD
=2.5V)
XOUT output high current (@1.8V, V
DD
=2.5V)
Output low voltage (V
DD
= 2.5V, I
OL
= 8mA)
Output high voltage (V
DD
= 2.5V, I
OH
= 8mA)
Static supply current*
Dynamic supply current (2.5V, 10MHz and no load)
Operating voltage
Power-up time (first locked cycle after power-up)**
Output impedance
* PD pin is pulled low
** V
DD
and XIN/CLKIN input are stable, PD pin is made high from low.
AC Electrical Characteristics for 2.5V Supply
Symbol
Parameter
CLKIN
ModOUT
f
d
t
LH
*
t
HL
*
t
JC
t
D
Input frequency
Output frequency
Frequency Deviation
Input Frequency = 6MHz
Input Frequency = 12MHz
Output rise time (measured from 0.7V to 1.7V)
Output fall time (measured from 1.7V to 0.7V)
Jitter (cycle to cycle)
Output duty cycle
Min
6
6
-
-
0.7
0.5
-
45
Typ
-
-
-1.75
- 0.95
1.1
0.8
-
50
Max
12
12
-
-
1.4
1.0
200
55
Unit
MHz
MHz
%
nS
nS
pS
%
* t
LH
and t
HL
are measured into a capacitive load of 15pF
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
4 of 12
September 2005
rev 1.6
DC Electrical Characteristics for 3.3V Supply
(Test condition: All parameters are measured at room temperature (+25°C) unless otherwise stated)
ASM3P2762A
Symbol
V
IL
V
IH
I
IL
I
IH
I
XOL
I
XOH
V
OL
V
OH
I
DD
I
CC
V
DD
t
ON
Z
OUT
Input low voltage
Input high voltage
Input low current
Input high current
Parameter
Min
V
SS
- 0.3
2.0
-
-
-
-
-
2.5
-
-
2.7
-
-
Typ
-
-
-
-
3
3
-
-
-
3
3.3
-
45
Max
0.8
V
DD
+ 0.3
-35
35
-
-
0.4
-
10
-
3.6
5
-
Unit
V
V
µA
µA
mA
mA
V
V
uA
mA
V
mS
Ω
XOUT output low current (@0.4V, V
DD
=3.3V)
XOUT output high current (@2.5V, V
DD
=3.3V)
Output low voltage (V
DD
= 3.3V, I
OL
= 8mA)
Output high voltage (V
DD
= 3.3V, I
OH
= 8mA)
Static supply current*
Dynamic supply current (3.3V, 10MHz and no load)
Operating voltage
Power-up time (first locked cycle after power-up)**
Output impedance
* PD pin is pulled low
** V
DD
and XIN/CLKIN input are stable, PD pin is made high from low.
AC Electrical Characteristics for 3.3V Supply
Symbol
CLKIN
ModOUT
f
d
t
LH
*
t
HL
*
t
JC
t
D
Input frequency
Output frequency
Frequency Deviation
Input Frequency = 6MHz
Input Frequency = 13MHz
Parameter
Min
6
6
-
-
0.5
0.4
-
45
Typ
-
-
-1.75
-0.9
1.0
0.9
-
50
Max
13
13
-
-
1.4
1.2
200
55
Unit
MHz
MHz
%
nS
nS
pS
%
Output rise time (measured from 0.8 to 2.0V)
Output fall time (measured at 2.0V to 0.8V)
Jitter (cycle to cycle)
Output duty cycle
*t
LH
and t
HL
are measured into a capacitive load of 15pF
Low Power Peak EMI Reducing Solution
Notice: The information in this document is subject to change without notice.
Each STM32 chip has an internal reference voltage, which is equivalent to a standard voltage measurement point and is connected to channel 17 of ADC1 inside the chip.According to the data in the data ...
Five MAX491 chips are used to implement the following functions: the RS422 signal from one MAX491 chip is sent to the other four MAX491 chips. The first chip should receive the signals from the four M...
[align=left][font=宋体]At present, wind direction and speed sensors at home and abroad can be divided into three categories. The first category is the propeller wind direction and speed sensor[/font];[f...
4, color camera VC-913D [img=184,104]http://co.163.com/neteaseivp/resource/paper/doc/20061111136949841451/image005.jpg [/img] Technical specifications: Image sensor: 1/3” SONY Super HAD CCD Effective ...
Does anyone have a mobile version of Chinese chess or chess code? Not in JAVA, but in C++ or C#. And it has to pass the compilation. Is 100 points enough? I don't think I got 200 points....
UnboxingFeelings: It is smaller than expected, and integrates many sensors. However, it would be better if it had an illumination sensor.Firmware UpgradeAfter downloading the APP, the APP automaticall...
At present, the development of wireless power supply technology for electric vehicles (EVs) is becoming more and more active. In 2012, Volvo of Sweden established Volvo Technology Japan in Tokyo as...[Details]
Traditional broadcasting systems generally need to be operated manually at a fixed time, and can only realize one-way broadcasting with few functions. Traditional bell ringing equipment has a singl...[Details]
1. Introduction
RFID (radio frequency identification) is a non-contact automatic identification technology that emerged in the 1990s. It uses the characteristics of radio frequency signal prop...[Details]
1. Circuit composition
The whole circuit consists of two parts:
1. Power saving control circuit
As shown in the figure below. Including delay circuit and drive circuit.
(1) Delay ci...[Details]
1. Introduction
With the growth of parking demand, the scale of parking lots is becoming larger and larger. A lot of research has been done on intelligent parking lots in China, but most of th...[Details]
Automotive applications are particularly sensitive to EMI events, which are unavoidable in a noisy electrical environment consisting of a central battery, bundled wiring harnesses, various inductiv...[Details]
Converged processors meet scalability requirements
In current embedded system design, solutions based on MCU, DSP, FPGA and ASIC account for more than 90% of the market share. These solutions ...[Details]
In order to highlight the concept of "energy saving and environmental protection" of intelligent buildings, solar street lights are designed for intelligent communities. The inclination and capacit...[Details]
Electronic systems are located at different points on the automotive power bus and therefore often need to operate under very stringent power requirements. These include load dump, cold crank, very lo...[Details]
To differentiate their products in a crowded and competitive market, manufacturers of handheld devices often consider battery life and power management as key selling points for cell phones, PDAs, ...[Details]
July 11, 2012, Beijing - Altera Corporation (NASDAQ: ALTR) today announced the launch of 40-Gbps Ethernet (40GbE) and 100-Gbps Ethernet (100GbE) intellectual property (IP) core products. These core...[Details]
The data collector of the automatic weather station is generally designed based on a single-chip microcomputer or a PC/104 bus controller. It has the characteristics of good compatibility with PC, low...[Details]
Although it is relatively easy to check the stability of a simple amplifier at lower frequencies, it may be much more difficult to evaluate the stability of a more complex circuit. This artic...[Details]
1. Background:
The instrument system parameter detection and control of the chemical production workshop of Tangshan Coal Gas Coking Plant are all analog instruments, some of which are eve...[Details]
1. Introduction
Testing the temperature of steel billets before rolling is an important measure to ensure the quality of steel. Traditional manual testing is difficult to ensure product qu...[Details]
stm32/stm8
京公网安备 11010802033920号
EEWORLD
