ASM3P2779A

Features:

Generates an EMI optimized clock signal at the output.
Integrated loop filter components.
Operates with a 3.3 / 2.5V Supply.
Operating current less than 4mA.
Low power CMOS design.
Input frequency range : 13MHz to 30MHz for 2.5V.
                                       : 13MHz to 30MHz for 3.3V.
Generates a 1X low EMI spread spectrum clock of the input frequency.
Frequency deviation: ±1% (Typ) @16MHz Input Frequency.
Available in 6-pin TSOT-23, 8-pin SOIC and 8-pin TSSOP packages.


Application

The ASM3P2779A is targeted towards all portable devices with very low power requirements like MP3 players and digital still cameras.


Pinout




Specifications

Symbol	Parameter	Rating	Unit
VDD, VIN	Voltage on any pin with respect to Ground	-0.5 to +7.0	V
TSTG	Storage temperature	-65 to +125
TA	Operating temperature	0 to 70
Ts	Max. Soldering Temperature (10 sec)	260
TJ	Junction Temperature	150
TDV	Static Discharge Voltage (As per JEDEC STD22- A114-B)	2	KV
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.

Description

The ASM3P2779A is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. The ASM3P2779A reduces electromagnetic interference (EMI) at the clock source,allowing system wide reduction of EMI of all clock dependent signals. The ASM3P2779A allows significant system cost savings by reducing the number of circuit board layers ferrite beads, shielding that are traditionally required to pass EMI regulations.

The ASM3P2779A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all digital method.

The ASM3P2779A 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'.