ASM3P2108A

Features:

􀂃 FCC approved method of EMI attenuation.
􀂃 Generates a 1X low EMI spread spectrum clock of the input frequency.
􀂃 Input frequency range: 25MHz to 45MHz.
􀂃 Internal loop filter minimizes external components and board space.
􀂃 Frequency deviation: - 1.3%( Typ) @32MHz.
􀂃 Low cycle-to-cycle jitter.
􀂃 5.0V ± 5% operating voltage range.
􀂃 TTL or CMOS compatible outputs.
􀂃 Available in 8-pin SOIC and TSSOP Packages.

Application

The ASM3P2108A is targeted towards EMI management for high speed digital applications such as PC peripheral devices, consumer electronics and embedded controller
systems.

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 ASM3P2108A is a versatile spread spectrum frequency modulator designed specifically for input clock frequencies from 25MHz to 45MHz. It can generate an EMI reduced clock from crystal, ceramic resonator, or system clock.

The ASM3P2108A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of down stream clock and data dependent signals. The ASM3P2108A allows significant system cost savings by reducing the number of circuit board layers ferrite beads, shielding and other passive components that are traditionally required to pass EMI regulations.

The ASM3P2108A uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all digital method.

The ASM3P2108A 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. ASM3P2108A 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'.