General Description
ASM8P18xx is a high performance, adjustable frequency, PWM controller with an integrated spread spectrum modulator for EMI reduction. It contains all the functions of a standard PWM controller along with a user configurable spread spectrum modulation with adjustable spread. ASM8P18xx allows significant system cost savings by reducing the number of PCB layers and shielding that are traditionally required to pass EMI regulation.
ASM8P18xx is the industry’s first general purpose EMI reduction IC, specifically designed for use in SMPS systems. ASM8P18xx is compatible to any other 3842 PWM controllers.
ASM8P18xx is capable of driving 1A maximum current output and it covers a wide supply voltage range from 7V DC to 30V DC. The PWM frequency is selectable from 40 KHz to 400 KHz.
ASM8P18xx provides under voltage lockout, thermal shutdown, overload, and undercurrent protection. It is available in 8-pin MicroSO, P-DIP and SOIC package.

*30V maximum operating voltage with CMOS technology
*Adjustable PWM frequencies (40 KHz to 400 KHz)
*Maximum Output drive current of 1A.
*Wide duty cycle range (0% minimum to 95% maximum)
*Spread spectrum modulation with adjustable spread.
*Under voltage lockout with hysteresis.
*Low startup current: 275?A maximum
*Pin compatible with industry standard 3842 PWM controller.
*Temperature range –40°C to +85°C.
*Thermal shutdown, overload and undercurrent protection.
*Frequency skip mode.
*Available in 8-pin plastic MicroSO, P-DIP and SOIC packages.

*Off-line converter
*DC-DC converter
*Monitor power supply
*Computer/DVD/STB power supply
*Wireless base station power supply
*Telecom power supply

ASM8P18S42ER, ASM8P1843, ASM8P18S43ER, ASM8P18S44ER, ASM8P18S45ER

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Product Description
The P278xA is a versatile spread spectrum frequency modulator designed specifically for digital camera and other digital video and imaging applications. The P278xA reduces electromagnetic interference (EMI) at the clock source, which provides system wide reduction of EMI of all clock dependent signals. The P278xA allows significant system cost savings by reducing the number of circuit board layers and shielding that are traditionally required to pass EMI regulations.
The P278xA uses the most efficient and optimized modulation profile approved by the FCC. The P278xA 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.

*Provides up to 15dB of EMI suppression
*FCC approved method of EMI attenuation
*Generates a 1X, 2X, and 4X low EMI spread spectrum clock of the input frequency
*Input frequency range from 3 to 78MHz
*External loop filter for spread % adjustment
*Spreading ranges from ±0.25% to ±5.0%
*Ultra low cycle-to-cycle jitter
*Zero-cycle slip
*3.3V operating voltage range
*10 mA output drives
*TTL or CMOS compatible outputs
*Ultra-low power CMOS design
*P278XA is available in 8 pin SOIC and TSSOP Packages
*Available for industrial and automotive temperature ranges.

The P278xA is targeted towards MFP, xDSL, fax modem, set-top box, USB controller, DSC, and embedded systems.

P278XA-08ST, P278XA-08SR, P278XA-08TT, P278XA-08TR
TAG EMI, ic, Reduction

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Proliferation of digital portable electronic equipment has created a noisy environment in which all devices become susceptible to Electromagnetic Interference (EMI). Interference form cell phone frequencies of 800-900 MHz and 1.9GHz as well as the growing wireless LAN frequencies of 2.4-6GHz can couple into the audio port of a handheld device and adversely affect its performance. FCC Part 15 sets maximum allowable emission and immunity levels for all digital devices.
LX7206 is an integrated low pass filter with ESD protection that filters out the undesired frequencies as well as protecting the port against both positive and negative ESD voltages. The device is a 3x2 array flip chip and measures 1.5 x 1.0 x 0.65 mm. The small size and profile of this device is ideally suited for portable applications. The absence of leadframe and bondwires minimizes inductance and optimizes the high frequency filter performance.
LX7206 exceeds the requirements of IEC61000-4-2 (15KV air discharge and 8KV contact discharge).

*Flip Chip construction
*Bi-directional EMI/RFI low-pass filter
*ESD protection with integrated line termination resistor
*Bi-directional TVS protects against negative ESD voltages in audio applications
*Low TVS operating voltage (5.0V)
*Low leakage current
*0.5mm Pitch Chip Scale Package designed for direct assembly on FR4 PCB using conventional assembly techniques

*Cell phones and Accessories
*Personal Digital Assistants (PDA’s)
*MP3 Players
*Desktops and Notebook Computers
*Digital Camcorders


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This device is a 4 line EMI filter array for wireless applications.
Greater than −25 dB attenuation is obtained at frequencies from 800 MHz to 4.0 GHz. The NUF4310MN has a cut−off frequency of 185 MHz. This WDFN package is specifically designed to enhance EMI filtering for low−profile or slim design electronics especially where space and height is a premium. It also offers ESD protection−clamping transients from static discharges. ESD protection is provided across all capacitors.

*EMI Filtering and ESD Protection
*Integration of 20 Discrete Components
*Compliance with IEC61000−4−2 (Level 4) >8 kV (Contact) [I/O Pins to GND]
*WDFN Package, 1.6 x 1.0 mm
*Moisture Sensitivity Level 1
*ESD Ratings: Machine Model = C Human Body Model = 3B
*This is a Pb−Free Device*

*Reduces EMI/RFI Emissions on a Data Line
*Low Profile Package; Typical Height of 0.75 mm
*Design−Friendly and Easy−to−Use Pin Configurations, Particularly for Portable Electronics
*Integrated Solution Offers Cost and Space Savings in WDFN Package
*Reduces Parasitic Inductances Which Offer a More “Ideal” Low Pass Filter Response
*Integrated Solution Improves System Reliability

*EMI Filtering and ESD Protection for Data Lines
*Keypad Interface and Protection for Portable Electronics
*Bottom Connector Interface for Mobile Handsets
*Notebook Computers and Digital Cameras
*LCD Display Interface in Mobile Handsets
*Camera Display Interface in Mobile Handsets


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The EClampTM2357N is a low pass filter array with integrated TVS diodes. It is designed to suppress unwanted EMI/RFI signals and provide electrostatic discharge (ESD) protection in portable electronic equipment. They have been optimized for protection of touch screen displays, secure digital (SD) card interfaces, and color LCD panels in cellular phones and other portable electronics.
The device consists of six pi filter circuits comprised of TVS diodes for ESD protection, and a resistor capacitor network for EMI/RFI filtering. A series resistor value of 100Ω and a component capacitance value of 10pF are used to achieve 20dB minimum attenuation from
1.0GHz to 3GHz. The device also includes 4 discrete TVS diodes for dedicated ESD protection. All of the TVS diodes provide effective suppression of ESD voltages in excess of ±15kV (air discharge) and ±8kV (contact discharge) per IEC 61000-4-2, level 4.

*EMI/RFI filter with integrated ESD protection
*ESD protection to IEC 61000-4-2 (ESD) Level4, ±15kV (air), ±8kV (contact)
*Filter performance: >30dB attenuation at 1.8GHz
*TVS working voltage: 5V
*Resistor: 100Ω +/− 15%
*Component Capacitance: 10pF (VR = 0V)
*EMI & ESD protection for six lines
*Dedicated ESD protection for four lines
*Solid-state technology

*Touch Screen Display Interfaces
*Secure Digital (SD) Memory Card Interfaces
*Multimedia Card Interfaces (MCI)
*Color LCD Panel Protection
*Cell Phone Handsets and Accessories


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* Optimized for Quasi-Resonant Converter (QRC)
* Low EMI through Variable Frequency Control and AVS (Alternating Valley Switching)
* High-Efficiency through Minimum Voltage Switching
* Narrow Frequency Variation Range over Wide Load and Input Voltage Variation
* Advanced Burst-Mode Operation for Low Standby Power Consumption
* Simple Scheme for Sync Voltage Detection
* Pulse-by-Pulse Current Limit
* Various Protection functions: Overload Protection (OLP), Over-Voltage Protection (OVP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) with Hysteresis, Output Short Protection (OSP)
* Under-Voltage Lockout (UVLO) with Hysteresis
* Internal Start-up Circuit
* Internal High-Voltage Sense FET (650V)
* Built-in Soft-Start (15ms)

* Power Supply for LCD TV and Monitor, VCR, SVR, STB, and DVD & DVD Recorder
* Adapter
Related Resourses
* AN-4134: Design Guidelines for Offline Forward Converters Using Fairchild Power Switch (FPS™)
* AN-4137: Design Guidelines for Offline Flyback Converters Using Fairchild Power Switch (FPS™)
* AN-4140: Transformer Design Consideration for Offline Flyback Converters Using Fairchild Power Switch (FPS™)
* AN-4141: Troubleshooting and Design Tips for Fairchild Power Switch (FPS™) Flyback Applications
* AN-4145: Electromagnetic Compatibility for Power Converters
* AN-4147: Design Guidelines for RCD Snubber of Flyback
* AN-4148: Audible Noise Reduction Techniques for Fairchild Power Switch Fairchild Power Switch(FPS™) Applications
* AN-4150: Design Guidelines for Flyback Converters Using FSQ-Series Fairchild Power Switch (FPS™)

A Quasi-Resonant Converter (QRC) generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ-series is an integrated Pulse-Width Modulation (PWM) controller and SenseFET specifically designed for quasi-resonant operation and Alternating Valley Switching (AVS). The PWM controller includes an integrated fixed-frequency oscillator, Under-Voltage Lockout (UVLO), Leading- Edge Blanking (LEB), optimized gate driver, internal softstart, temperature-compensated precise current sources for a loop compensation, and self-protection circuitry.
Compared with a discrete MOSFET and PWM controller solution, the FSQ-series can reduce total cost, component count, size, and weight; while simultaneously increasing efficiency, productivity, and system reliability.
This device provides a basic platform that is well suited for cost-effective designs of quasi-resonant switching flyback converters.


TAG EMI, Power, Switch

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