Semtech protects 3G/CDMA phones from EMI and ESD threats

April 4, 2006

Semtech, a supplier of analog and mixed-signal semiconductors for communications, portable devices, computers, and industrial equipment, announced the EClamp237xP family of devices designed to protect against the increased risk of electrostatic discharge (ESD) and increased levels of electromagnetic interference (EMI) and radio frequency interference (RFI) in 3G and CDMA phones that have high-resolution displays and video and digital camera features.

As manufacturers add more of these capabilities, they use more parallel data lines to connect the display and cameras to the baseband controller, increasing the amount of EMI and RFI that can distort display signals, and also increasing the ESD risk to the baseband controller. The EClamp237xP devices meet these challenges with IEC-standard levels of ESD protection, low capacitance and resistance, and a rugged package that consolidates more than 32 discrete components to help conserve board space in these space-constrained applications.

The new EClamp237xP family includes the four-line EClamp2374P, the six-line EClamp2376P and the eight-line EClamp2378P. The devices feature a TVS diode on each line for ESD protection and a resistor-capacitor network for EMI/RFI filtering. All models of the EClamp237xP family feature low series resistance of 100 ohms combined with a capacitance of 20pF to deliver more than 30dB of attenuation from 1.8GHz to 2.5GHz.

The devices in the EClamp237xP family all feature very low clamping voltage to protect the sensitive baseband controller. The devices are designed to protect and filter high-speed parallel interfaces that operate at speeds up to 60Mbs without signal degradation.

"The high bandwidth of today's LCD interfaces means that the nature of a protection device must change to provide high levels of protection without impacting the signal quality," said Tom Dugan, Semtech marketing manager for protection products. "We've cut the resistance and capacitance dramatically in the EClamp237xP family compared to the competition in this space without impacting the device's legacy of low clamping voltages and superior ESD protection."

The EClamp237xP devices are packaged in the Semtech Leadless Package (SLP) that has the narrow form factor and manufacturing durability to replace "flip chip" based alternatives. All devices in the family feature a uniform narrow 1.6 mm width, and a uniform low 0.6 mm profile but differ in length depending upon the number of lines the device supports.

The EClamp237xP devices also feature a flow through design that alleviates the need for signal routing for a faster and more convenient layout. EClamp237xP devices are RoHS/WEEE compliant to meet worldwide environmental and regulatory requirements.

Key Features of the EClamp237xP Family

-- ESD protection to IEC 61000-4-2 Level 4 (+/-15kV air; +/-8kV contact)

-- Filter performance: 30dB minimum attenuation 1.8GHz to 2.5GHz

-- TVS working voltage: 5V

-- Resistor: 100 ohms +/-15 percent

-- Total capacitance: 20pF (VR=0V)

-- 4-, 6-, and 8-line versions available

-- Uniform width (1.6 mm) and height (0.6 mm); EClamp2374P length is 2.1 mm, EClamp2376P length is 3.0 mm, EClamp2378P length is 4.0 mm