1-GHz Triple Current Feedback Amplifier Provides Optimal Slew Rate

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Intersil's EL5367

Milpitas, Calif. — Intersil Corp. introduced what it claims is the world's fastest triple amplifier — breaking the 1-GHz barrier. With a total supply current of just 25 mA and the ability to run from a single supply voltage from 5 V to 12 V, the EL5367 offers very high performance for extremely little power consumption. The new EL5367 drives resolutions greater than QXGA (2048 pixel x 1536 pixel video graphics standard) at gain of 2 for very high-speed video and monitor applications.

“This performance leading triple amplifier is a direct response to our customers' requests for more performance with lower power,” said Sameer Vuyyuru, Intersil's director of marketing for high-speed analog products. “As our display partners strive towards ever greater resolutions, they can rely on Intersil to provide the silicon solutions they need.”

The EL5367 is a current-feedback operational amplifier that offers a wide -3 dB bandwidth of 1 GHz and a low supply current of 8.5 mA per amplifier. The EL5367 works with supply voltages ranging from a single 5 V to 12 V and it is also capable of swinging to within 1 V of either supply on the output. Because of their current-feedback topology, the EL5367 does not have the normal gain-bandwidth product associated with voltage-feedback operational amplifiers. This device is ideal for driving high-resolution video. With a gain of 2 bandwidth of 800 MHz on all three channels this device will drive a double terminated 75Ω cable easily.

This combination of high bandwidth and low power, together with aggressive pricing make the EL5367 an ideal choice for many low-power and high bandwidth applications such as portable, handheld or battery-powered equipment used for high speed video and monitor applications, as well as a number of RF and IF frequency designs.

EL5367 Key Features:

  • Gain of 1 bandwidth equals 1 GHz
  • Gain of 2 bandwidth equals 800 MHz into a 150 Ω load
  • 6000 V/μs slew rate (typical
  • Single and dual supply operation from 5 V to 12 V
  • Low supply current – 8.5 mA a channel
  • Good DC performance Vos less than 5 mV
  • 16-lead QSOP packaging
  • 600 MHz and 200 MHz versions also available

The EL5367 is now available in 16-lead QSOP packaging for a price of $2.99 in 1,000 unit quantities.

Click here for the EL5367 datasheet

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Priced competitively, this product should do well, said Susie Inouye, senior industry analyst for Databeans Inc., Reno, Nevada. “What makes this product attractive to the display OEMs is the fact that it has 3 channels, which will drive the RGB signals in the design. “You could use another product if you needed a high performance gain bandwidth (GBW), but you would need to use 3 of them,” she said.

While this isn't the first time Intersil or its competitors broke the GHz barrier, it is the first time 1 GHz was reached in the triple form, Vuyyuru said.

Companies making similar products include Analog Devices Inc. (AD8009), Maxim Integrated Products Inc. (MAX4223), National Semiconductor Corp. (LMH6738), and Texas Instruments Inc. (OPA695). None appear to have a 1-GHz triple amplifier.

National Semiconductor's device is a 750-MHz triple amplifier, and the company does have plans to make a 1-GHz triple amplifier in the future. “Our designers are looking into speeding up the LMH6738 (750 MHz) to truly achieve 1 GHz with a smooth response. This product is on our roadmap,” according to the company.

ADI's AD8009 is a single amplifier. The company said it has a 1.4-GHz single amplifier that will be in production by the end of November and it plans to start sampling a 1.5-GHz triple amp early next year.

The MAX4223 is also a single amplifier. Maxim also has a dual amplifier with a 1-GHz bandwidth (MAX4225), and a triple 2:1 mux-amp with a 225-MHz bandwidth (MAX4027). The company said it doesn't expect to release a 1-GHz triple amplifier in the near future.

TI's OPA695 is a single-channel device too. Speed claims by various companies are typically somewhat slippery — over 200 MHz, gain of +1 bandwidths (that are normally used) can be strongly influenced by board parasitics, said Michael Steffes, strategic marketing manager for TI's high-speed signal processing products.

“We typically focus on gain of 2 numbers as the minimum useable gain in any real application above 200 MHz. The OPA695 does offer 1.7 GHz at a gain of 1 and 1.4 GHz at a gain of 2 with minimal peaking built into those numbers. The EL5367 shows about 1 GHz at a gain of 1 and 800 MHz at a gain of 2. It is an intrinsically slower device than the OPA695, but it is a triple and we don't yet have our OPA695 out as a triple channel device yet,” he said.

The reason triple amplifiers (channels) are important is because if you are trying to handle RGB signals that are coming out of your PC and being displayed on a monitor, you need a triple to drive it because there are three signals, Vuyyuru. said. At this speed, you can handle the highest resolution that any display maker has to offer, he added.

The EL5367 device is a culmination of Intersil's current feedback amplifier family, which began rolling out products about six months ago. Other devices in the family include the EL536x family of triple current feedback amplifiers. More products will follow as bandwidth areas are pushed up higher, Vuyyuru. said.

Intersil is able to reach the 1-GHz bandwidth with a secret patent pending custom architecture that reduces crosstalk or provides isolation between the three different channels or amplifiers, Vuyyuru said.

Besides the speed of the triple amplifier, the slew rate is also an important feature because when you go from white to black or black to white in a display, you need to do it within one-quarter of a pixel. Intersil's slew rate is 5,500 V/μs. Although others have reached this slew rate, they haven't done it in a triple at 1 GHz, Vuyyuru said.

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