hf/rf ZONE Products for the week of August 4, 2003
Intersil Says . . .
EL5166/7: 1.4-GHz Current Feedback Amplifiers for
Video and Communications
New Elantec EL5166/5167 feature 1.4 Gigahertz bandwidths and
6,000 volt per microsecond slew rates
Intersil Corporation, a world leader in the design and manufacture of high performance analog and wireless networking solutions, introduced three 1.4 GHz current feedback amplifiers (CFAs) with capacitive drive capability. The latest addition to Intersil's new high speed operational amplifier portfolio, the Elantec EL5166 and EL5167 are designed to meet the high bandwidth, high slew rate requirements of today's high performance video, test and instrumentation, and other high frequency applications.
Intersil's Elantec EL5166 and EL5167 feature unity gain bandwidths of 1.4 GHz. The EL5166 and EL5167 offer 6,000 volt-per-microsecond slew rates while exhibiting low distortion of 1.7 nanovolts (nV) per root hertz. With a supply current of just 8.3 milliamps (mA) and operating from a +/- 5V split supply, Intersil's new current feedback amplifiers offer very high performance while consuming very little power.
"We continue to add best-in-class products to our Elantec family of op amps, and the EL5166 and EL5167 offer unmatched CFA performance," said Sameer Vuyyuru, Intersil's director of marketing for video and op amps. "This initial offering of current feedback amps is ideally suited for a variety of high performance video, cable driver and high frequency applications where high slew rates and wide -3dB bandwidths are critical factors. When combined with their low power consumption, these high performance CFAs are particularly well suited for portable, handheld and battery-powered applications. Intersil will continue to add single, dual and triple CFAs to this new family of op amps in the coming months."
Intersil's EL5166 and EL5167 feature excellent gain flatness, with typical
performance of 1.4 GHz at -3dB and 100 MHz at 0.1dB. They feature differential
gain and differential phase of 0.01% and 0.03 degrees, respectively. Both
devices operate with supply voltages ranging from a single 5-volt to 10-volt
supply or off a split +/-5V supply, and have a wide common mode output range.
The EL5166 incorporates an enable and disable function to reduce the supply
current to 100 microamps per amplifier. As with all current feedback amplifiers,
CFA stability is dependent upon the feedback resistor used.
analogZONE Says . . .
This is one of the years of the op amp -- maybe we should have particular product years like the Chinese year rotation! -- and different vendors are coming up with solutions that are really unexpected. No more so than this pair of products from Intersil. I can almost hear the conversation in the product planning meetings when performance numbers would have been suggested, negotiated and tentatively promised. And I would expect the product most considered as the target to beat would have been the AD8009 with its 1-GHz small signal bandwidth, and 5000 V/µs slew rate. If so, Intersil has handsomely passed the bandwidth number and slightly betters the slew rate. It also matches the kind of current that can be sourced/sank at between 160 mA and 200 mA. But the quiescent is improved from 14 mA to 8.5 mA -- and then they go and better the price by 30 cents.
I have only seen slew rate higher than this once before in a commercial monolithic part and that was the THS3201 which offers 9000 V/µs with a unity gain bandwidth of 2 GHz, but it draws 21 mA and can only sink/source 115 mA.
Yes, the op amp world is one of comparison and contrasts and where the Intersil parts really shine is to get the great balance of the basic specifications they have, with a great price and the right technology for the applications where they are likely to be used. Because these are current feedback amplifiers the gain can be readily controlled (in feedback) with minimal effects on the -3 dB bandwidth. A gain of +2 gives, for example, a bandwidth of 800 MHz, while the 0.1 dB bandwidth is an outstanding 100 MHz. This makes it probably suitable for just about any video standard currently in use, or proposed. It is also a genuine relief to see a company quote NTSC differential phase and gain numbers in realistic, measurable quantities instead of the absurd numbers that are the norm.
These parts can drive double-terminated cables with no problem and the decoupling that therefore takes place should allow the load to be quite highly capacitive.
The EL5166 adds an enable/disable function with the enable time (the important one out of the two switching times) being a super, typical, 170 ns. The input noise voltage at a typical 1.7 nV/rtHz is just about where it should be.
The numbers in the preliminary data sheet are specified for a ±5 V rail. The output swing numbers (and these are not rail-to-rail products) suggest that there will be little difference in numbers with a single volt rail.
These parts are likely to become important assets in the video and cable driving businesses and there is more to come from the company -- it's rather nice to see the Elantec roots still coming to the party in the video environment; they will also find sockets, of course, in instrumentation and test equipment.
The EL5166 and EL5167 are in production, with the EL5166 in either an SO-8 or SOT-23-6, and the EL5167 in a SOT-23-5, both priced at $1.29 in 1000-piece lots.