audio/videoZONE Products for the week of April 21, 2003
Zarlink Semiconductor Says . . .
ZLTM40162/6: High-Performance Operational Amplifiers
for DSL, Video
Best-in-class performance ratings reflect leading silicon
process, innovative design
Zarlink Semiconductor expanded its high-performance analog portfolio with two operational amplifier chips that amplify broadband signals with unmatched clarity and precision. The ZLTM40162/166 chips also deliver the lowest standby (quiescent) current rating in their class.
Operational amplifiers are analog chips that deliver high gain by boosting signal amplitudes by large margins. The devices are used to amplify, buffer, filter, and condition signals in a broad range of electronic equipment, including video, audio, and networking systems. In most operational amplifiers, key performance characteristics such as output drive, speed, linearity, and power efficiency are tuned to meet the requirements of specific applications.
Zarlink's ZL40162/166 chips are dual-matched voltage-feedback amplifiers with large output drive currents typically more than 200 mA (milliamps). The chips also display exceptional ratings for linearity, power consumption, and surge protection, making them well suited for driving broadband signals in DSL (digital subscriber line) modems and video equipment.
"DSL modems, commercial video systems, and professional video equipment require operational amplifiers that deliver a challenging mix of high-performance capabilities," said Peter Minett, product line marketing manager, High-Performance Analog group, Zarlink Semiconductor. "Our ZL40162/66 devices meet this need by providing industry-leading combinations of drive, linearity, and bandwidth."
Both of Zarlink's new amps are built in the company's world-class HJV
(high-performance, process version J, high-voltage) process, a complementary
silicon bipolar technology that maximizes performance in high-voltage, high-speed
analog devices.
analogZONE Says...
I always have my eye open for high-grade video op amps and I didn't, quite honestly, expect to see one from Zarlink - not a name I associate with the video markets.
The two op amps offered here are similar but with subtle differences. With the high-voltage process it has available Zarlink has been able to optimize the ZL40162 for DSL drivers while, although the ZL40166 can also be used for that purpose, it is really optimized for video use - but what sort of video use requires definition.
Both parts can drive 18.8 V p-p across a 50 Ohm load differentially, or 9.4 V p-p single-ended across 25 Ohm, and both can source or sink 200 mA with a 9-V supply and driving 9.4 V p-p. Both have similar input noise performance with 3.8 nV/rtHz input noise voltage and 2.7 pA input noise current, and in the standby mode they draw a very small 7 mA/A. But the ZL40166 has a higher slew rate and bandwidth (240 V/µs and 192 MHz) compared to the ZL40162 (195 V/µs and 158 MHz) and also exhibits marginally better SFDR numbers, although the data sheets are not very helpful in that area.
"Baseband PAL or NTSC video signals generally have an amplitude of 2V pk-pk" says the data sheet for the ZL40166. Really? I would re-write that as "Composite video signals generally have a peak amplitude of 1 V."
The datasheet gives the 0.1 dB maximally flat bandwidth as 32 MHz typical. Unfortunately it quotes if with a 100 Ohm load, so that's not much use for the video designer. Differential gain and phase are correctly quoted for a double-terminated load of 150 Ohm with numbers of 0.005% and -0.07 degrees, but how do you measure differential gain to three decimal places and differential phase to two decimal places? The absolute accuracy of the Tektronix VM700T, for example is ±0.3% and ±0.3 degrees. If the measurements were from the performance from a chain of devices divided by the number in the chain then they are totally invalid.
The ZL40166 is obviously very suited for use as a composite video driver and we hope that if it is serious about the market that Zarlink will also release a triple version. I have to guess that the part will be usable for professional-grade component signals but the data sheet needs to show the device characterized under the right conditions.
Both parts will do extremely well in the internal and external DSL modem market as well as in other high-level line drive applications.
Both the ZL40162 and ZL40166 are in production in SOIC-8 and are priced at $2.30 in 1000-piece lots.
Data Sheet (ZL40162)
Data Sheet (ZL40166)