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audio/videoZONE Products for the week of August 4, 2008
Cadeka Microcircuits Says…
CLC3800/01/02: Low-Power Triple-Channel SD Video Amplifiers
For cost sensitive consumer and industrial applications
Cadeka Microcircuits, the industry’s fastest growing analog supplier, has introduced the CLC3800 and CLC3801 low power, triple video amplifiers. These amplifiers are designed to meet the requirements of today’s cost-sensitive, standard definition (SD) consumer and industrial video applications. Carrying the Comlinear brand, these amplifiers offer superb performance consuming only 26.4mW and offering industry leading differential gain/phase (0.05%/0.02°).
The Comlinear CLC3800 and CLC3801 feature integrated 8MHz, 4th-order low pass filters designed to cleanly pass SD video signals while filtering out noise and other unwanted signals, resulting in a crisper, cleaner video signal. These amplifiers also integrate high-performance, fixed-gain video drivers that utilize Cadeka’s vast amplifier design expertise. The CLC3800 offers a fixed gain of 6dB. If additional gain is required, the CLC3801 video amplifier offers a fixed gain of 9dB. The two gain options make these amplifiers well suited for use with a variety of video DACs and encoders.
Each channel of the CLC3800 or CLC3801 can drive two AC- or DC-coupled video loads. This allows today’s STB, PVR, LCDTV, portable DVD, or video surveillance systems to provide the end user with additional output configurations. Examples of these include:
- Configuration 1: Dual RGB, YPbPr, or YUV
- Configuration 2: 2 S-Video and dual CV
- Configuration 3: 6 CV channels
“The introduction of the COMLINEAR CLC3800 and CLC3801 further strengthens our video amplifier portfolio,” explains Jay Dokter, Cadeka’s Executive Vice President of Sales and Marketing. “The extremely low power dissipation provides a huge thermal and power consumption benefit to consumer and portable video equipment manufacturers.”
EN-Genius Says…
The Comlinear brand moves on at Cadeka. This announcement of three triple-channel video amplifiers should hardly take us by surprise…
The CLC3800 is a 6 dB amplifier offering gain replacement for properly terminated 1 V inputs (RGB or Y). If the input is less, then the CLC3801 offers a fixed 9 dB of gain and the CLC3802 offers 12 dB. The inputs must be dc-coupled.
The amplifiers add an offset voltage to the video signal – to prevent sync clipping and distortion – which puts sync tip at about 350 mV on the output. The outputs can be either ac-coupled (Cadeka suggests at least 220 µF to avoid frame tilt) or dc-coupled and they can drive either a single 75 Ω load or two of them. Performance is much better driving 150 Ω.
Before the amplification stage(s) Cadeka has placed a 4th order LPF with a -1 dB point at 7.6 MHz, quickly falling to -3 dB at 8.5 MHz. The filters are identical, of course, because when using narrower bandwidth signals you still want the timing of all the channels to be identical. The filter stopband attenuation at the magic 27 MHz is a typical 48 dB. Propagation delay through the amplifiers is a typical 65 ns, with a group delay to NTSC color subcarrier of 5.6 ns.
Differential gain (NTSC, again, with a 3 V rail) is 0.05% with a dc-coupled output into 150 Ω, and 0.34% into 75 Ω; ac-coupled the figure is 0.13%. The same deterioration with load occurs with differential phase with the numbers at 0.02º, 0.2º, and 0.05º.
SNR out to 4.2 MHz (NTC-7 weighted) is a typical 68 dB but that is a bit negated by channel-to-channel crosstalk of 60 dB (at 1 MHz), or 58 dB with a single 75 Ω load, and a PSRR of 52 dB (no load). At 3 V on the rail (it can be from 3 V to 7 V, or higher – absolute maximum rating is 14 V) typical supply current – with no load – is only 8.8 mA, which increases to 9.5 mA with a 5 V rail. It should be remembered that dc loads will always take higher current and thermal considerations may not allow safe thermal operation at higher supply voltages. The operating temperature range is from -40ºC to +125ºC.
There is a lot of video business out there, it is growing apace, and Cadeka will get its share after buyers realize who the main players are in this new resurrection of the Comlinear brand. The performance is better than most (and certainly far better than consumer products need, or expect) while the power consumption points them at lightning speed straight at sockets in portable products. They should do enormously well, and they are priced to attract attention.
The CLC3800 and CLC3801 are sampling in Pb-free SOIC-8. They will be priced at $0.30 in 1000-piece lots. DFN-8 packaging will be available later in 2008. No deliveries are quoted for the CLC3802
Data Sheet
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