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audio/videoZONE Products for the week of September 28, 2009
Texas Instruments Says…
OPA1612: Op Amp Provides Low Noise, Distortion and Quiescent Current
Dual-channel, bipolar-input amplifier delivers leading sound in pro audio applications
Texas Instruments Incorporated (TI) introduced the industry's highest performance dual-channel, bipolar-input audio operational amplifier. The OPA1612, from TI's Burr-Brown Audio line, offers designers 60 percent less noise and 50 percent lower distortion as compared to competitive devices, resulting in clear, crisp sound. The amplifier supports multiple channels without significant power consumption in applications such as professional audio and broadcast studio equipment, microphone pre-amplifiers, analog and digital mixing consoles, high-end A/V receivers and audio test and measurement equipment.
EN-Genius Says…
When you read an audio amplifier data sheet distortion number with four zeros after the decimal point you know you are looking at a very special product.
The single OPA1161 and dual OPA1162 have a typical THD + N number of 0.000015% at 1 kHz with a gain of +1. Noise is at -136 dB! Heck, I didn’t even know you could make measurements that low… SMPTE/DIN (60 Hz + 7 kHz) IMD is also down at -136 dB.
At unity gain (the parts are unity-gain stable) the GBW product is 40 MHz although the slew rate is a surprisingly low 27 V/µs. Overload recovery time is also a fairly slow 500 ns. The channel separation in the dual OPA1162 is 130 dB at 1 kHz – suggesting to me that there are two die.
The noise numbers are superb for standard pin-out op amps: the input voltage noise is a typical 1.2 µV p-p while the input noise voltage density is a marvelous 1.1 nV/rtHz at 1 kHz.
The parts are dual rail – typical for professional audio to avoid crossover problems – with a possible supply operating range from ±2.25 V to ±18 V. Quiescent current, per channel, is a maximum 4.5 mA.
The open-loop gain is a minimum of 114 dB into a 10 kΩ load, and 110 dB into 2 kΩ. In those conditions the output can be within 200 mV of the rails and within 600 mV, respectively.
In a review of National’s LME49600 audio buffer in December 2008, I chastised TI for neglecting the audio users of their BUF634. After the LME49600 had been previewed at AES 2007 the Internet blogs were alive with curiosity and National introduced the part at a heady price: over $4.
The OPA1611 is not a replacement for either of those parts in designs where a load current of more than 200 mA is needed (the maximum here is about 40 mA), but the design technology and performance are clearly a long way towards getting such a replacement… These are a pair of superbly performing parts priced to take the market place by storm. They should certainly be show stoppers at AES2009 next month, except I don’t see TI on the Exhibitors’ List for the convention; that may not be such a bad thing because a lot of the users will be Exhibitors. Many of the Digikey buyers of smaller volumes would probably like to see a TO-263 package offering. The higher volume users will be content with what is now available. The OPA1611 and OPA1612 will get into professional, broadcast, T&M, and other high-end applications: they will probably end up in the next audio analyzers that TI themselves purchase.
Both the OPA1611 and OPA1612 are in production in SO-8 priced at $1.75 and $2.75, respectively, both in 1000-piece lots.
Data Sheet
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