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National debuts rail-to-rail, current feedback op amps

Posted: 08 Oct 2007 ?? ?Print Version ?Bookmark and Share

Keywords:operational amplifier? signal integrity?

LME49721, LME49713

National Semiconductor Corp. has introduced a 5V rail-to-rail input and output (RRIO) and a 36V current feedback operational amplifier.

The LME49721 RRIO op amp's combined specifications provide the high-fidelity performance and signal conditioning required by high-end portable devices and applications where supply rails are limited to lower voltages. The LME49713 current feedback op amp delivers ultralow distortion, low noise, extended bandwidth past 190MHz and fast settling times down to 50ns.

Both op amps join a family of high-performance, high-fidelity op amps that includes the LM4562, which set a new industry standard with 0.00003 percent total harmonic distortion plus noise (THD+N).

The dual 5V LME49721 RRIO op amp maximizes signal integrity by allowing the input signal and output signals to swing within 20 mV of either rail. Its low 4nV/square root Hz input referred noise density and 0.0018 percent THD+N make it well-suited for lower-voltage supply-rail applications (1.1V to 2.5V) such as 5V DACs, portable audio devices, signal conditioning, DAQ, process control and test equipment.

The single LME49713 current feedback op amp features 1.9nV/square root Hz input noise density, THD+N of 0.00008 percent and 150 output drive. Its 1,900V/?s slew rate ensures accurate bandwidth and high dynamic range for all signal conditioning applications, including crosspoint switchers, multimedia broadcast systems, HDTV-compatible systems, line drivers and distribution amplifiers.

Technical features
The LME49721 provides output current capability up to 100mA. It is unity-gain stable over a wide supply range of 1.1V to 2.75V, with power-supply rejection rate (PSRR) of more than 100db and a typical low input bias current of 40fA. The output stage of the LME49721 can swing to within 20mV of either power supply voltage when driving 2K loads or to within 30mV when driving 600 loads. To ensure high dynamic range, it has a slew rate of 8.5V/?s while allowing the input signal to drive to the rails.

The LME49713 is unity-gain stable over a wide supply range of plus or minus 5V to 18V. Over this supply range, the LME49713 input circuitry maintains a PSRR of more than 100db and a common-mode rejection rate (CMRR) of 88dB. The settling time to within 0.1 percent is 50ns for a 10V step.

The LME49721 is available now in an 8-lead SOIC package and is priced at $1.50 each in 1,000-unit quantities. The LME49713's 8-lead, narrow-body SOIC package is priced at $2.49 each in 1,000-unit quantities.

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