FROM EDN EUROPE: Differential op-amp improves data acquisition resolution
By Graham Prophet -- EDN, March 3, 2005
Using a complementary silicon-germanium and CMOS technology, Texas Instruments has built a fully-differential op-amp that is optimised for driving high-speed analogue-to-digital converters at up to 100 MHz. Its (small-signal) bandwidth is 1900 MHz with a slew rate of 6.6 kV/μsec and noise of under 2 nV/
. As it has differential input and output, it can replace multi-amplifier circuit configurations that were previously needed to complete a differential signal chain. TI says it also delivers significant improvements in second- and third-order harmonic distortion figures, and reduces settling time, compared to previous amplifiers, to under 2 nsec (to 1%). Users in wireless base-station design will appreciate the distortion figures; in imaging, the low noise; and in measurement, the dc precision, with common-mode output of 5 mV. Gain, common-mode voltage and output impedance are essentially independent of each other and can be controlled separately. The THS4509 is packaged in a 16-pin QFN outline, and will be priced at $3.75 (1000). An evaluation module is available.
Texas Instruments, +49 8161 803311, www.ti.com.
