Differential amps drive 12-bit A/D converters

Santa Clara, Calif. — Today National Semiconductor Corp. unveiled two high-speed, low-distortion differential amplifiers and two high-speed, low-power, 12-bit analog-to-digital converters (A/D converters) that provide the most accurate signal capture at the lowest power consumption.

The LMH6550 and the ADC12DL040 operate seamlessly to provide a high-quality signal-path solution. The pair produces 11.1 effective number of bits (ENOB) and 80 dB of spurious free dynamic range (SFDR) with a 20 MHz input frequency.

The ADC12DL040 and ADC12DL065 are dual, high-performance, low-power A/D converters capable of converting analog input signals into 12-bit digital words at 40 and 65 megasamples per second (Msamples/s), respectively. These A/D converters provide excellent dynamic performance and 250 MHz full-power bandwidth. Operating on a single 3-V power supply, the ADC12DL040 achieves 11.1 ENOB with input signals up to 20 MHz and consumes just 210 mW at 40 Msamples/s. The ADC12DL065 also achieves 11.1 ENOB and consumes 320 mW at 65 MSPS.

The LMH6550 and LMH6551 are fully differential, high-speed amplifiers designed for driving 10- to 14-bit, high-performance A/D converters such as the ADC12DL040 and ADC12DL065.

Both amplifiers have fully differential voltage feedback topology, which allows balanced inputs to A/D converters, and they can be used either as single-ended-to-differential or as differential-to-differential amplifiers.

The LMH6550 has SFDR of -86 dBc at 10 MHz, wide 400 MHz bandwidth and high 3000 V/μs slew rates. It also has a 10-ns shutdown/disable function and operates at +5 V or ±5-V supply voltages.

The LMH6551 has SFDR of -85 dBc at 10 MHz, wide 370 MHz bandwidth and high 2400 V/μs slew rates. It also has an output balance error of -70 dB and operates at +3 V, +5 V or ±5-V supply voltages.

The LMH6550 and LMH6551, available now in SOIC-8 packaging, are priced at $2.29 and $1.60, respectively, in 1,000-unit quantities. Click here for the LMH6550 data sheet. Click here for the LMH6551 data sheet.

The ADC12DL040, available now in a TQFP-64 package, is priced at $15 in 1,000-unit quantities.Click here for the ADC12DL040 data sheet. The ADC12DL065, available in April and packaged in a TQFP-64, will be priced at $17 in 1,000-unit quantities. Click here for the ADC12DL065 data sheet.

National Semiconductor , 1-408-721-5000,

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