Low Power Analog-to-Digital Converters

Linear Technology Corp.'s family of lowpower 14-bit and 12-bit, 25Msps to 125Msps analog-to-digital converters (ADCs)dissipate less than 1mW per mega sample per sec from a 1.8V supply. The LTC2145family includes two-channel simultaneous sampling, parallel output ADCs, offeringa choice of full-rate CMOS, or double data rate (DDR) CMOS or DDR LVDS digitaloutputs with programmable digital output timing, programmable LVDS outputcurrent and optional LVDS output termination. At 25Msps the 14-bit and 12-bit versions of the LTC2140 consume 24mW perchannel, while the 125Msps LTC2145 consumes 95mW per channel. While claimingthe lowest power dissipation, AC performance has not been compromised. At14-bits, these devices achieve over 73.2dB SNR performance with 90dB of SFDR atbaseband. At 12-bits, the SNR performance is better than 70.6dB. This A dcfamily offers a pin-compatible upgrade path to the low power LTC2185 16-bit Adc family to provide a 3dB performance upgrade while maintaining portability insuch applications as handheld test and instrumentation, radar/LIDAR, medicalimaging, PET/SPECT scanners, military radios, smart antenna systems and a rangeof low-power communication systems.

Pin-compatible speedgrade options include 25Msps (24mW/ch), 40Msps (33mW/ch), 65Msps (46mW/ch),80Msps (55mW/ch), 105Msps (75mW/ch) and 125Msps (95mW/ch). Additional powersavings can be achieved by placing the devices in standby (16mW) or shutdown(1mW). Analog full power bandwidth of 750MHz and ultralowjitter of 0.08ps_RMS allows undersampling of IF frequencies withexcellent noise performance. These devices incorporate Linear Technology'sdigital output randomizer and alternate bit polarity (ABP) mode feature forreduced digital feedback.

Available in 9 x 9mmQFN packages, designers can benefit from the flexible choice of interfaces thatminimize pin count and ease routing to FPGAs. These A dcs will be available inproduction quantities beginning in May through June 2011.

Low Power Analog-to-Digital Converters