96.5dB SNR performance and 18mW low power features

November 8, 2011 – Linear Technology Korea (Country Manager Hong Sa-kwak, www.linear.com ) announced the development of a serial 18-bit 1.6 Msps pseudo-differential SAR ADC (Product Name: LTC2369-18). This product supports a unipolar input range of 0V to 5V while achieving excellent performance with 96.5dB SNR and -120dB THD. The pseudo-differential input feature simplifies ADC driver requirements, enabling single-ended driving, and offers the benefit of reduced unexpected signals on both inputs. As a result, the signal chain becomes less complex, and power requirements are reduced.

The LTC2369-18, operating from a 2.5V supply, consumes only 18mW of power, and its low-power shutdown mode consumes only about 2.25µW. When used with the recommended single-ended ADC driver LT6202, power consumption is reduced to just 53mW, which is 40% lower than that of a fully differential drive circuit. The LTC2369-18 is the industry's highest-performing 18-bit pseudo-differential SAR ADC, featuring lossless code, a maximum INL of ±2.5LSB, and guaranteed operation over a temperature range of -40ºC to 125ºC.

The pin/software compatible 16-bit 2Msps LTC2370-16 complements the LTC2369-18. The LTC2370-16 features excellent performance, such as a 94dB SNR and a ±0.85LSB maximum INL. The LTC2369-18 and LTC2370-16 are the first products in a family of 18/16-bit high-performance pseudo-differential SAR ADCs with speeds ranging from 250ksps to 2Msps. These products provide a user-friendly SPI interface and offer Busy and Chain pins, I/O voltages from 1.8V to 5V, and an internal oscillator to simplify digital timing and minimize the number of external components. By providing true no-latency operation, they enable precise one-shot measurements after long idle periods without minimum sample rate requirements.

With the development of the LTC2369-18 family of pseudo-differential SAR ADCs, the LTC2379-18 family of fully differential SAR ADCs with a maximum SNR of 102 dB, which was announced earlier this year, has been expanded. Characterized by high SNR, fast throughput, and low power consumption, Linear’s complete family of high-performance pseudo- and fully differential 18/16-bit SAR ADCs is ideal for high-performance medical, industrial, and automotive applications.

The LTC2369-18 and LTC2370-16 are available in small 16-pin MSOP and 4mm x 3mm DFN packages, priced at $29.95 and $24.50 per unit, respectively, in 1,000-unit quantities. To achieve AC performance free from defects and degradation, the use of the low-noise, low-power LT6202 ADC driver is recommended. Additionally, for high-precision applications, the LTC6655 is recommended, a precision external reference featuring high accuracy of up to ±0.025%, 2 ppm/ºC drift, and low noise of 0.25 ppm P-P. The DC1813A integrated demo board utilizing the LT6202 ADC driver and LTC6655 reference is available for purchase on the company website www.linear.com or through local offices. For more details, please refer to www.linear.com/product/LTC2369 .

Image Caption: 18-bit zero-latency pseudo-differential SAR ADC featuring 1.6 Msps throughput and 96.5 dB SNR

Product Features: LTC2369-18
• 1.6 Msps throughput rate
• ±2.5 LSB INL (maximum)
• 18-bit lossless code guaranteed
• Low Power: 18mW@1.6Msps , 18μW@1.6ksps
• 96.5dB SNR (Typical) @ fIN = 2kHz
• –120dB THD(typical)@fIN = 2kHz
• Guaranteed Operation up to 125°C
• 2.5V supply
• Pseudo-differential unipolar input range: 0V ~ VREF
• VREF Input Range 2.5V ~ 5.1V
• No Pipeline Delay, No Cycle Latency
• 1.8V ~ 5V I/O voltage
• SPI-compatible serial I/O in daisy-chain mode
• Internal conversion clock
16-pin MSOP & 4mm x 3mm DFN Package