DC2094A-D Analog Devices

DEMO MANUAL DC2094A LTC2348 16-/18-Bit, Octal 200ksps SAR ADCs DESCRIPTION Demonstration circuit 2094A shows the proper way to drive The DC2094 demonstrates the DC and AC performance of the LTC 2348 family of ADCs. The LTC2348 are low noise, the LTC2348 in conjunction with the DC590/DC2026 and high speed, simultaneous sampling 16-/18-bit successive DC890 data collection boards. Use the DC590/DC2026 to approximation register(SAR) ADCs. The following text demonstrate DC performance such as peak-to-peak noise refers to both parts in the family, the only difference being and DC linearity. Use the DC890 if precise sampling rates the number of bits. The LTC2348 has a flexible SoftSpan are required or to demonstrate AC performance such as interface that allows conversion-by-conversion control of SNR, THD, SINAD and SFDR. The DC2094 is intended the input voltage span on a per-channel basis. An internal to demonstrate recommended grounding, component 2.048V reference and 2X buffer simplify basic operation placement and selection, routing and bypassing for this while an external reference can be used to increase the ADC. A suggested driver circuit for the analog inputs is input range and the SNR of the ADC. also presented. Design files for this circuit board including schematic and BOM are available at DEMO MANUAL DC2094A DC2094A CONNECTION DIAGRAM Figure 1. DC2094A Connection Diagram DC890 QUICK START PROCEDURE Check to make sure that all switches and jumpers are Run the PScope software (Pscope.exe version K79 or set to their default settings as described in the DC2094A later), which can be downloaded, from www.linear.com/ Jumpers section of this manual. The default connections designtools/software. configure the ADC to use the onboard reference and regula- Complete software documentation is available from the tors to generate all the required bias voltages. The analog Help menu. Updates can be downloaded from the Tools inputs by default are DC coupled. Connect the DC2094A menu. Check for updates periodically as new features to a DC890 USB High Speed Data Collection Board using may be added. connector P1. Then, connect the DC890 to a host PC with The PScope software should recognize the DC2094A and a standard USB A/B cable. Apply 16V to the indicated configure itself automatically. terminals. Then apply a low jitter signal source to J5 and J6. Use J7 to route the signal sources of J5 and J6 to the Click the Collect button (see Figure 2) to begin acquiring desired AIN0-AIN7 inputs. Observe the recommended data. The Collect button then changes to Pause, which input voltage range for each analog input. Connect a low can be clicked to stop data acquisition. jitter 2.5V sine wave or square wave to connector J1. P-P See Table 1 for the appropriate clock frequency. Note that J1 has a 50 termination resistor to ground. dc2094afb 2