DEMO MANUAL DC1908A LTC2338/LTC2337/LTC2336/ LTC2328/LTC2327/LTC2326 18-Bit/16-Bit,1Msps/500ksps/250ksps True Bipolar Low Power, Single Supply ADCs DESCRIPTION The LTC 2338/LTC2337/LTC2336/LTC2328/LTC2327/ peak-to-peak noise and DC linearity. Use the DC718 if LTC2326 are true bipolar, low power, low noise ADCs precise sampling rates are required or to demonstrate AC with serial outputs that can operate from a single 5V performance such as SNR, THD, SINAD and SFDR. The supply. The following text refers to the LTC2338-18 but demonstration circuit 1908A is intended to demonstrate applies to all parts in the family, the only difference being recommended grounding, component placement and the maximum sample rates and the number of bits. The selection, routing and bypassing for this ADC. Suggested LTC2338-18 supports a 20.48V fully differential input driver circuits for the analog inputs will be presented. range with a 100dB SNR, consumes only 50mW and Design files for this circuit board are available at achieves 4LSB INL max with no missing codes at 18 DEMO MANUAL DC1908A ASSEMBLY OPTIONS Table 1. DC1908A Assembly Options ASSEMBLY VERSION U1 PART NUMBER MAX CONVERSION RATE OF BITS MAX CLK FREQUENCY AIN+ RANGE AIN RANGE DC1908A-A LTC2338CMS-18 1Msps 18 62MHz 10.24V 10.24V DC1908A-B LTC2337CMS-18 500ksps 18 31MHz 10.24V 10.24V DC1908A-C LTC2336CMS-18 250ksps 18 15.5MHz 10.24V 10.24V DC1908A-D LTC2328CMS-18 1Msps 18 62MHz 10.24V Grounded Internally DC1908A-E LTC2327CMS-18 500ksps 18 31MHz 10.24V Grounded Internally DC1908A-F LTC2326CMS-18 250ksps 18 15.5MHz 10.24V Grounded Internally DC1908A-G LTC2328CMS-16 1Msps 16 50MHz 10.24V Grounded Internally DC1908A-H LTC2327CMS-16 500ksps 16 25MHz 10.24V Grounded Internally DC1908A-I LTC2326CMS-16 250ksps 16 12.5MHz 10.24V Grounded Internally DC718 QUICK START PROCEDURE Check to make sure that all switches and jumpers are set Complete software documentation is available from the as shown in the connection diagram of Figure 1. The de- Help menu. Updates can be downloaded from the Tools fault connections configure the ADC to use the internal menu. Check for updates periodically as new features reference. The analog input is DC coupled. Connect the may be added. DC1908A to a DC718 USB high speed data collection The PScope software should recognize the DC1908A and board using connector P1. Then, connect the DC718 to configure itself automatically. a host PC with a standard USB A/B cable. Apply 16V Click the Collect button (See Figure 4) to begin acquiring to the indicated terminals. Then apply a low jitter signal data. The Collect button then changes to Pause, which source to AIN+ (J4). Connect a low jitter 62MHz 3.3V P-P can be clicked to stop data acquisition. sine wave or square wave to CLK IN (J1). Note that CLK IN has a 50 termination resistor to ground. Run the PScope software (Pscope.exe version K72 or later) supplied with the DC718 or download it from www. linear.com/software. DC590 SETUP IMPORTANT To avoid damage to the DC1908A or DC590, with a standard USB A/B cable. Connect the DC1908A to a make sure that VCCIO (JP6) of the DC590 is set to 3.3V DC590 USB serial controller using the supplied 14-conduc- before connecting the DC590 to the DC1908A. tor ribbon cable. Apply a signal source to AIN+ or AIN+ and AIN depending on how the DC1908A is configured. To use the DC590 with the DC1908A, it is necessary to Run the QuikEval software supplied with the DC590 or apply 16V and ground to the +16V, 16V and GND ter- download it from www.linear.com/software. The correct minals or disable amplifier U10 by moving R32 and R35 control panel will be loaded automatically. Click the COL- to R31 and R38 respectively. Disabling U10 will require LECT button (See Figure 5) to begin reading the ADC. that both AIN+ and AIN (J6) be driven with a low output impedance signal source. Connect the DC590 to a host PC dc1908af 2