DC778A Analog Devices

DEMO MANUAL DC778A LTC2602 Dual 16-Bit Rail-to-Rail V DAC OUT DESCRIPTION Demonstration circuit 778A features the LTC 2602 dual Another feature of this board is the onboard LTC2422 16-Bit DAC. This device establishes a new board-density 20-bit ADC for monitoring DAC output voltage. The 16ppm benchmark for 16-bit DACs and advances performance total error of this device is adequate for taking meaningful standards for output drive, load regulation, and crosstalk measurements of various LTC2602 parameters. in single-supply, voltage-output DACs. Design files for this circuit board are available at DC778A has many features for evaluating the performance DEMO MANUAL DC778A QUICK START PROCEDURE Connect the DC778A to a DC590 USB serial controller correct control panel will be loaded automatically. Click using the supplied 14-conductor ribbon cable. Connect the COLLECT button to begin outputting codes to the DAC the DC590 to a host PC with a standard USB A/B cable. and reading back the resulting output voltage. Run the QuikEval evaluation software supplied with the Complete software documentation is available from the DC590 or download it from www.linear.com/software. The Help menu item, as features may be added periodically. Figure 2. QuikEval Software Screenshot HARDWARE SETUP Analog Connections Jumpers VOUTA, VOUTB LTC2602 Outputs JP1 V Select. Select 5V, 4.096V or 2.5V reference. REF To apply an external reference through the VREF turret, VREF The VREF turret is connected directly to the refer- remove this jumper. ence terminals of the LTC2602 and LTC2422 ADC. When one of the onboard references is being used, the reference JP2 V Select. V is taken either from the onboard 5V CC CC voltage may be monitored at this point. An external refer- reference or the 5V regulated supply from the controller ence may also be applied to this turret after removing JP1. board. Selecting the 5V reference for V and V allows CC REF characterization of rail-to-rail operation of the LTC2600. Grounding and Power Connections JP3 ADC Disable. Set to ON for operation with the DC590 Power (V ) Normally DC778A is powered by the DC590 serial controller. When using in the customers end ap- CC controller. V can be supplied to this turret, however plication, the ADC can be completely disabled by setting CC the power supply on the DC590 must be disabled Refer jumper to DISABLE. to the DC590 quick start guide for more details on this For very sensitive noise measurements when using the mode of operation. LTC supplied software, set the output voltage and stop reading voltage via the collect button on the control panel. dc778af 2