Data Sheet LTC2688 16-Channel, 16-Bit Voltage Output SoftSpan DAC FEATURES FUNCTIONAL BLOCK DIAGRAM 16 independent SoftSpan DACs Independently programmable output ranges: 0 V to 5 V, 0 V to 10 V, 5 V, 10 V, 15 V Full 16-bit resolution at all ranges Flexible single- or dual-supply operation Maximum INL error: 3 LSB Precision 4.096 V reference, 5 ppm/C maximum A/B toggle or sinusoidal dither using up to 3 toggle pins Multiplexer for output voltage and load current sense Outputs drive 20 mA guaranteed 6 mm 6 mm, 40-lead LFCSP APPLICATIONS Optical networking Instrumentation Data acquisition Automatic test equipment Figure 1. Process control and industrial automation GENERAL DESCRIPTION The LTC2688 is a 16-channel,16-bit, 15 V digital-to-analog con- verter (DAC) with an integrated precision reference. The LTC2688 is guaranteed monotonic and has built in rail-to-rail output buffers that can source or sink up to 20 mA. This SoftSpan DAC offers five output ranges up to 15 V. The range of each channel is independently programmable. The internal 4.096 V precision reference sets the accuracy of the output voltage. An external reference can be used for additional range options. Three toggle pins support Input Register A and Input Register B toggle or sinusoidal dither at multiple frequencies. An analog multiplexer simplifies measurement of pin voltages, load currents, and junction temperature. Programmable offset and gain registers improve the accuracy of the DAC outputs. The serial peripheral interface (SPI) and MICROWIRE -compati- ble, 3-wire serial interface operates on logic levels as low as 1.71 V and clock rates up to 50 MHz. Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliableas i. However, no responsibility is assumed by Analog DOCUMENT FEEDBACK Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and TECHNICAL SUPPORT registered trademarks are the property of their respective owners.Data Sheet LTC2688 TABLE OF CONTENTS Features................................................................ 1 Read Commands............................................. 22 Applications........................................................... 1 Offset and Gain Adjustment............................. 23 Functional Block Diagram......................................1 Analog Mux...................................................... 25 General Description...............................................1 Toggle and Dither Operation............................ 26 Specifications........................................................ 3 Daisy-Chain Mode............................................33 Timing Characteristics........................................6 Power-Down Mode...........................................33 Absolute Maximum Ratings...................................7 Asynchronous DAC Update Using LDAC.........35 Thermal Resistance........................................... 7 Fault Detection................................................. 35 ESD Caution.......................................................7 Configuration Register......................................36 Pin Configuration and Function Descriptions........ 8 Reference Modes.............................................36 Typical Performance Characteristics...................10 Voltage Outputs................................................36 Terminology......................................................... 17 Thermal Overload Protection........................... 37 Theory of Operation.............................................18 Applications Information...................................... 38 Power-On Reset...............................................18 Printed Circuit Board Layout............................ 38 Power Supply Sequencing............................... 18 Command Addresses..........................................39 Serial Interface................................................. 19 Outline Dimensions............................................. 41 Writing Codes to DACs.................................... 21 Ordering Guide.................................................41 Span Selection and Channel Settings..............22 Evaluation Boards............................................ 42 REVISION HISTORY 6/2021Revision 0: Initial Version analog.com Rev. 0 2 of 42