LTC2688IUJ-16#PBF

Overview

The LTC2688IUJ-16#PBF is a 16-channel, 16-bit digital-to-analog converter (DAC) featuring SoftSpan technology for independently programmable output ranges. It supports unipolar (0 V to 5 V, 0 V to 10 V) and bipolar (±5 V, ±10 V, ±15 V) configurations with full resolution across all spans. The device integrates a precision 4.096 V reference with a maximum temperature coefficient of ±5 ppm/°C. Built-in rail-to-rail output buffers guarantee ±20 mA drive capability. Key specifications include ±3 LSB integral nonlinearity (INL), ±1 LSB differential nonlinearity (DNL), and a settling time of 3.5 µs for a 0 V to 5 V range step. It operates on a single analog supply (VCC: 4.75 V to 5.25 V) and a digital I/O supply (IOVCC: 1.71 V to VCC).

Feature Summary

• 16 independent channels with SoftSpan technology allowing five selectable output ranges per channel.
• Integrated precision 4.096 V reference with ±5 ppm/°C temperature coefficient.
• Rail-to-rail output buffers capable of sourcing or sinking up to ±20 mA.
• Built-in analog multiplexer for monitoring DAC outputs, load currents, and junction temperature.

Applications

• Optical networking systems
• Precision instrumentation
• Data acquisition systems
• Automatic test equipment
• Process control and industrial automation

Procurement Notes

Verify the specific suffix 'IUJ-16' corresponds to the Industrial temperature grade (-40°C to +85°C), 16-bit resolution, and LFCSP-40 package. Confirm that the internal reference mode is required, as external references alter the REF pin configuration. Ensure the application voltage rails match the selected SoftSpan range to avoid clipping or fault conditions.

Selection Notes

Select this component when high channel count and flexible voltage ranges are required in a compact footprint. The -16 suffix denotes 16-bit resolution; use -12 for lower cost if 12-bit accuracy suffices. The 'I' suffix indicates an extended temperature range suitable for industrial environments. Verify that the IOVCC logic level compatibility matches the host controller's voltage domain.

Part Context

This part belongs to the LTC2688 family of SoftSpan DACs. The 'IUJ' designation specifies the Industrial temperature range and the 40-lead Lead Frame Chip Scale Package (LFCSP). Other variants include the C suffix for Commercial temperature and H suffix for Extended temperature. The -16 variant provides 16-bit resolution, while -12 offers 12-bit resolution.

Replacement Considerations

Direct replacements within the same family include LTC2688CUJ-16#PBF (Commercial temp) and LTC2688HUJ-16#PBF (Extended temp). For lower channel counts, consider the LTC2686 (8-channel) or LTC2687 (4-channel). Ensure thermal management is adequate for the LFCSP package under maximum load conditions.

FAQ

How is the output range programmed?

Each of the 16 channels has independently programmable span registers. Users can select from five ranges: 0 V to 5 V, 0 V to 10 V, ±5 V, ±10 V, or ±15 V via SPI commands.

What is the function of the TGP pins?

The TGP0, TGP1, and TGP2 pins support asynchronous toggle operations between Input Register A and B, or sinusoidal dithering. They allow hardware-controlled updates without CPU intervention.

Can the device operate with a single supply?

Yes, the LTC2688 supports flexible single- or dual-supply operation. For unipolar ranges, V− can be connected to GND. For bipolar ranges, negative supplies are required.