DS1021S-50/T&R

Overview

The DS1021S-50/T&R is a programmable 8-bit silicon delay line manufactured by Analog Devices Inc./Maxim Integrated. It provides a maximum delay of 137.5 ns with an incremental step of 0.5 ns, starting from a base delay of 10 ns. The device operates on a single 4.75 V to 5.25 V supply and functions within a temperature range of 0°C to 70°C. It features both 3-wire serial and 8-bit parallel programming interfaces, housed in a 16-pin SOIC package.

Feature Summary

• Supports dual programming modes via 3-wire serial port or 8-bit parallel interface for flexible timing control.
• Delivers precise leading and trailing edge accuracy across 256 equal delay steps.
• Enables cascading multiple units through daisy-chain serial output capabilities.

Applications

• Timing adjustment in digital logic circuits
• Programmable delay generation for signal synchronization
• System timing calibration requiring variable latency

Procurement Notes

Verify the specific suffix against official documentation to confirm packaging type and compliance status. Confirm availability as distribution channels may vary. Ensure the component meets required environmental standards for the intended deployment environment before finalizing orders.

Selection Notes

Select the -50 variant when a maximum delay of 137.5 ns with 0.5 ns resolution is sufficient. Choose the -25 model if higher precision with 0.25 ns steps and a 73.75 ns maximum limit are required. Ensure the design supports either serial or parallel input constraints based on system architecture.

Part Context

This component belongs to the DS1021 series of programmable silicon delay lines. It serves as a CMOS alternative to hybrid delay lines, offering space-saving surface mount packaging. The series includes variants with different delay resolutions to suit various timing precision requirements.

Replacement Considerations

DS1021S-25/T&R: Offers 0.25 ns steps and a 73.75 ns max delay instead of 0.5 ns steps and 137.5 ns.

FAQ

How does the serial readout process affect the programmed delay?

The serial readout is destructive; however, connecting the serial output (Q) to the serial input (D) through a 1K to 10K ohm resistor restores the value and maintains the programmed delay without requiring additional settling time.

What are the requirements for unused input pins in CMOS designs?

Unused input pins must be connected to well-defined logic levels and must not be allowed to float to ensure proper operation and prevent instability.

Can multiple DS1021 devices be used together?

Yes, multiple devices can be daisy-chained by connecting the serial output of one unit to the serial input of the next, allowing for cascaded programming.