Analog Devices Inc./Maxim Integrated DS1021S-50/T&R

Overview

DS1021S-50/T&R from Dallas Semiconductor (now Maxim Integrated) is a programmable 8-bit silicon delay line in 16-pin SOIC package, delivering precise 10 ns inherent delay with 0.5 ns incremental steps up to 137.5 ns maximum. It supports both 3-wire serial and 8-bit parallel programming, features TTL/CMOS compatibility, and maintains leading/trailing edge accuracy for timing-critical signal alignment in test equipment and digital synchronization circuits.

For engineers reviewing the DS1021S-50/T&R datasheet, DS1021S-50/T&R pinout, DS1021S-50/T&R application, or DS1021S-50/T&R equivalent, key selection considerations include its 0.5 ns step resolution, 50 MHz max serial clock frequency, 50 µs enable-to-delay settling time, dual programming interface flexibility, and SOIC-16 surface-mount compatibility with vapor-phase, IR, and wave soldering processes.

Technical Context

The DS1021S-50/T&R implements an all-CMOS 8-bit programmable delay architecture with two distinct operating modes: parallel (S = 1) and serial (S = 0). In parallel mode, P0–P7 directly encode the 256-step delay value; in serial mode, data is shifted MSB-first via D/C/Q pins with E acting as load strobe. Both modes preserve input logic polarity at OUT without inversion.

It guarantees ±8 ns maximum deviation from programmed delay across 0°C to 70°C, operates at VCC = 5.0 V ± 5%, and requires no external components for basic operation. Unused serial pins (D, C) must be tied to defined logic levels; Q/P0 may float when unused. Settling time tEDV = 50 µs applies after any delay change.

Key Specifications

Pinout & Package

DS1021S-50/T&R is housed in a 16-pin small-outline integrated circuit (SOIC) package with 300-mil body width, optimized for automated assembly and thermal reliability under vapor-phase, IR, and wave soldering profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable delay line applications.

Compared with DS1021S-50/T&R, the DS1021S-25/T&R offers higher resolution but reduced range and tighter input pulse constraints, while the MAX9622EUA+ provides greater tap depth and lower voltage operation at the cost of different interface architecture and smaller package - neither is pin-compatible, requiring layout revision.

Availability

DS1021S-50/T&R is available at Aetrix Electronics and suitable for test instrumentation, digital logic synchronization, programmable pulse generation, and serial configuration chain management requiring stable component supply and long-lifecycle support.

Supply support for DS1021S-50/T&R includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Dallas Semiconductor, acquired by Maxim Integrated in 2001, specialized in precision timing, data communication, and mixed-signal ICs for industrial, instrumentation, and computing markets.

The DS1021S-50/T&R belongs to the DS1021 family of programmable silicon delay lines, designed specifically to replace hybrid delay modules in commercial-grade timing-critical systems where reliability, solderability, and programmability are essential.

FAQ

What is the inherent delay (step zero) of the DS1021S-50/T&R?

The DS1021S-50/T&R has a fixed inherent delay of 10.0 ns ± 2 ns at step zero, which serves as the baseline offset before applying any programmable increment. This value is measured between the 1.5 V points of corresponding rising or falling edges at IN and OUT, and remains constant regardless of programming mode or supply voltage within specification.

Can the DS1021S-50/T&R operate with a 3.3 V supply?

No, the DS1021S-50/T&R is specified only for VCC = 4.75 V to 5.25 V operation. Its input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and output drive strength are designed for 5 V TTL/CMOS compatibility. Using 3.3 V will result in undefined logic states, failure to meet timing specifications, and potential damage if VIH/VIL boundaries are violated.

How does the DS1021S-50/T&R handle rising and falling edges?

The DS1021S-50/T&R delivers matched delay for both rising (tPLH) and falling (tPHL) edges within ±8 ns of the programmed value, ensuring consistent edge alignment critical for differential signaling and clock/data recovery. This edge accuracy is guaranteed across the full 0°C to 70°C operating range and does not require separate calibration.

Is the DS1021S-50/T&R pin-compatible with the DS1021S-25/T&R?

Yes, the DS1021S-50/T&R and DS1021S-25/T&R share identical 16-pin SOIC packaging, pin assignments, and electrical interface definitions. They differ only in internal delay step size and maximum range; no PCB layout changes are required when substituting between these variants in existing designs.

What is the maximum serial clock frequency supported by the DS1021S-50/T&R?

The DS1021S-50/T&R supports a maximum serial clock (C) frequency of 10 MHz, as specified in its AC electrical characteristics. This allows full 8-bit delay value loading in under 1 µs, enabling rapid reconfiguration in dynamic timing adjustment applications such as adaptive test pattern generation or real-time skew correction.