Analog Devices Inc./Maxim Integrated DS1020-50

Overview

DS1020-50 from Dallas Semiconductor (now Maxim Integrated) is a programmable 8-bit all-silicon delay line IC with fixed step-zero delay of 10 ns ±2 ns, maximum nominal delay of 137.5 ns, and 0.5 ns per-step resolution. It supports both 3-wire serial and 8-bit parallel programming, delivers TTL/CMOS-compatible output driving capability (8 mA sink), and operates at 5 V over 0°C to 70°C for precision timing in digital test and synchronization circuits.

For engineers reviewing the DS1020-50 datasheet, DS1020-50 pinout, DS1020-50 application, or DS1020-50 equivalent, key selection considerations include its non-inverting delay behavior, dual-programming interface flexibility, rising/falling edge accuracy within ±8 ns tolerance, settling time of 50 µs after delay change, and compatibility with daisy-chained serial configuration for multi-device timing calibration.

Technical Context

The DS1020-50 implements an 8-bit user-programmable CMOS delay path where delay value is set via P0–P7 parallel inputs or serially loaded MSB-first through D/C/Q pins. Its internal architecture guarantees identical propagation delay for both rising and falling edges, with inherent 10 ns base delay plus up to 255 × 0.5 ns increments.

It features dual-mode operation controlled by S pin: parallel mode (S=1) enables direct latch-based delay setting using static logic levels on P0–P7, while serial mode (S=0) allows cascaded programming via daisy-chained Q-to-D connections - supporting synchronized delay calibration across multiple units without external microcontroller intervention.

Key Specifications

Pinout & Package

DS1020-50 is available in 16-pin DIP (300-mil) and 16-pin SOIC packages. Both share identical pin mapping and electrical characteristics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1023-50 and ICS853S551AGI, the DS1020-50 provides optimal balance of 5 V compatibility, dual programming flexibility, and 0.5 ns resolution for mid-range digital timing applications - avoiding unnecessary complexity of integrated oscillators or incompatible voltage/interface constraints.

Availability

DS1020-50 is available at Aetrix Electronics and suitable for digital test equipment calibration, logic analyzer timing adjustment, and programmable clock skew control requiring stable component supply, long-lifecycle availability, and consistent parametric performance across production batches.

Supply support for DS1020-50 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 analog, timing, and secure memory ICs for industrial, instrumentation, and communications markets.

The DS1020 family was designed to replace hybrid delay lines with monolithic CMOS alternatives offering superior reliability, programmability, and solderability - specifically targeting digital system timing calibration and synchronization tasks.

FAQ

What is the minimum and maximum delay achievable with the DS1020-50?

The DS1020-50 has a fixed step-zero delay of 10 ns ±2 ns and supports 256 discrete delay values up to a maximum nominal delay of 137.5 ns. This corresponds to 0 to 255 steps × 0.5 ns per step added to the base delay. The actual delay for any programmed value is listed in Table 2 of the datasheet, e.g., binary 00000000 yields 10.0 ns, while 11111111 yields 137.5 ns. The DS1020-50 does not support delays below 10 ns or above 137.5 ns under specified operating conditions.

Does the DS1020-50 invert the input signal at the output?

No, the DS1020-50 reproduces the input logic state at the output without inversion. The output waveform matches the input waveform in polarity, with only a programmable time delay introduced between IN and OUT. This non-inverting behavior is explicitly confirmed in the device description and functional block diagram, and applies identically to both rising and falling edges across the full 10–137.5 ns delay range.

Can the DS1020-50 be used in serial daisy-chain configurations?

Yes, the DS1020-50 supports daisy-chaining via its serial interface: the Q output of one device connects to the D input of the next, with shared C and E lines. Each device shifts out its current 8-bit register contents on Q while loading new data on D, enabling simultaneous programming of multiple DS1020-50 units using a single serial controller. The datasheet confirms this topology in Figure 3 and specifies that total serial bits equal 8 × number of devices, all MSB-first.

What are the power supply requirements for reliable operation of the DS1020-50?

The DS1020-50 requires a regulated +5 V supply within 4.75 V to 5.25 V (±5%), with typical active current draw of 30 mA at 1 MHz input frequency. Decoupling capacitance (e.g., 0.1 µF ceramic near VCC/GND pins) is strongly recommended to suppress switching noise. Operation outside this voltage range may cause timing inaccuracy or functional failure, and the device is not rated for 3.3 V or mixed-voltage operation.

How does the DS1020-50 handle unused pins in parallel and serial modes?

In parallel mode (S = 1), unused P1–P7 pins must be tied to valid logic levels (VCC or GND); floating inputs risk undefined delay behavior due to CMOS sensitivity. In serial mode (S = 0), P1–P7 become don't-care and may float, but D and C must remain actively driven. Q/P0 may float when unused in either mode. The datasheet explicitly mandates these connections to ensure deterministic operation and avoid increased ICC or timing jitter.