Analog Devices Inc./Maxim Integrated DS1818-20/T&R

Overview

DS1818-20/T&R from Maxim Integrated is a 3.3V fixed-threshold supervisory IC with pushbutton reset capability, temperature-compensated voltage monitoring, 150ms reset timeout, and open-drain active-low RST output. It ensures reliable microprocessor startup and recovery in power-fail and manual-reset scenarios.

For engineers reviewing the DS1818-20/T&R datasheet, DS1818-20/T&R pinout, DS1818-20/T&R application, or DS1818-20/T&R equivalent, key selection criteria include its 2.47V–2.64V trip point (20% tolerance), 35µA max quiescent current, SOT-23/TO-92 package options, pushbutton-synchronized reset timing, and guaranteed 100–250ms reset pulse width.

Technical Context

The DS1818-20/T&R implements a precision comparator with temperature-compensated reference to detect VCC deviations beyond ±20% of 3.3V. Its internal logic holds RST active for ≥100ms after VCC returns to tolerance, ensuring processor stabilization.

It supports dual reset initiation modes: automatic power-monitoring reset triggered by VCC dropout, and manual reset via external pushbutton connected to the open-drain RST pin - which also serves as both output and input for button detection with 1µs minimum debounce threshold.

Key Specifications

Pinout & Package

SOT-23 and TO-92 packages available; DS1818-20/T&R is supplied in tape-and-reel (T&R) format in SOT-23.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar supervisory IC applications.

Compared with MAX809SEUR+T and TPS3808G12QDBVRQ1, DS1818-20/T&R uniquely combines pushbutton integration, 20% trip tolerance for relaxed design margins, and ultra-low 35µA ICC - making it optimal for cost-sensitive industrial and consumer devices needing robust manual + power-fail reset in minimal footprint.

Availability

DS1818-20/T&R is available at Aetrix Electronics and suitable for industrial control panels, smart utility meters, medical handhelds, and POS terminals requiring stable component supply and long-term manufacturability.

Supply support for DS1818-20/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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for industrial, computing, and communications systems.

The DS1818-20/T&R belongs to Maxim's EconoReset™ family of supervisory ICs, engineered for low-cost, high-reliability power monitoring and reset control in space-constrained embedded applications.

FAQ

What is the exact VCC trip point range for DS1818-20/T&R?

The DS1818-20/T&R has a guaranteed VCC trip point range of 2.47V to 2.64V, corresponding to ±20% tolerance around the nominal 3.3V threshold. This range is specified over the full operating temperature range (−40°C to +85°C) and is validated per the DS1818 datasheet revision 1, page 4, under DC Electrical Characteristics. The DS1818-20/T&R uses a temperature-compensated reference to maintain this accuracy without external calibration.

Does DS1818-20/T&R require an external pull-up resistor on the RST pin?

No, DS1818-20/T&R integrates an internal pull-up resistor of 3.5–7.5kΩ, eliminating the need for an external component in most applications. The datasheet confirms this feature under "Efficient Open-Drain Output with Internal 5.5kΩ Pullup Resistor" and lists typical value as 5.5kΩ. DS1818-20/T&R remains compatible with standard CMOS reset inputs and supports direct connection to microcontrollers without additional passive components.

How does DS1818-20/T&R handle pushbutton reset timing?

DS1818-20/T&R detects a pushbutton press when the RST pin is pulled low for ≥1µs. Upon release, it asserts an active-low reset pulse lasting 100–250ms (typical 150ms). This timing is internally generated and independent of external RC networks. The DS1818-20/T&R timing diagram (Figure 3) and AC Electrical Characteristics table confirm tPB = 1µs and tPBRST = 100–250ms, ensuring reliable, bounce-free manual reset.

What package types are offered for DS1818-20/T&R?

DS1818-20/T&R is supplied in SOT-23 package in tape-and-reel (T&R) format. While the DS1818 family also includes TO-92 variants, the "/T&R" suffix specifically denotes the SOT-23 version optimized for automated PCB assembly. Pinout is identical across packages: Pin 1 = RST, Pin 2 = VCC, Pin 3 = GND. Mechanical drawings are available in the DS1818 datasheet, section "Mechanical Drawings".

Is DS1818-20/T&R suitable for automotive applications?

No, DS1818-20/T&R is rated for industrial temperature range (−40°C to +85°C) and is not AEC-Q100 qualified. It lacks automotive-specific features such as watchdog timers, enable inputs, or extended reliability testing. For automotive use, consider alternatives like TPS3808G12QDBVRQ1. DS1818-20/T&R is intended for commercial and industrial embedded systems where cost, simplicity, and pushbutton-integrated reset are primary requirements.