Analog Devices Inc./Maxim Integrated DS1818-5+

Overview

DS1818-5+ from Maxim Integrated is a 3.3V fixed-threshold supervisory IC with pushbutton reset capability, temperature-compensated voltage monitoring, 150ms reset pulse width, active-low open-drain RST output, and 35µA max quiescent current-used for reliable microprocessor power-fail detection and restart in embedded control systems.

For engineers reviewing the DS1818-5+ datasheet, DS1818-5+ pinout, DS1818-5+ application, or DS1818-5+ equivalent, key selection considerations include its 2.98V–3.15V trip range (5% tolerance), internal 5.5kΩ pullup, pushbutton debounce timing, TO-92/SOT-23 dual-package support, and guaranteed 100–250ms reset assertion window after VCC recovery or button release.

Technical Context

The DS1818-5+ integrates a precision temperature-compensated voltage reference and comparator to detect VCC deviations outside ±5% of 3.3V. It asserts RST low on power-down, holds reset for 150ms after VCC returns to tolerance, and supports manual reset via external pushbutton connected to the RST pin.

Its open-drain RST output includes an internal 5.5kΩ pullup resistor, enabling direct interface with microprocessor reset inputs without external components. The device operates across -40°C to +85°C and draws ≤35µA under normal conditions, making it suitable for low-power industrial and commercial applications.

Key Specifications

Pinout & Package

DS1818-5+ is available in both TO-92 and SOT-23 packages. Both variants share identical pin functions and electrical behavior.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TTR+T and TPS3808G33DBVR, the DS1818-5+ uniquely combines pushbutton reset, internal pullup, and 5% trip tolerance in both TO-92 and SOT-23 packages-reducing design effort for cost-sensitive industrial controllers requiring manual and power-fail reset in one device.

Availability

DS1818-5+ is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, POS terminals, and network router control boards requiring stable component supply, long-term lifecycle support, and consistent parametric performance across temperature.

Supply support for DS1818-5+ 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, communications, computing, and consumer applications.

The DS1818-5+ belongs to Maxim's EconoReset™ family of supervisory ICs, engineered specifically for cost-effective, low-power microprocessor reset and power-monitoring in space- and budget-constrained embedded systems.

FAQ

What is the exact VCC trip voltage range for DS1818-5+?

The DS1818-5+ has a guaranteed VCC trip point of 2.98V to 3.15V at 25°C, corresponding to ±5% tolerance around 3.3V. This range is temperature-compensated and maintained across the full -40°C to +85°C operating range, ensuring consistent brown-out detection regardless of ambient conditions. The DS1818-5+ datasheet specifies these limits under DC Electrical Characteristics.

Does DS1818-5+ require an external pullup resistor on the RST pin?

No, the DS1818-5+ includes an internal 5.5kΩ pullup resistor on the RST pin, eliminating the need for an external component in most standard microprocessor reset interfaces. External pullup is only required if the load demands more current than the internal resistor can source-typically when driving multiple devices or long traces with high capacitance. The DS1818-5+ datasheet confirms this in the DC Electrical Characteristics table.

How does DS1818-5+ handle pushbutton reset timing?

The DS1818-5+ detects any low pulse ≥1µs on the RST pin as a valid pushbutton press and asserts reset for 100–250ms after the button is released. This built-in timing removes the need for software debouncing or external RC networks. The DS1818-5+ timing diagram (Figure 3) and AC Electrical Characteristics table specify tPB = 1µs and tPBRST = 100–250ms, ensuring reliable manual reset across temperature and voltage.

Can DS1818-5+ operate below 3.3V supply voltage?

Yes, the DS1818-5+ operates over VCC = 1.0V to 5.5V per Recommended DC Operating Conditions. However, its 3.3V trip threshold remains fixed and valid only when VCC is within specification. Below ~2.7V, the internal reference may not stabilize, and reset assertion becomes unreliable. The DS1818-5+ datasheet explicitly states that trip point parameters are characterized for 2.7V ≤ VCC ≤ 3.3V.

What package options are available for DS1818-5+?

The DS1818-5+ is offered in both TO-92 and SOT-23 packages, with identical pinout (RST-VCC-GND) and electrical specifications. The TO-92 variant supports through-hole assembly and prototyping, while the SOT-23 enables compact surface-mount designs. Mechanical drawings for both packages are published in the DS1818-5+ datasheet's Mechanical Drawings section.