Analog Devices Inc./Maxim Integrated MAX6855UK19D1+T

Overview

The MAX6855UK19D1+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 1.9V reset threshold (±2.5%), and a 10ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and operates across –40°C to +85°C for reliable power-up/brownout monitoring in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK19D1+T datasheet, MAX6855UK19D1+T pinout, MAX6855UK19D1+T application, or MAX6855UK19D1+T equivalent, key selection criteria include its 1.9V VTH accuracy, guaranteed RESET validity down to VCC = 1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), and compatibility with CMOS-level MR signaling in space-constrained designs.

Technical Context

This device integrates voltage monitoring, manual reset assertion, and precise reset timing in a single BiCMOS IC. Its internal 10kΩ MR pullup eliminates external components, while the push-pull active-high RESET output ensures clean logic-level signaling without external pullups. The reset assertion is triggered by VCC falling below 1.9V, MR low pulse ≥1µs, or watchdog timeout - though MAX6855 lacks WDI functionality per Selector Guide.

The reset deassertion follows a fixed 10ms minimum timeout after VCC rises above 1.9V and MR releases. Timing stability is maintained across temperature (±0.5% VTH drift from –40°C to +85°C) and supply voltage (1.2V–5.5V operation), with VOL ≤0.3V at ISINK = 1.2mA and VOH ≥0.8×VCC at ISOURCE = 500µA.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K25DBVR and MAX6315US23D3+, the MAX6855UK19D1+T delivers 7× lower ICC, precise 1.9V threshold matching modern low-voltage MCUs, and active-high push-pull output eliminating external components - critical for miniaturized medical and portable designs.

Availability

MAX6855UK19D1+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and handheld terminals requiring stable component supply with long-term lifecycle support and lead-free compliance.

Supply support for MAX6855UK19D1+T 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 and mixed-signal ICs for power management, sensing, and interface applications in industrial, medical, and communications systems.

The MAX6855UK19D1+T belongs to the MAX6854–MAX6869 nanopower supervisory family, engineered specifically for ultra-low-power, space-constrained battery-operated devices requiring reliable reset control without external components.

FAQ

What is the exact reset threshold voltage of the MAX6855UK19D1+T?

The MAX6855UK19D1+T has a factory-trimmed reset threshold voltage of 1.9V with ±2.5% tolerance over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "19" corresponds to 1.853V (min), 1.900V (typ), and 1.948V (max). The device guarantees valid RESET operation down to VCC = 1.1V, making it suitable for deep brownout detection in low-voltage systems.

Does the MAX6855UK19D1+T include a watchdog timer function?

No, the MAX6855UK19D1+T does not include a watchdog timer. Per the Selector Guide and Pin Description tables, only MAX6864–MAX6869 variants feature WDI input; MAX6855 is explicitly listed without WDI or CT pins and belongs to the manual-reset-only subgroup (MAX6854/MAX6855/MAX6856). Its functionality is limited to VCC monitoring, MR-triggered reset, and fixed 10ms timeout.

What is the RESET output configuration of the MAX6855UK19D1+T?

The MAX6855UK19D1+T features an active-high push-pull RESET output (Pin 1), as confirmed in the MAX6855-specific Pin Description table. Unlike open-drain variants, it drives high actively without requiring an external pullup resistor. VOH is guaranteed ≥0.8×VCC at ISOURCE = 500µA, and VOL ≤0.3V at ISINK = 1.2mA, enabling direct interfacing with standard CMOS inputs.

Can the MAX6855UK19D1+T operate from a 1.2V supply?

Yes, the MAX6855UK19D1+T operates from 1.2V to 5.5V per Electrical Characteristics table. At VCC = 1.2V, it maintains functional reset assertion and deassertion, though RESET output drive strength is reduced. Crucially, the device guarantees RESET validity down to VCC = 1.1V - ensuring deterministic behavior even during severe brownout conditions common in battery-powered systems.

What is the minimum pulse width required on the MR input of the MAX6855UK19D1+T?

The MR input of the MAX6855UK19D1+T requires a minimum low pulse width of 1µs to reliably trigger a reset, as specified in the Electrical Characteristics table under "MR Minimum Pulse Width (tMPW)". The device also provides 200ns glitch rejection, preventing false resets from noise spikes. MR is internally pulled up to VCC via 10kΩ, so leaving it unconnected defaults to inactive (no reset).