Analog Devices Inc./Maxim Integrated MAX6855UK33D1+T

Overview

The MAX6855UK33D1+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.3V reset threshold (±2.5%), and 10ms minimum reset timeout period. It monitors VCC, provides manual reset input (MR), and asserts an active-low push-pull RESET output - designed for reliable power-on reset and brownout protection in battery-constrained portable systems.

For engineers reviewing the MAX6855UK33D1+T datasheet, MAX6855UK33D1+T pinout, MAX6855UK33D1+T application, or MAX6855UK33D1+T equivalent, this device serves as a precision voltage monitor with guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), and no external components required - critical for low-power wearable and medical sensor designs.

Technical Context

The MAX6855UK33D1+T implements a precision bandgap-based voltage detector with 2.5% threshold tolerance and 0.5% hysteresis, coupled with a fixed 10ms internal reset timeout timer. Its MR input features 10kΩ internal pullup, 1µs minimum pulse width, and 200ns glitch rejection - enabling robust manual reset triggering without external debounce.

This variant belongs to the MAX6854–MAX6869 family but excludes watchdog timer (WDI) and CT select functionality. It delivers active-high push-pull RESET output referenced to VCC, with VOH ≥ 0.8×VCC (ISOURCE = 500µA) and VOL ≤ 0.3V (ISINK = 1.2mA), ensuring clean logic-level compatibility across 1.2V–5.5V supply ranges.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and ADM6803-33ARTZ-RL, the MAX6855UK33D1+T uniquely combines 170nA ICC, 10ms timeout, active-high push-pull output, and integrated MR pullup - making it optimal for next-generation battery-powered medical and wearable devices demanding minimal footprint and longest possible runtime.

Availability

MAX6855UK33D1+T is available at Aetrix Electronics and suitable for portable medical sensors, wearable health monitors, and industrial handheld terminals requiring stable component supply with long-term lifecycle support.

Supply support for MAX6855UK33D1+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.

The MAX6854–MAX6869 product line was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable equipment - emphasizing nanoscale ICC, guaranteed low-VCC reset validity, and minimal external component count.

FAQ

What is the exact reset threshold voltage of the MAX6855UK33D1+T?

The MAX6855UK33D1+T has a factory-trimmed reset threshold of 3.3V with ±2.5% tolerance (3.2175V to 3.3825V). This value is specified over the full -40°C to +85°C temperature range and is guaranteed by design - not just typical. The threshold remains stable across temperature, with normalized VTH variation less than ±0.5% from -40°C to +85°C per the datasheet's typical operating characteristics.

Does the MAX6855UK33D1+T include a watchdog timer function?

No, the MAX6855UK33D1+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides only VCC monitoring and manual reset (MR) functionality. Watchdog capability is exclusive to the MAX6864–MAX6869 variants, identifiable by suffixes containing 'S' or 'L' in the ordering code - absent in MAX6855UK33D1+T.

What type of reset output does the MAX6855UK33D1+T provide?

The MAX6855UK33D1+T provides an active-high push-pull RESET output (pin 1). When asserted, RESET goes high; when deasserted, it returns low. This eliminates the need for an external pullup resistor and ensures strong drive capability: VOH ≥ 0.8×VCC at 500µA source current, and VOL ≤ 0.3V at 1.2mA sink current - fully compatible with standard CMOS µP reset inputs.

Can the MAX6855UK33D1+T operate reliably below 1.8V supply?

Yes, the MAX6855UK33D1+T operates from VCC = 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V. At 1.2V, its supply current is 190nA (typ), and RESET output remains functional with VOL ≤ 0.3V (ISINK = 100µA) and VOH ≥ 0.8×VCC (ISOURCE = 200µA). This makes it suitable for single-cell LiFePO₄ or NiMH systems where rail voltage drops near end-of-life.

Is the MR input of the MAX6855UK33D1+T compatible with open-drain logic drivers?

Yes, the MR input of the MAX6855UK33D1+T is fully compatible with open-drain (or open-collector) logic drivers. Its internal 10kΩ pullup to VCC ensures clean logic-high default state, and the input accepts VIH ≥ 0.7×VCC and VIL ≤ 0.3×VCC. With 1µs minimum pulse width and 200ns glitch rejection, it reliably detects brief manual reset pulses even when driven through long traces or optocouplers.