Analog Devices Inc./Maxim Integrated MAX6855UK34D2+T

Overview

The MAX6855UK34D2+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, providing voltage monitoring, manual reset input (MR), and fixed 40ms minimum reset timeout. It asserts an active-high push-pull RESET output when VCC drops below its factory-trimmed 3.315V–3.400V threshold (suffix "34"), during MR assertion, or at power-up/brownout - with guaranteed RESET validity down to VCC = +1.1V. It targets ultra-low-power portable systems such as glucose monitors and battery-powered PDAs.

For engineers reviewing the MAX6855UK34D2+T datasheet, MAX6855UK34D2+T pinout, MAX6855UK34D2+T application, or MAX6855UK34D2+T equivalent, key selection criteria include its 170nA typical supply current, 3.4V nominal reset threshold, 40ms reset timeout (D2), active-high push-pull output, and immunity to sub-40µs VCC transients - all critical for reliable low-voltage embedded reset management.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over –40°C to +85°C, coupled with a digital reset timeout timer that holds RESET asserted for ≥40ms after VCC rises above VTH and MR deasserts. Its MR input features 200ns glitch rejection, 1µs minimum pulse width, and internal 10kΩ pullup to VCC - enabling direct connection to momentary switches without external components.

The active-high push-pull RESET output delivers VOH ≥ 0.8×VCC (at ISOURCE = 500µA, VCC ≥ 2.38V) and VOL ≤ 0.3V (at ISINK = 1.2mA, VCC ≥ 2.38V), ensuring robust logic-level compatibility with µP reset inputs across its 1.2V–5.5V operating range. No watchdog or CT pin functionality is present - confirming MAX6855UK34D2+T as a dedicated voltage-monitoring + manual-reset variant.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (RoHS-compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6855UK34D2+T, the TPS3837K33DBVR offers longer timeout but lacks nanopower efficiency and active-high drive, while MAX6315US33D2+T matches package and threshold closely but doubles supply current and reverses reset polarity - making MAX6855UK34D2+T optimal for ultra-low-power, active-high reset systems.

Availability

MAX6855UK34D2+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, industrial handheld scanners, and smart wearables requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6855UK34D2+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, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX685x family delivers nanopower supervisory functions targeting battery-critical portable electronics - emphasizing ultra-low ICC, wide VCC range, and guaranteed reset validity at sub-1.2V rails.

FAQ

What is the exact reset threshold voltage range for MAX6855UK34D2+T?

The MAX6855UK34D2+T has a factory-trimmed reset threshold range of 3.315V (min) to 3.400V (max), corresponding to suffix "34" per Maxim's Threshold Suffix Guide. This 3.4V nominal threshold ensures accurate brownout detection for 3.3V systems with ±3% supply tolerance, and is guaranteed over –40°C to +85°C with ±2.5% accuracy.

Does MAX6855UK34D2+T include a watchdog timer function?

No, MAX6855UK34D2+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides only voltage monitoring and manual reset (MR) functionality. Watchdog capability is exclusive to MAX6864–MAX6869 variants - confirmed by absence of WDI pin and no watchdog-related parameters in the MAX6855 pin description or electrical characteristics.

What is the reset timeout period of MAX6855UK34D2+T and how is it configured?

The MAX6855UK34D2+T has a fixed 40ms minimum reset timeout period (suffix "D2"), as defined in Table 4 of the datasheet. This value is factory-programmed and non-adjustable - unlike MAX6861–MAX6863, which use the CT pin for selection. The timeout begins when VCC rises above VTH and MR deasserts, and ensures µP reset pulse compliance with industry-standard initialization requirements.

What output type does MAX6855UK34D2+T provide and why does it matter?

MAX6855UK34D2+T provides an active-high push-pull RESET output (pin 1), meaning it drives the output high during reset assertion and actively pulls low when deasserted. This eliminates the need for an external pullup resistor, reduces component count, improves noise immunity, and directly interfaces with µPs requiring high-active reset inputs - unlike open-drain or active-low variants.

Can MAX6855UK34D2+T operate reliably at very low supply voltages?

Yes, MAX6855UK34D2+T guarantees valid RESET assertion down to VCC = +1.1V, as specified in the Electrical Characteristics table. This ensures deterministic reset behavior during deep brownout conditions common in battery-powered systems nearing end-of-life, preventing undefined µP states and improving system robustness in medical and portable applications.