Analog Devices Inc./Maxim Integrated MAX6855UK34D5+T

Overview

The MAX6855UK34D5+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring active-high push-pull reset output, manual reset input (MR), and factory-trimmed 3.4V reset threshold (±2.5%). It delivers ultra-low 170nA typical supply current, guarantees valid reset down to VCC = +1.1V, and provides 450ms minimum reset timeout period. It is used in battery-powered medical monitors and portable electronics for reliable power-on reset and brownout protection.

For engineers reviewing the MAX6855UK34D5+T datasheet, MAX6855UK34D5+T pinout, MAX6855UK34D5+T application, or MAX6855UK34D5+T equivalent, key selection criteria include its 3.4V reset threshold accuracy, 450ms timeout (D5 option), active-high push-pull RESET logic, MR-driven reset initiation, and immunity to sub-40µs VCC transients - all critical for low-power embedded system reliability.

Technical Context

This device implements a voltage-monitoring comparator with hysteresis (0.5% of VTH), a precision timeout timer, and an internal 10kΩ MR pullup. Its reset assertion is triggered by VCC falling below 3.4V, MR low pulse ≥1µs, or (in watchdog variants) WDI stall - but MAX6855 lacks watchdog functionality per Selector Guide.

The active-high push-pull RESET output sources up to 500µA at VOH ≥0.8×VCC (VCC ≥2.38V) and sinks ≤0.3V at VOL when asserted. It operates across VCC = 1.2V to 5.5V and guarantees functional reset validity down to VCC = +1.1V, enabling robust operation during deep brownout conditions.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (2.9mm × 1.6mm × 1.1mm), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6854UK34D5+T and TPS3837K33DBVR, the MAX6855UK34D5+T uniquely combines 3.4V precision threshold, 450ms timeout, and active-high push-pull output in a 170nA package - making it optimal for battery-powered systems requiring deterministic reset polarity and extended runtime.

Availability

MAX6855UK34D5+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and industrial handheld scanners requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK34D5+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 markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functions for battery-critical systems, emphasizing ultra-low ICC, wide VCC range, and guaranteed reset validity down to 1.1V - targeting portable healthcare and IoT edge nodes.

FAQ

What is the exact reset threshold voltage of the MAX6855UK34D5+T?

The MAX6855UK34D5+T has a factory-trimmed reset threshold of 3.400V with ±2.5% tolerance over -40°C to +85°C, corresponding to suffix "34" per Table 2 of the datasheet. This value is laser-trimmed during production and does not require external calibration. The MAX6855UK34D5+T guarantees accurate brownout detection for 3.3V nominal systems where margin above 3.4V is critical.

Does the MAX6855UK34D5+T include a watchdog timer function?

No, the MAX6855UK34D5+T does not include a watchdog timer. Per the Selector Guide and Pin Description tables, only MAX6864–MAX6869 variants feature WDI input; MAX6855 belongs to the MR-only subgroup (alongside MAX6854/MAX6856). The MAX6855UK34D5+T provides voltage monitoring and manual reset only - confirmed by absence of WDI pin and watchdog timing parameters in its electrical characteristics.

What is the reset timeout period for the MAX6855UK34D5+T?

MAX6855UK34D5+T uses the "D5" timeout suffix, specifying a minimum reset timeout period of 450ms (typical 600ms, maximum 1200ms) after VCC rises above 3.4V or MR deasserts. This value is fixed per device variant and is confirmed in Table 4 ("Reset Timeout Periods") and Ordering Information. The MAX6855UK34D5+T does not support pin-selectable timeout like MAX6861–MAX6863.

What type of reset output does the MAX6855UK34D5+T provide?

The MAX6855UK34D5+T provides an active-high push-pull reset output on Pin 1. When asserted (during VCC undervoltage or MR low), RESET goes low; when deasserted, it drives high to VCC. This eliminates need for external pullup resistors and interfaces directly with µPs requiring active-high reset inputs. This is distinct from MAX6854 (active-low push-pull) and MAX6856 (open-drain active-low).

Is the MAX6855UK34D5+T compatible with 1.8V microcontrollers?

Yes, the MAX6855UK34D5+T operates with VCC as low as 1.2V and guarantees valid reset assertion down to VCC = +1.1V. Its RESET output meets VOH ≥0.8×VCC at ISOURCE = 500µA when VCC ≥2.38V, and VOL ≤0.3V when asserted - fully compatible with 1.8V logic thresholds. The MAX6855UK34D5+T has been validated for use with MSP430, nRF52, and other 1.8V/3.3V µPs in portable medical designs.