Analog Devices Inc./Maxim Integrated MAX6855UK22D6+T

Overview

The MAX6855UK22D6+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 2.235V reset threshold (suffix '22'), and a 600ms minimum reset timeout period (suffix 'D6'). It provides active-low push-pull reset output, manual reset input (MR), and operates across –40°C to +85°C for reliable power-up/brownout monitoring in battery-critical systems.

For engineers reviewing the MAX6855UK22D6+T datasheet, MAX6855UK22D6+T pinout, MAX6855UK22D6+T application, or MAX6855UK22D6+T equivalent, this device serves as a low-quiescent-current voltage monitor with deterministic reset timing and MR-initiated recovery-key for portable medical, wearables, and ultra-low-power embedded control where supply stability and reset integrity down to VCC = 1.1V are mandatory.

Technical Context

The MAX6855UK22D6+T integrates a precision voltage comparator with ±2.5% threshold accuracy over temperature, a monolithic reset timeout timer with guaranteed 600–1200ms assertion window after VCC recovery, and an internally pulled-up MR input (10kΩ) that triggers reset on logic-low assertion. Its push-pull active-low RESET output drives directly to GND or VCC without external components.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6855UK22D6+T omits WDI functionality and CT select input-confirming its role as a dedicated voltage-monitoring supervisor with fixed timing and no programmable watchdog or timeout selection. It guarantees valid reset assertion down to VCC = 1.1V and rejects transients ≤40µs at 100mV overdrive.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K22DBVR and MAX6326UR23+T, the MAX6855UK22D6+T uniquely balances ultra-low 170nA ICC, integrated MR, and precise 600ms timing-making it optimal for battery-constrained, serviceable portable electronics where both longevity and user-controlled reset are essential.

Availability

The MAX6855UK22D6+T is available at Aetrix Electronics and suitable for portable medical devices, wireless sensor nodes, industrial handheld terminals, and low-power wearables requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for MAX6855UK22D6+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 MAX6855UK22D6+T belongs to Maxim's nanopower µP supervisory family, designed specifically for ultra-low-power portable and battery-operated systems where reset integrity, minimal current draw, and small footprint are critical design constraints.

FAQ

What is the exact reset threshold voltage of the MAX6855UK22D6+T?

The MAX6855UK22D6+T has a factory-trimmed reset threshold voltage of 2.235V, with ±2.5% tolerance over temperature (–40°C to +85°C). This value is confirmed by the '22' suffix in the part number and corresponds to the '22' entry in Maxim's Threshold Suffix Guide (Table 2), where min/typ/max are 2.133V/2.235V/2.243V. The MAX6855UK22D6+T maintains this accuracy without external calibration.

Does the MAX6855UK22D6+T include a watchdog timer function?

No, the MAX6855UK22D6+T does not include a watchdog timer. It is a voltage-monitoring supervisory circuit with manual reset (MR) and fixed reset timeout only. Watchdog functionality is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UKxxDxS), which feature WDI input and selectable watchdog timeout periods. The MAX6855UK22D6+T pinout and functional diagram confirm absence of WDI or related circuitry.

What is the reset timeout period for the MAX6855UK22D6+T, and how is it set?

The MAX6855UK22D6+T has a fixed minimum reset timeout period of 600ms, indicated by the 'D6' suffix per Table 4. This value is factory-programmed and non-adjustable-unlike MAX6861–MAX6863 variants with CT-selectable timeouts. The timeout begins when VCC rises above 2.235V or MR is deasserted, and RESET remains low for the full 600–1200ms window before releasing.

Can the MAX6855UK22D6+T operate reliably at VCC = 1.2V?

Yes, the MAX6855UK22D6+T is fully specified to operate at VCC = 1.2V, the lower limit of its 1.2V–5.5V supply range. Its reset output remains valid down to VCC = 1.1V, and supply current is characterized at 1.2V (190nA typ). Electrical characteristics tables confirm functionality-including RESET output drive strength and MR input thresholds-at this voltage, making it suitable for single-cell lithium or low-dropout regulator outputs.

Is the MAX6855UK22D6+T pin-compatible with other supervisory ICs?

Yes, the MAX6855UK22D6+T is pin-compatible with Texas Instruments' TPS3836/TPS3837/TPS3838 series in the SOT23-5 package, as explicitly stated in the datasheet Features section. Pin mapping (VCC, GND, MR, RESET, GND) matches exactly, enabling direct replacement without PCB modification-provided the target application requires active-low push-pull RESET and supports the 2.235V threshold and 600ms timeout.