Analog Devices Inc./Maxim Integrated MAX6855UK37D1+T

Overview

The MAX6855UK37D1+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring active-high push-pull reset output, manual reset input (MR), and factory-trimmed 3.700V reset threshold with 10ms minimum reset timeout. It monitors VCC supply integrity, asserts reset during brownout or MR activation, and guarantees valid reset operation down to VCC = +1.1V. Designed for ultra-low-power portable systems including glucose monitors and patient monitors.

For engineers reviewing the MAX6855UK37D1+T datasheet, MAX6855UK37D1+T pinout, MAX6855UK37D1+T application, or MAX6855UK37D1+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options - all grounded in Maxim's official electrical characteristics and functional descriptions.

Technical Context

The MAX6855UK37D1+T implements a voltage-monitoring comparator with 2.5% threshold accuracy over temperature, coupled to a fixed 10ms reset timeout timer and an internally pulled-up manual reset input. Its active-high push-pull RESET output drives high when VCC falls below 3.700V or MR is asserted, remaining high for ≥10ms after VCC recovers and MR deasserts.

No watchdog timer or CT select input is present - per Selector Guide and Pin Description, MAX6855 is MR-enabled but lacks WDI and CT pins. It belongs to the non-watchdog, non-pin-selectable subgroup (MAX6854/MAX6855/MAX6856) with fixed reset timeout and push-pull active-high output configuration.

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 MAX6854UK37D1+T, the MAX6855UK37D1+T enables direct interface to active-high reset µPs without logic inversion, while TPS3837K33DBVR trades nanopower efficiency for higher drive strength and longer timeout - making MAX6855UK37D1+T optimal for ultra-low-power medical wearables demanding precise 3.7V monitoring and minimal current draw.

Availability

MAX6855UK37D1+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and portable medical diagnostics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6855UK37D1+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, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6855UK37D1+T belongs to the nanopower µP supervisory family engineered specifically for battery-critical portable medical and handheld electronics - prioritizing sub-µA quiescent current, guaranteed low-VCC operation, and factory-trimmed voltage thresholds.

FAQ

What is the exact reset threshold voltage of the MAX6855UK37D1+T?

The MAX6855UK37D1+T has a factory-trimmed reset threshold of 3.700V, with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "37" corresponds to 3.700V nominal, and in Electrical Characteristics where VTH is specified as VTH ±2.5%. The MAX6855UK37D1+T uses this exact threshold to supervise 3.3V–3.6V rails in portable medical devices.

Does the MAX6855UK37D1+T include a watchdog timer function?

No, the MAX6855UK37D1+T does not include a watchdog timer. Per the Selector Guide and Pin Configuration diagrams, MAX6855 is explicitly listed without WDI (Watchdog Input) functionality. Only MAX6864–MAX6869 variants incorporate watchdog capability. The MAX6855UK37D1+T provides voltage monitoring, manual reset input (MR), and fixed 10ms reset timeout - making it suitable for applications where software-level watchdog supervision is handled externally.

What is the function of Pin 1 on the MAX6855UK37D1+T?

Pin 1 of the MAX6855UK37D1+T is the RESET output, configured as an active-high push-pull driver. As documented in the MAX6854/MAX6855/MAX6856 Pin Description table, this pin transitions high when VCC drops below 3.700V or MR is asserted, and remains high for ≥10ms after VCC exceeds the threshold and MR deasserts. Unlike open-drain variants, the MAX6855UK37D1+T requires no external pullup resistor on Pin 1.

Can the MAX6855UK37D1+T operate reliably at VCC = 1.2V?

Yes, the MAX6855UK37D1+T is fully specified to operate at VCC = 1.2V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. Its reset output remains valid down to VCC = +1.1V, and supply current is characterized at 1.2V (7µA max when reset asserted). At 1.2V, the device continues to monitor VCC and assert RESET correctly, supporting ultra-low-voltage battery discharge scenarios in medical wearables.

Is the MAX6855UK37D1+T pin-compatible with other devices in the MAX68xx family?

The MAX6855UK37D1+T shares the same 5-pin SOT23-5 footprint and pinout (RESET, GND, MR, GND, VCC) with MAX6854 and MAX6856, but differs in reset polarity: MAX6854 is active-low push-pull, MAX6855 is active-high push-pull, and MAX6856 is open-drain active-low. Therefore, while physically pin-compatible, electrical interface requires verification of µP reset input polarity. The MAX6855UK37D1+T is not pin-compatible with MAX6861–MAX6869 (which add CT pin) or MAX6864–MAX6869 (which add WDI pin).