Analog Devices Inc./Maxim Integrated MAX6855UK16D4+T

Overview

MAX6855UK16D4+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, providing active-high push-pull reset output, manual reset input (MR), and factory-trimmed 1.575V reset threshold. It asserts reset during VCC brownout, manual trigger, or watchdog timeout (not applicable to MAX6855), with guaranteed reset validity down to VCC = +1.1V. Used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6855UK16D4+T datasheet, MAX6855UK16D4+T pinout, MAX6855UK16D4+T application, or MAX6855UK16D4+T equivalent, key selection criteria include its 170nA typical supply current, 1.575V reset threshold tolerance (±2.5%), 1200ms minimum reset timeout, MR input with 10kΩ internal pullup, and immunity to sub-40µs VCC transients at 100mV overdrive.

Technical Context

The MAX6855UK16D4+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and a monolithic reset timeout generator. Its active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 1.2mA load when asserted, while sourcing ≥0.8×VCC at 500µA when deasserted.

It features a dedicated MR input with 1µs minimum pulse width, 250ns MR-to-reset delay, and 200ns glitch rejection. The device operates across VCC = 1.2V to 5.5V and guarantees functional reset assertion down to VCC = +1.1V - critical for low-voltage battery systems.

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 TPS3837K33DBVR and MAX6361KA16D4+T, the MAX6855UK16D4+T uniquely delivers active-high push-pull reset at 170nA with 1.575V threshold and 1200ms timeout - optimizing for ultra-low-power, single-cell medical and portable instrumentation where reset polarity and current budget are critical.

Availability

MAX6855UK16D4+T is available at Aetrix Electronics and suitable for glucose monitoring systems, patient vital sign monitors, industrial handheld scanners, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for MAX6855UK16D4+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 communications markets.

The MAX685x family targets ultra-low-power microprocessor supervision in battery-critical applications, emphasizing nanopower operation, factory-trimmed accuracy, and robust reset timing - specifically engineered for portable medical and IoT edge devices.

FAQ

What is the reset threshold voltage of the MAX6855UK16D4+T?

The MAX6855UK16D4+T has a factory-trimmed reset threshold of +1.575V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is encoded in the "16" suffix per Maxim's Threshold Suffix Guide (Table 2), and is guaranteed valid down to VCC = +1.1V - making it suitable for single-cell lithium and alkaline battery systems where voltage droop must trigger reliable reset before µP corruption occurs. The MAX6855UK16D4+T does not require external resistors to set this threshold.

Does the MAX6855UK16D4+T include a watchdog timer?

No, the MAX6855UK16D4+T does not include a watchdog timer. Per Maxim's Selector Guide and Pin Description tables, only MAX6864–MAX6869 variants feature WDI input and watchdog functionality. The MAX6855UK16D4+T is a manual-reset-only supervisory circuit with VCC monitoring and reset timeout - confirmed by its pinout (no WDI pin) and absence of watchdog-related electrical characteristics in its datasheet section.

What is the function of Pin 1 and Pin 4 on the MAX6855UK16D4+T?

On the MAX6855UK16D4+T in SOT23-5 package, Pin 1 is the active-high push-pull RESET output, and Pin 4 is a second GND terminal - not an I.C. or CT pin. This dual-GND configuration (Pins 2 and 4) improves noise immunity and thermal performance. Unlike MAX6858/MAX6860 (which use Pins 1–2 as I.C.), or MAX6861–MAX6863 (which use Pin 1 as CT), the MAX6855UK16D4+T assigns Pin 1 exclusively to RESET and Pins 2 & 4 to GND, as shown in the "MAX6854/MAX6855/MAX6856 Pin Description" table.

What is the minimum reset timeout period for the MAX6855UK16D4+T?

The MAX6855UK16D4+T has a minimum reset timeout period of 1200ms, indicated by the "D4" suffix per Table 4 (Reset Timeout Periods). This is the longest standard timeout option in the MAX685x family and ensures sufficient hold time for complex µP boot sequences, EEPROM writes, or sensor initialization in low-power medical devices. Typical and maximum values are 1800ms and 2400ms respectively, with guaranteed minimum of 1200ms across -40°C to +85°C.

Is the MAX6855UK16D4+T pin-compatible with other MAX685x devices?

The MAX6855UK16D4+T shares the same 5-pin SOT23-5 footprint and pin assignments (RESET, GND, MR, GND, VCC) with MAX6854 and MAX6856, but differs functionally: MAX6854 uses active-low push-pull RESET (Pin 1), MAX6856 uses active-low open-drain RESET (Pin 1), while MAX6855UK16D4+T uses active-high push-pull RESET (Pin 1). Thus, direct PCB replacement is not possible without verifying µP reset polarity and adjusting firmware or external circuitry.