Analog Devices Inc./Maxim Integrated MAX6856UK16D3+T

Overview

The MAX6856UK16D3+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 150ms minimum reset timeout. It asserts an active-low open-drain RESET output when VCC drops below 1.575V (factory-trimmed threshold), MR is pulled low, or during power-up/brownout. Designed for ultra-low-power portable systems including glucose monitors and battery-powered PDAs.

For engineers reviewing the MAX6856UK16D3+T datasheet, MAX6856UK16D3+T pinout, MAX6856UK16D3+T application, or MAX6856UK16D3+T equivalent, key selection criteria include its 170nA typical supply current, guaranteed RESET validity down to VCC = +1.1V, immunity to short VCC transients, and compatibility with 1.2V–5.5V supply rails.

Technical Context

This device integrates a precision voltage monitor with hysteresis (±2.5% VTH), a fixed-reset-timeout generator (D3 = 150ms min), and a CMOS-compatible manual reset input with 10kΩ internal pullup. The open-drain RESET output requires an external pullup and supports logic-level interfacing across multiple supply domains.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6856UK16D3+T omits WDI functionality and CT select input-confirming it belongs to the MR-only, fixed-tRP subgroup. Its functional diagram shows direct VCC monitoring, MR assertion path, and RESET timeout timer with no watchdog logic or configuration pins.

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 TPS3836K33DBVR and MAX6315US29D3+, the MAX6856UK16D3+T delivers 7× lower supply current and precise 1.575V threshold-critical for sub-2V battery systems-while retaining open-drain output for flexible voltage-domain interfacing.

Availability

MAX6856UK16D3+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and industrial handheld scanners requiring stable component supply across extended product lifecycles.

Supply support for MAX6856UK16D3+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 demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family delivers nanopower supervisory functions targeting battery-constrained portable electronics-emphasizing ultra-low ICC, wide VCC range, and robust reset timing without external components.

FAQ

What is the exact reset threshold voltage of the MAX6856UK16D3+T?

The MAX6856UK16D3+T has a factory-trimmed reset threshold of +1.575V, with ±2.5% tolerance over temperature (–40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "16" corresponds to 1.575V nominal. The device guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for deep-brownout protection in low-voltage systems.

Does the MAX6856UK16D3+T include a watchdog timer function?

No, the MAX6856UK16D3+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, MAX6856 belongs to the MR-only subgroup (no WDI pin) and lacks watchdog circuitry. Watchdog functionality is exclusive to MAX6864–MAX6869 variants, which feature Pin 4 as WDI. The MAX6856UK16D3+T provides only VCC monitoring, manual reset input (MR), and fixed 150ms reset timeout.

What is the reset timeout period for the MAX6856UK16D3+T, and how is it set?

The MAX6856UK16D3+T has a fixed minimum reset timeout period of 150ms (D3 option), as indicated by the "D3" suffix in its part number. Unlike MAX6861–MAX6863, it does not feature a CT pin for runtime selection. This timeout is factory-programmed and non-adjustable-ensuring consistent power-up sequencing across all units without external components or configuration overhead.

What type of reset output does the MAX6856UK16D3+T provide, and what are its drive requirements?

The MAX6856UK16D3+T provides an active-low open-drain RESET output (Pin 1). It requires an external pullup resistor to a logic rail (≤5.5V). When asserted, it sinks current (VOL ≤ 0.3V at ISINK = 1.2mA for VCC ≥ 2.38V); when deasserted, it presents high impedance. Leakage is ≤25nA, enabling use with high-value pullups in ultra-low-power designs.

Is the MAX6856UK16D3+T pin-compatible with other supervisory ICs, and which ones?

The MAX6856UK16D3+T is pin-compatible with the TPS3836/TPS3837/TPS3838 series per the datasheet Features section, sharing identical 5-pin SOT23-5 layout and function mapping (VCC, GND, MR, RESET, GND). However, electrical differences-including 170nA vs. ~1µA supply current and 1.575V vs. 3.08V/3.3V thresholds-require validation of timing and voltage margins before drop-in replacement.