Analog Devices Inc./Maxim Integrated MAX6856UK46D3+T

Overview

MAX6856UK46D3+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.625V reset threshold (±2.5%), and 150ms minimum reset timeout period. It monitors VCC, provides manual reset input (MR), and asserts an active-low open-drain RESET output - designed for reliable power-up/brownout protection in battery-critical portable medical and consumer devices.

For engineers reviewing the MAX6856UK46D3+T datasheet, MAX6856UK46D3+T pinout, MAX6856UK46D3+T application, or MAX6856UK46D3+T equivalent, key selection criteria include its guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, open-drain output compatibility with mixed-voltage systems, and absence of external components.

Technical Context

The MAX6856UK46D3+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and a fixed-timing reset timeout generator. Its internal 10kΩ MR pullup enables direct switch interfacing without external biasing, while the open-drain RESET output supports level-shifting across 0–5.5V logic domains.

No watchdog timer or CT pin functionality is present - this variant belongs to the MAX6856 base family (not MAX686x), confirming it lacks WDI input and pin-selectable timeout. It shares pinout and core supervision behavior with MAX6854/MAX6855 but differs in reset output type (open-drain only) and threshold configuration.

Key Specifications

Pinout & Package

MAX6856UK46D3+T is housed in a RoHS-compliant, lead-free 5-pin SOT23-5 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and MAX6361LUR29+T, the MAX6856UK46D3+T uniquely delivers 4.625V precision supervision with nanopower operation and open-drain flexibility - critical for long-life, multi-voltage portable medical designs.

Availability

MAX6856UK46D3+T is available at Aetrix Electronics and suitable for portable glucose monitors, low-power wearable sensors, medical patient monitors, and industrial handheld terminals requiring stable component supply across extended temperature ranges and lifecycle commitments.

Supply support for MAX6856UK46D3+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 demanding industrial, medical, and communications applications - emphasizing low power, high accuracy, and robustness.

The MAX6856UK46D3+T belongs to the nanopower µP supervisory family targeting battery-powered portable equipment, with design focus on ultra-low ICC, guaranteed low-VCC reset validity, and minimal external component requirements.

FAQ

What is the exact reset threshold voltage of MAX6856UK46D3+T?

The MAX6856UK46D3+T features a factory-trimmed reset threshold of 4.625V, with guaranteed tolerance of ±2.5% over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "46" corresponds to 4.625V nominal. The device asserts RESET when VCC falls below this threshold and holds it for the full D3 timeout period (150ms min) after VCC recovers.

Does MAX6856UK46D3+T include a watchdog timer function?

No, the MAX6856UK46D3+T does not include a watchdog timer. It belongs to the MAX6856 base variant (per Selector Guide and Pin Description), which provides only VCC monitoring and manual reset (MR) functionality. Watchdog capability is exclusive to MAX6864–MAX6869 variants, identifiable by presence of WDI pin - absent in MAX6856UK46D3+T's 5-pin SOT23 pinout.

What is the RESET output configuration of MAX6856UK46D3+T?

The MAX6856UK46D3+T features an active-low open-drain RESET output (Pin 1). It requires an external pullup resistor to the target logic voltage (e.g., 1.8V, 3.3V, or 5V). This configuration enables level-shifting and wired-OR reset bus architectures. Unlike push-pull variants, it cannot source current - confirmed in MAX6856 Pin Description and Selector Guide.

Can MAX6856UK46D3+T operate reliably below 1.8V supply?

Yes, the MAX6856UK46D3+T operates with VCC as low as 1.2V and guarantees valid RESET assertion down to VCC = +1.1V - critical for detecting deep brownout conditions. Its 170nA typical supply current remains stable across 1.2V–5.5V, enabling use in ultra-low-voltage energy-harvesting or backup-battery circuits where other supervisors fail.

Is MAX6856UK46D3+T pin-compatible with other MAX68xx supervisory ICs?

The MAX6856UK46D3+T shares the identical 5-pin SOT23-5 pinout with MAX6854, MAX6855, MAX6858, and MAX6860–MAX6869 family members. However, functional pin assignments differ: MAX6856UK46D3+T uses Pins 1/2/3/4/5 as RESET/GND/MR/GND/VCC, whereas MAX6864 uses Pin 1 for RESET and Pin 4 for WDI. Physical compatibility exists, but electrical substitution requires verification of MR, RESET type, and feature set.