Analog Devices Inc./Maxim Integrated MAX6856UK19D3+T

Overview

The MAX6856UK19D3+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 1.9V 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 detection in battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6856UK19D3+T datasheet, MAX6856UK19D3+T pinout, MAX6856UK19D3+T application, or MAX6856UK19D3+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), no external components requirement, and compatibility with 1.2V–5.5V supply rails.

Technical Context

The MAX6856UK19D3+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and a fixed 150ms reset timeout timer. Its MR input features internal 10kΩ pullup, 1µs minimum pulse width, and 200ns glitch rejection - enabling robust manual reset initiation without external debounce.

This device belongs to the MAX6854–MAX6869 family of nanopower supervisors but excludes watchdog functionality (no WDI pin) and CT select input. It delivers open-drain RESET output with 25nA leakage when deasserted and guarantees VOL ≤ 0.3V at ISINK = 50µA (VCC ≥ 1.1V), supporting direct interface to low-voltage µP reset inputs.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and ADM6806-20ARTZ-R7, the MAX6856UK19D3+T uniquely delivers 170nA ICC at 1.9V threshold - making it the only viable choice for multi-year coin-cell-powered applications requiring precise low-voltage supervision.

Availability

MAX6856UK19D3+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, wireless sensor nodes, and industrial handheld terminals requiring stable component supply across long production lifecycles.

Supply support for MAX6856UK19D3+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 management, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 product line targets ultra-low-power microprocessor supervision in battery-constrained systems, emphasizing nanoscale ICC, wide VCC range, and robust reset timing without external components.

FAQ

What is the exact reset threshold voltage of the MAX6856UK19D3+T?

The MAX6856UK19D3+T has a factory-trimmed reset threshold of 1.9V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "19" corresponds to 1.9V nominal. The device guarantees reset assertion when VCC falls below this threshold and remains asserted until VCC exceeds 1.9V and the 150ms timeout elapses.

Does the MAX6856UK19D3+T include a watchdog timer function?

No, the MAX6856UK19D3+T does not include a watchdog timer. Per the Selector Guide and Pin Configurations, MAX6856 variants lack the WDI pin and associated watchdog circuitry - unlike MAX6864–MAX6869 parts. The MAX6856UK19D3+T provides only VCC monitoring, manual reset (MR), and fixed 150ms reset timeout, making it a dedicated voltage supervisor without code-execution monitoring capability.

What is the function of Pin 4 on the MAX6856UK19D3+T?

Pin 4 on the MAX6856UK19D3+T is a second GND terminal, electrically connected to Pin 2 internally. Its inclusion improves noise immunity and thermal performance in the 5-pin SOT23 package. Both ground pins must be soldered to the same PCB ground plane; splitting or isolating them compromises reset accuracy and transient immunity as specified in the Absolute Maximum Ratings and Typical Operating Characteristics.

Can the MAX6856UK19D3+T drive a 3.3V microcontroller reset input?

Yes, the MAX6856UK19D3+T can drive a 3.3V µP reset input using its open-drain RESET output (Pin 1). Connect an external pullup resistor from Pin 1 to the 3.3V supply rail. When RESET is asserted, the device sinks current to pull the node low; when deasserted, the external pullup raises it to 3.3V. Leakage is limited to 25nA, ensuring minimal power penalty - confirmed in the Electrical Characteristics table under "Open-Drain RESET Leakage Current".

Is the MAX6856UK19D3+T pin-compatible with other SOT23-5 supervisors?

The MAX6856UK19D3+T shares the standard 5-pin SOT23-5 footprint and pinout (VCC–GND–MR–GND–RESET) with TPS3836/TPS3837/TPS3838 devices, as noted in the Features section. However, electrical compatibility requires verification: TPS3836 variants use push-pull outputs and different thresholds, so direct substitution is only viable if the target design accommodates open-drain logic and 1.9V supervision - not guaranteed across all TPS383x derivatives.