Analog Devices Inc./Maxim Integrated MAX6855UK19D5+T

Overview

MAX6855UK19D5+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 1.9V reset threshold (±2.5%), and 300ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and operates across -40°C to +85°C for reliable power-up/brownout monitoring in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK19D5+T datasheet, MAX6855UK19D5+T pinout, MAX6855UK19D5+T application, or MAX6855UK19D5+T equivalent, this page delivers verified electrical parameters, functional pin definitions, real-world use cases in glucose monitors and patient monitors, and two validated alternative parts with documented technical differences.

Technical Context

The MAX6855UK19D5+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and guaranteed reset validity down to VCC = +1.1V. Its internal timer enforces a fixed 300ms (min) reset assertion after VCC rises above 1.9V or MR deasserts, with 250ns MR-to-reset delay and 1µs minimum MR pulse width.

This variant belongs to the MAX6854–MAX6869 family configured for manual reset only-no watchdog timer or CT input-and delivers active-high push-pull RESET referenced to VCC, eliminating external pullup requirements while supporting logic-level compatibility across 1.2V–5.5V supply range.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6855UK19D5+T, TPS3837K25DBVR offers lower cost but lacks active-high drive and precise 1.9V threshold, while MAX6326UR29+T provides tighter threshold accuracy at the expense of 6× higher supply current and incompatible reset voltage.

Availability

MAX6855UK19D5+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and portable medical devices requiring stable component supply with long-term lifecycle support and full traceability.

Supply support for MAX6855UK19D5+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 systems.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical applications-delivering nanoscale current consumption without sacrificing reset accuracy or timing reliability.

FAQ

What is the exact reset threshold voltage of MAX6855UK19D5+T?

The MAX6855UK19D5+T has a factory-trimmed reset threshold of 1.900V with ±2.5% tolerance (1.853V to 1.948V), confirmed in Table 2 of the datasheet under suffix "19". This value is guaranteed over -40°C to +85°C and enables precise supervision of 1.8V/1.9V logic rails without external calibration. The MAX6855UK19D5+T uses this threshold to assert reset whenever VCC falls below the specified window.

Does MAX6855UK19D5+T include a watchdog timer function?

No, MAX6855UK19D5+T does not include a watchdog timer. Per the Selector Guide and Pin Description tables, it belongs to the MR-only configuration group (MAX6854/MAX6855/MAX6856) with no WDI pin or watchdog circuitry. The "D5" suffix denotes 300ms reset timeout only; watchdog capability is exclusive to MAX6864–MAX6869 variants. MAX6855UK19D5+T relies solely on voltage monitoring and manual reset input.

What is the function of Pin 4 on MAX6855UK19D5+T?

Pin 4 on MAX6855UK19D5+T is a second ground (GND) terminal, electrically connected to Pin 2 internally. Its inclusion improves noise immunity and thermal performance in high-density PCB layouts by reducing ground loop impedance. Unlike variants with I.C. or CT pins, MAX6855UK19D5+T uses both Pin 2 and Pin 4 exclusively for grounding-no external connection or biasing is required beyond tying them to the system ground plane.

Can MAX6855UK19D5+T operate with VCC below 1.2V?

MAX6855UK19D5+T guarantees functional reset assertion down to VCC = +1.1V, but its specified operating range begins at 1.2V. Below 1.2V, supply current and timing parameters are not characterized-though the device will continue asserting RESET until VCC falls below 1.1V. For designs requiring guaranteed behavior below 1.2V, MAX6855UK19D5+T should be used only where 1.1V–1.2V operation is a fail-safe condition, not a normal mode. The MAX6855UK19D5+T datasheet explicitly states VCC ≥ 1.2V for full specification compliance.

What does the "+T" suffix indicate in MAX6855UK19D5+T?

The "+T" suffix in MAX6855UK19D5+T indicates lead-free, RoHS-compliant packaging per Maxim's ordering convention-replacing the legacy "-T" leaded version. It confirms the device uses matte-tin termination on the 5-pin SOT23-5 package with no lead content, meeting global environmental regulations. This marking is distinct from functional suffixes ("UK19" = 1.9V threshold, "D5" = 300ms timeout) and applies solely to material composition and finish. All electrical specifications for MAX6855UK19D5+T remain identical to the leaded variant.