Analog Devices Inc./Maxim Integrated MAX6865UK20D3L+T

Overview

MAX6865UK20D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.000V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and guarantees valid reset down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK20D3L+T datasheet, MAX6865UK20D3L+T pinout, MAX6865UK20D3L+T application, or MAX6865UK20D3L+T equivalent, key selection criteria include its factory-trimmed 2.000V threshold, L-suffix 209s watchdog timeout, D3 150ms minimum reset timeout, active-high push-pull output, and immunity to sub-40µs VCC transients at 100mV overdrive.

Technical Context

The MAX6865UK20D3L+T implements a BiCMOS-based supervisory architecture with independent voltage monitor, edge-triggered watchdog timer (cleared on WDI transitions), and internal 10kΩ MR pullup. Its reset assertion logic combines three independent triggers - VCC falling below 2.000V ±2.5%, MR low, or WDI static for ≥209s - with guaranteed deassertion after 150ms minimum timeout following recovery.

Unlike passive reset ICs, it features temperature-stable reset threshold (±0.5%VTH hysteresis, <±0.01 normalized drift from −40°C to +85°C) and operates across full 1.2V–5.5V VCC range while maintaining 170nA ICC at 2.5V/25°C. The active-high push-pull RESET output delivers VOH ≥0.8×VCC at 500µA source, enabling direct interface with 1.71V+ µP reset inputs without external level-shifting.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (2.9mm × 1.6mm × 1.1mm), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK20D3S+T, the MAX6865UK20D3L+T's 209s watchdog better supports long-duration firmware tasks; compared with TPS3837K20DBVR, its nanopower consumption and integrated watchdog deliver superior reliability and runtime in portable medical electronics.

Availability

MAX6865UK20D3L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and industrial handheld equipment requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK20D3L+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 MAX6865UK20D3L+T belongs to the MAX6854–MAX6869 nanopower supervisory family, engineered specifically for ultra-low-power battery-operated systems requiring reliable reset supervision, manual reset capability, and configurable watchdog protection.

FAQ

What is the exact reset threshold voltage of the MAX6865UK20D3L+T?

The MAX6865UK20D3L+T has a factory-trimmed reset threshold of 2.000V 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 "20" corresponds to 2.000V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep brownout detection in low-voltage systems.

Does the MAX6865UK20D3L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK20D3L+T includes a watchdog timer with L-suffix configuration, providing a typical timeout period of 209s (minimum 95s, maximum 487s). This is explicitly defined in Table 3 (Watchdog Timeout) and confirmed by the "L" character in the part number suffix. The timer clears on any WDI edge and expires only if WDI remains static beyond this period, triggering a full reset sequence.

What type of RESET output does the MAX6865UK20D3L+T provide, and how is it configured?

The MAX6865UK20D3L+T provides an active-high push-pull RESET output, as indicated by its position in the Selector Guide (row MAX6865, column "Push-Pull Active High") and confirmed in the MAX6864/MAX6865/MAX6866 Pin Description section. This eliminates the need for an external pullup resistor and allows direct interfacing with µP reset inputs requiring high-active signaling, delivering VOH ≥0.8×VCC at 500µA source current.

What is the minimum reset timeout period for the MAX6865UK20D3L+T, and how is it selected?

The MAX6865UK20D3L+T has a fixed minimum reset timeout period of 150ms, designated by the "D3" suffix in its part number. This value is specified in Table 4 (Reset Timeout Periods) as D3 = 150ms (min), 225ms (typ), 300ms (max). Unlike MAX6861–MAX6863 variants, the MAX6865 does not feature a CT pin for dynamic timeout selection - the D3 timeout is permanently configured at wafer trim.

How does the MAX6865UK20D3L+T handle VCC supply transients, and what is its immunity specification?

The MAX6865UK20D3L+T is immune to short VCC transients up to 40µs duration when the overdrive is 100mV, as shown in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure MAX684 toc05). This immunity prevents false resets caused by switching noise or motor commutation spikes. The device also features guaranteed reset validity down to VCC = +1.1V, ensuring deterministic behavior during gradual brownout conditions.