Analog Devices Inc./Maxim Integrated MAX6865UK26D6L+T

Overview

MAX6865UK26D6L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.625V reset threshold (suffix '26'), 1200ms minimum reset timeout (suffix 'D6'), and 209s typical watchdog timeout (suffix 'L'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout - designed for battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK26D6L+T datasheet, MAX6865UK26D6L+T pinout, MAX6865UK26D6L+T application, or MAX6865UK26D6L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and integrated 10kΩ MR pullup - all critical for reliable low-voltage brownout recovery in space-constrained portable electronics.

Technical Context

The MAX6865UK26D6L+T implements a dual-trigger reset architecture: it asserts reset when VCC falls below 2.625V (±2.5%), when MR is pulled low, or when WDI remains static beyond 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - ensuring robust software execution monitoring without false timeouts.

This device uses BiCMOS process with 2848 transistors and operates across –40°C to +85°C. The push-pull active-high RESET output is referenced to VCC and guarantees VOH ≥ 0.8×VCC (ISOURCE = 500µA) and VOL ≤ 0.3V (ISINK = 1.2mA), enabling direct interfacing with µP reset inputs without external level-shifting.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), footprint compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K26DBVR and MAX6365K26D6+T, the MAX6865UK26D6L+T uniquely delivers ultra-low 170nA ICC *with* integrated watchdog - enabling single-chip supervision in battery-sensitive medical wearables where both power efficiency and software reliability are non-negotiable.

Availability

MAX6865UK26D6L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and portable MP3 players requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for MAX6865UK26D6L+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 MAX68xx family targets ultra-low-power microprocessor supervision in battery-operated equipment, emphasizing nanoscale current consumption, wide VCC range, and integrated watchdog functionality for safety-critical firmware monitoring.

FAQ

What is the exact reset threshold voltage of MAX6865UK26D6L+T?

The MAX6865UK26D6L+T has a factory-trimmed reset threshold of 2.625V, with ±2.5% tolerance over –40°C to +85°C. This value is defined by the '26' suffix per Table 2 in the datasheet and is verified across temperature and supply voltage variations. The MAX6865UK26D6L+T guarantees reset assertion when VCC falls below this threshold and deassertion only after VCC exceeds it plus hysteresis.

Does MAX6865UK26D6L+T support active-high or active-low reset output?

The MAX6865UK26D6L+T provides an active-high push-pull RESET output (pin 1), meaning RESET goes high during reset condition and returns low afterward. This is confirmed by the MAX6865-specific pin description and functional diagram. Unlike MAX6864/MAX6866 variants, the MAX6865UK26D6L+T does not offer open-drain or active-low configurations - its output is strictly push-pull active-high.

What is the watchdog timeout period for MAX6865UK26D6L+T?

The MAX6865UK26D6L+T features a watchdog timeout period of 95s (min), 209s (typ), and 487s (max), denoted by the 'L' suffix per Table 3. This long timeout supports firmware with extended processing loops, such as sensor data aggregation or wireless transmission handshakes. The timer resets on any WDI edge, MR assertion, or RESET assertion - ensuring responsiveness without false triggers.

Can MAX6865UK26D6L+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK26D6L+T operates with VCC from 1.2V to 5.5V and guarantees valid reset assertion down to VCC = +1.1V. At 1.2V, its supply current is 190nA (typ), and RESET output meets VOH ≥ 0.8×VCC and VOL ≤ 0.3V specifications. This makes the MAX6865UK26D6L+T suitable for ultra-low-voltage applications like energy-harvesting sensors or backup power domains.

Is external pullup required for the MR input on MAX6865UK26D6L+T?

No, the MR input on MAX6865UK26D6L+T includes an internal 10kΩ pullup resistor to VCC, eliminating the need for external components. The datasheet explicitly states MR is "internally pulled up to VCC through 10kΩ" and recommends leaving MR unconnected or tying it to VCC if unused. This simplifies PCB layout and reduces BOM count in space-constrained designs using the MAX6865UK26D6L+T.