Analog Devices Inc./Maxim Integrated MAX6865UK23D5L+T

Overview

The MAX6865UK23D5L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.313V reset threshold (suffix '23'), 300ms minimum reset timeout (suffix 'D5'), and 209s typical watchdog timeout (suffix 'L'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout (WDI), targeting battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK23D5L+T datasheet, MAX6865UK23D5L+T pinout, MAX6865UK23D5L+T application, or MAX6865UK23D5L+T equivalent, key selection criteria include guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and compatibility with noisy low-power systems requiring robust brownout and software fault recovery.

Technical Context

This device integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy over temperature, a manual reset input with 250ns MR-to-reset delay and internal 10kΩ pullup, and a watchdog timer that clears on any WDI edge and expires after 209s (typ) if inactive - all operating from 1.2V to 5.5V supply.

The MAX6865UK23D5L+T uses BiCMOS process technology (2848 transistors) and implements a fixed-function analog timing architecture: reset timeout is generated by an internal RC-based timer (D5 = 300ms min), while watchdog timeout relies on a separate oscillator with ±25% variation over -40°C to +85°C, as confirmed by normalized tWD vs. temperature curves.

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 MAX6864UK23D5S+T and TPS3837K23DBVR, the MAX6865UK23D5L+T uniquely balances ultra-low ICC (170nA), long watchdog timeout (209s), and guaranteed 1.1V reset validity - making it optimal for energy-constrained medical and sensor nodes where both longevity and fault coverage are non-negotiable.

Availability

MAX6865UK23D5L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and low-power industrial sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK23D5L+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family was designed specifically for nanopower microprocessor supervision in space- and energy-constrained portable systems, emphasizing ultra-low ICC, wide VCC range, and integrated watchdog functionality without external components.

FAQ

What is the exact reset threshold voltage of the MAX6865UK23D5L+T?

The MAX6865UK23D5L+T has a factory-trimmed reset threshold voltage of 2.313V, with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is defined by the '23' suffix in the part number and is verified per Electrical Characteristics table in the datasheet. The MAX6865UK23D5L+T guarantees valid reset assertion down to VCC = +1.1V, ensuring reliable operation even during severe brownout conditions.

Does the MAX6865UK23D5L+T require external components for basic operation?

No, the MAX6865UK23D5L+T operates fully autonomously with no external components required for core supervision functions. Only a 0.1µF ceramic bypass capacitor from VCC to GND is recommended for noise suppression in noisy environments. The MR input features an internal 10kΩ pullup, and the push-pull active-high RESET output drives CMOS loads directly - eliminating need for pullup resistors or timing capacitors. This simplifies design and reduces BOM count.

How does the watchdog timer in the MAX6865UK23D5L+T clear and expire?

The MAX6865UK23D5L+T watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than the 209s typical timeout period. It does not monitor level duration alone - edge detection is mandatory. The timer is also cleared when reset is asserted or MR is pulled low. Once expired, it triggers a full reset pulse for the 300ms timeout period, after which normal supervision resumes.

Can the MAX6865UK23D5L+T be used with a 1.2V supply rail?

Yes, the MAX6865UK23D5L+T is fully specified to operate from VCC = 1.2V to 5.5V. At 1.2V, its supply current remains ultra-low (≤400nA max), and reset output remains valid (VOH ≥ 0.8×VCC). However, note that the 2.313V reset threshold means the device will assert reset immediately at 1.2V - so it must supervise a higher-voltage rail (e.g., 2.3V or 3.3V) while being powered from a separate 1.2V domain only if level-shifting is implemented. Its native use case is monitoring rails ≥2.3V.

What is the maximum VCC transient duration the MAX6865UK23D5L+T can ignore?

The MAX6865UK23D5L+T is immune to VCC transients ≤40µs in duration when the overdrive is 100mV above its 2.313V threshold (i.e., up to 2.413V). This immunity is characterized in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph. Shorter transients (e.g., 200ns MR glitches or 10µs switching noise) are rejected without triggering reset, enhancing robustness in electrically noisy portable systems where the MAX6865UK23D5L+T is commonly deployed.