Analog Devices Inc./Maxim Integrated MAX6865UK23D4L+T

Overview

The MAX6865UK23D4L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 2.313V reset threshold, 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered systems to assert active-high push-pull RESET during brownout, power-up, or software fault conditions.

For engineers reviewing the MAX6865UK23D4L+T datasheet, MAX6865UK23D4L+T pinout, MAX6865UK23D4L+T application, or MAX6865UK23D4L+T equivalent, this device serves as a precision, low-power reset and watchdog solution for portable medical and consumer electronics where supply stability and code execution integrity are critical.

Technical Context

The MAX6865UK23D4L+T integrates a precision voltage monitor, a glitch-immune manual reset input with 250ns MR-to-reset delay, and a watchdog timer that triggers reset if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup eliminates external components.

It guarantees valid RESET assertion down to VCC = +1.1V and tolerates short VCC transients - e.g., ≤40µs for a 100mV overdrive - ensuring robust operation in noisy, low-voltage environments typical of glucose monitors and handheld devices.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK23D4L+T and TPS3837K23DBVR, the MAX6865UK23D4L+T uniquely delivers active-high RESET, 170nA quiescent current, and integrated watchdog - making it optimal for space-constrained, battery-critical medical and industrial devices requiring both voltage and software fault coverage.

Availability

MAX6865UK23D4L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign equipment, industrial handheld scanners, and low-power IoT edge sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK23D4L+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 MAX6854–MAX6869 family was engineered specifically for nanopower, battery-operated systems requiring simultaneous voltage supervision and software execution monitoring - targeting portable healthcare, wearables, and remote sensing.

FAQ

What is the exact reset threshold voltage of the MAX6865UK23D4L+T?

The MAX6865UK23D4L+T has a factory-trimmed reset threshold voltage of 2.313V, with guaranteed tolerance of ±2.5% over -40°C to +85°C. This value is fixed per the "23" suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the official datasheet. The MAX6865UK23D4L+T uses this precise threshold to supervise 2.3V–2.4V supply rails common in low-power microcontrollers and analog front-ends.

Does the MAX6865UK23D4L+T require external components for basic operation?

No, the MAX6865UK23D4L+T operates autonomously with zero external components for core functionality: its MR input includes a 10kΩ internal pullup to VCC, the RESET output is push-pull active-high (no pullup resistor needed), and the watchdog timer requires only a clean WDI signal from the host µP. A 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression but is not strictly mandatory in low-noise layouts.

How does the watchdog timer in the MAX6865UK23D4L+T respond to µP activity?

The MAX6865UK23D4L+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 209s (typical, L-suffix). It does not require toggling - a single edge suffices - and remains disabled while RESET is asserted. This behavior allows flexible firmware integration, such as pulsing WDI at subroutine entry/exit, as documented in Figure 6 of the MAX6865UK23D4L+T datasheet.

Can the MAX6865UK23D4L+T operate reliably below 1.8V?

Yes, the MAX6865UK23D4L+T is fully specified from VCC = 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V. At 1.2V, its supply current remains ultra-low (~190nA typ), and RESET output high-level voltage meets VOH ≥ 0.8 × VCC with 200µA source current. This makes the MAX6865UK23D4L+T suitable for single-cell LiFePO₄ (2.5–3.6V) and alkaline/coin-cell (1.0–1.5V) applications where other supervisors fail.

What is the meaning of the 'D4L' suffix in MAX6865UK23D4L+T?

In MAX6865UK23D4L+T, 'D4' denotes the 1200ms minimum reset timeout period (per Table 4), and 'L' specifies the 209s typical watchdog timeout (per Table 3). The '23' indicates the 2.313V reset threshold (Table 2), 'UK' identifies the SOT23-5 package, and '+T' confirms lead-free RoHS-compliant packaging. All suffixes are factory-programmed and non-configurable in-circuit.