Analog Devices Inc./Maxim Integrated MAX6865UK19D2L+T

Overview

The MAX6865UK19D2L+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%), 40ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK19D2L+T datasheet, MAX6865UK19D2L+T pinout, MAX6865UK19D2L+T application, or MAX6865UK19D2L+T equivalent, key selection criteria include its 1.9V VTH tolerance at -40°C to +85°C, guaranteed RESET validity down to VCC = 1.1V, MR glitch rejection of 200ns, and compatibility with noisy low-voltage systems requiring <200nA quiescent current.

Technical Context

The MAX6865UK19D2L+T implements a precision bandgap-based voltage monitor with 2.5% hysteresis, a digital watchdog timer cleared by WDI edges (min pulse width 150ns), and an internal 10kΩ MR pullup. Its reset assertion logic combines VCC monitoring, MR input, and watchdog expiration - all triggering the same active-high push-pull RESET output with fixed 40ms timeout (D2 option).

Unlike variants with CT or open-drain outputs, the MAX6865UK19D2L+T uses dedicated WDI and MR inputs, supports no timeout select, and guarantees valid RESET operation down to VCC = 1.1V while maintaining 0.8×VCC VOH and 0.3V VOL under specified load conditions.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK19D2L+T, the MAX6864UK19D2L+T removes MR functionality to reduce complexity and cost in unattended systems, while the TPS3837K25DBVR trades nanopower operation and watchdog capability for broader voltage tolerance and simpler qualification in non-portable designs.

Availability

MAX6865UK19D2L+T is available at Aetrix Electronics and suitable for glucose monitoring systems, portable patient monitors, industrial handheld scanners, and low-power IoT edge sensors requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6865UK19D2L+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, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6865UK19D2L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power battery-operated medical and portable electronics requiring guaranteed reset behavior across wide temperature and voltage ranges.

FAQ

What is the exact reset threshold voltage of the MAX6865UK19D2L+T?

The MAX6865UK19D2L+T has a factory-trimmed reset threshold of 1.9V 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 "19" corresponds to 1.9V nominal VTH. The device guarantees valid RESET assertion down to VCC = 1.1V, making it suitable for systems with steep battery discharge curves.

Does the MAX6865UK19D2L+T support both manual reset and watchdog functionality?

Yes, the MAX6865UK19D2L+T integrates both manual reset (MR) and watchdog timer (WDI) functions. MR is an active-low input with internal 10kΩ pullup and 200ns glitch rejection; WDI is edge-sensitive and clears the 209s watchdog timer on any rising or falling transition. Both independently trigger the same active-high push-pull RESET output, as verified in the Pin Description and Selector Guide sections.

What is the reset timeout period for the MAX6865UK19D2L+T?

The MAX6865UK19D2L+T uses the D2 reset timeout option, providing a minimum reset pulse width of 40ms. This is defined in Table 4 (Reset Timeout Periods) and confirmed by the "D2" suffix in the part number. The timeout is fixed and non-adjustable - unlike MAX6861–MAX6863 variants, this device does not feature a CT pin for dynamic timeout selection.

How does the MAX6865UK19D2L+T watchdog timer operate?

The MAX6865UK19D2L+T watchdog timer expires after 209s (typical) if no edge is detected on the WDI pin. It resets on any rising or falling edge (min pulse width 150ns) and remains disabled while RESET is asserted. The L suffix indicates the long timeout variant, distinct from the 3.3s S option. Watchdog activity increases supply current proportionally to switching frequency, as shown in Figure MAX6854 toc10.

Is the MAX6865UK19D2L+T pin-compatible with other MAX68xx devices?

The MAX6865UK19D2L+T uses the standard 5-pin SOT23-5 package with identical pinout to MAX6864/MAX6866 variants: Pin 1 = RESET (active-high push-pull), Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. It is not pin-compatible with MAX6861–MAX6863 (CT pin replaces WDI) or MAX6854–MAX6856 (no WDI). Mechanical compatibility is confirmed in the Pin Configurations diagram on page 15.