Analog Devices Inc./Maxim Integrated MAX6866UK46D3L+T

Overview

MAX6866UK46D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.625V reset threshold (±2.5%), 300ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-low open-drain RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6866UK46D3L+T datasheet, MAX6866UK46D3L+T pinout, MAX6866UK46D3L+T application, or MAX6866UK46D3L+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, compatibility with 1.2V–5.5V supply range, and lead-free SOT23-5 packaging for space-constrained portable designs.

Technical Context

The MAX6866UK46D3L+T implements a voltage-monitoring comparator with hysteresis (0.5% of VTH), a precision timeout generator for reset assertion, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

It operates across -40°C to +85°C with supply voltage from 1.2V to 5.5V, guarantees VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.12V), and supports open-drain RESET output requiring external pullup - distinct from push-pull variants in the same family.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm height - optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK46D3L+T, MAX6866UK46D3L+T provides open-drain flexibility for multi-voltage domain reset buses; versus TPS3838K33DBVR, it delivers 90% lower supply current and integrated watchdog - critical for long-life portable medical devices.

Availability

MAX6866UK46D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient loggers, industrial scanners, and low-power IoT sensors requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6866UK46D3L+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications, with emphasis on reliability and low-power innovation.

The MAX6854–MAX6869 family was developed specifically for nanopower supervisory functions in battery-critical portable electronics - delivering ultra-low ICC, wide VCC range, and integrated watchdog without external timing components.

FAQ

What is the exact reset threshold voltage of MAX6866UK46D3L+T?

The MAX6866UK46D3L+T has a factory-trimmed reset threshold of +4.625V, with tolerance of ±2.5% over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "46" corresponds to nominal 4.625V. The device guarantees valid RESET assertion down to VCC = +1.1V, independent of threshold accuracy.

Does MAX6866UK46D3L+T support both manual reset and watchdog functionality?

Yes, MAX6866UK46D3L+T integrates both manual reset (MR pin) and watchdog timer (WDI pin). MR is an active-low input with 10kΩ internal pullup; WDI detects rising/falling edges and triggers reset if static for >209s (typ). Both functions independently assert the same open-drain RESET output, with reset held for 300ms minimum after either event.

What package type and lead finish does MAX6866UK46D3L+T use?

MAX6866UK46D3L+T uses a 5-pin SOT23-5 package with lead-free (RoHS-compliant) finish. The "+T" suffix explicitly denotes lead-free packaging per Maxim's ordering convention. Dimensions are 2.9mm × 1.6mm × 0.95mm, compatible with standard SMT reflow profiles.

Can MAX6866UK46D3L+T operate from a 1.8V supply?

Yes, MAX6866UK46D3L+T operates across VCC = 1.2V to 5.5V. At 1.8V, its supply current is 170nA (typ), RESET output VOL is ≤0.3V at ISINK = 500µA, and it guarantees RESET validity down to VCC = +1.1V. However, the 4.625V threshold means it will assert reset immediately at 1.8V - so it must monitor a higher-voltage rail, not its own VCC.

Is MAX6866UK46D3L+T pin-compatible with other parts in the MAX68xx family?

MAX6866UK46D3L+T shares the same 5-pin SOT23-5 pinout as MAX6864/MAX6865/MAX6866 variants (pin 1=RESET, 2=GND, 3=MR, 4=WDI, 5=VCC), but is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify pin function alignment using the Selector Guide.