Analog Devices Inc./Maxim Integrated MAX6814XK+TG51

Overview

MAX6814XK+TG51 from Maxim Integrated is a low-power, 5-pin SC70 watchdog timer IC that monitors microprocessor software execution by detecting WDI input transitions. It features a 1.6s typical watchdog timeout period, 140ms minimum active-low push-pull WDO pulse, 4µA supply current at 2.5V, and operates across –40°C to +85°C. It is used in embedded controllers for fault detection and system reset initiation.

For engineers reviewing the MAX6814XK+TG51 datasheet, MAX6814XK+TG51 pinout, MAX6814XK+TG51 application, or MAX6814XK+TG51 equivalent, key selection criteria include undervoltage lockout threshold (2.19V), WDI pulse width tolerance (50ns), WDO output drive capability (1.2mA sink), and compatibility with µP I/O timing constraints in safety-critical monitoring.

Technical Context

The MAX6814XK+TG51 implements a monolithic BiCMOS watchdog timer with internal edge-sensitive transition detector on WDI and a dedicated WDO pulse generator. Its 1.6s timeout is temperature-stable (±0.2s over –40°C to +85°C) and resets on any rising or falling edge at WDI - including pulses as short as 50ns.

It integrates undervoltage lockout (UVLO) at 2.19V, forcing WDO low during brownout and holding it low for ≥140ms after VCC recovers. The WDI input is internally serviced when unconnected, disabling watchdog via periodic internal toggling every ~1.4s - eliminating need for external pull-up/down or clock source.

Key Specifications

Pinout & Package

MAX6814XK+TG51 is housed in a 5-pin SC70 package (package code X5+1, outline 21-0076), measuring 2.0mm × 1.25mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar watchdog timer applications.

Compared with MAX6814XK+TG51, MAX6361KA+T offers reduced integration (no UVLO), while TPS3808G125DBVR trades fixed timing for configurability - making MAX6814XK+TG51 optimal for compact, self-contained, ultra-low-power watchdog functions where deterministic 1.6s/140ms timing and brownout immunity are mandatory.

Availability

MAX6814XK+TG51 is available at Aetrix Electronics and suitable for industrial PLC monitoring, medical infusion pump control, and smart energy meter firmware guard requiring stable component supply and long-term lifecycle support.

Supply support for MAX6814XK+TG51 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 high-reliability semiconductor solutions for industrial, medical, and communications markets.

The MAX6814XK+TG51 belongs to Maxim's supervisory and watchdog timer product line, engineered specifically for autonomous, low-power microprocessor monitoring in space- and power-constrained embedded systems.

FAQ

What is the watchdog timeout period of the MAX6814XK+TG51?

The MAX6814XK+TG51 has a typical watchdog timeout period of 1.6 seconds, with a guaranteed range of 1.12s to 2.40s over temperature and voltage. This value defines the maximum interval between valid WDI transitions before the device asserts the WDO output. The timeout is factory-trimmed and stable across –40°C to +85°C, making MAX6814XK+TG51 suitable for timing-critical embedded monitoring where predictable fault detection latency is essential.

Does the MAX6814XK+TG51 include undervoltage lockout functionality?

Yes, the MAX6814XK+TG51 integrates an undervoltage lockout (UVLO) circuit with a threshold of 2.19V. When VCC falls below this level, WDO is forced low and remains low for at least 140ms after VCC rises above the threshold. This ensures reliable reset assertion during power brownout or startup, and is a built-in feature of MAX6814XK+TG51 - no external components are needed to achieve this behavior.

Can the MAX6814XK+TG51 watchdog be disabled without modifying hardware?

Yes, the MAX6814XK+TG51 watchdog can be disabled by leaving the WDI pin unconnected or driving it with a three-stated output. In this state, the internal circuitry services WDI every ~1.4s, preventing timeout. This feature is inherent to MAX6814XK+TG51's design and requires no external jumpers, solder bridges, or configuration registers - enabling field firmware updates without hardware changes.

What is the minimum pulse width the MAX6814XK+TG51 WDI input can detect?

The MAX6814XK+TG51 WDI input reliably detects pulse widths as short as 50ns, provided the signal meets VIH/VIL thresholds (0.7×VCC and 0.3×VCC). This specification is tested and guaranteed across temperature and voltage, allowing direct connection to fast µP GPIO pins without external pulse stretching. The 50ns minimum ensures robust operation even with high-speed toggling in the MAX6814XK+TG51's timing-critical monitoring role.

Is the MAX6814XK+TG51 RoHS-compliant and lead-free?

Yes, the MAX6814XK+TG51 is RoHS-compliant and lead-free. The "+T" suffix in the part number explicitly denotes lead(Pb)-free/RoHS-compliant packaging, per Maxim's ordering convention. The device uses a 5-pin SC70 package with matte tin lead finish and conforms to JEDEC J-STD-020 moisture sensitivity level 1, making MAX6814XK+TG51 suitable for modern lead-free reflow assembly processes.