Analog Devices Inc./Maxim Integrated MAX813LESA-T

Overview

MAX813LESA-T from Maxim Integrated is a precision microprocessor supervisory circuit providing active-high reset output, watchdog timer, power-fail warning, and manual-reset input in an 8-pin SO package. It asserts RESET when VCC drops below 4.65V (±2%), delivers a guaranteed 200ms reset pulse width, and monitors battery or auxiliary supplies via its 1.25V PFI threshold-used in industrial controllers and embedded systems requiring reliable power-up/down sequencing.

For engineers reviewing the MAX813LESA-T datasheet, MAX813LESA-T pinout, MAX813LESA-T application, or MAX813LESA-T equivalent, this page delivers verified electrical parameters, thermal operating range (–40°C to +85°C), SO-8 package footprint, and real-world use cases for critical μP power monitoring-including brownout response, watchdog timeout (1.6s), and low-battery detection.

Technical Context

The MAX813LESA-T integrates four core supervisory functions on a single die: a precision voltage monitor with 4.65V reset threshold and 40mV hysteresis, a 1.6-second watchdog timer with edge-sensitive WDI input, a 1.25V comparator for PFI-based power-fail or low-battery signaling, and a debounced TTL/CMOS-compatible manual-reset input with 250μA internal pull-up.

Its RESET output remains valid down to VCC = 1.2V (guaranteed 0.9V high-level output at that rail), and all outputs are fully specified across –40°C to +85°C. The device uses a bandgap reference and precision comparator architecture to ensure monotonic reset assertion/deassertion without chatter during supply ramping or brownout recovery.

Key Specifications

Pinout & Package

MAX813LESA-T is housed in an 8-pin Small Outline (SO) package (JEDEC MS-012, 150mil width), RoHS-compliant, with 1.27mm pitch and gull-wing leads. Thermal performance supports continuous operation at up to +85°C ambient with ≤471mW dissipation (derating 5.88mW/°C above +70°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX813LESA-T, MAX706ESA-T offers earlier reset but lacks active-high RESET and has different threshold tolerance, while MAX809SEUR+T sacrifices all supervision features for minimal size and leakage-neither serves as a functional or pin-compatible substitute.

Availability

MAX813LESA-T is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, telecom remote terminal units, and automotive infotainment gateways requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX813LESA-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 industrial, medical, and communications applications-with emphasis on reliability, integration, and ruggedized operation.

The MAX813L series belongs to Maxim's μP supervisory product line, engineered specifically for robust power-monitoring in mission-critical embedded systems where deterministic reset timing, watchdog integrity, and multi-rail supervision are mandatory.

FAQ

What is the reset threshold voltage for MAX813LESA-T, and how tightly is it specified?

The MAX813LESA-T has a nominal reset threshold of 4.65V with a guaranteed tolerance of ±2% over the full –40°C to +85°C operating range. This specification ensures consistent reset behavior across temperature and supply variations, and is validated per Maxim's Electrical Characteristics table (page 2 of datasheet). The 40mV hysteresis further prevents chatter near the trip point. MAX813LESA-T's precision enables reliable coordination with 5V logic families under worst-case conditions.

Does MAX813LESA-T provide both active-high and active-low reset outputs?

No-MAX813LESA-T provides only an active-high RESET output. Unlike the MAX707/MAX708, it does not include a complementary active-low RESET pin. The device's naming convention ('L' suffix) and Pin Description table (page 5) confirm RESET is the sole reset output. MAX813LESA-T's block diagram (Figure 1) shows no RESET signal path. For dual-output capability, MAX707ESA-T or MAX708ESA-T would be required instead.

Can MAX813LESA-T monitor a 3.3V supply, and how is that implemented?

Yes-MAX813LESA-T can monitor a 3.3V supply using its PFI input. Connect the 3.3V rail to PFI through a resistor divider that scales it to ≤1.25V (e.g., 1.25V/3.3V ≈ 37.9% ratio). When the scaled voltage falls below 1.25V, PFO pulls low to signal undervoltage. The PFI input draws only ±25nA, minimizing loading. This method is explicitly validated in the Applications Information section (page 6) of the MAX813L datasheet and confirmed in Figure 6.

What is the minimum VCC required for MAX813LESA-T to guarantee valid RESET output?

MAX813LESA-T guarantees valid RESET output down to VCC = 1.2V, as stated in the Electrical Characteristics table (page 2) under "RESET Output Voltage" for MAX813LE/M grade. At VCC = 1.2V and ISOURCE = 4μA, RESET is guaranteed ≥0.9V. This ensures clean deassertion during deep brownout recovery-critical for systems experiencing cold-crank or battery sag. The 1.2V minimum applies specifically to the 'E' temperature grade (–40°C to +85°C), which matches MAX813LESA-T.

Is the watchdog timer in MAX813LESA-T enabled by default, and how is it cleared?

Yes-the watchdog timer in MAX813LESA-T is enabled by default when WDI is actively driven (not floating). It clears on any rising or falling edge at WDI, when RESET is asserted, or when WDI is three-stated. Floating WDI disables the watchdog entirely, causing WDO to assert only during VCC brownout. This behavior is documented in the Pin Description (page 5) and Detailed Description (page 6) sections, and confirmed in Figure 1 and Figure 3 of the MAX813L datasheet.