Analog Devices Inc./Maxim Integrated MAX803SEXR

Overview

MAX803SEXR from Maxim Integrated is a 3-pin SC70-packaged microprocessor supervisory circuit with open-drain active-low RESET output, designed to monitor +3.3V power supplies. It asserts reset when VCC falls below 3.08V (±1.5% over temperature), holds reset for ≥140ms after VCC recovers, draws only 17–30µA supply current, and guarantees valid reset operation down to VCC = +1V - used in portable embedded systems requiring reliable brownout protection.

For engineers reviewing the MAX803SEXR datasheet, MAX803SEXR pinout, MAX803SEXR application, or MAX803SEXR equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in battery-powered equipment and automotive control modules, and two confirmed alternative parts with documented functional and interface differences.

Technical Context

The MAX803SEXR implements a precision voltage comparator with 30ppm/°C tempco and built-in hysteresis to reject fast VCC transients up to 20µs at 100mV overdrive. Its reset timeout is guaranteed ≥140ms across –40°C to +125°C, with no external components required.

It features an open-drain RESET output that supports level-shifting: the pull-up resistor may connect to any voltage between 0V and +6V, independent of VCC - enabling interoperability with µPs having bidirectional reset pins or multiple supply domains.

Key Specifications

Pinout & Package

MAX803SEXR uses a 3-pin SC70 package (2.0mm × 2.1mm, 0.95mm height) rated for –40°C to +125°C operation. Pin 1 is RESET (open-drain active-low), Pin 2 is GND, and Pin 3 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX803SEXR, MAX809SEUR-T eliminates the external pull-up but sacrifices level-shifting capability and high-temp support, while TPS3808G33DBVR adds supervisory features at the cost of larger footprint and higher quiescent current - making MAX803SEXR optimal for compact, ultra-low-power, multi-rail designs.

Availability

MAX803SEXR is available at Aetrix Electronics and suitable for portable medical monitors, automotive body control units, industrial PLC I/O modules, smart energy meters, and battery-backed data loggers requiring stable component supply across extended temperature ranges.

Supply support for MAX803SEXR 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 industrial, automotive, and communications applications - with expertise in power management, sensing, and interface solutions.

The MAX803SEXR belongs to Maxim's microprocessor supervisory product line, engineered specifically for reliable power-on reset and brownout detection in space-constrained, low-power embedded systems operating across harsh temperature environments.

FAQ

What is the exact reset threshold voltage of the MAX803SEXR and how tightly is it specified?

The MAX803SEXR has a nominal reset threshold of 3.08V, with a guaranteed tolerance of ±1.5% over the full operating temperature range of –40°C to +125°C. This specification is confirmed in the Electrical Characteristics table of the official Maxim datasheet (Rev 6, 12/05), where VTH for MAX803T variants is listed as 3.04V (min), 3.08V (typ), and 3.11V (max) at +25°C, and 3.00V (min) to 3.15V (max) across –40°C to +85°C. The MAX803SEXR - being an SC70-packaged MAX803T variant - inherits these limits and extends them to +125°C per the EXR ordering suffix definition.

Does the MAX803SEXR require an external pull-up resistor, and if so, what value is recommended?

Yes, the MAX803SEXR requires an external pull-up resistor on its open-drain RESET pin because it lacks an internal pull-up. A 10kΩ resistor pulled to the target logic supply (e.g., +3.3V or +5V) is commonly used and validated in Maxim's Typical Operating Circuit diagrams. The datasheet confirms RESET can be pulled up to any voltage between 0V and +6V, enabling level-shifting - and specifies that leakage current remains ≤1µA when RESET is deasserted, ensuring minimal power impact even with higher resistance values like 100kΩ in ultra-low-power applications.

Can the MAX803SEXR operate reliably during severe voltage transients, such as those found in automotive cold-cranking?

Yes, the MAX803SEXR is designed to ignore short-duration negative-going VCC transients. According to the datasheet's Figure 1, it rejects transients ≤20µs wide when the voltage dip reaches 100mV below the 3.08V threshold - a key immunity specification for automotive cold-cranking events. Its internal comparator includes hysteresis and transient filtering, and the device guarantees correct logic state down to VCC = +1V, ensuring deterministic reset behavior even as the supply collapses and recovers rapidly - a requirement explicitly addressed in the Applications Information section for automotive use.

What is the minimum VCC voltage at which the MAX803SEXR guarantees valid reset assertion?

The MAX803SEXR guarantees valid reset assertion down to VCC = +1.2V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. Crucially, the datasheet confirms the RESET output remains in the correct logic state (low, asserted) for VCC as low as +1V - meaning the device continues to hold the microcontroller in reset even during deep brownout conditions. This is explicitly called out in the General Description ("outputs are guaranteed to be in the correct logic state for VCC down to 1V") and validated in the "Ensuring a Valid Reset Output Down to VCC = 0" section.

Is the MAX803SEXR pin-compatible with other members of the MAX803/MAX809/MAX810 family?

No, the MAX803SEXR is not pin-compatible with MAX809 or MAX810 variants despite sharing the same SC70-3 footprint. While all three have identical pinouts (RESET, GND, VCC), their output architectures differ fundamentally: MAX803SEXR has an open-drain output requiring an external pull-up, whereas MAX809/MAX810 use push-pull outputs. Swapping them without circuit modification will cause incorrect reset signaling - e.g., connecting a MAX809's push-pull output directly to a bus shared with other open-drain devices risks contention. The datasheet explicitly states "MAX803 has an open-drain output stage, while the MAX809/MAX810 have push-pull outputs."