Analog Devices Inc./Maxim Integrated MAX6348XR35+

Overview

MAX6348XR35+ from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor 3.3V power supplies and assert a reset signal during brownout or power-up conditions. It features a factory-trimmed 3.3V reset threshold (±1.5% at +25°C), 100ms minimum reset timeout, ultra-low 1µA max supply current, and operates from VCC = 1V to 5.5V. It is used in portable battery-powered systems requiring reliable power-on reset with transient immunity.

For engineers reviewing the MAX6348XR35+ datasheet, MAX6348XR35+ pinout, MAX6348XR35+ application, or MAX6348XR35+ equivalent, key selection criteria include its open-drain RESET output, 3.3V threshold accuracy over temperature, SC70-3 package footprint, and compatibility with bidirectional µP reset pins such as those on Motorola 68HC11 derivatives.

Technical Context

The MAX6348XR35+ implements a precision bandgap-based voltage comparator with hysteresis (9.5mV typical) to detect VCC falling below 3.3V, holding RESET low for ≥100ms after recovery. Its internal reference is trimmed at wafer level to achieve ±1.5% initial accuracy at +25°C and ±2.5% over –40°C to +85°C.

Designed for low-power embedded systems, it draws ≤1µA at 3.3V and remains functional down to VCC = 1V - enabling operation during deep brownout. The open-drain RESET output requires an external pull-up and supports wired-OR configurations with microcontrollers having bidirectional reset pins.

Key Specifications

Pinout & Package

MAX6348XR35+ is housed in a 3-pin SC70-3 package (2.0mm × 2.1mm × 0.9mm), compatible with SOT23-3 footprints but with smaller footprint and thermal profile.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6328UR33+T, MAX6348XR35+ offers superior initial threshold accuracy (±1.5% vs. ±2.5%) critical for high-reliability medical devices; compared with TPS3808G33DBVR, it provides native open-drain flexibility for multi-source reset arbitration without added components.

Availability

MAX6348XR35+ is available at Aetrix Electronics and suitable for portable medical sensors, automotive body control modules, industrial PLC I/O modules, smart energy meters, and battery-backed instrumentation requiring stable component supply and long-term lifecycle support.

Supply support for MAX6348XR35+ 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX63xx family was designed specifically for ultra-low-power, precision voltage monitoring in space- and energy-constrained embedded systems - delivering integrated reset functionality without external passive components.

FAQ

What is the exact reset threshold voltage of MAX6348XR35+ and how tightly is it specified?

The MAX6348XR35+ has a factory-trimmed nominal reset threshold of 3.3V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +85°C operating range. This specification is verified per Maxim's production test flow and documented in the Electrical Characteristics table of the official datasheet. The "R35" suffix explicitly denotes the 3.3V variant within the MAX6348 family.

Does MAX6348XR35+ require an external pull-up resistor on the RESET pin?

Yes, MAX6348XR35+ features an open-drain RESET output and requires an external pull-up resistor to a valid logic rail (e.g., 3.3V or 5V). Typical values range from 4.7kΩ to 10kΩ. This configuration enables wired-OR reset busing - for example, connecting MAX6348XR35+'s RESET to the same net as a watchdog timer or manual reset switch without conflict.

Can MAX6348XR35+ operate reliably below 2.5V, and what is its minimum functional VCC?

Yes, MAX6348XR35+ is fully specified down to VCC = 1.0V, ensuring correct reset assertion and release behavior even during deep brownout conditions. Its internal comparator and bias circuitry remain functional at 1V, and the device guarantees proper state (RESET asserted) for all VCC < 3.3V - making it suitable for energy-harvesting and ultra-low-power applications where supply rails dip below standard logic thresholds.

Is MAX6348XR35+ pin-compatible with older Maxim reset supervisors like MAX809?

No, MAX6348XR35+ is not pin-compatible with MAX809. While both are 3-pin reset ICs, MAX809 uses SOT23-3 with pinout GND–VCC–RESET, whereas MAX6348XR35+ (SC70-3/SOT23-3) follows the pinout GND–RESET–VCC. Swapping them without PCB revision will result in incorrect power connection and failure. Always verify pin mapping using the top-view diagram in the MAX6348 datasheet.

What is the maximum transient duration that MAX6348XR35+ can ignore on the VCC line?

At a 100mV overdrive (i.e., VCC = 3.2V when threshold = 3.3V), MAX6348XR35+ ignores transients up to approximately 200µs, as shown in the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph in the datasheet. This immunity prevents false resets caused by switching regulator noise or ESD-induced supply droop, and is a key differentiator versus basic RC-based reset circuits.