Analog Devices Inc./Maxim Integrated MAX6348XR37-T

Overview

MAX6348XR37-T from Maxim Integrated is an ultra-low-power open-drain microprocessor supervisory circuit that monitors 3.7V power supplies and asserts an active-low reset signal when VCC falls below 3.700V, maintaining reset for ≥100ms after recovery. It operates from 1.2V to 5.5V, draws ≤1.0µA at 3V, and is housed in a 3-pin SC70-3 package for portable and battery-powered systems.

For engineers reviewing the MAX6348XR37-T datasheet, MAX6348XR37-T pinout, MAX6348XR37-T application, or MAX6348XR37-T equivalent, key selection criteria include its factory-trimmed 3.700V reset threshold (±2.5% over –40°C to +85°C), open-drain output with 0.1µA leakage, 100ms minimum reset timeout, immunity to fast VCC transients, and compatibility with bidirectional µP reset pins such as Motorola 68HC11.

Technical Context

The MAX6348XR37-T implements a precision bandgap-based voltage comparator with 40ppm/°C tempco and 9.5mV hysteresis to detect VCC drops below its 3.700V threshold. Its internal timing circuit guarantees a minimum 100ms reset assertion period after VCC rises above threshold, independent of supply ramp rate.

As an open-drain device, it requires an external pull-up resistor and interfaces directly with bidirectional microcontroller reset pins without level-shifting. It remains functional down to VCC = 1.2V and ignores transients ≤200mV overdrive for durations under 100µs, per typical operating characteristics.

Key Specifications

Pinout & Package

MAX6348XR37-T is packaged in a 3-pin SC70-3 (X3-2 outline) with 0.65mm pitch, footprint-compatible with SOT23-3 but smaller (2.0mm × 1.25mm). The package supports leaded and lead-free assembly (–T suffix denotes lead-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6348XR37-T, the MAX6348UR37-T offers identical supervision performance in a mechanically distinct SOT23 package, while TPS3808G33DBVR provides lower cost for 3.3V-only applications but cannot replace the 3.700V open-drain function without redesigning reset bus topology.

Availability

MAX6348XR37-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart meter data loggers, and automotive body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6348XR37-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 industrial, communications, computing, and consumer applications.

The MAX63xx family delivers ultra-low-power, precision voltage supervision for microprocessor-based systems, targeting battery-operated and noise-prone environments where reliability and minimal quiescent current are critical.

FAQ

What is the exact reset threshold voltage of MAX6348XR37-T and how tightly is it specified?

The MAX6348XR37-T has a factory-trimmed nominal reset threshold of 3.700V. At +25°C, this is guaranteed within ±1.5% (3.645V to 3.755V); over the full –40°C to +85°C operating range, tolerance widens to ±2.5% (3.607V to 3.792V), as confirmed in Table 1 of the official datasheet. This precision eliminates need for external calibration.

Does MAX6348XR37-T support operation at VCC below 2.5V, and what is its minimum functional supply voltage?

Yes, MAX6348XR37-T operates down to VCC = 1.2V across the full temperature range, and its reset comparator remains valid even at this level. The device guarantees correct reset state (asserted when VCC < threshold) for all VCC ≥ 1.2V, enabling use in deep brownout scenarios where other supervisors fail.

Why does MAX6348XR37-T use an open-drain output instead of push-pull, and what design impact does this have?

MAX6348XR37-T uses open-drain output to enable wired-OR reset busing and direct interfacing with microprocessors having bidirectional reset pins (e.g., Motorola 68HC11). This requires an external pull-up resistor but avoids contention during reset arbitration. Push-pull alternatives like MAX6347XR37-T cannot safely share the same reset line without additional logic.

How does MAX6348XR37-T handle short voltage transients on the VCC line, and what is the maximum glitch duration it ignores?

MAX6348XR37-T rejects negative-going VCC transients based on overdrive magnitude: for a 100mV drop below threshold, it ignores glitches up to ~150µs; for a 200mV drop, immunity drops to ~100µs. This behavior is characterized in the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph (Figure 4), preventing false resets from digital switching noise.

Is MAX6348XR37-T pin-compatible with older Maxim supervisors like MAX809, and what are the key mechanical considerations?

MAX6348XR37-T is functionally and pinout-compatible with MAX809-series supervisors in the same SC70-3 package, sharing identical 1-GND / 2-RESET / 3-VCC pin assignment. However, MAX809 uses SOT23-3, so direct PCB replacement requires verifying land pattern compatibility - SC70-3 (X3-2) has smaller pads and tighter pitch than SOT23-3 (U3-1).