Analog Devices Inc./Maxim Integrated MAX6348UR44-T

Overview

MAX6348UR44-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor 4.38V power supplies and assert reset during brownout, power-up, and power-down events. It features 1µA max supply current, 100ms min reset timeout, factory-trimmed ±1.5% threshold accuracy at +25°C, and operation down to 1.2V VCC. It is used in portable battery-powered systems requiring reliable, low-power reset assertion.

For engineers reviewing the MAX6348UR44-T datasheet, MAX6348UR44-T pinout, MAX6348UR44-T application, or MAX6348UR44-T equivalent, key selection criteria include open-drain output compatibility with bidirectional µP reset pins (e.g., Motorola 68HC11), transient immunity against negative-going VCC glitches up to 200µs at 100mV overdrive, and SOT23-3 footprint suitability for space-constrained designs.

Technical Context

The MAX6348UR44-T implements a precision bandgap-based reset comparator with 4.38V factory-trimmed threshold and 9.5mV hysteresis, ensuring stable reset deassertion after VCC recovery. Its internal timing circuit guarantees ≥100ms reset pulse width following VCC rise above threshold, independent of temperature across –40°C to +85°C.

As an open-drain device, it requires an external pull-up resistor to interface with µP reset inputs and supports bidirectional reset control-enabling either the supervisor or the microcontroller to assert system reset. It ignores fast transients on VCC due to built-in noise filtering, with maximum tolerable glitch duration decreasing as overdrive increases (e.g., ≤200µs at 100mV overdrive).

Key Specifications

Pinout & Package

MAX6348UR44-T is housed in a 3-pin SOT23-3 package with gull-wing leads, JEDEC MO-178AA compliant, RoHS-compliant (lead-free version uses "+T" suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6328UR44-T, MAX6348UR44-T adds guaranteed -40°C to +85°C operation and tighter production testing; versus TPS3808G33DBVR, it provides exact 4.38V threshold matching, lower max current (1µA vs 2.5µA typ), and open-drain compatibility with legacy µP interfaces.

Availability

MAX6348UR44-T is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC modules, battery-powered instrumentation, and automotive infotainment subsystems requiring stable component supply and long-term lifecycle support.

Supply support for MAX6348UR44-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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer markets.

The MAX63xx family was designed specifically for ultra-low-power, precision voltage supervision in microprocessor-based systems where board space, battery life, and reset reliability are critical constraints.

FAQ

What is the exact reset threshold voltage of MAX6348UR44-T and how tightly is it specified?

The MAX6348UR44-T has a factory-trimmed nominal reset threshold of 4.38V. At +25°C, this is guaranteed within ±1.5% (4.314V to 4.446V); over the full –40°C to +85°C operating range, tolerance widens to ±2.5% (4.270V to 4.489V). This specification is verified per Maxim's production test flow and documented in the Electrical Characteristics table of the official datasheet.

Does MAX6348UR44-T require an external pull-up resistor on its RESET pin?

Yes, MAX6348UR44-T features an open-drain RESET output and requires an external pull-up resistor to a valid logic rail (e.g., VCC or another system voltage). Typical values range from 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements. Without this resistor, the RESET signal cannot transition high and will remain indeterminate.

Can MAX6348UR44-T operate reliably below 2.5V VCC?

Yes, MAX6348UR44-T is fully functional down to 1.2V VCC across its entire temperature range. Its internal bandgap reference and comparator remain stable and accurate at these low voltages, enabling use in ultra-low-power systems such as energy-harvesting sensors or deeply sleep-capable wearables where supply rails dip below conventional logic thresholds.

How does MAX6348UR44-T handle short voltage transients on the VCC line?

MAX6348UR44-T incorporates transient immunity circuitry that rejects negative-going VCC glitches. For example, at 100mV overdrive (i.e., VCC = 4.28V), it tolerates transients up to 200µs without asserting reset. The maximum allowable glitch duration decreases as overdrive increases - a design feature that prevents false resets during switching regulator noise or ESD-induced dips.

Is MAX6348UR44-T pin-compatible with other members of the MAX63xx family?

Yes, MAX6348UR44-T shares identical SOT23-3 pinout (GND, RESET, VCC) and footprint with all MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348 variants. This allows drop-in replacement across threshold and output-type variants - for example, substituting MAX6348UR44-T for MAX6328UR44-T requires no PCB change, only verification of temperature range compliance.