Analog Devices Inc./Maxim Integrated MAX6328XR27-T

Overview

MAX6328XR27-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit designed to monitor VCC supply voltage and assert a reset signal when voltage falls below 2.70V (±2.5% over temperature), with a minimum 100ms reset timeout after recovery. It operates from 1.2V to 5.5V, draws ≤1.0µA supply current at 3V, and is housed in a 3-pin SC70-3 package for space-constrained portable and battery-powered systems.

For engineers reviewing the MAX6328XR27-T datasheet, MAX6328XR27-T pinout, MAX6328XR27-T application, or MAX6328XR27-T equivalent, key selection criteria include its factory-trimmed 2.70V reset threshold, open-drain output compatibility with bidirectional µP reset pins (e.g., Motorola 68HC11), ultra-low power consumption, transient immunity, and SC70-3 footprint suitability for high-density PCB layouts.

Technical Context

The MAX6328XR27-T implements a precision bandgap-based reset comparator with 40ppm/°C tempco and 6.3mV hysteresis to prevent chatter during brownout conditions. Its reset assertion logic is fully specified from -40°C to +85°C, with guaranteed correct state down to VCC = 1.0V.

Reset timing is internally generated: VCC-to-reset delay is ≤20µs when VCC drops 100mV below threshold, and the power-up reset timeout is 100–280ms, calibrated to meet MIL-STD and industrial reliability requirements without external components.

Key Specifications

Pinout & Package

MAX6328XR27-T is packaged in a 3-pin SC70-3 outline (package code X3-2), with 0.65mm lead pitch and exposed pad not present. Pin 1 = GND, Pin 2 = RESET (open-drain), Pin 3 = VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD2-T and TPS3808G12DBVR, the MAX6328XR27-T offers the unique combination of open-drain output, ultra-low 1µA supply current, and SC70-3 footprint - making it optimal for battery-backed, multi-source reset architectures where board space and energy efficiency are primary constraints.

Availability

MAX6328XR27-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX6328XR27-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, communications, and consumer applications.

The MAX6328XR27-T belongs to the MAX6326/MAX6327/MAX6328 family of ultra-low-power µP supervisory circuits, engineered specifically for battery-operated and space-constrained systems demanding high reliability and minimal quiescent current.

FAQ

What is the exact reset threshold voltage of MAX6328XR27-T and how does it vary with temperature?

The MAX6328XR27-T has a nominal reset threshold of 2.70V at +25°C, with a tolerance of ±1.5% at room temperature and ±2.5% over the full operating range of -40°C to +85°C. Its temperature coefficient is 40ppm/°C, meaning the threshold drifts by approximately 0.108mV/°C - ensuring predictable brownout behavior across industrial environments. This specification is guaranteed and production-tested per the datasheet Electrical Characteristics table.

Does MAX6328XR27-T require an external pull-up resistor on the RESET pin?

Yes, MAX6328XR27-T requires an external pull-up resistor on the RESET pin because it features an open-drain output. The resistor value must be selected to ensure adequate rise time and noise immunity while limiting current draw - typically 10kΩ to 100kΩ pulled to the same VCC rail or a compatible logic voltage. Without this resistor, the RESET signal cannot transition high, preventing proper µP release from reset.

Can MAX6328XR27-T operate reliably at VCC = 1.2V?

Yes, MAX6328XR27-T is guaranteed to maintain correct reset state (i.e., assert RESET when VCC < 2.70V and hold it asserted until VCC rises above threshold plus hysteresis) down to VCC = 1.2V across the full temperature range. This capability enables use in deep brownout scenarios and ultra-low-power wake-up circuits where the supply may dip below normal operating voltage before recovery.

How does the transient immunity of MAX6328XR27-T compare to standard RC reset circuits?

Unlike RC-based reset generators, MAX6328XR27-T rejects fast VCC transients up to 100µs duration at 200mV overdrive (per Typical Operating Characteristics graph), thanks to its internal comparator hysteresis and filtered sensing path. Standard RC circuits lack this discrimination and often generate false resets during EMI events or switching noise - whereas MAX6328XR27-T's architecture ensures deterministic reset behavior in electrically harsh environments.

Is MAX6328XR27-T pin-compatible with MAX809 series devices?

No, MAX6328XR27-T is not pin-compatible with the MAX809 series. While both use SC70-3 packages, the pinout differs: MAX6328XR27-T uses Pin 1 = GND, Pin 2 = RESET, Pin 3 = VCC; MAX809 variants use Pin 1 = VCC, Pin 2 = GND, Pin 3 = RESET. Swapping them without PCB revision will cause functional failure. However, they are functionally comparable alternatives within the same application space.