Analog Devices Inc./Maxim Integrated MAX6315US28D4+T

Overview

The MAX6315US28D4+T from Analog Devices is a low-power CMOS microprocessor supervisory circuit that monitors VCC supply voltage and asserts an open-drain active-low RESET signal when voltage falls below 2.83V or when manual reset (MR) is asserted. It features a factory-trimmed 2.83V reset threshold, 1120ms minimum reset timeout period, 5μA typical supply current at +25°C, and operates across –40°C to +125°C. It is used in battery-powered controllers and embedded systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6315US28D4+T datasheet, MAX6315US28D4+T pinout, MAX6315US28D4+T application, or MAX6315US28D4+T equivalent, key selection criteria include its SOT23-4 open-drain reset output, immunity to short VCC transients, guaranteed operation over temperature, and compatibility with μP reset inputs requiring extended timeout for firmware initialization.

Technical Context

The MAX6315US28D4+T implements a precision voltage-monitoring comparator with laser-trimmed internal resistors to set the 2.83V reset threshold, and an internal monostable timer that guarantees RESET remains asserted for ≥1120ms after VCC rises above threshold or MR deasserts. Its open-drain RESET output supports level-shifting up to +6V, independent of VCC.

It integrates a 63kΩ internal pullup on MR, enabling direct connection of a momentary switch to GND without external components. The device is immune to VCC transients ≤100ns and maintains reset assertion down to VCC = 1.0V, ensuring robust operation during deep brownouts.

Key Specifications

Pinout & Package

MAX6315US28D4+T is housed in a RoHS-compliant 4-pin SOT23 package (package code U4+1), with 1.3mm × 2.9mm footprint and 0.95mm height. Pin 1 is GND, Pin 2 is RESET (open-drain), Pin 3 is MR (manual reset input), and Pin 4 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6315US28D3+T and TPS3808G33DBVR, the MAX6315US28D4+T uniquely combines a 2.83V precision threshold, 1120ms timeout, integrated MR pullup, and open-drain level-shifting - making it optimal for battery-powered and mixed-rail systems requiring extended reset hold times and field-serviceable reset initiation.

Availability

MAX6315US28D4+T is available at Aetrix Electronics and suitable for industrial PLC controllers, battery-powered data loggers, automotive body control modules, and medical handheld diagnostics requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6315US28D4+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The MAX6315US28D4+T belongs to the MAX6315 family of micropower supervisory circuits designed specifically for reliable power-on reset, brownout detection, and manual reset coordination in space-constrained, low-power embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6315US28D4+T?

The MAX6315US28D4+T has a factory-trimmed nominal reset threshold voltage of 2.83V, with tolerance of ±3.5% over the full operating temperature range of –40°C to +125°C. This value is laser-trimmed during manufacturing and specified in the Ordering Information table of the official datasheet. The MAX6315US28D4+T does not support user adjustment or external resistor programming of the threshold.

Does the MAX6315US28D4+T require an external pullup resistor on the RESET pin?

Yes, the MAX6315US28D4+T features an open-drain RESET output and requires an external pullup resistor to establish a valid logic-high level. A 10kΩ resistor pulled to a voltage ≤6V is recommended and sufficient in most designs. The MAX6315US28D4+T itself does not provide internal pullup on RESET - this is distinct from its internal MR pullup.

Can the MAX6315US28D4+T operate with VCC below 2.83V and still assert RESET?

Yes - the MAX6315US28D4+T continues asserting RESET as long as VCC remains below 2.83V (within its operational range), and remains asserted for the full 1120ms timeout after VCC rises above threshold. It functions down to VCC = 1.0V, ensuring reset remains active even during deep brownout conditions where other supervisors may release prematurely.

Is the MR pin of the MAX6315US28D4+T compatible with direct switch-to-ground connection?

Yes - the MAX6315US28D4+T includes a 63kΩ internal pullup resistor on the MR pin, allowing direct connection of a normally-open momentary switch between MR and GND. No external resistor or debounce circuitry is required, though a 0.1μF capacitor from MR to GND is recommended in electrically noisy environments.

What is the maximum allowable voltage on the RESET pin of the MAX6315US28D4+T?

The RESET pin of the MAX6315US28D4+T is rated for voltages up to +6.0V, independent of VCC. This allows the MAX6315US28D4+T to drive reset lines referenced to higher supply rails (e.g., 5.0V) while monitoring a lower VCC (e.g., 2.8V), enabling level-shifted reset signaling in mixed-voltage systems.