Analog Devices Inc./Maxim Integrated MAX6448UK31L

Overview

MAX6448UK31L from Maxim Integrated is a single-supply microprocessor supervisor IC with one extended-setup manual reset input (MR1) and one immediate-assertion manual reset input (MR2), fixed 3.075V VCC reset threshold, 6.72s MR1 setup timeout, and push-pull active-low RESET output in 5-pin SOT23 package. It monitors VCC only, asserts RESET for ≥140ms after brownout recovery or valid MR1/MR2 activation, and operates across –40°C to +85°C for industrial embedded systems requiring robust power-on reset and front-panel hard-reset control.

For engineers reviewing the MAX6448UK31L datasheet, MAX6448UK31L pinout, MAX6448UK31L application, or MAX6448UK31L equivalent, key selection criteria include its 3.075V fixed reset threshold, dual-mode manual reset (6.72s extended + immediate MR2), guaranteed RESET validity down to VCC = 1.0V, 6µA supply current, and immunity to <100ns glitches on MR2 - critical for set-top boxes, DVD players, and industrial equipment with mechanical pushbuttons.

Technical Context

The MAX6448UK31L implements a precision bandgap-based voltage monitor for VCC with factory-trimmed 3.075V threshold (±1.5% over temperature) and 60ppm/°C tempco. Its dual manual reset architecture separates long-duration system reset (MR1, 6.72s setup) from immediate diagnostic or card-detect functions (MR2 rising-edge triggered).

RESET assertion is strictly one-shot: after MR2 rising edge, it pulses low for 140ms minimum and resets internal timer on subsequent edges within 210ms; MR1 requires sustained low state for full 6.72s before pulse initiation. Both inputs feature internal 50kΩ pullups and 100ns glitch rejection on MR2.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (U5+1), 2.9mm × 1.6mm footprint, lead(Pb)-free, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6447UK31L, MAX6448UK31L eliminates external pullup components via push-pull output; compared with MAX6444US31L, it adds MR2 for immediate diagnostics - making MAX6448UK31L optimal for systems requiring both secure long-press reset and responsive card-detect or test-mode functionality.

Availability

MAX6448UK31L is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and industrial HMI panels requiring stable component supply, long-term lifecycle support, and guaranteed extended-temperature operation.

Supply support for MAX6448UK31L 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 and mixed-signal ICs for industrial, communications, and consumer applications, with expertise in power management and supervisory circuits.

The MAX6443–MAX6452 family delivers ultra-low-power, high-immunity microprocessor supervisors targeting systems with mechanical user interfaces and stringent brownout resilience requirements - especially where nuisance resets must be eliminated.

FAQ

What is the exact reset threshold voltage of the MAX6448UK31L?

The MAX6448UK31L has a factory-trimmed VCC reset threshold of 3.075V, with ±1.5% tolerance over the full –40°C to +85°C temperature range and 60ppm/°C tempco. This value is confirmed in Table 1 of the datasheet under suffix "31", and applies specifically to the MAX6448UK31L - not to other variants in the MAX6443–MAX6452 family.

How does the MR2 input on the MAX6448UK31L differ from MR1?

The MR2 input on the MAX6448UK31L responds to a rising-edge transition with immediate 140ms RESET assertion, while MR1 requires a sustained low state for 6.72 seconds. MR2 also features 210ms internal deassertion debouncing and 100ns glitch rejection - making it ideal for smart-card detect or test-mode triggers - whereas MR1 is designed for secure, intentional system reset.

Does the MAX6448UK31L require an external pullup resistor on the RESET pin?

No, the MAX6448UK31L uses a push-pull RESET output, so no external pullup resistor is required. This differs from open-drain variants like MAX6447UK31L. The push-pull driver can sink 1.2mA at VCC ≥ 2.55V and guarantees valid logic levels down to VCC = 1.0V, simplifying design and improving noise margin.

What is the minimum VCC voltage at which the MAX6448UK31L guarantees valid RESET operation?

The MAX6448UK31L guarantees valid RESET output down to VCC = 1.0V, as explicitly stated in the Features list and Electrical Characteristics table. Below 1.0V, RESET current-sinking capability declines rapidly; for applications requiring validity down to 0V, a 100kΩ external pulldown resistor is recommended - but this applies only to push-pull versions like the MAX6448UK31L.

Can the MAX6448UK31L monitor voltages other than VCC?

No, the MAX6448UK31L monitors VCC only. Unlike MAX6449–MAX6452 variants, it lacks the RSTIN pin and adjustable-threshold comparator. Its fixed 3.075V threshold is optimized for 3.3V supply rails. For dual-rail monitoring or sub-3V thresholds, consider MAX6449UTxxL or MAX6451UTxxL instead - those include RSTIN and support externally adjustable thresholds down to 0.63V.