Analog Devices Inc./Maxim Integrated MAX16040PLA23+T

Overview

The MAX16040PLA23+T from Maxim Integrated is an 8-pin μDFN battery-backup supervisory IC with auxiliary adjustable-reset input (RESETIN), active-low open-drain reset output, and power-fail comparator. It operates from 1.2V to 5.5V, features a factory-set 2.32V reset threshold, 140ms minimum reset timeout, and draws only 13µA quiescent current. It is used in portable equipment for SRAM backup and brownout protection during VCC drop.

For engineers reviewing the MAX16040PLA23+T datasheet, MAX16040PLA23+T pinout, MAX16040PLA23+T application, or MAX16040PLA23+T equivalent, key selection criteria include its RESETIN comparator threshold (1.235V), battery switchover hysteresis (40mV), open-drain reset structure, -40°C to +85°C operation, and 2mm × 2mm μDFN-8 package compatibility with space-constrained embedded designs.

Technical Context

The MAX16040PLA23+T implements a precision 1.235V internal reference for its RESETIN comparator, enabling user-adjustable monitoring of secondary supplies via external resistor dividers. Its battery switchover logic activates when VCC falls below both the 2.32V reset threshold and VBATT, with 40mV hysteresis to prevent chatter during slow VCC decay.

It integrates an independent power-fail comparator (PFI/PFO) referenced to the same 1.235V threshold, asserting PFO low on voltage droop. The open-drain RESET output supports wired-OR configurations and requires an external pull-up; it remains valid down to 1.2V VCC and asserts for ≥140ms after VCC recovery.

Key Specifications

Pinout & Package

MAX16040PLA23+T is housed in an 8-pin, 2mm × 2mm µDFN package with exposed pad (thermal performance optimized for low-power operation). Pin 1 is marked by a dot; pin numbering follows standard counter-clockwise convention from the dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX16036PLA23+T, MAX16040PLA23+T saves board space with its 8-pin μDFN but omits chip-enable gating; versus TPS3808G33DBVR, it offers lower reset voltage, user-adjustable RESETIN, and open-drain flexibility at the cost of higher complexity and narrower VCC range.

Availability

MAX16040PLA23+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC data loggers, point-of-sale terminals, and smart meters requiring stable component supply and long-term lifecycle support.

Supply support for MAX16040PLA23+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 demanding industrial, computing, and communications applications.

The MAX16033–MAX16040 family delivers low-power, small-footprint supervisory solutions for battery-backed memory and microprocessor systems requiring reliable power monitoring and switchover control.

FAQ

What is the factory-set reset threshold voltage for the MAX16040PLA23+T?

The MAX16040PLA23+T has a factory-set reset threshold of 2.32V (minimum 2.25V, maximum 2.38V) with ±7mV tolerance over temperature. This value is laser-trimmed during production and applies to the VCC supply monitoring function. The device uses this threshold to assert RESET when VCC falls below 2.32V and maintain it for ≥140ms after VCC rises above the threshold. The MAX16040PLA23+T does not support field adjustment of this primary reset threshold.

How does the RESETIN input function in the MAX16040PLA23+T?

The RESETIN input in the MAX16040PLA23+T connects to an internal 1.235V comparator. When the voltage at RESETIN falls below 1.235V, the device asserts RESET regardless of VCC level. This allows monitoring of auxiliary power rails (e.g., 3.3V, 5V) using an external resistor divider. The MAX16040PLA23+T specifies RESETIN input current ≤25nA, enabling use of high-value resistors (up to 1MΩ) without significant threshold error. RESET remains asserted for ≥140ms after RESETIN rises above 1.235V.

What is the battery switchover behavior of the MAX16040PLA23+T?

The MAX16040PLA23+T switches OUT from VCC to BATT when two conditions are met: VCC falls below the 2.32V reset threshold and VCC is at least 40mV lower than VBATT. This 40mV hysteresis prevents rapid toggling during slow VCC decay. In backup mode, OUT is sourced from BATT, and RESET is asserted. The device draws only 1–2µA from BATT (at 2.8V) while VCC = 0V, maximizing battery life. The MAX16040PLA23+T does not power up from BATT alone-it requires VCC for initial startup.

Does the MAX16040PLA23+T support both push-pull and open-drain reset outputs?

No-the MAX16040PLA23+T exclusively features an active-low open-drain RESET output, as indicated by the "P" in its part number suffix (MAX16040Pxx). It requires an external pull-up resistor to VCC or another appropriate rail. Unlike the "L"-suffixed variants (e.g., MAX16040LLA23+T), the MAX16040PLA23+T does not provide push-pull drive capability. This open-drain configuration enables wired-OR connections with other reset sources and simplifies level-shifting in multi-rail systems.

What package type and dimensions does the MAX16040PLA23+T use?

The MAX16040PLA23+T uses an 8-pin, 2mm × 2mm µDFN package with exposed thermal pad. Its footprint measures 2.0mm × 2.0mm with 0.5mm pin pitch, and total height is 0.55mm max. This compact package supports high-density PCB layouts typical in portable and industrial edge devices. The device is RoHS-compliant and lead-free ("+T" denotes tape-and-reel packaging). Pin 1 is identified by a dot; the pinout matches the MAX16037–MAX16040 8-pin variant group per Maxim's datasheet.