Analog Devices Inc./Maxim Integrated MAX6468US22D3+

Overview

MAX6468US22D3+ from Maxim Integrated is a push-pull, active-low microprocessor supervisory reset circuit monitoring +2.188V nominal supply voltage with 150ms minimum reset timeout, factory-trimmed threshold accuracy (±2.5% over -40°C to +85°C), and operation down to VCC = +1V - used in automotive engine control units to ensure deterministic µP reset during cold-crank brownout events.

For engineers reviewing the MAX6468US22D3+ datasheet, MAX6468US22D3+ pinout, MAX6468US22D3+ application, or MAX6468US22D3+ equivalent, key selection criteria include its SOT143-4 package, edge-triggered manual reset with 150ms one-shot pulse, immunity to <100ns MR glitches, 3µA supply current at 1.8V, and guaranteed RESET validity to VCC = +1V.

Technical Context

The MAX6468US22D3+ implements a precision bandgap-based voltage comparator with hysteresis to detect VCC drops below its +2.188V threshold, triggering an internal monostable that asserts active-low RESET for ≥150ms after recovery. Its MR input uses edge-triggered logic with 150ms rising-edge debounce to reject switch bounce.

Unlike open-drain variants (e.g., MAX6467), the MAX6468US22D3+ features a push-pull RESET output capable of sourcing 500µA at VCC ≥ +2.5V while sinking 1.2mA, eliminating external pull-up resistors. It operates across -40°C to +125°C with BiCMOS process technology and 748 transistor count.

Key Specifications

Pinout & Package

MAX6468US22D3+ is housed in a 4-pin SOT143-4 package (3.0mm × 1.5mm × 1.3mm height), surface-mount, lead-free (RoHS-compliant), rated for -40°C to +125°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6386US22D3+, MAX6468US22D3+ eliminates external pull-up and simplifies layout; versus TLV809E22DBZR, it adds MR support and higher temperature rating (+125°C vs. +85°C), making it suitable for automotive and industrial environments where manual reset and extended thermal range are mandatory.

Availability

MAX6468US22D3+ is available at Aetrix Electronics and suitable for automotive engine control units, industrial programmable logic controllers, medical infusion pump controllers, DSL modem power management, and GPS navigation systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6468US22D3+ 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, automotive, and communications applications.

The MAX6468US22D3+ belongs to the MAX6467/MAX6468 family of microprocessor supervisory circuits engineered specifically for robust reset generation in harsh environments - emphasizing accuracy, low power, and immunity to voltage transients in automotive and industrial control systems.

FAQ

What is the exact reset threshold voltage of MAX6468US22D3+ and how is it trimmed?

The MAX6468US22D3+ has a factory-trimmed nominal reset threshold of +2.188V, with ±2.5% tolerance over -40°C to +85°C and ±3% over -40°C to +125°C. This value is laser-trimmed during wafer test to match the '22' suffix designation in the ordering code and is verified per device - not binned or statistically selected. The threshold is referenced to an internal bandgap and remains stable across temperature and supply variations.

Does MAX6468US22D3+ require an external pull-up resistor on the RESET pin?

No, MAX6468US22D3+ does not require an external pull-up resistor because it features a push-pull RESET output. Unlike the open-drain MAX6467 variant, the MAX6468US22D3+ actively drives RESET high (VOH ≥ 0.8×VCC) when deasserted and low (VOL ≤ 0.3V) when asserted, enabling direct connection to µP RESET inputs without additional components.

What is the function of the MR pin on MAX6468US22D3+ and how does its debounce work?

The MR pin on MAX6468US22D3+ is an edge-triggered manual reset input that initiates a fixed 150ms one-shot RESET pulse on each detected falling edge. After MR rises, the device enforces a 150ms rising-edge debounce period (tDEB) during which subsequent falling edges are ignored - preventing false resets from mechanical switch bounce. An internal 1.5kΩ pull-up to VCC allows MR to float unused.

Can MAX6468US22D3+ operate reliably during automotive cold-crank conditions?

Yes, MAX6468US22D3+ is qualified for automotive use (-40°C to +125°C) and maintains valid RESET assertion down to VCC = +1V. During cold-crank, when battery voltage may dip below 6V with high ripple, the device continues monitoring and asserting RESET until VCC recovers above +2.188V and sustains for ≥150ms - ensuring µP reset integrity even under worst-case brownout.

How does the 100ns MR glitch rejection specification impact system design?

MAX6468US22D3+ rejects MR input pulses shorter than 100ns, meaning noise spikes or EMI-induced transients on the manual reset line will not trigger unintended resets. This eliminates the need for RC filters or firmware debouncing, simplifying PCB layout and reducing µP processing overhead - especially valuable in electrically noisy automotive or industrial environments where MR traces may run near motors or switching regulators.