Analog Devices Inc./Maxim Integrated MAX6404BS33

Overview

MAX6404BS33 from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-trimmed 3.30V reset threshold (±2.5% over –40°C to +85°C), 100ms minimum reset timeout, and 500nA typical supply current at 3.0V. It monitors regulated system voltage in portable battery-powered equipment and asserts RESET high during brownout or power-up sequencing.

For engineers reviewing the MAX6404BS33 datasheet, MAX6404BS33 pinout, MAX6404BS33 application, or MAX6404BS33 equivalent, this device is selected for low-voltage, space-constrained designs requiring guaranteed reset validity down to VCC = 1.0V, immunity to short VCC transients, and no external components.

Technical Context

The MAX6404BS33 integrates a precision bandgap reference comparator and internal reset timer, asserting active-high RESET when VCC falls below 3.30V and holding it high for ≥100ms after VCC rises above threshold. Its push-pull output drives directly without pullup, and manual reset (MR) input features 50kΩ internal pullup and 1µs minimum pulse width support.

Designed for BiCMOS process with 512 transistors, the device operates across 1.2V–5.5V supply range and guarantees correct logic state down to VCC = 1.0V. Reset threshold hysteresis is 9.5mV, tempco is 40ppm/°C, and VCC-to-RESET delay is 20µs under specified overdrive conditions.

Key Specifications

Pinout & Package

MAX6404BS33 is housed in a 4-bump (2×2 mm) UCSP chip-scale package - footprint 70% smaller than SC70 - with solder bumps on underside for direct PCB mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6401BS33-T and TPS3808G33DBVR, MAX6404BS33-T delivers lower quiescent current, guaranteed 3.30V threshold within its designated family group, and push-pull output eliminating external components - making it optimal for compact, long-life 3.3V system supervision.

Availability

MAX6404BS33 is available at Aetrix Electronics and suitable for portable medical sensors, wearable fitness trackers, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and tape-and-reel delivery for automated assembly.

Supply support for MAX6404BS33 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) is a semiconductor company specializing in analog, mixed-signal, and power-management ICs for industrial, automotive, and consumer applications.

The MAX6400–MAX6405 family was designed specifically for ultra-low-power microprocessor supervision in space-constrained, battery-operated systems - emphasizing minimal footprint, sub-µA current, and factory-trimmed voltage thresholds.

FAQ

What is the exact reset threshold voltage of MAX6404BS33 and how accurate is it over temperature?

The MAX6404BS33 has a factory-trimmed nominal reset threshold of 3.30V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40°C to +85°C. This specification is confirmed in Table 1 of the datasheet and applies specifically to the MAX6404BS33 variant within the 3.30V–4.63V family group. The MAX6404BS33 achieves this accuracy using a precision bandgap reference comparator and laser trimming during production.

Does MAX6404BS33 require external components for basic reset functionality?

No, MAX6404BS33 requires no external components for core supervision functionality. It integrates a precision voltage reference, comparator, reset timer, and 50kΩ internal pullup on the MR pin. The active-high push-pull RESET output drives directly into a microcontroller's reset input without needing a pullup resistor - unlike open-drain alternatives. Only a bypass capacitor on VCC is recommended for noise suppression, but not required for functional operation.

What is the minimum supply voltage at which MAX6404BS33 guarantees correct reset logic state?

MAX6404BS33 guarantees correct output logic state - including valid active-high RESET assertion - down to VCC = 1.0V. This is explicitly stated in the General Description and Electrical Characteristics sections of the datasheet. The device remains functional and maintains defined reset behavior even during deep brownout conditions, enabling robust recovery in low-voltage battery scenarios.

How does the manual reset (MR) input behave on MAX6404BS33?

On MAX6404BS33, the MR input is active-low with an internal 50kΩ pullup to VCC. When MR is pulled low (e.g., via momentary switch to GND), RESET goes high immediately and remains high for the full reset timeout period (≥100ms) after MR returns high. The minimum MR pulse width is 1µs, and the input rejects glitches <100ns. No external pullup or debouncing circuitry is needed, simplifying hardware design.

What package type and dimensions does MAX6404BS33 use, and what are its assembly implications?

MAX6404BS33 uses a 4-bump UCSP (chip-scale package) measuring 2mm × 2mm with solder bumps on the underside. It is 70% smaller than SC70 and requires reflow soldering at peak temperatures up to +235°C. Assembly must follow Maxim's UCSP reliability guidelines - including board material selection, stencil design, and thermal profile - because mechanical stress performance depends heavily on user PCB layout and process, not just the die itself.