Analog Devices Inc./Maxim Integrated MAX6337US20D3-T

Overview

MAX6337US20D3-T from Maxim Integrated is an ultra-low-voltage, open-drain microprocessor supervisory circuit designed for 1.8V–3.3V digital systems. It monitors VCC and asserts an active-low RESET signal when supply voltage falls below 2.00V or when manual reset (MR) is triggered, with a guaranteed 100ms minimum timeout period and valid operation down to VCC = 1.0V. Used in portable equipment and automotive controllers for reliable power-on/brownout reset generation.

For engineers reviewing the MAX6337US20D3-T datasheet, MAX6337US20D3-T pinout, MAX6337US20D3-T application, or MAX6337US20D3-T equivalent, key selection considerations include its 2.00V factory-trimmed reset threshold, 100ms reset timeout, open-drain output architecture, -40°C to +125°C operating range, and SOT143 package compatibility with MAX811/MAX6314 families.

Technical Context

The MAX6337US20D3-T implements a precision bandgap-based reset comparator with ±1.8% (25°C) and ±3% (-40°C to +125°C) threshold accuracy at 2.00V, immune to fast VCC transients up to 24µs at 10V/ms slew rate. Its internal 20kΩ MR pull-up enables direct switch-to-GND manual reset without external components.

As an open-drain supervisor, it interfaces natively with bidirectional µP reset pins (e.g., Motorola 68HC11) via external pull-up; RESET remains asserted during VCC < 2.00V or MR low, then holds for ≥100ms after recovery. It draws only 3.0–6.0µA at 1.8V and operates continuously from VCC = 1.0V to 5.5V.

Key Specifications

Pinout & Package

MAX6337US20D3-T is housed in a 4-pin SOT143 package (JEDEC TO-236AB), measuring 2.9mm × 1.3mm × 1.0mm, with gull-wing leads and lead-free (RoHS-compliant) finish available as MAX6337US20D3+T.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6337US20D3-T, MAX6314US20D3-T provides stronger drive capability and deeper brownout support but forfeits open-drain flexibility; TLV809E20DBZR offers lower power and broader VCC range but omits manual reset and extended temperature qualification.

Availability

MAX6337US20D3-T is available at Aetrix Electronics and suitable for portable instrumentation, automotive body electronics, and industrial sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6337US20D3-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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX633x family delivers ultra-low-voltage, low-power supervisory circuits targeting space- and power-constrained embedded systems where deterministic reset behavior under brownout and transient conditions is mission-critical.

FAQ

What is the factory-trimmed reset threshold voltage for MAX6337US20D3-T?

The MAX6337US20D3-T has a factory-trimmed reset threshold of 2.00V, with ±1.8% tolerance at +25°C and ±3% over the full -40°C to +125°C operating range. This value is laser-trimmed during production and documented in Table 1 of the MAX6335/MAX6336/MAX6337 datasheet. The 2.00V point ensures reliable supervision of 1.8V logic rails with adequate margin, and is confirmed by the "US20" suffix in the part number.

Does MAX6337US20D3-T support manual reset functionality, and how is it implemented?

Yes, MAX6337US20D3-T includes a debounced manual-reset input (MR) that asserts RESET when pulled low. The MR pin features an internal 20kΩ pull-up resistor, allowing direct connection of a normally open momentary switch to GND-no external components required. MR pulse width must exceed 160µs at VCC = 2.6V to guarantee recognition, and RESET remains active for the full 100ms timeout after MR returns high. This behavior is fully specified in the Electrical Characteristics table.

What is the minimum supply voltage at which MAX6337US20D3-T guarantees correct RESET/RESET output state?

MAX6337US20D3-T guarantees correct RESET output state down to VCC = 1.0V, unlike the MAX6335/MAX6336 variants which guarantee down to 0.7V. This specification is explicitly stated in the General Description and confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Below 1.0V, the open-drain output may not maintain valid logic levels due to reduced sink capability, making the device unsuitable for applications requiring reset assertion at sub-1.0V conditions.

Can MAX6337US20D3-T be used with microcontrollers that have bidirectional reset pins?

Yes, MAX6337US20D3-T is specifically designed for interoperability with µPs featuring bidirectional reset pins, such as the Motorola 68HC11. Its open-drain active-low RESET output connects directly to the µP's reset pin via a single external pull-up resistor, enabling either device to assert reset. This configuration is illustrated in Figure 1 of the datasheet and eliminates the need for additional logic or level-shifting circuitry-making MAX6337US20D3-T ideal for legacy and mixed-vendor embedded systems.

What are the key differences between MAX6337US20D3-T and MAX6336US20D3-T?

The core difference is output structure: MAX6337US20D3-T uses an open-drain active-low RESET, while MAX6336US20D3-T uses a push/pull active-low RESET. This makes MAX6337US20D3-T suitable for wired-OR buses and bidirectional µP interfaces, whereas MAX6336US20D3-T drives both high and low actively. Additionally, MAX6336US20D3-T guarantees correct RESET state down to VCC = 0.7V, while MAX6337US20D3-T guarantees only to VCC = 1.0V. Both share identical 2.00V threshold, 100ms timeout, and SOT143 packaging.