Analog Devices Inc./Maxim Integrated MAX6808US46-T

Overview

MAX6808US46-T from Maxim Integrated is a precision voltage detector IC designed for power-supply monitoring in microprocessor-based systems. It features a factory-preset 4.6V ±2% reset threshold, active-low open-drain RESET output, and operates down to VCC = 1.0V - enabling reliable brownout detection in battery-powered and portable equipment.

For engineers reviewing the MAX6808US46-T datasheet, MAX6808US46-T pinout, MAX6808US46-T application, or MAX6808US46-T equivalent, key selection criteria include its 4-pin SOT143 package with manual-reset (MR) input, 35µA supply current, immunity to fast VCC transients (≤100V/µs), and compatibility with multi-rail reset bus architectures via open-drain topology.

Technical Context

The MAX6808US46-T implements a precision bandgap-based voltage comparator with internal hysteresis (VHYST = 0.02–0.03 × VTH−), ensuring stable reset assertion/deassertion during supply ramp-up and brownout conditions. Its open-drain RESET output supports wired-OR configurations and level-shifting across multiple supply domains up to +6V.

This variant integrates a manual-reset input (MR) with 80kΩ internal pulldown resistance, enabling external reset initiation via momentary switch or logic signal. MR functionality is exclusive to the 4-pin SOT143 package - not available in SC70, SOT23, µMAX, or SO variants.

Key Specifications

Pinout & Package

MAX6808US46-T is housed in a 4-pin SOT143 package (JEDEC TO-236AB), with exposed pad option not specified. Pin 1 is RESET (active-low open-drain), Pin 2 is GND, Pin 3 is VCC, and Pin 4 is MR (active-high manual reset input).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage detector applications.

Compared with MAX6806US46-T and TLV803EC46DBZR, the MAX6808US46-T uniquely combines 4.6V precision detection, open-drain output for bus sharing, and integrated MR in a 4-pin SOT143 - making it optimal for portable instruments and field-serviceable embedded systems requiring both autonomous and user-initiated reset control.

Availability

MAX6808US46-T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, bar-code scanners, critical µP and µC power monitoring, and intelligent instruments requiring stable component supply and long-term industrial availability.

Supply support for MAX6808US46-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, computing, and communications markets.

The MAX6806/MAX6807/MAX6808 family was designed specifically for precision power-supply monitoring in digital systems - delivering factory-trimmed thresholds, low IQ, and robust transient immunity without external components.

FAQ

What is the reset threshold voltage of the MAX6808US46-T?

The MAX6808US46-T has a factory-preset reset threshold of 4.60V ±2% (VTH−) at +25°C, guaranteed over −40°C to +85°C. This value is trimmed during production and does not require external calibration. The hysteresis is 0.02–0.03 × VTH−, ensuring stable switching during supply ramping. The MAX6808US46-T maintains this accuracy across its full operating temperature range and supply voltage window (1.0V to 5.5V).

Does the MAX6808US46-T support manual reset functionality?

Yes, the MAX6808US46-T supports manual reset via its dedicated MR pin (Pin 4 in SOT143). The MR input is active-high with VIH ≥ 0.7×VCC and VIL ≤ 0.6V, and includes an internal 80kΩ pulldown resistor - allowing the pin to be left unconnected if unused. When asserted, MR forces RESET low regardless of VCC level, enabling operator-initiated or firmware-controlled system recovery. This feature is exclusive to the SOT143 package variants of the MAX6808US46-T.

What is the purpose of the open-drain RESET output in the MAX6808US46-T?

The open-drain RESET output in the MAX6808US46-T enables wired-OR reset bus configurations, allowing multiple devices (e.g., voltage detectors, watchdog timers, or µPs) to share a single reset line. It also supports level-shifting - the pullup resistor can connect to any supply up to +6V, making the MAX6808US46-T compatible with mixed-voltage systems. This architecture prevents contention with bidirectional µP reset pins (e.g., Motorola 68HC11), unlike push-pull outputs found in MAX6806/MAX6807 variants.

Can the MAX6808US46-T operate reliably during fast power-supply transients?

Yes, the MAX6808US46-T is explicitly characterized for immunity to negative-going VCC transients up to 100V/µs. Its internal comparator design rejects short-duration dips that would falsely trigger reset in less robust detectors. Data sheet Figure 3 shows maximum allowable transient duration versus overdrive magnitude - for example, a 100mV overdrive (VTH− − VCC) permits transients up to ~40µs without asserting reset. Adding a 0.1µF ceramic capacitor close to the VCC pin further enhances transient immunity in noisy environments.

What is the minimum supply voltage at which the MAX6808US46-T guarantees valid RESET output?

The MAX6808US46-T guarantees valid RESET output down to VCC = 1.0V. Below this voltage, the internal circuitry ceases to sink current and the RESET pin becomes high-impedance. For applications requiring asserted RESET all the way to ground, a 100kΩ external pulldown resistor on the RESET line is recommended - as shown in Figure 4 of the datasheet. This ensures predictable low-state behavior during deep brownout or complete power loss, preventing floating inputs on downstream logic.