Analog Devices Inc./Maxim Integrated MAX6709OUB+T

Overview

The MAX6709OUB+T from Maxim Integrated is a quad voltage monitor IC designed for multivoltage system supervision, featuring four independent adjustable-threshold inputs (each referenced to 0.62V), ±2.0% threshold accuracy, 35µA typical supply current, and operation from 2.0V to 5.5V. It delivers four active-low open-drain PWRGD outputs with 10µA internal pullups to VCC and supports wire-ORed power-good signaling in desktop computers and telecom equipment.

For engineers reviewing the MAX6709OUB+T datasheet, MAX6709OUB+T pinout, MAX6709OUB+T application, or MAX6709OUB+T equivalent, this device serves as a precision, low-quiescent-current solution for monitoring four independently configurable supply rails-especially where factory-trimmed fixed thresholds are insufficient and external resistor-divider flexibility is required.

Technical Context

The MAX6709OUB+T implements four high-input-impedance comparators with an internally trimmed 0.62V bandgap reference, enabling adjustable monitoring down to 0.609V (min) with 60ppm/°C temperature coefficient. Each input operates independently, with hysteresis fixed at 0.3×V_TH and propagation delay under 5µs (rising) and 30µs (falling).

An integrated undervoltage lockout circuit forces all PWRGD outputs low when VCC drops below 2.0V, and the 10-pin µMAX package supports operation across –40°C to +85°C. All outputs are open-drain with weak internal 10µA pullups to VCC-compatible with external pullups up to 5.5V and immune to supply transients.

Key Specifications

Pinout & Package

Package: 10-pin µMAX (3.0mm × 3.0mm, 0.6mm height), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6714OUB+T and TPS3307-33DGNR, the MAX6709OUB+T uniquely provides four fully adjustable inputs in a single 10-pin µMAX package-enabling precise, scalable supervision of arbitrary rail combinations without sacrificing channel count or quiescent current efficiency.

Availability

The MAX6709OUB+T is available at Aetrix Electronics and suitable for desktop computers, telecommunications equipment, and servers requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.

Supply support for MAX6709OUB+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 semiconductor company specializing in high-performance analog, mixed-signal, and power management solutions for industrial, computing, and communications markets.

The MAX6709 belongs to Maxim's precision voltage supervisor product line, engineered specifically for multivoltage system integrity in space- and power-constrained applications where flexibility, accuracy, and low ICC are critical.

FAQ

What is the function of the four INx pins on the MAX6709OUB+T?

The four INx pins (IN1–IN4) on the MAX6709OUB+T serve as high-impedance adjustable voltage monitor inputs, each internally compared to a 0.62V reference. When an external resistor divider scales a target supply voltage to match this reference, the corresponding PWRGDx output asserts low upon undervoltage. This architecture enables precise supervision of arbitrary rail voltages-including nonstandard values-without external comparators or trimming components. The MAX6709OUB+T thus delivers configurable, factory-calibrated accuracy across all four channels.

Does the MAX6709OUB+T provide built-in hysteresis, and how does it affect threshold stability?

Yes, the MAX6709OUB+T integrates fixed hysteresis equal to 0.3×V_TH per channel, eliminating the need for external feedback resistors. This hysteresis prevents output oscillation during slow or noisy supply transitions near the trip point-such as during power-up ramp or thermal drift-by creating a small voltage window between assert and deassert thresholds. For example, at a 3.3V nominal input with 5% tolerance, hysteresis adds ~10mV of separation, ensuring clean, chatter-free PWRGD signaling critical for reliable system boot and fault isolation in the MAX6709OUB+T.

Can the MAX6709OUB+T outputs be wire-ORed, and what design considerations apply?

Yes, all four PWRGD outputs of the MAX6709OUB+T are active-low open-drain with 10µA internal pullups to VCC, making them inherently suitable for wire-OR connection into a single system-level power-good signal. To implement this, tie all PWRGDx outputs together and add one external pullup resistor (e.g., 10kΩ) to the target logic voltage (up to 5.5V). Internal circuitry blocks reverse current flow, so the external pullup does not load VCC. This configuration simplifies board routing and reduces gate count versus discrete OR-ing logic-key for compact, high-density designs using the MAX6709OUB+T.

What is the minimum operating voltage for the MAX6709OUB+T, and how does undervoltage lockout behave?

The MAX6709OUB+T operates from 2.0V to 5.5V, and its internal undervoltage lockout (UVLO) circuit forces all PWRGD outputs low whenever VCC drops below 2.0V. This behavior persists down to VCC = 1.0V (guaranteed from 0°C to +70°C), ensuring deterministic fault signaling even during deep brownouts. Unlike many supervisors that release outputs unpredictably near cutoff, the MAX6709OUB+T maintains safe, known states-critical for preventing partial initialization or metastability in downstream logic during power collapse scenarios.

How accurate is the 0.62V internal reference in the MAX6709OUB+T across temperature and supply variation?

The MAX6709OUB+T's internal 0.62V reference exhibits ±2.0% total accuracy over –40°C to +85°C and 2.0V–5.5V VCC, with a temperature coefficient of 60ppm/°C. Electrical characteristics tables confirm worst-case threshold deviation remains within ±2.0% across full operating conditions-no additional calibration or compensation is needed. This stability directly translates to predictable trip points for all four adjustable inputs, enabling robust, maintenance-free supervision in thermally demanding environments where the MAX6709OUB+T is deployed.