Analog Devices Inc./Maxim Integrated MAX6709FUB+T

Overview

The MAX6709FUB+T from Maxim Integrated is a low-power, quad voltage monitor IC designed for multivoltage system supervision. It provides four independent active-low open-drain power-good outputs (PWRGD1–PWRGD4), monitors 3.3V, 2.5V, and 1.8V nominal supplies with ±5% tolerance, and includes one adjustable input (IN1) with 0.62V internal reference-enabling custom thresholds down to 0.62V. It operates from 2.0V to 5.5V supply and consumes only 35µA typical current, making it suitable for telecom power sequencing and embedded system reset coordination.

For engineers reviewing the MAX6709FUB+T datasheet, MAX6709FUB+T pinout, MAX6709FUB+T application, or MAX6709FUB+T equivalent, key selection criteria include factory-trimmed threshold accuracy (±2.0%), 10µA internal pullup per output, immunity to supply transients, -40°C to +85°C operation, and compatibility with wire-ORed power-good signaling in dense PCB layouts.

Technical Context

The MAX6709FUB+T integrates four precision comparators, an internal 0.62V bandgap reference, and factory-laser-trimmed resistor-divider networks for fixed-threshold inputs (IN2 = 3.3V, IN3 = 2.5V, IN4 = 1.8V). Its adjustable IN1 input bypasses internal dividers and connects directly to a comparator's noninverting input, requiring external resistive scaling for thresholds >0.62V.

Hysteresis is built-in at 0.3% of threshold voltage, eliminating need for external feedback components. An undervoltage lockout circuit forces all PWRGD_ outputs low when VCC drops below 2.0V, and all outputs remain functional down to VCC = 1V (guaranteed 0°C to +70°C), ensuring robust behavior during brownout conditions.

Key Specifications

Pinout & Package

Package: 10-pin µMAX (3.0mm × 3.0mm, 0.6mm height, 0.5mm pitch), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6714DUB+T and TPS3307-33DBVR, the MAX6709FUB+T uniquely delivers four independent, factory-trimmed PWRGD outputs with mixed-voltage support (3.3V/2.5V/1.8V + adjustable) and 35µA operation-making it optimal for multirail sequencing where discrete power-good status per rail is mandatory.

Availability

The MAX6709FUB+T is available at Aetrix Electronics and suitable for telecommunications infrastructure, server motherboard design, and notebook embedded controller applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6709FUB+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, communications, and computing markets.

The MAX6709FUB+T belongs to Maxim's precision voltage supervisor product line, engineered specifically for multivoltage system power integrity assurance in space-constrained, thermally demanding applications.

FAQ

What is the exact threshold voltage for each input on the MAX6709FUB+T?

The MAX6709FUB+T has factory-trimmed thresholds: IN2 = 3.3V (-5%) → 3.15V, IN3 = 2.5V (-5%) → 2.38V, IN4 = 1.8V (-5%) → 1.71V. IN1 is adjustable with 0.62V internal reference; its threshold is set externally via resistor divider. All thresholds have ±2.0% accuracy over -40°C to +85°C, as specified in the MAX6709 electrical characteristics table.

Does the MAX6709FUB+T provide reset timing or a dedicated reset output?

No, the MAX6709FUB+T does not include reset timing or a dedicated RESET output. It provides only four independent active-low open-drain PWRGD outputs (PWRGD1–PWRGD4). For integrated reset functionality with timeout, the MAX6714 series (e.g., MAX6714DUB+T) is required. The MAX6709FUB+T is strictly a voltage monitor-not a reset generator.

Can unused inputs on the MAX6709FUB+T be left floating?

No. Fixed-threshold inputs (IN2, IN3, IN4) are internally terminated and may be left unconnected. However, the adjustable IN1 input must be tied to GND if unused-leaving it floating violates Absolute Maximum Ratings and risks unpredictable comparator behavior. This requirement is explicitly stated in the "Unused Inputs" section of the MAX6709 datasheet.

What is the maximum sink current supported by each PWRGD output of the MAX6709FUB+T?

Each PWRGD output of the MAX6709FUB+T is rated for 2mA sink current at VCC = 5V (VOL ≤ 0.3V), and 1.2mA at VCC = 2.5V. These values are guaranteed in the Electrical Characteristics table under "Output Low Voltage." Exceeding these limits degrades VOL and may cause logic misinterpretation in downstream circuits.

Is the MAX6709FUB+T pin-compatible with other variants in the MAX6709 family?

Yes, all MAX6709 variants-including MAX6709FUB+T-share identical 10-pin µMAX package and pinout. Differences exist only in factory-trimmed threshold configurations (e.g., MAX6709AUB uses 10% tolerance; MAX6709FUB+T uses 5%). No PCB layout change is needed when substituting within the MAX6709 family, provided the selected variant matches the required voltage and tolerance profile.