Analog Devices Inc./Maxim Integrated MAX6745XKRD3+T

Overview

The MAX6745XKRD3+T from Maxim Integrated is a low-power dual-voltage microprocessor supervisor IC with one factory-trimmed reset threshold (VCC1), independent power-fail comparator input (PFI), and push-pull active-low RESET output. It monitors primary supply VCC1 (3.075V nominal threshold) and asserts reset if VCC1 falls below threshold or PFI drops below 0.488V. Designed for battery-powered portable equipment requiring reliable power sequencing and early power-fail detection.

For engineers reviewing the MAX6745XKRD3+T datasheet, MAX6745XKRD3+T pinout, MAX6745XKRD3+T application, or MAX6745XKRD3+T equivalent, key selection criteria include its 3.075V/0.488V dual-threshold architecture, 150ms reset timeout, 6µA supply current, SC70-5 package, and dedicated PFI/PFO functionality for orderly shutdown in power-sensitive systems.

Technical Context

The MAX6745XKRD3+T implements a dual-supply monitoring architecture where VCC1 (primary I/O supply) is compared against a precision 3.075V factory-trimmed threshold, while PFI accepts an external voltage divider to trigger PFO when input falls below 0.488V. Reset assertion is immediate on threshold violation, with no hysteresis added externally - internal hysteresis is fixed at 0.5% of threshold.

Its push-pull RESET output drives actively high or low without external pullup, eliminating board-level components required by open-drain variants. The device operates across -40°C to +85°C and draws only 6µA total supply current (ICC1 + ICC2), enabling use in always-on, energy-constrained applications such as GPS modules and handheld POS terminals.

Key Specifications

Pinout & Package

MAX6745XKRD3+T is housed in a 5-pin SC70-5 package (2.0mm × 2.1mm, 0.65mm pitch), optimized for compact portable PCB layouts. Pin 1 is RESET (push-pull active-low), Pin 2 is GND, Pin 3 is PFI (power-fail input), Pin 4 is PFO (open-drain active-low power-fail output), and Pin 5 is VCC1 (primary supply input).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-threshold supervisory applications.

Compared with MAX6742XKRD3+T and TPS3808G30DBVR, the MAX6745XKRD3+T uniquely integrates push-pull RESET drive and dedicated PFI/PFO functionality in SC70-5, delivering both simplified layout and coordinated power-fail response without external components.

Availability

MAX6745XKRD3+T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, multivoltage systems, and handheld controllers requiring stable component supply with long-term lifecycle support.

Supply support for MAX6745XKRD3+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) designs precision analog and mixed-signal ICs for power management, sensing, and interface applications in industrial, medical, and portable markets.

The MAX6736–MAX6745 family delivers ultra-low-power dual/triple-voltage supervision for space-constrained, battery-dependent systems where simultaneous supply monitoring and early power-fail warning are essential.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6745XKRD3+T?

The MAX6745XKRD3+T has a factory-trimmed VCC1 reset threshold of 3.075V, with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 1 of the datasheet under suffix "T", and applies specifically to the MAX6745 variant with RSTIN replaced by PFI/PFO functionality. The threshold is referenced internally and does not require external calibration.

Does the MAX6745XKRD3+T support manual reset functionality?

No, the MAX6745XKRD3+T does not include a manual reset (MR) input. Unlike MAX6736–MAX6739 or MAX6740–MAX6744 variants, the MAX6745 is configured with PFI and PFO pins instead of MR. Its reset assertion is triggered solely by VCC1 falling below 3.075V or PFI falling below 0.488V. This is confirmed by the Pin Description table and Selector Guide, which list MR as "-" for MAX6745.

What is the purpose of the PFI and PFO pins on the MAX6745XKRD3+T?

The PFI (Pin 3) is a dedicated power-fail comparator input that triggers PFO (Pin 4) when voltage falls below 0.488V. PFO is an open-drain active-low output used to signal imminent supply collapse - e.g., battery sag or DC-DC failure - enabling firmware to perform safe shutdown before VCC1 reset occurs. This dual-stage alerting is a core differentiator of the MAX6745XKRD3+T versus single-threshold supervisors.

Can the MAX6745XKRD3+T monitor negative supply voltages?

Yes, the MAX6745XKRD3+T can monitor negative supplies using the PFI input with an external resistor network as shown in Figure 4B of the datasheet. By connecting PFI to a voltage divider referenced to the negative rail, the device asserts PFO when the negative voltage magnitude drops below the trip point derived from the 0.488V internal reference. Accuracy depends on resistor tolerance and PFI input leakage (<±10nA), but the method is validated in the Applications Information section.

What is the reset timeout period for the MAX6745XKRD3+T, and is it adjustable?

The MAX6745XKRD3+T has a fixed minimum reset timeout period of 150ms, indicated by the "D3" suffix in the part number. This value is factory-set and not user-adjustable. The timeout begins after VCC1 rises above 3.075V and remains asserted for the full duration regardless of intermediate fluctuations, provided the supply stays above threshold. Electrical Characteristics table confirms tRP = 150ms (min) for D3 variants.