Analog Devices Inc./Maxim Integrated MAX6791TPLD3+

Overview

The MAX6791TPLD3+ from Maxim Integrated is a dual-output, high-voltage linear regulator with integrated supervisory functions, designed for automotive power management. It delivers up to 150mA per output (OUT1 and fixed 5V OUT2), operates from 5V to 72V input, consumes only 68μA quiescent current, and features a 50ms reset timeout period (D3) with 87.5% reset threshold on OUT1 - ideal for engine control units under load-dump conditions.

For engineers reviewing the MAX6791TPLD3+ datasheet, MAX6791TPLD3+ pinout, MAX6791TPLD3+ application, or MAX6791TPLD3+ equivalent, key selection criteria include its dual-regulator architecture, AEC-Q100-relevant thermal robustness (−40°C to +125°C), watchdog windowing capability (MAX6791-specific), HOLD self-latching function, and TQFN-20EP package with exposed pad for thermal dissipation.

Technical Context

The MAX6791TPLD3+ implements two independent LDO regulators: OUT1 is adjustable (1.8V–11V) or preset (5V/3.3V/2.5V/1.8V), while OUT2 is fixed at 5V. Its supervisory block integrates a push-pull or open-drain RESET output with fixed 87.5% threshold relative to OUT1 and capacitor-adjustable or factory-set 50ms timeout (D3 code).

It features a windowed watchdog timer (enabled via WDS0/WDS1 pins) with selectable fast/slow fault detection (tWD1/tWD2), disable capability (WD-DIS or WDS0/WDS1 logic), and HOLD input that sustains regulation after ENABLE1 release - enabling ignition-key-triggered self-holding without external circuitry.

Key Specifications

Pinout & Package

Package: 20-pin thermally enhanced TQFN with exposed pad (EP), 5mm × 5mm footprint, rated for 2.7W continuous dissipation at +70°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output automotive LDO applications.

Compared with MAX6792TPLD3+, the MAX6791TPLD3+ offers identical regulation and supervision but with distinct watchdog window ratio encoding; compared with TPS7B8750QKVURQ1, it provides dual outputs, 72V tolerance, HOLD latching, and windowed watchdog - essential for complex automotive ECUs requiring functional safety and multi-rail flexibility.

Availability

The MAX6791TPLD3+ is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera ECUs, and electric power steering systems requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX6791TPLD3+ 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, mixed-signal, and power-management ICs for automotive, industrial, and communications markets.

The MAX6791–MAX6796 family targets automotive power-supply supervision, combining high-voltage LDO regulation with watchdog, reset, power-fail, and reverse-battery protection in a single AEC-Q100-aligned package.

FAQ

What output voltage options does the MAX6791TPLD3+ support?

MAX6791TPLD3+ supports preset output voltages of 5.0V, 3.3V, 2.5V, or 1.8V on OUT1, and a fixed 5.0V on OUT2. OUT1 can also be adjusted from 1.8V to 11V using an external resistor divider connected to SET1. The "D3" in the part number specifies a 50ms reset timeout period and 87.5% reset threshold on OUT1, not output voltage - voltage selection is determined by the first placeholder in the ordering code (e.g., "L" = 5V, "T" = 3.3V).

How does the HOLD function work in the MAX6791TPLD3+?

The HOLD input in MAX6791TPLD3+ is an active-low control that sustains regulator operation after ENABLE1 is deasserted. When HOLD is pulled low after initial power-up, OUT1 and OUT2 remain enabled even if ENABLE1 returns low - enabling ignition-key-triggered self-holding without external latches. Releasing HOLD (high or floating) shuts down both outputs. HOLD is internally pulled up to OUT1 with a 2μA current source, so connecting it to OUT1 provides automatic hold behavior.

Is the MAX6791TPLD3+ AEC-Q100 qualified?

The MAX6791TPLD3+ is not individually listed as AEC-Q100 qualified in the provided documentation; however, related variants like MAX6795TPLD2/V+ and MAX6795TPSD2/V+ are explicitly marked "/V+" for automotive qualification. MAX6791TPLD3+ shares the same -40°C to +125°C operating range, thermal shutdown, and construction as qualified parts, but formal AEC-Q100 certification applies only to /V+ suffix versions. For safety-critical automotive designs, specify /V+ variants or confirm qualification status with Analog Devices.

What is the purpose of the GATEP pin on the MAX6791TPLD3+?

The GATEP pin on MAX6791TPLD3+ drives the gate of an external p-channel MOSFET to implement reverse-battery protection. When battery polarity is reversed, GATEP pulls the MOSFET gate low, blocking current flow and protecting downstream circuitry. This replaces lossy series diodes, reducing voltage drop and power dissipation - especially critical during cold-cranking when battery voltage sags below 6V. GATEP operates with IN-to-GATEP clamp voltage of 13.8V–18.8V and drive capability up to 12V.

Can the watchdog timer in the MAX6791TPLD3+ be disabled?

Yes, the watchdog timer in MAX6791TPLD3+ can be disabled using either WD-DIS pin (drive low) or WDS0/WDS1 logic inputs (e.g., WDS0=HIGH, WDS1=LOW per Table 4). Disabling the watchdog halts timeout monitoring on WDI, preventing unintended RESET assertions. The watchdog remains disabled until re-enabled via pin state change; RESET assertion clears the watchdog counter regardless of enable state. This flexibility supports development/debug modes or systems where firmware-level supervision suffices.