Analog Devices Inc./Maxim Integrated MAX5023SASA+

Overview

MAX5023SASA+ from Maxim Integrated is a high-voltage linear regulator with integrated microprocessor reset and watchdog timer, operating from +6.5V to +65V input and delivering up to 150mA at fixed +3.3V output. It features -60V reverse-battery protection, 60μA no-load quiescent current, and automotive-grade operation from -40°C to +125°C. It is used in vehicle ignition-supplied modules requiring robust brownout detection and fail-safe reset timing.

For engineers reviewing the MAX5023SASA+ datasheet, MAX5023SASA+ pinout, MAX5023SASA+ application, or MAX5023SASA+ equivalent, key selection criteria include its 1.6s watchdog timeout, active-low open-drain RESET with 200ms timeout, HOLD-enabled self-holding circuit, and SO-EP thermal performance (θ_JA = 41°C/W).

Technical Context

The MAX5023SASA+ implements a BiCMOS linear regulator with internal bandgap reference, thermal shutdown at +150°C (20°C hysteresis), and reverse-battery protection down to -60V. Its reset supervisor uses the same reference as the regulator, asserting RESET when V_OUT falls below 2.805V–2.970V (−7.5% threshold for +3.3V version) and holding low for 140–260ms after recovery.

The watchdog timer monitors WDI transitions and triggers RESET if no edge occurs within 1.12–2.08s; it remains asserted for the full reset timeout period, ignoring subsequent WDI activity until deassertion. The HOLD input enables latch-up behavior via an internal 4µA pullup to OUT, allowing EN-independent regulation control.

Key Specifications

Pinout & Package

MAX5023SASA+ is housed in an 8-pin SO-EP (Small Outline–Exposed Pad) package with thermally enhanced copper pad soldered to PCB ground plane for 1.5W dissipation at +70°C ambient. The exposed pad (EP) must be connected to GND for optimal thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage linear regulator applications.

Compared with MAX5023SASA+, MAX5024SASA+ trades watchdog supervision for output adjustability, while TPS7B8133QDGNRQ1 offers AEC-Q100 qualification and lower input voltage but omits both HOLD and WDI-making MAX5023SASA+ uniquely suited for ignition-latched, watchdog-secured systems.

Availability

MAX5023SASA+ is available at Aetrix Electronics and suitable for automotive body control, industrial PLC power supplies, fire alarm panels, and telecom remote terminal units requiring stable component supply across extended temperature and voltage ranges.

Supply support for MAX5023SASA+ 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 demanding industrial, automotive, and communications applications.

The MAX5023/MAX5024 product line delivers high-voltage linear regulation with integrated system supervision-targeting automotive and industrial systems needing robust power sequencing, fault detection, and latch-up resilience without external components.

FAQ

What is the exact reset threshold voltage for MAX5023SASA+?

The MAX5023SASA+ has a −7.5% reset threshold relative to its +3.3V output, specified as 2.805V (min), 2.887V (typ), and 2.970V (max) over temperature. This threshold is monitored continuously and asserts the open-drain RESET output low when V_OUT falls below the value, holding it low for 140–260ms after recovery. The MAX5023SASA+ uses the same internal bandgap reference for both regulation and reset, ensuring tight correlation between output voltage and reset point.

Does MAX5023SASA+ support reverse-battery protection, and how is it implemented?

Yes, MAX5023SASA+ withstands −60V applied to the IN pin with only 0.1–10µA reverse current flow. This is achieved through internal bipolar transistor structures and substrate isolation in its BiCMOS process-not external diodes. The protection operates continuously across the full −40°C to +125°C temperature range and does not degrade with repeated exposure, making it suitable for automotive jump-start scenarios where battery polarity may be inadvertently reversed.

How does the HOLD function work in MAX5023SASA+, and what is its design impact?

In MAX5023SASA+, the HOLD pin is an active-low input that, when pulled low after EN is asserted, forces the regulator to remain ON even if EN subsequently returns low. This creates a self-holding circuit without external components. Internally, HOLD connects to OUT via a 4µA current source-so floating HOLD or connecting it to OUT achieves the same latched state. This feature simplifies ignition-switched automotive modules where the MCU must stay powered after key-off for wake-on-LIN/CAN.

What is the watchdog timeout behavior of MAX5023SASA+, and can it be disabled?

The MAX5023SASA+ watchdog timer asserts RESET if the WDI input remains static (high or low) for longer than 1.12–2.08s. Once asserted, RESET stays low for the full 140–260ms timeout period regardless of WDI activity. The watchdog cannot be disabled-it is always active. To prevent false resets, the host µP must toggle WDI with edges spaced ≤1.12s apart. This behavior ensures fail-safe recovery in locked-up microcontrollers without software intervention.

What thermal performance can be expected from MAX5023SASA+ in a real PCB layout?

MAX5023SASA+ achieves θ_JA = 41°C/W when its exposed pad is soldered to ≥1in² of 2-oz copper on an inner layer, per JEDEC JESD51-7. At +70°C ambient, it dissipates 1.538W; derating is 19.2mW/°C above that. For example, at +95°C ambient, allowable dissipation drops to 1.057W-supporting ~117mA into +5V output from +14V input. Performance assumes proper thermal vias under the EP and no adjacent heat sources; insufficient copper reduces current capability significantly.