Analog Devices Inc./Maxim Integrated MAX6320PUK26CY-T

Overview

MAX6320PUK26CY-T from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low open-drain reset output, 2.63V factory-trimmed reset threshold (±2.5% over -40°C to +125°C), 140ms minimum reset timeout, and 1.6s typical watchdog timeout. It monitors VCC supply voltage, accepts manual reset input, and asserts reset during power-up, brownout, or software hang conditions in embedded control systems.

For engineers reviewing the MAX6320PUK26CY-T datasheet, MAX6320PUK26CY-T pinout, MAX6320PUK26CY-T application, or MAX6320PUK26CY-T equivalent, key selection criteria include its guaranteed reset validity down to VCC = 1V, immunity to short negative VCC transients (<4µs at 100mV under VTH), open-drain output compatible with mixed-voltage reset buses up to 6V, and AEC-Q100 qualification for automotive-grade reliability.

Technical Context

The MAX6320PUK26CY-T implements a precision bandgap-based reset threshold detector with 40ppm/°C temperature coefficient and 3mV hysteresis, paired with independent reset and watchdog timers. Its open-drain RESET output requires an external pullup resistor and supports bidirectional reset bus interfacing when combined with microcontrollers featuring active-pullup capability.

It features a manual reset input (MR) with internal 52kΩ pullup, 100ns glitch rejection, and 1.5µs minimum pulse width at full temperature range; the watchdog input (WDI) clears on any edge transition and tolerates 50ns pulses, with internal servicing if left unconnected.

Key Specifications

Pinout & Package

Supplied in a RoHS-compliant 5-pin SOT23 package (package code U5+2A, outline 21-0057), footprint-compatible with JEDEC MS-012AC and land pattern 90-0174.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6320PUK29CY-T, the MAX6320PUK26CY-T provides earlier brownout detection at 2.63V for 2.7–3.3V systems, while TLV809E26DBVR offers lower cost and smaller footprint but omits watchdog, manual reset, and open-drain flexibility-making it unsuitable for systems requiring fault recovery beyond power monitoring.

Availability

MAX6320PUK26CY-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, portable medical devices, and battery-powered sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6320PUK26CY-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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.

The MAX6316–MAX6322 family delivers highly integrated, AEC-Q100-qualified μP supervisory circuits targeting systems needing reliable power monitoring, watchdog supervision, and manual reset in minimal PCB area-especially where open-drain reset flexibility and wide temperature operation are critical.

FAQ

What is the exact reset threshold voltage of the MAX6320PUK26CY-T and how does it vary with temperature?

The MAX6320PUK26CY-T has a factory-trimmed nominal reset threshold of 2.63V at +25°C, with tolerance of ±1.5% at room temperature and ±2.5% across –40°C to +125°C. Its temperature coefficient is 40ppm/°C, meaning drift is limited to approximately ±10.5mV over the full range-verified in production testing per Table 1 of the datasheet. This ensures predictable brownout behavior in automotive and industrial environments where ambient temperature swings widely.

Does the MAX6320PUK26CY-T require an external pullup resistor on the RESET pin, and what value is recommended?

Yes, the MAX6320PUK26CY-T features an open-drain RESET output and requires an external pullup resistor. A 10kΩ resistor to the target logic supply (up to 6V) is sufficient in most applications, as confirmed by Electrical Characteristics specifying VOL ≤0.4V at 3.2mA sink current. The value must balance logic-high noise margin against total bus capacitance and sink current requirements-larger values reduce power but increase rise time; smaller values improve speed but raise static current.

Can the MAX6320PUK26CY-T operate reliably during severe VCC brownout conditions, and down to what voltage does reset remain valid?

Yes, the MAX6320PUK26CY-T guarantees valid reset assertion down to VCC = 1.0V, as explicitly stated in Absolute Maximum Ratings and Electrical Characteristics. This ensures deterministic system behavior even during deep brownout events where other supervisors may release reset prematurely. Below 1.0V, internal circuitry ceases operation-but the open-drain RESET remains pulled low externally via the pullup, preserving safe state until full power recovery.

How does the watchdog timer in the MAX6320PUK26CY-T respond if the WDI pin is left unconnected?

When WDI is unconnected, the MAX6320PUK26CY-T's internal watchdog timer is automatically serviced at intervals equal to 7/8 of the nominal watchdog timeout period (i.e., ~1.4s for the 1.6s version), preventing unintended reset assertion. This behavior is documented in the Watchdog Input section and eliminates need for external pullup/down-though intentional WDI toggling remains required for true software hang detection in production firmware.

Is the MAX6320PUK26CY-T pin-compatible with other members of the MAX6316–MAX6322 family, and what are the key compatibility constraints?

The MAX6320PUK26CY-T shares identical 5-pin SOT23 pinout and electrical interface with all MAX6316–MAX6322 variants-including RESET, GND, MR, WDI, and VCC assignments. However, functional compatibility depends on reset output type: MAX6320P-series use open-drain RESET, whereas MAX6316L/MAX6317H use push/pull. Swapping requires verifying external pullup presence and logic polarity-direct replacement is not assured without matching output architecture.