Analog Devices Inc./Maxim Integrated MAX6302CPA

Overview

MAX6302CPA from Maxim Integrated is an active-high, open-drain microprocessor supervisory circuit designed for reliable reset and watchdog monitoring in low-power embedded systems. It features adjustable reset threshold (≥1.22V), adjustable reset timeout (via external capacitor on SRT), adjustable watchdog timeout (via SWT), 500× watchdog extension mode (WDS pin), and 4µA supply current at +5V. It is used in battery-powered medical instruments and portable controllers requiring stable brownout detection and software hang protection.

For engineers reviewing the MAX6302CPA datasheet, MAX6302CPA pinout, MAX6302CPA application, or MAX6302CPA equivalent, key selection criteria include its active-high open-drain RESET output, guaranteed operation down to VCC = 1.31V, power-supply transient immunity, and compatibility with manual reset and wake-up timer configurations using external R/C networks.

Technical Context

The MAX6302CPA implements a precision bandgap-based reset comparator referenced to 1.22V, with external resistor divider programming of VRST = 1.22 × (R1 + R2)/R2. Its reset assertion timing is governed by a 500nA current source charging CSRT, yielding tRP = 2.67 × CSRT (CSRT in pF, tRP in µs).

Watchdog timing uses the same 500nA current source on SWT, with tWD = 2.67 × CSWT in normal mode (WDS = GND) or tWD × 500 in extended mode (WDS = VCC). The WDI input detects ≥30ns transitions and clears the watchdog timer; WDS state changes also reset the counter and determine timeout scaling.

Key Specifications

Pinout & Package

MAX6302CPA is housed in an 8-pin PDIP (Plastic Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; pins are numbered counterclockwise from top-left when viewed from top.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6304CPA, MAX6302CPA offers open-drain flexibility for wired-OR reset buses and bidirectional µP interfaces, while TPS3808G01DBVR trades adjustability for lower IQ and broader supply range - neither is pin-compatible, and both require PCB layout revision for substitution.

Availability

MAX6302CPA is available at Aetrix Electronics and suitable for medical portable monitors, battery-powered data loggers, industrial embedded controllers, set-top box power management, and critical µP monitoring applications requiring stable component supply across extended production lifecycles.

Supply support for MAX6302CPA 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 demanding industrial, medical, and communications applications, emphasizing low power, high reliability, and integration.

The MAX6301–MAX6304 family was engineered specifically for adjustable µP supervision in space-constrained, battery-sensitive systems - delivering programmable reset and watchdog functions in miniature PDIP/SO/µMAX packages with sub-5µA quiescent current.

FAQ

What is the minimum VCC required for MAX6302CPA to assert RESET reliably?

The MAX6302CPA guarantees valid active-high RESET output behavior for VCC ≥ 1.31V. Below this voltage, output drive capability degrades; however, the device remains functional down to VCC = 1V, where RESET is guaranteed logic-low. For full specification compliance, operate within the +1.31V to +5.5V range stated in the datasheet. The MAX6302CPA's design ensures deterministic reset assertion even during gradual brownout conditions.

Can MAX6302CPA monitor voltages other than VCC?

Yes, the MAX6302CPA can monitor any DC voltage by connecting it to the RESET IN pin through an external resistor divider. The reset threshold VRST is calculated as 1.22 × (R1 + R2)/R2, allowing precise supervision of 3.3V, 2.5V, or custom rails. Layout best practices require short, low-leakage traces to RESET IN to avoid threshold errors from stray capacitance or probe loading - the MAX6302CPA's high-impedance input makes it especially sensitive to such effects.

How does the WDS pin affect watchdog behavior in MAX6302CPA?

The WDS pin on the MAX6302CPA selects between two watchdog modes: when pulled low (GND), it enables normal-mode timeout (tWD); when pulled high (VCC), it activates extended mode, multiplying tWD by 500. A state change on WDS immediately resets the watchdog counter to zero. In extended mode, leaving WDI unconnected disables the watchdog function entirely - the MAX6302CPA internally pulses WDI near timeout expiration to prevent false resets.

Is MAX6302CPA compatible with bidirectional µP reset pins?

Yes, the MAX6302CPA's open-drain, active-high RESET output is inherently compatible with bidirectional µP reset I/Os (e.g., Motorola 68HC11). A single external pullup resistor enables either the µP or the MAX6302CPA to assert reset - the MAX6302CPA pulls RESET low to deassert and releases it (high-impedance) to allow the µP to drive high. This eliminates contention and simplifies interface design without additional logic.

What capacitor types are recommended for SRT and SWT on MAX6302CPA?

Ceramic capacitors with leakage <10nA are recommended for both SRT and SWT pins on the MAX6302CPA. These pins connect to precision 500nA current sources; high-leakage dielectrics (e.g., standard electrolytics or certain tantalums) cause timing errors in reset and watchdog periods. X7R or C0G ceramics in 0805 or smaller packages minimize parasitic capacitance and ensure accurate tRP = 2.67 × CSRT and tWD = 2.67 × CSWT relationships across temperature.