Analog Devices Inc./Maxim Integrated MAX6303CSA+T

Overview

MAX6303CSA+T from Maxim Integrated is an active-low, push-pull microprocessor supervisory circuit with adjustable reset threshold (≥1.22V), adjustable reset timeout (2.8–5.2 ms with 1500pF), and adjustable watchdog timeout (2.8–5.2 ms normal mode / 1.4–2.6 s extended mode). It features 4µA supply current, power-supply transient immunity, and guaranteed RESET assertion down to VCC = 1V - used in battery-powered medical instruments and embedded controllers for reliable brownout detection and hang recovery.

For engineers reviewing the MAX6303CSA+T datasheet, MAX6303CSA+T pinout, MAX6303CSA+T application, or MAX6303CSA+T equivalent, key selection criteria include its push-pull active-low reset output, 8-pin SO package, ±1nA reset input leakage, 63µs VCC-to-RESET delay, and compatibility with external resistor-divider threshold setting and capacitor-timed timeouts.

Technical Context

The MAX6303CSA+T implements a precision bandgap-based reset comparator with 20mV hysteresis and a 500× watchdog timeout multiplier via WDS pin control. Its SRT and SWT pins source 500nA precision timing currents, enabling accurate µs-scale reset and ms/s-scale watchdog periods using external capacitors.

It integrates independent reset and watchdog logic: reset asserts when RESET IN falls below VRST (set by R1/R2 divider), then holds low for tRP; watchdog resets the µP if WDI transitions are missed within tWD - with timeout scaling determined by WDS state and CSWT value.

Key Specifications

Pinout & Package

MAX6303CSA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant with lead-free finish (+ suffix), 1.75mm body width, and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6302CSA+T, the MAX6303CSA+T offers push-pull drive eliminating external components, while TPS3808G125DBVR trades adjustability for lower cost and smaller size - making MAX6303CSA+T optimal for designs requiring programmable supervision with minimal board area overhead.

Availability

MAX6303CSA+T is available at Aetrix Electronics and suitable for medical instrumentation, industrial PLCs, portable diagnostics, and smart energy meters requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for MAX6303CSA+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 industrial, medical, and communications applications, with emphasis on low-power, high-reliability solutions.

The MAX6301–MAX6304 family was engineered specifically for microprocessor supervision in battery-critical and noise-prone environments - delivering adjustable reset/watchdog functionality in miniature packages with sub-µA quiescent current.

FAQ

What is the minimum VCC required for guaranteed RESET assertion in MAX6303CSA+T?

The MAX6303CSA+T guarantees RESET assertion at or above VCC = 1V. Below 1V, output drive strength degrades significantly; for applications requiring valid reset down to 0V, a 100kΩ pulldown resistor on the RESET pin is recommended per the datasheet Figure 9. This behavior is confirmed in the Electrical Characteristics table under "Guaranteed RESET Asserted At or Above VCC = 1V" for MAX6303.

How do I calculate the reset threshold voltage for MAX6303CSA+T?

Use the formula VRST = 1.22 × (R1 + R2) / R2, where VRST is the desired reset threshold (e.g., 3.0V), and R2 is typically chosen as 1MΩ for low current consumption. Solve for R1: R1 = R2 × (VRST / 1.22 − 1). For VRST = 3.0V and R2 = 1MΩ, R1 ≈ 1.46MΩ. This calculation is explicitly defined in the Pin Description and Detailed Description sections for MAX6303CSA+T.

Can the watchdog function be disabled on MAX6303CSA+T?

Yes - in extended mode (WDS = VCC), the watchdog function is automatically disabled when WDI is left unconnected or driven three-state, due to internal pulsing that services the timer before timeout. In normal mode (WDS = GND), the watchdog cannot be disabled; WDI must be actively toggled. This behavior is documented in the Watchdog Timer section and Figure 8 of the MAX6303CSA+T datasheet.

What capacitor types are recommended for SRT and SWT on MAX6303CSA+T?

Ceramic capacitors are recommended for both SRT and SWT pins due to their low leakage (<10nA) and stability over temperature. The datasheet specifies CSRT and CSWT must be low-leakage types to avoid timing errors caused by the 500nA precision current sources. X7R or C0G dielectrics are preferred; electrolytic or tantalum caps are unsuitable due to higher leakage and voltage coefficient.

Does MAX6303CSA+T support monitoring voltages other than VCC?

Yes - the RESET IN pin accepts any externally derived voltage (e.g., from a DC-DC converter output or battery sense rail), not just VCC. As shown in Figure 4 of the datasheet, a resistor divider connected to VIN (non-VCC source) sets VRST identically to the VCC-monitoring configuration. The MAX6303CSA+T's high-impedance input (±1nA leakage) ensures minimal loading on sensitive monitoring nodes.