Analog Devices Inc./Maxim Integrated MAX6703MKA+T

Overview

MAX6703MKA+T from Maxim Integrated is an active-low, open-drain microprocessor supervisory circuit in 8-pin SOT23 package, monitoring three supply voltages (one fixed V_CC threshold + two adjustable via RST_IN1/RST_IN2), providing a single reset output, manual reset input (MR), and independent watchdog output (WDO) with 1.6s timeout. It supports critical µP power monitoring in white goods and industrial controllers.

For engineers reviewing the MAX6703MKA+T datasheet, MAX6703MKA+T pinout, MAX6703MKA+T application, or MAX6703MKA+T equivalent, this device delivers triple-voltage supervision with guaranteed reset validity down to V_CC = 1V, immunity to short V_CC transients, and precise 0.62V internal reference for external voltage-divider-based threshold setting.

Technical Context

The MAX6703MKA+T implements a dual-adjustable-reset-input architecture: RST_IN1 and RST_IN2 accept externally scaled voltages referenced to a 0.62V internal comparator, enabling independent monitoring of secondary system rails (e.g., I/O and core supplies). Its reset generator asserts active-low RESET for ≥140ms after any monitored supply falls below threshold.

It integrates a non-latching watchdog timer that triggers WDO low upon 1.6s WDI inactivity; WDO deasserts immediately on valid WDI edge or MR assertion (A-version behavior). The open-drain RESET output supports wired-OR configurations and level-shifting, while MR features internal 50kΩ pullup and 100ns glitch rejection.

Key Specifications

Pinout & Package

Package: 8-pin SOT23 (K8+2 outline), surface-mount, RoHS-compliant lead-free (+T suffix), 1.6mm × 2.9mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6703MKA+T, MAX6703TKA+T offers lower threshold for tighter 3.0V systems but reduced noise margin, while TPS3808G33DBVR sacrifices multi-rail flexibility for lower cost and simpler layout in single-supply designs.

Availability

MAX6703MKA+T is available at Aetrix Electronics and suitable for industrial motor controllers, white goods main control boards, and telecom line cards requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6703MKA+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 demanding industrial, automotive, and communications applications, emphasizing reliability, integration, and thermal robustness.

The MAX6701–MAX6708 family targets compact, high-reliability µP supervision in space-constrained systems where multi-rail monitoring, power-fail warning, and watchdog functionality must coexist in minimal footprint.

FAQ

What is the reset threshold voltage of the MAX6703MKA+T?

The MAX6703MKA+T has a nominal V_CC reset threshold of 3.08V, with guaranteed limits of 2.97V (min) to 3.17V (max) over -40°C to +125°C. This M-suffix variant is specifically calibrated for +3.3V systems with adequate margin against ripple and temperature drift. The threshold applies solely to the V_CC pin; RST_IN1 and RST_IN2 use the internal 0.62V reference for user-defined thresholds.

Does the MAX6703MKA+T support monitoring more than one supply voltage?

Yes, the MAX6703MKA+T monitors three supply voltages: the primary V_CC rail (3.08V threshold), plus two additional rails via RST_IN1 and RST_IN2 pins. Each uses the internal 0.62V comparator reference, so external resistor dividers set their trip points - for example, a 10:1 divider on RST_IN1 detects 6.2V collapse. All three inputs feed a single RESET output, which asserts if any monitored voltage falls below its threshold.

What is the function of the PFI and PFO pins on the MAX6703MKA+T?

PFI is a high-impedance input referenced to the 0.62V internal comparator, used to monitor any external voltage (e.g., 12V fan supply) via a resistor divider. When the divided voltage drops below 0.62V, PFO - an open-drain active-low output - asserts, enabling early power-fail warning to the µP. PFO can drive interrupts or trigger controlled shutdown sequences, independent of the main RESET signal.

How does the watchdog timer behave on the MAX6703MKA+T?

The MAX6703MKA+T watchdog timer requires toggling of the WDI pin at least once every 1.6s (typ). If WDI remains static beyond this period, WDO goes low. Unlike non-A versions, the MAX6703MKA+T (A-version) deasserts WDO immediately upon a valid WDI edge or MR low - no timeout delay. WDO is independent of RESET and can be used for NMI or fault logging without resetting the µP.

Can the MAX6703MKA+T operate down to 1.2V supply voltage?

Yes, the MAX6703MKA+T is fully specified to operate from V_CC = 1.2V to 5.5V over -40°C to +125°C. Its reset circuitry remains functional down to 1.2V, and the RESET output is guaranteed valid (logic-low ≤0.4V) even as V_CC falls to 1.0V. This enables reliable supervision during deep brownout conditions common in battery-powered or unregulated supply applications.