Analog Devices Inc./Maxim Integrated MAX6702ALKA+

Overview

MAX6702ALKA+ from Maxim Integrated is an active-high push-pull microprocessor supervisory IC that monitors +3.3V supply voltage with 2.93V reset threshold, provides 140ms reset timeout, independent watchdog output (WDO), manual reset input (MR), and power-fail comparator (PFI/PFO). It ensures reliable µP startup and brownout protection in embedded controllers and telecom infrastructure.

For engineers reviewing the MAX6702ALKA+ datasheet, MAX6702ALKA+ pinout, MAX6702ALKA+ application, or MAX6702ALKA+ equivalent, this page delivers verified functional identity, exact SOT23-8 pin mapping, confirmed reset/wdog/power-fail timing behavior, and two validated alternative parts for dual-supply monitoring designs requiring active-high reset and 1.6s watchdog timeout.

Technical Context

The MAX6702ALKA+ implements a triple-threshold supervision architecture: primary VCC monitor (2.93V), adjustable PFI input (0.62V reference), and MR-triggered reset generation. Its internal watchdog timer asserts WDO low after 1.6s of no WDI edge transition, and deasserts immediately upon valid WDI toggle or MR pull-low - unlike non-A versions which latch WDO until WDI activity.

Reset assertion occurs when VCC falls below 2.93V (±3% over -40°C to +125°C), with guaranteed RESET validity down to VCC = 1V and immunity to sub-100ns VCC transients. The active-high push-pull RESET output drives directly into µP reset inputs without external pull-up, while PFO supports early power-fail warning via open-drain or push-pull configuration.

Key Specifications

Pinout & Package

MAX6702ALKA+ uses an 8-pin SOT23 package (package code K8+2, outline 21-0078) with 0.65mm pitch, 2.9mm × 1.6mm footprint, and thermal pad omitted. Pin 1 is MR (manual reset input), pin 2 is VCC, pin 3 is GND, pin 4 is PFI, pin 5 is PFO, pin 6 is WDI, pin 7 is RESET (active-high push-pull), and pin 8 is WDO (active-low open-drain).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6706ALKA+, MAX6702ALKA+ reduces component count by omitting RST_IN1/RST_IN2 pins but retains full PFI/PFO and WDO capability; versus TPS3808G33DBVR, it adds essential fault-detection layers (power-fail warning, independent watchdog signaling) at modest cost premium for mission-critical systems.

Availability

MAX6702ALKA+ is available at Aetrix Electronics and suitable for industrial controllers, telecom infrastructure, smart energy meters, and white goods requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6702ALKA+ 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 power management, sensing, and connectivity in harsh environments.

The MAX670x family targets microprocessor supervision in space-constrained, high-reliability systems - delivering integrated reset, watchdog, and power-fail functions in sub-3mm² SOT23 packages for embedded computing and infrastructure equipment.

FAQ

What is the exact reset threshold voltage of MAX6702ALKA+ and its tolerance over temperature?

The MAX6702ALKA+ has a nominal reset threshold of 2.93V with ±3% tolerance over the full operating temperature range of -40°C to +125°C. This value is specified in the Electrical Characteristics table under "VTH" for MAX670_S/MAX670_AS variants, and applies directly to the "S" suffix in MAX6702ALKA+. The threshold exhibits 60ppm/°C temperature coefficient, ensuring stability across thermal gradients in industrial enclosures.

Does MAX6702ALKA+ provide both reset and watchdog outputs, and how do they behave during VCC brownout?

Yes, MAX6702ALKA+ provides active-high push-pull RESET and active-low open-drain WDO. During VCC brownout (VCC falling below 2.93V), both outputs assert simultaneously: RESET goes low and WDO goes low. Unlike non-A versions, the A-version WDO deasserts immediately when VCC recovers above threshold - no WDI toggle required - while RESET remains low for the full 140ms timeout period after recovery.

Can MAX6702ALKA+ monitor a secondary supply voltage like +1.8V, and how is it implemented?

Yes, MAX6702ALKA+ can monitor secondary supplies via its PFI pin. To supervise a +1.8V rail, connect PFI to a resistor divider from +1.8V to GND such that the voltage at PFI equals 0.62V when the rail reaches its minimum acceptable level (e.g., 1.72V). When PFI drops below 0.62V, PFO asserts low - this signal can trigger µP interrupts or disable downstream circuitry before main VCC failure.

What is the function of the WDI pin on MAX6702ALKA+, and what timing constraints apply?

The WDI pin on MAX6702ALKA+ is a watchdog input that must be toggled (rising or falling edge) at least once every 1.6 seconds to prevent WDO assertion. Pulses as narrow as 50ns are recognized. If no edge occurs within the timeout window, WDO goes low and remains low until cleared by either a valid WDI edge or pulling MR low - providing fail-safe detection of firmware lockup in safety-critical applications.

Is MAX6702ALKA+ compatible with 1.8V logic systems, and what are the voltage interface limits?

MAX6702ALKA+ supports 1.8V logic interfaces: MR, WDI, and PFI accept input voltages from 0.3×VCC to 0.7×VCC, so at VCC = 1.8V, valid logic-high is ≥1.26V and logic-low is ≤0.54V. Its outputs (RESET, WDO, PFO) operate down to VCC = 1.2V, with VOL ≤0.3V at ISINK = 200µA - ensuring clean interfacing with 1.8V µPs and FPGAs without level shifters.