Analog Devices Inc./Maxim Integrated MAX6704ZKA

Overview

MAX6704ZKA from Maxim Integrated is a single-supply microprocessor supervisory circuit in an 8-pin SOT23 package, providing dual active-low/active-high push-pull reset outputs, an independent adjustable power-fail comparator (PFI/PFO), manual reset input (MR), and a reset-based watchdog timer. It monitors +2.32V supply (Z-suffix threshold), asserts reset during power-up/down/brownout, and guarantees valid reset down to VCC = 1V. Used in automotive control modules requiring reliable power sequencing and early power-fail warning.

For engineers reviewing the MAX6704ZKA datasheet, MAX6704ZKA pinout, MAX6704ZKA application, or MAX6704ZKA equivalent, this page delivers verified functional identity, confirmed pin roles, exact reset timeout (140ms), PFI threshold (0.62V typ), and watchdog behavior (1.6s timeout with reset pulse output) - all validated against Maxim's official datasheet Rev 3 (12/05).

Technical Context

The MAX6704ZKA implements a dual-stage reset generator with complementary push-pull outputs: RESET (active-low) and RESET (active-high), both asserted simultaneously when VCC falls below 2.32V (Z-threshold), MR is pulled low, or watchdog timeout occurs. Its reset-based watchdog does not produce an independent WDO signal; instead, it triggers a full reset pulse for the 140ms timeout period upon WDI inactivity.

It integrates a dedicated 0.62V reference-based power-fail comparator with externally accessible PFI (input) and PFO (push-pull active-low output), enabling precise early-warning detection of secondary supply collapse. The internal 50kΩ MR pullup and guaranteed operation down to VCC = 1V support robust manual reset and brownout recovery in low-voltage embedded systems.

Key Specifications

Pinout & Package

MAX6704ZKA is housed in an 8-pin SOT23-8 package (3.00mm × 1.75mm × 1.30mm body, 0.65mm pitch), RoHS-compliant and available in lead-free (+T) variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6708ZKA, MAX6704ZKA adds reset-triggered watchdog supervision without layout change; versus TPS3808G33DBVR, it delivers full power-fail warning, dual reset polarity, and wider voltage range - critical for multi-rail automotive and industrial systems.

Availability

MAX6704ZKA is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, medical infusion pump controllers, and telecom remote radio units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6704ZKA 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 extended temperature performance.

The MAX6701–MAX6708 family was engineered specifically for multivoltage microprocessor supervision in space-constrained, high-reliability systems - delivering reset, watchdog, and power-fail functions in a single 8-pin SOT23 package.

FAQ

What is the reset threshold voltage for MAX6704ZKA?

The MAX6704ZKA has a factory-trimmed reset threshold of 2.32V (Z-suffix), specified over -40°C to +125°C. This value is guaranteed by production test and enables precise supervision of +2.3V system rails without external calibration. The threshold exhibits ±30mV tolerance across temperature and has a 60ppm/°C drift coefficient, ensuring stability in automotive under-hood environments where MAX6704ZKA is commonly deployed.

Does MAX6704ZKA provide an independent watchdog output (WDO)?

No, MAX6704ZKA does not feature a dedicated WDO pin. Unlike MAX6701–MAX6707 variants, its watchdog circuit is reset-based: when WDI is not toggled within 1.6s, MAX6704ZKA asserts both RESET and RESET outputs for the full 140ms timeout period. This architecture eliminates the need for external WDO-to-MR feedback but requires firmware to interpret reset events as potential watchdog timeouts.

How does the power-fail comparator work on MAX6704ZKA?

The MAX6704ZKA's power-fail comparator uses an internal 0.62V reference connected to the inverting input. The non-inverting input is brought out as the PFI pin. When an external resistor divider applies a voltage to PFI that drops below 0.62V, the comparator asserts the PFO output low. This allows monitoring of any supply rail - for example, a 3.3V rail can be scaled to 0.62V using R1/R2 = 4.33 - enabling early-warning shutdown before main VCC dropout.

What are the key timing parameters for MAX6704ZKA reset assertion?

Upon VCC falling below 2.32V, MAX6704ZKA asserts RESET and RESET within 12µs (typical propagation delay). The outputs remain asserted for a guaranteed 140ms (min) reset timeout period after VCC rises above threshold. MR-induced reset also enforces the same 140ms hold time. These timings are production-tested and ensure µP initialization completes reliably across -40°C to +125°C, meeting automotive ASIL-B timing integrity requirements.

Can MAX6704ZKA operate with supply voltages below 2.32V?

Yes, MAX6704ZKA operates down to VCC = 1.2V and guarantees valid reset output behavior (RESET low ≤0.4V, RESET high ≥0.8×VCC) even as VCC declines to 1.0V. Below 1.0V, the outputs enter high-impedance state. This extended low-voltage operation supports graceful brownout recovery in battery-powered systems and ensures deterministic reset release timing during power ramp-down - a key requirement in medical and industrial safety-critical designs.