Analog Devices Inc./Maxim Integrated MAX692ACSA

Overview

The MAX692ACSA from Maxim Integrated is a microprocessor supervisory circuit providing reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts an active-low RESET output during power-up, brownout (VCC < 4.40V), and watchdog timeout (1.6s), delivers VOUT from VCC or VBATT via internal PMOS switches, and monitors supply integrity using a 1.25V reference comparator. It is used in battery-backed embedded controllers requiring reliable power monitoring.

For engineers reviewing the MAX692ACSA datasheet, MAX692ACSA pinout, MAX692ACSA application, or MAX692ACSA equivalent, key selection criteria include its 4.40V reset threshold, 200ms reset pulse width, 1.6s watchdog timeout, battery-switchover hysteresis (40mV), and guaranteed RESET assertion down to VCC = 1V - all critical for fail-safe μP initialization in industrial and portable systems.

Technical Context

The MAX692ACSA integrates four independent functional blocks: a precision reset generator with 4.40V ±2% threshold and 200ms delay, a 1.6s watchdog timer cleared by WDI edges or reset assertion, a power-fail comparator comparing PFI to a 1.25V internal reference, and a dual-path battery switchover circuit that connects VOUT to VCC (5Ω switch) above threshold or to VBATT (80Ω switch) below threshold with 40mV hysteresis.

Its RESET output remains low for 200ms after VCC rises above 4.40V and stays asserted while VCC < 1V; the watchdog disables when WDI is floating or three-stated; PFO goes low when PFI < 1.25V; and backup mode draws ≤5.0µA at TMIN–TMAX with VCC = 0V and VBATT = 2.8V.

Key Specifications

Pinout & Package

MAX692ACSA is housed in an 8-pin SO (Small Outline) package with standard JEDEC MS-012AC outline, 1.27mm pitch, and RoHS-compliant lead-free option available (add '+' suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX802MCSA, MAX692ACSA omits guaranteed ±2% PFI accuracy but matches all timing, threshold, and switchover specs; versus MAX706RCSA, it supports 5V brownout detection and battery backup - making it irreplaceable in portable +5V systems requiring RAM retention.

Availability

MAX692ACSA is available at Aetrix Electronics and suitable for industrial PLCs, portable medical devices, smart energy meters, and ruggedized handheld terminals requiring stable component supply across extended product lifecycles.

Supply support for MAX692ACSA 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, automotive, and communications applications, with expertise in power management and reliability-critical subsystems.

The MAX692A family was developed specifically for microprocessor-based systems needing integrated power monitoring, reset control, and battery backup - targeting cost-sensitive, space-constrained embedded applications operating from +5V rails.

FAQ

What is the guaranteed minimum VCC level at which MAX692ACSA asserts RESET?

The MAX692ACSA guarantees RESET assertion down to VCC = 1V. This ensures reliable reset hold during deep brownout conditions before the supply collapses completely. The device maintains logic-low RESET output until VCC recovers above 4.40V and sustains it for 200ms thereafter. This specification is explicitly confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables of the official MAX692A datasheet.

Does MAX692ACSA support active-high reset output?

No, MAX692ACSA provides only an active-low RESET output. The active-high variant is the MAX805L series (e.g., MAX805LCSA), which outputs RESET instead of RESET. MAX692ACSA's pin 7 is strictly RESET (active-low push-pull). Attempting to use it as active-high will result in inverted reset behavior incompatible with μPs requiring active-high assertion.

What is the maximum allowable VBATT voltage for MAX692ACSA?

The maximum allowable VBATT voltage for MAX692ACSA is 4.55V, as specified in Table 2 of the datasheet. Exceeding this risks excessive substrate diode conduction when VCC is near the 4.40V reset threshold, potentially causing latch-up or accelerated battery drain. Lithium cells with 3.0V–3.6V nominal voltage are ideal; higher-voltage sources require series regulation.

Can the watchdog timer in MAX692ACSA be disabled?

Yes, the watchdog timer in MAX692ACSA is automatically disabled when the WDI pin is left floating or connected to a high-impedance (three-state) buffer. The internal timer clears and remains inactive until WDI receives a defined logic edge. This allows designers to retain the IC's reset and switchover functions while omitting watchdog supervision where firmware robustness is assured.

Is MAX692ACSA pin-compatible with other supervisory ICs?

Yes, MAX692ACSA is pin-compatible with MAX692 (legacy) and MAX692A variants in the same 8-pin SO package. It is not compatible with MAX690A (4.65V threshold) or MAX805L (active-high RESET) due to differing reset thresholds and output polarity. Pin compatibility is confirmed in the "Pin Configurations" section and ordering table of the datasheet.