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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

Analog Devices Inc./Maxim Integrated MAX691AEUE+

Name: MAX691AEUE+
Brand: Analog Devices Inc./Maxim Integrated
SKU: MAX691AEUE+
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MAX691AEUE+

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Supervisors

Package:: 16-TSSOP (0.173", 4.40mm Width)

Datasheet:: MAX691AEUE+.pdf

Description:: IC SUPERVISOR 1 CHANNEL 16TSSOP

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Product details

Overview

The MAX691AEUE+ from Maxim Integrated is a microprocessor supervisory circuit that monitors 5V supply voltage, asserts reset below 4.65V (typ), provides battery switchover down to 1V VCC, gates chip-enable signals with ≤10ns propagation delay, and delivers watchdog timeout control for embedded controllers in industrial instrumentation and critical power monitoring systems.

For engineers reviewing the MAX691AEUE+ datasheet, MAX691AEUE+ pinout, MAX691AEUE+ application, or MAX691AEUE+ equivalent, this page delivers verified specifications including reset threshold hysteresis (15mV), battery-backup supply current (≤1µA), CE IN-to-CE OUT resistance (75–150Ω), and guaranteed RESET validity at VCC = 1V - all confirmed for the 16-pin TSSOP package with −40°C to +85°C operation.

Technical Context

The MAX691AEUE+ integrates dual reset outputs (active-low RESET and active-high RESET), a programmable watchdog timer with internal oscillator (1.6s nominal timeout), and bidirectional power-path control between VCC and VBATT via low-R_ON PMOS switches (VCC-to-VOUT: 0.8–1.4Ω; VBATT-to-VOUT: 15–30Ω). It features an uncommitted power-fail comparator (PFI/PFO) with ±25nA leakage and 25–60µs response.

Its chip-enable gating uses a transmission gate architecture enabling CE IN-to-CE OUT pass-through during normal operation and automatic disable during reset assertion, with 15µs forced hold time if CE IN is low at reset onset. The BATT ON output signals switchover status with 0.1–0.4V low-state voltage at 3.2mA sink.

Key Specifications

Parameter	Value and Actual Design Meaning
Reset Threshold Voltage	4.65V typical; ensures reliable μP reset initiation during 5V supply brownout before system instability occurs.
Reset Timeout Period	200ms typical on power-up; guarantees sufficient hold time for full μP initialization and memory stabilization.
VCC Supply Current	30µA typical in normal operation; enables low-power system monitoring without burdening main supply.
Battery-Backup Current	≤1µA at TA = +25°C; extends backup capacitor or coin-cell life for months in standby monitoring mode.
CE Propagation Delay	6–10ns with 50Ω source / 50pF load; supports high-speed μP bus timing without CE skew-induced write corruption.
RESET Output Validity	Guaranteed down to VCC = 1V; maintains deterministic reset state even during deep undervoltage conditions.
Power-Fail Accuracy	±2% for MAX800L/M variants; MAX691AEUE+ does not specify this guarantee - only MAX800L/M do.

Pinout & Package

MAX691AEUE+ is housed in a 16-pin TSSOP package (body width 4.4mm, lead pitch 0.65mm), RoHS-compliant and lead-free (denoted by '+' suffix), rated for −40°C to +85°C operation.

Pin/Terminal	Circuit Role	Design Meaning
1 VBATT	Battery-Backup Input	Connects to backup capacitor or Li-ion cell; enables seamless switchover when VCC drops below reset threshold and VBATT > VCC.
2 VOUT	Output Supply Voltage	Primary system supply rail; sourced from VCC (normal) or VBATT (backup); requires 0.1µF decoupling to GND.
3 VCC	Main 5V Supply Input	Regulated 4.75–5.5V input; monitored for reset generation and CE gating enable/disable logic.
4 GND	Ground Reference	0V reference for all analog comparators, digital logic, and output drivers; must be low-impedance connection.
5 BATT ON	Battery-On Status Output	Open-drain logic-high signal indicating VBATT is active; sinks 3.2mA at ≤0.4V for external PNP base drive.
6 LOW LINE	Reset Comparator Buffer	Active-low buffered copy of reset comparator output; used for independent power-fail flagging or status LEDs.
7 OSC IN	External Oscillator Input	Accepts timing capacitor (for RC oscillator) or external clock; sets watchdog/reset timeout periods when OSC SEL = GND.
8 OSC SEL	Oscillator Select Input	Drives internal oscillator (floating/high) or enables external timing (low); has 10µA internal pull-up.
9 PFI	Power-Fail Input	Non-inverting input to uncommitted comparator; triggers PFO low when voltage falls below 1.25V (±25nA leakage).
10 PFO	Power-Fail Output	Open-drain comparator output; sinks 3.2mA at ≤0.4V; used for low-battery warning or early power-loss detection.
11 WDI	Watchdog Input	Three-level input (high/low/floating); resets watchdog timer on edge or ≥100ns pulse; floating disables watchdog.
12 CE OUT	Chip-Enable Output	Gated CE signal passed from CE IN; held low for 15µs after reset assertion to prevent RAM write errors.
13 CE IN	Chip-Enable Input	High-impedance during reset; presents 75Ω series resistance in enabled mode; connect to μP CE or GND if unused.
14 WDO	Watchdog Output	Active-low watchdog fault indicator; goes low on timeout and remains low until next WDI transition.
15 RESET	Active-Low Reset Output	Open-drain output asserted low during brownout/reset; valid down to VCC = 1V; requires external pull-up.
16 RESET	Active-High Reset Output	Open-drain inverse of RESET; high-impedance when RESET is active; used for μPs requiring active-high reset.

Key Features

Feature	Design Value
Guaranteed RESET validity at VCC = 1V	Enables deterministic reset behavior during severe brownouts where most supervisors fail, critical for safety-critical firmware recovery.
On-board CE signal gating with ≤10ns delay	Prevents spurious writes to CMOS RAM/EEPROM during power transitions without adding external logic or timing margin.
Dual reset outputs (RESET / RESET)	Supports both active-low and active-high μP reset inputs on same device, eliminating need for external inverters or dual-supervisor designs.
MaxCap®/SuperCap-compatible battery switchover	Allows use of large-value backup capacitors (e.g., 0.47F) with low-leakage path (≤1µA), extending backup runtime beyond coin cells.
Uncommitted PFI/PFO comparator	Provides flexible power-fail or low-battery detection independent of reset function, enabling dual-purpose monitoring without extra ICs.

Applications

Industrial Programmable Logic Controller (PLC)	Medical Infusion Pump Controller
Use Scenario: Continuous operation in factory environments with fluctuating 5V rails and requirement for nonvolatile RAM retention during brief AC outages. IC Role / Device Role / Timing Role: Supervises VCC, asserts RESET to halt CPU on brownout, switches VOUT to VBATT to sustain SRAM, and gates CE to prevent corrupted register writes. Use Value: Prevents data loss and unsafe actuator states by ensuring deterministic reset and uninterrupted memory backup with ≤1µA battery drain.	Use Scenario: Battery-powered portable infusion pump requiring FDA-grade reliability, with backup power for dose history storage during main supply interruption. IC Role / Device Role / Timing Role: Monitors 5V DC-DC output, initiates controlled shutdown via RESET, enables VBATT-to-VOUT switchover, and signals battery-on status to MCU for UI alerting. Use Value: Guarantees dose log integrity and safe motor stop via validated 200ms reset hold and 1V-minimum RESET assertion.
Test & Measurement Data Logger	Rack-Mounted Network Appliance
Use Scenario: Field-deployed environmental logger capturing sensor data hourly; must retain configuration and last reading across 10-second grid dips. IC Role / Device Role / Timing Role: Provides precise 4.65V reset threshold, powers real-time clock and FRAM from VOUT, and uses PFI/PFO to trigger early low-battery alerts before backup depletion. Use Value: Eliminates need for discrete comparators and reset ICs - single-chip solution reduces BOM count and PCB area while meeting IEC 61000-4-11 immunity.	Use Scenario: Carrier-grade Ethernet switch with hot-swap power modules; requires coordinated reset sequencing and CE protection during module insertion/removal. IC Role / Device Role / Timing Role: Generates synchronized RESET across multiple ASICs, gates CE lines to isolate memory during power ramp, and uses WDO to detect firmware hangs in management CPU. Use Value: Enables zero-downtime field upgrades by preventing partial writes during power transients and providing watchdog-triggered recovery without manual reboot.

Industrial Programmable Logic Controller (PLC)

Medical Infusion Pump Controller

Use Scenario: Continuous operation in factory environments with fluctuating 5V rails and requirement for nonvolatile RAM retention during brief AC outages.

IC Role / Device Role / Timing Role: Supervises VCC, asserts RESET to halt CPU on brownout, switches VOUT to VBATT to sustain SRAM, and gates CE to prevent corrupted register writes.

Use Value: Prevents data loss and unsafe actuator states by ensuring deterministic reset and uninterrupted memory backup with ≤1µA battery drain.

Use Scenario: Battery-powered portable infusion pump requiring FDA-grade reliability, with backup power for dose history storage during main supply interruption.

IC Role / Device Role / Timing Role: Monitors 5V DC-DC output, initiates controlled shutdown via RESET, enables VBATT-to-VOUT switchover, and signals battery-on status to MCU for UI alerting.

Use Value: Guarantees dose log integrity and safe motor stop via validated 200ms reset hold and 1V-minimum RESET assertion.

Test & Measurement Data Logger

Rack-Mounted Network Appliance

Use Scenario: Field-deployed environmental logger capturing sensor data hourly; must retain configuration and last reading across 10-second grid dips.

IC Role / Device Role / Timing Role: Provides precise 4.65V reset threshold, powers real-time clock and FRAM from VOUT, and uses PFI/PFO to trigger early low-battery alerts before backup depletion.

Use Value: Eliminates need for discrete comparators and reset ICs - single-chip solution reduces BOM count and PCB area while meeting IEC 61000-4-11 immunity.

Use Scenario: Carrier-grade Ethernet switch with hot-swap power modules; requires coordinated reset sequencing and CE protection during module insertion/removal.

IC Role / Device Role / Timing Role: Generates synchronized RESET across multiple ASICs, gates CE lines to isolate memory during power ramp, and uses WDO to detect firmware hangs in management CPU.

Use Value: Enables zero-downtime field upgrades by preventing partial writes during power transients and providing watchdog-triggered recovery without manual reboot.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX691ACUE+	Same functionality and pinout, but rated for 0°C to +70°C industrial range (vs. −40°C to +85°C for MAX691AEUE+).	Suitable for commercial-grade equipment without extended temperature requirements.	Select MAX691ACUE+ only if ambient operating temperature stays above −40°C and below +70°C; otherwise MAX691AEUE+ ensures full spec compliance.
MAX693AESE+	4.4V reset threshold (vs. 4.65V), wider VCC range (4.5–5.5V), identical TSSOP footprint and temperature rating.	Designed for systems with tighter 5V tolerance or legacy 4.5V logic rails.	Choose MAX693AESE+ when system VCC may dip to 4.5V regularly; MAX691AEUE+ is optimal for standard 4.75–5.5V 5V supplies.

Compared with MAX691ACUE+, MAX691AEUE+ extends operational reliability to harsher environments; compared with MAX693AESE+, it raises reset threshold for improved noise immunity on stable 5V rails - both alternatives require no PCB changes but differ in thermal and voltage-margin suitability.

Availability

MAX691AEUE+ is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion pumps, test-and-measurement data loggers, and rack-mounted network appliances requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX691AEUE+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.

The MAX691A family was designed specifically for robust microprocessor supervision in mission-critical systems - delivering guaranteed reset assertion at ultra-low VCC, integrated CE protection, and battery switchover with minimal quiescent current.

FAQ

What is the guaranteed minimum VCC level at which MAX691AEUE+ asserts RESET?

The MAX691AEUE+ guarantees RESET assertion down to VCC = 1V, with saturation voltage ≤0.3V at 50μA sink current. This is confirmed in the Electrical Characteristics table under "RESET Output Voltage" with VCC = 1V, VBATT = 0V, and VCC falling. Below 1V, R_DS(ON) increases, but the 1V guarantee ensures deterministic reset behavior where competing supervisors typically fail.

Does MAX691AEUE+ support external timing capacitors for watchdog timeout adjustment?

Yes, MAX691AEUE+ supports external timing capacitors on OSC IN when OSC SEL is tied to GND. As specified in Table 1 and Figure 3, connecting a capacitor (e.g., 47pF) between OSC IN and GND sets both watchdog and reset timeout periods - for example, a 47pF cap yields ~100ms short watchdog timeout and ~200ms reset timeout. This is fully supported and characterized in the datasheet.

Can MAX691AEUE+ be used without a backup battery?

Yes, MAX691AEUE+ operates fully without a backup battery: connect VBATT to GND, tie VOUT to VCC, and leave BATT ON unconnected. All supervision functions - reset generation, CE gating, watchdog, PFI/PFO - remain active. The device draws only 30µA from VCC in normal operation and requires no VBATT-related components for basic 5V monitoring.

What is the maximum continuous output current capability of MAX691AEUE+ on VOUT?

MAX691AEUE+ supports up to 250mA continuous current from VOUT when sourced from VCC, with VCC-to-VOUT on-resistance of 0.8–1.4Ω (depending on grade). For currents exceeding 250mA, the internal parallel diode conducts, but sustained >250mA is not recommended due to thermal limits. In battery-backup mode (VBATT-to-VOUT), max continuous current is 25mA.

Is MAX691AEUE+ pin-compatible with older MAX691 versions?

Yes, MAX691AEUE+ is explicitly described as a "pin-compatible upgrade" to MAX691, MAX693, and MAX695 per the General Description. Pin mapping, electrical behavior, and functional blocks match identically - including dual RESET outputs, CE gating, PFI/PFO, and WDI/WDO. No PCB redesign is needed when upgrading from MAX691CPE/MAX691CSE to MAX691AEUE+.

MAX691AEUE+ Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 16-TSSOP (0.173", 4.40mm Width)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Battery Backup Circuit

Number of Voltages Monitored:: 1

Voltage - Threshold:: 4.65V

Output:: Push-Pull, Push-Pull

Reset:: Active High/Active Low

Reset Timeout:: 140ms Minimum

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-TSSOP

MAX691AEUE+ FAQ

1.How can I place an order for MAX691AEUE+ through Aetrix?

Please submit a Request for Quotation (RFQ) for MAX691AEUE+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MAX691AEUE+ reliable?

The price and inventory of MAX691AEUE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX691AEUE+ is usually 5 days.

3.What payment methods are accepted for MAX691AEUE+?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX691AEUE+ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MAX691AEUE+?

MAX691AEUE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MAX691AEUE+ order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MAX691AEUE+?

For technical support, including MAX691AEUE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX691AEUE+ requirements.

6.How does Aetrix verify that MAX691AEUE+ is sourced from the original manufacturer or authorized distributors?

All MAX691AEUE+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX691AEUE+ meets industry standards.

7.What is the process for return or replacement of MAX691AEUE+?

All MAX691AEUE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX691AEUE+, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MAX691AEUE+ part is unused and in its original packaging.

Return procedure for MAX691AEUE+:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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