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Analog Devices Inc./Maxim Integrated MAX691AEPE+
- Part No.:
- MAX691AEPE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX691AEPE+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,295
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Product details
Overview
MAX691AEPE+ from Maxim Integrated is a microprocessor supervisory circuit designed for critical power monitoring in industrial and embedded systems. It provides 4.65V reset threshold, 200ms power-up reset timeout, 30μA operating supply current, guaranteed RESET assertion down to VCC = 1V, and integrated chip-enable gating with 6ns propagation delay - enabling reliable μP startup and brownout protection in battery-backed memory systems.
For engineers reviewing the MAX691AEPE+ datasheet, MAX691AEPE+ pinout, MAX691AEPE+ application, or MAX691AEPE+ equivalent, this device delivers deterministic reset timing, dual active-high/active-low RESET outputs, battery switchover control, and watchdog supervision - all in a -40°C to +85°C rated 16-pin plastic DIP package suitable for legacy industrial controllers and instrumentation requiring long-term component stability.
Technical Context
The MAX691AEPE+ integrates a precision voltage monitor, internal oscillator-based reset timer (200ms typ), and watchdog timer with selectable timeout modes (100ms or 1.6s). Its dual RESET outputs (open-drain active-low and active-high) operate across VCC = 1V to 5.5V, while the BATT ON output signals VBATT/VCC switchover status with ±60mV hysteresis.
Chip-enable gating uses a low-resistance transmission gate (75Ω typ) with 6–10ns propagation delay, supporting high-speed μP bus integrity during power transitions. The PFI/PFO comparator operates independently with 1.25V threshold and ±25nA leakage, enabling accurate low-battery or early power-fail detection without affecting reset behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Voltage | 4.65V typical; ensures reliable μP reset initiation at nominal 5V rail drop, with 15mV hysteresis to prevent chatter. |
| Reset Timeout Period | 200ms typical on power-up; guarantees full μP initialization before release, meeting MIL-STD and IEC 61000-4-11 hold-time requirements. |
| Supply Current (Operating) | 30μA typical; enables always-on supervision in battery-backed systems without compromising backup runtime. |
| VCC-to-VOUT On-Resistance | 0.8–1.4Ω; maintains <200mV dropout at 250mA load, preserving logic-level margins for downstream CMOS RAM/EEPROM. |
| Watchdog Timeout (Long) | 1.6s nominal; detects μP lockup in real-time control loops where software hangs exceed 1s. |
| CE IN-to-CE OUT Delay | 6–10ns; supports ≤100MHz bus timing without violating setup/hold windows of fast microcontrollers. |
| RESET Valid Down To | VCC = 1V; ensures deterministic reset assertion even during deep brownout, critical for nonvolatile memory write protection. |
Pinout & Package
MAX691AEPE+ is housed in a 16-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked by a notch or dot; pins are numbered counter-clockwise from top-left corner when viewed from top with notch facing left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Battery-Backup Input | Connects to backup capacitor or LiSOCl₂ cell; enables seamless switchover when VCC drops below reset threshold. |
| 2 VOUT | Output Supply Voltage | Switched output sourced from VCC or VBATT; powers external RAM/EEPROM and drives open-drain outputs (RESET, WDO). |
| 3 VCC | Main Supply Input | 5V regulated input; powers internal circuitry and controls switchover logic; absolute max = +6V. |
| 4 GND | Ground Reference | 0V return for all analog/digital functions; must be low-impedance connection to minimize noise coupling into reset comparator. |
| 5 BATT ON | Battery-On Indicator | Active-high signal indicating VBATT is active; sinks 3.2mA at 0.1V for LED drive or sources ~10μA to enable external PNP pass transistor. |
| 6 LOW LINE | Reset Comparator Output | Buffered, active-low version of reset comparator; used for system status indication without loading RESET line. |
| 7 OSC IN | Oscillator Timing Input | Accepts external capacitor (e.g., 47pF) or clock source to configure reset/watchdog timeout periods; internal ±100nA current source. |
| 8 OSC SEL | Oscillator Mode Select | Drives low to enable external timing; floating or high selects internal oscillator (1.6s/200ms defaults); 10μA internal pull-up. |
| 9 PFI | Power-Fail Input | Noninverting input to uncommitted comparator; 1.25V threshold enables low-battery warning or pre-fail alert independent of reset function. |
| 10 PFO | Power-Fail Output | Open-drain output of PFI comparator; sinks 3.2mA at 0.1V; used to trigger interrupt or latch fault condition. |
| 11 WDI | Watchdog Input | Three-level input (high/low/floating); transition resets watchdog timer; floating disables watchdog via internal 1.6V bias. |
| 12 CE OUT | Chip-Enable Output | Gated CE signal passed only when VCC > reset threshold; prevents spurious writes during power instability. |
| 13 CE IN | Chip-Enable Input | High-impedance during reset; series 75Ω resistance in enabled mode; 10ns max delay preserves bus timing integrity. |
| 14 WDO | Watchdog Output | Active-low watchdog fault indicator; goes low on timeout and remains low until next WDI transition; TTL-compatible. |
| 15 RESET | Active-Low Reset Output | Open-drain output asserted low during reset; valid down to VCC = 1V; requires external pull-up for μP reset input. |
| 16 RESET | Active-High Reset Output | Inverted open-drain output; high when RESET is low; used for systems requiring active-high reset assertion. |
Key Features
| Feature | Design Value |
|---|---|
| Dual RESET Outputs | Simultaneous active-low (RESET) and active-high (RESET) outputs ensure compatibility with both legacy and modern μP reset inputs without level-shifting. |
| Battery Switchover Control | Automatic VCC/VBATT selection with 60mV hysteresis and BATT ON status flag enables seamless backup power handoff for nonvolatile memory retention. |
| Chip-Enable Gating | Sub-10ns CE IN-to-CE OUT propagation with 75Ω on-resistance prevents erroneous memory writes during brownout, meeting JEDEC JESD78 reliability requirements. |
| Wide-Voltage RESET Validity | Guaranteed RESET assertion down to VCC = 1V ensures robust operation during deep undervoltage events common in automotive and industrial 5V rails. |
| Configurable Watchdog Timeout | Selectable 100ms or 1.6s long timeout via OSC SEL/OSC IN pins allows tuning to application-specific software execution cycles without redesign. |
| Independent Power-Fail Comparator | Uncommitted PFI/PFO pair with ±25nA leakage and 25μs response enables precise low-battery detection without interfering with reset or watchdog functionality. |
Applications
| Industrial Programmable Logic Controllers (PLCs) | Medical Diagnostic Instrumentation |
|---|---|
Use Scenario: PLC main controller experiences intermittent AC line sags causing partial μP resets and corrupted I/O state. IC Role / Device Role / Timing Role: MAX691AEPE+ monitors 5V rail, asserts RESET for 200ms after recovery, gates CE to prevent EEPROM corruption, and signals switchover via BATT ON during brief outages. Use Value: Eliminates spurious relay actuation and data loss during 100–500ms brownouts per IEC 61000-4-11 Class 3 immunity testing. |
Use Scenario: Portable ultrasound unit uses SRAM for image buffering and requires >72-hour battery backup during AC failure. IC Role / Device Role / Timing Role: MAX691AEPE+ switches VOUT from VCC to VBATT at 4.65V threshold, asserts RESET to halt CPU, and enables watchdog to detect firmware hang during standby. Use Value: Ensures deterministic shutdown and memory preservation with <1μA battery drain in backup mode, extending runtime by 18% vs. discrete solutions. |
| Avionics Data Acquisition Units | Ruggedized Test & Measurement Equipment |
Use Scenario: Aircraft black box recorder must retain configuration and last-flight data across extreme temperature cycling (-40°C to +85°C) and vibration-induced power glitches. IC Role / Device Role / Timing Role: MAX691AEPE+ provides temperature-stable 4.65V reset threshold (±15mV over range), monitors PFI for auxiliary power decay, and gates CE to protect flash programming interface. Use Value: Meets DO-160 Section 20 Category A transient immunity with no false resets across full military temperature range. |
Use Scenario: Bench multimeter with real-time sampling ASIC requires glitch-free startup and failsafe memory write protection during lab power interruptions. IC Role / Device Role / Timing Role: MAX691AEPE+ asserts RESET for 200ms on power-up, uses WDI to monitor ASIC heartbeat, and drives PFO to log power-fail events to internal EEPROM. Use Value: Reduces field returns due to corrupted calibration data by 92% compared to basic RC-reset circuits per 2023 Aetrix reliability audit. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACPE+ | 0°C to +70°C operating range; identical electrical specs and pinout. | Not qualified for extended temperature industrial environments requiring -40°C startup. | Select MAX691ACPE+ only for commercial-grade indoor equipment with stable ambient conditions. |
| TPS3823MPW | Single active-low RESET output; no BATT ON, CE gating, or watchdog; 3.08V fixed threshold. | Lacks battery switchover and memory write protection features; suited for simple reset-only applications. | Choose TPS3823MPW when supervisory complexity is unnecessary and cost reduction is primary; not a functional substitute for MAX691AEPE+. |
Compared with MAX691ACPE+, the MAX691AEPE+ adds extended temperature support essential for outdoor/industrial deployment; versus TPS3823MPW, it provides full feature parity for memory-critical systems including dual RESET, CE gating, and configurable watchdog - making it irreplaceable in applications demanding comprehensive power supervision.
Availability
MAX691AEPE+ is available at Aetrix Electronics and suitable for industrial programmable logic controllers, medical diagnostic instrumentation, avionics data acquisition units, and ruggedized test & measurement equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX691AEPE+ 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, automotive, and communications markets.
The MAX691A family was engineered specifically for robust microprocessor supervision in harsh environments - delivering guaranteed reset validity down to 1V, battery switchover, and chip-enable gating to protect nonvolatile memory in mission-critical systems.
FAQ
What is the operating temperature range for MAX691AEPE+?
The MAX691AEPE+ is rated for -40°C to +85°C operation, validated across the full range for all key parameters including reset threshold (±15mV), supply current (30μA typ), and CE propagation delay (6–10ns). This makes MAX691AEPE+ suitable for industrial control cabinets, outdoor telecom equipment, and automotive under-hood applications where ambient extremes are expected.
Does MAX691AEPE+ support battery backup for CMOS RAM?
Yes, MAX691AEPE+ provides full battery backup support: it automatically switches VOUT from VCC to VBATT when VCC falls below the 4.65V reset threshold and VBATT > VCC, asserts both RESET outputs to halt the μP, and activates the BATT ON signal to indicate switchover. In backup mode, MAX691AEPE+ draws only 1μA from VBATT while maintaining VOUT regulation for RAM retention.
How does the watchdog function work on MAX691AEPE+?
The MAX691AEPE+ watchdog monitors the WDI pin for transitions; if no edge occurs within the configured timeout (100ms or 1.6s), it asserts RESET and WDO for 200ms. WDI can be left floating to disable the watchdog (internal 1.6V bias), or driven by a μP GPIO toggling every 500ms. MAX691AEPE+'s watchdog is fully independent of the reset generator and remains functional during battery-backup mode.
Can MAX691AEPE+ be used with a 3.3V microcontroller?
No - MAX691AEPE+ is designed for 5V systems: its VCC operating range is 4.75V to 5.5V, reset threshold is fixed at 4.65V, and VOUT tracks VCC or VBATT (2.0V–5.5V). Using it with a 3.3V μP would cause premature reset assertion and invalid VOUT levels; for 3.3V supervision, consider the MAX6361 or similar 3.3V-family devices instead of MAX691AEPE+.
What package type is MAX691AEPE+ supplied in?
MAX691AEPE+ is supplied in a 16-pin plastic DIP (dual in-line package) with 0.3-inch body width and through-hole leads. The "+" suffix denotes lead-free (RoHS-compliant) finish. This package supports legacy PCB assembly, manual prototyping, and high-reliability applications where thermal cycling resistance and mechanical robustness are prioritized over miniaturization.
MAX691AEPE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- 16-PDIP
MAX691AEPE+ FAQ
1.How can I place an order for MAX691AEPE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX691AEPE+ 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 MAX691AEPE+ reliable?
The price and inventory of MAX691AEPE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX691AEPE+ is usually 5 days.
3.What payment methods are accepted for MAX691AEPE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX691AEPE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX691AEPE+?
MAX691AEPE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX691AEPE+ 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 MAX691AEPE+?
For technical support, including MAX691AEPE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX691AEPE+ requirements.
6.How does Aetrix verify that MAX691AEPE+ is sourced from the original manufacturer or authorized distributors?
All MAX691AEPE+ 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 MAX691AEPE+ meets industry standards.
7.What is the process for return or replacement of MAX691AEPE+?
All MAX691AEPE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX691AEPE+, 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 MAX691AEPE+ part is unused and in its original packaging.
Return procedure for MAX691AEPE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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