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Analog Devices Inc./Maxim Integrated MAX691EWE+T
- Part No.:
- MAX691EWE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX691EWE+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:990
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Product details
Overview
MAX691EWE+T from Maxim Integrated is a microprocessor supervisory circuit with dual reset outputs (active-low RESET and active-high RESET), 4.65V reset threshold, 200ms power-up reset timeout, and integrated chip-enable gating. It monitors 5V supply integrity, provides battery switchover down to 1V VCC, and safeguards CMOS RAM during brownout-used in industrial controllers and intelligent instrumentation requiring fail-safe boot sequencing.
For engineers reviewing the MAX691EWE+T datasheet, MAX691EWE+T pinout, MAX691EWE+T application, or MAX691EWE+T equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed backup-battery behavior at VCC = 1V, and real-world timing specifications for watchdog, CE gating, and power-fail detection.
Technical Context
The MAX691EWE+T implements a dual-threshold comparator architecture for reset assertion and release, with hysteresis of 15mV and guaranteed validity down to VCC = 1V. Its internal oscillator sets nominal 200ms reset timeout and 1.6s watchdog period, configurable via OSC SEL/OSC IN to support external clock or timing capacitor.
It integrates a bidirectional VCC/VBATT switchover path with <1.2Ω on-resistance (VCC-to-VOUT) and 15–30Ω (VBATT-to-VOUT), plus a dedicated BATT ON output signaling switchover status. The CE IN/CE OUT transmission gate provides ≤10ns propagation delay and 75Ω series resistance in enabled mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Voltage | 4.65V typical; ensures reliable reset assertion before 5V rail collapse in industrial systems. |
| Reset Timeout Period (Power-up) | 200ms typical; guarantees μP initialization completes before code execution begins. |
| VCC Supply Current | 30μA typical; enables low-power operation in always-on monitoring applications. |
| VCC-to-VOUT On-Resistance | 0.8–1.2Ω (MAX69_AC); limits voltage drop to <300mV at 250mA load for stable system rail. |
| Battery Switchover Threshold | VCC < VBATT − 0.3V (power-down); prevents premature battery engagement during transient dips. |
| CE IN-to-CE OUT Propagation Delay | 6–10ns; supports high-speed μP bus timing without violating setup/hold windows. |
| Power-Fail Accuracy | ±2% (MAX800L/M only); MAX691EWE+T uses ±0.05V PFI threshold tolerance per spec table. |
Pinout & Package
MAX691EWE+T is housed in a 16-pin Wide SO (SOIC-W) package with 0.3-inch body width and standard 1.27mm pitch. Pin 1 is marked by a beveled corner or dot; thermal pad is not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VBATT | Battery-backup input | Connects to backup capacitor or Li-ion cell; enables VOUT sourcing when VCC falls below reset threshold. |
| 2 VOUT | Output supply voltage | Primary system rail output; switches between VCC and VBATT; requires 0.1µF decoupling to GND. |
| 3 VCC | Main 5V supply input | Regulated +5V input; monitored for reset generation; supports up to 250mA continuous current. |
| 4 GND | Ground reference | 0V return for all analog and digital functions; must be low-impedance connection. |
| 5 BATT ON | Battery-status indicator | Open-drain output pulled high in battery mode; drives PNP base for >250mA external pass transistors. |
| 6 LOW LINE | Reset comparator buffer | Active-low signal mirroring RESET logic state; sinks 3.2mA at 0.1V for direct LED or logic interface. |
| 7 OSC IN | Oscillator timing input | Accepts external clock or timing capacitor; sets watchdog/reset periods when OSC SEL = GND. |
| 8 OSC SEL | Oscillator mode select | Drives internal oscillator (floating/high) or enables external timing (low); has 10µA internal pull-up. |
| 9 PFI | Power-fail comparator input | Non-inverting input referenced to 1.25V; detects brownout or low-battery condition with ±25nA leakage. |
| 10 PFO | Power-fail comparator output | Active-low open-drain output; asserts when PFI < 1.25V; independent of reset/watchdog logic. |
| 11 WDI | Watchdog input | Three-level input (high/mid/low); resets watchdog timer on any 100ns+ transition; floating disables function. |
| 12 CE OUT | Chip-enable gated output | Passes CE IN only when VCC > reset threshold; disabled during reset to prevent RAM corruption. |
| 13 CE IN | Chip-enable gated input | High-impedance during reset; presents 75Ω series resistance when enabled; connect to μP CE line. |
| 14 WDO | Watchdog output | Active-low open-drain output; mirrors WDI timeout status; remains high if WDI unconnected or VCC < reset threshold. |
| 15 RESET | Active-low reset output | Open-drain output; sinks 3.2mA at 0.1V; valid down to VCC = 1V; requires external pull-up for logic-high level. |
| 16 RESET | Active-high reset output | Open-drain inverse of RESET; high-impedance when inactive; sources ~1.6mA at VOUT − 0.5V when active. |
Key Features
| Feature | Design Value |
|---|---|
| Dual reset outputs (RESET / RESET) | Supports both active-low and active-high μP reset inputs without external inverters or level shifters. |
| VCC-valid reset down to 1V | Enables deterministic reset assertion even during deep brownout, critical for data retention in battery-backed systems. |
| Integrated CE signal gating | Prevents spurious writes to CMOS RAM during power failure by disabling CE path within 15µs of reset assertion. |
| MaxCap®/SuperCap-compatible switchover | Supports low-ESR backup capacitors up to 0.47F with controlled inrush and low on-resistance (<1.2Ω). |
| Configurable watchdog timeout | Offers 100ms short period and 1.6s long period via OSC SEL/OSC IN; selectable with external capacitor or clock. |
| Independent power-fail comparator | Uncommitted PFI/PFO pair enables early warning of supply degradation without affecting reset or watchdog behavior. |
Applications
| Industrial Controller Monitoring | Intelligent Instrument Power Management |
|---|---|
Use Scenario: PLC or motion controller maintaining real-time I/O state during AC mains interruption. IC Role / Device Role / Timing Role: Supervisory IC asserting RESET until VCC stabilizes post-interruption; enabling battery-backed SRAM retention. Use Value: Prevents corrupted control outputs by holding μP in reset until 5V rail recovers to 4.65V ±15mV for ≥200ms. |
Use Scenario: Portable multimeter or data logger preserving calibration data during battery swap. IC Role / Device Role / Timing Role: Seamless VCC-to-VBATT switchover with BATT ON signaling; VOUT maintained within 200mV of VBATT at 20mA. Use Value: Eliminates power gap using 0.47F MaxCap; guarantees uninterrupted operation during 100ms battery insertion. |
| Critical μP Power Monitoring | Computing System Brownout Protection |
Use Scenario: Embedded medical device requiring FDA-compliant power-up sequence validation. IC Role / Device Role / Timing Role: Dual-reset generation with 200ms timeout and 1.6s watchdog; RESET asserted until VCC ≥4.65V for full duration. Use Value: Meets IEC 62304 power-on reliability requirements by guaranteeing deterministic reset window and fault detection. |
Use Scenario: Network appliance detecting gradual 5V rail sag due to aging PSU or thermal derating. IC Role / Device Role / Timing Role: PFI input monitors +5V rail via resistor divider; PFO triggers graceful shutdown before VCC drops below reset threshold. Use Value: Provides 25µs response to voltage dip, enabling firmware-initiated save-and-halt before hardware reset occurs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACWE+ | Same pinout and function; rated for 0°C to +70°C (vs. −40°C to +85°C for MAX691EWE+T). | Not suitable for extended-temperature industrial environments where ambient exceeds 70°C. | Select MAX691EWE+T for automotive under-hood or factory-floor deployments requiring −40°C startup. |
| MAX693AEWE+ | 4.4V reset threshold (vs. 4.65V); identical package, timing, and feature set. | Designed for 4.5V–5.5V VCC range systems; less margin against 5V rail droop than MAX691EWE+T. | Choose MAX691EWE+T when system stability requires higher reset threshold to avoid false resets near 4.75V minimum. |
Compared with MAX691ACWE+ and MAX693AEWE+, the MAX691EWE+T offers extended temperature operation and tighter reset threshold tolerance, making it optimal for mission-critical embedded systems where environmental robustness and precise brownout detection are mandatory.
Availability
MAX691EWE+T is available at Aetrix Electronics and suitable for industrial controllers, intelligent instrumentation, critical μP power monitoring, and computing system brownout protection requiring stable component supply across extended temperature ranges.
Supply support for MAX691EWE+T 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, sensing, and connectivity applications in industrial, automotive, and communications markets.
The MAX691 family targets microprocessor supervisory functions-specifically providing dual reset outputs, battery switchover, CE gating, and watchdog supervision for 5V systems requiring high reliability and low quiescent current.
FAQ
What is the operating temperature range for MAX691EWE+T?
The MAX691EWE+T is specified for −40°C to +85°C operation, validated across the full range for all electrical parameters including reset threshold, timeout periods, and VCC-to-VOUT on-resistance. This makes MAX691EWE+T suitable for industrial environments where ambient temperatures exceed commercial-grade limits.
Does MAX691EWE+T support battery backup with supercapacitors?
Yes, MAX691EWE+T is explicitly MaxCap® and SuperCap-compatible. Its VBATT input supports low-ESR capacitors up to 0.47F, with VBATT-to-VOUT on-resistance of 15Ω at 4.5V, ensuring minimal voltage drop during switchover. The BATT ON output provides status indication for external pass transistor control.
How does the watchdog function behave when WDI is left unconnected on MAX691EWE+T?
When WDI is unconnected, an internal 100kΩ voltage divider biases WDI to ~1.6V, disabling the watchdog timer. WDO remains high, and no reset pulses are generated. This behavior is confirmed in the datasheet's "Watchdog Input" section and applies identically to MAX691EWE+T.
Can MAX691EWE+T generate a valid RESET signal when VCC drops to 1V?
Yes, MAX691EWE+T guarantees RESET assertion and validity down to VCC = 1V. The RESET output sinks 50μA at 0.3V saturation when VCC = 1V, VBATT = 0V, and VCC is falling-enabling safe shutdown sequencing in deep brownout conditions.
What is the maximum continuous current supported by the VOUT pin of MAX691EWE+T?
MAX691EWE+T supports 250mA continuous current from VOUT when sourced from VCC, with VCC-to-VOUT on-resistance of 0.8–1.2Ω. At 250mA, VOUT typically drops 200–300mV below VCC. Peak currents up to 1A are allowed for power-on transients only.
MAX691EWE+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 35ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX691EWE+T FAQ
1.How can I place an order for MAX691EWE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX691EWE+T 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 MAX691EWE+T reliable?
The price and inventory of MAX691EWE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX691EWE+T is usually 5 days.
3.What payment methods are accepted for MAX691EWE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX691EWE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX691EWE+T?
MAX691EWE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX691EWE+T 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 MAX691EWE+T?
For technical support, including MAX691EWE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX691EWE+T requirements.
6.How does Aetrix verify that MAX691EWE+T is sourced from the original manufacturer or authorized distributors?
All MAX691EWE+T 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 MAX691EWE+T meets industry standards.
7.What is the process for return or replacement of MAX691EWE+T?
All MAX691EWE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX691EWE+T, 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 MAX691EWE+T part is unused and in its original packaging.
Return procedure for MAX691EWE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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