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Analog Devices Inc./Maxim Integrated MAX807MEWE+
- Part No.:
- MAX807MEWE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX807MEWE+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX807MEWE+ from Maxim Integrated is a full-featured microprocessor supervisory circuit designed for power monitoring, battery switchover, and watchdog functions in embedded µP systems. It provides active-low and active-high RESET outputs, manual reset input (MR), 200ms reset timeout, ±1.5% reset threshold accuracy (4.425V), and 2ns CE gate propagation delay. It supports VCC down to 1V and delivers 250mA output current in normal mode - ideal for industrial controllers and portable instrumentation requiring reliable brownout protection.
For engineers reviewing the MAX807MEWE+ datasheet, MAX807MEWE+ pinout, MAX807MEWE+ application, or MAX807MEWE+ equivalent, key selection considerations include its dual RESET outputs, battery-backed CMOS RAM support, low-line comparator with 52mV offset above reset threshold, and integrated chip-enable gating for data integrity during power transitions.
Technical Context
The MAX807MEWE+ integrates five independent comparators (RESET, LOW LINE, PFI, BATT OK, and watchdog transition detector) with a state machine and oscillator to coordinate reset assertion, power-fail warning, battery switchover, and watchdog timeout. Its BiCMOS process enables ±1.5% reset threshold accuracy at 4.425V while maintaining 70µA typical supply current in normal operation.
It implements dual-path power switching: VCC-to-OUT (250mA, <1.4Ω on-resistance) and BATT-to-OUT (20mA, <12Ω on-resistance), with automatic switchover when VCC falls below VBATT and the reset threshold. The CE IN/CE OUT transmission gate features 2ns propagation delay (50Ω source, 50pF load) and disables during reset to prevent memory corruption.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.425V ±1.5% - ensures µP remains held in reset until regulated +5V supply stabilizes within specification. |
| Reset Timeout Period | 200ms - guarantees sufficient time for µP initialization and peripheral stabilization after power-up or brownout recovery. |
| Supply Current (Normal) | 70µA typical - enables long battery life in portable equipment without compromising supervision fidelity. |
| VCC-to-OUT On-Resistance | 1.4Ω max - minimizes voltage drop under 250mA load, preserving RAM write margin during main supply operation. |
| Battery Switchover Threshold | VBATT − 0.25V min - allows seamless transition to backup battery before VCC drops below µP minimum operating voltage. |
| Low-Line Comparator Offset | 52mV above reset threshold - provides early non-maskable interrupt (NMI) for orderly software shutdown prior to reset assertion. |
| Watchdog Timeout | 1.6s typical - detects µP lockup or firmware hang without requiring external timing components. |
Pinout & Package
MAX807MEWE+ is housed in a 16-pin TSSOP package (4.4mm × 5.0mm, 0.65mm pitch), optimized for space-constrained industrial and portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PFI | Power-Fail Input | Non-inverting comparator input for custom power-fail detection; threshold set externally via resistor divider (VPFT = 2.265V). |
| GND | Ground Reference | Common return for all analog and digital functions; requires local 0.1µF bypass to minimize noise coupling. |
| VCC | Main Supply Input | +4.35V to +5.5V nominal input; powers internal circuitry and sources CE OUT and RESET when active. |
| BATT | Backup Battery Input | Accepts 2.0V–6.0V battery; automatically takes over OUT supply when VCC falls below reset threshold and VBATT. |
| OUT | Output Supply to RAM | Switched output connected to VCC or BATT; must be bypassed with 0.1µF capacitor to GND for stability. |
| BATT ON | Battery-On Status Flag | CMOS output high when OUT is sourced from BATT; drives external PMOS/PNP switch for >250mA loads. |
| LOW LINE | Low-Line Warning Output | Active-low NMI signal asserted when VCC falls to 52mV above reset threshold - triggers controlled shutdown. |
| RESET | Active-Low Reset Output | Strong-pull-down / weak-pullup output; guaranteed valid down to VCC = 1V; wire-OR capable with other reset sources. |
| RESET | Active-High Reset Output | CMOS-output inverse of RESET; sources/sinks current but not wire-OR compatible. |
| WDO | Watchdog Fault Output | Asserts low if WDI is not toggled within 1.6s; connects to MR to generate automatic watchdog-triggered resets. |
| WDI | Watchdog Input | Edge-sensitive input; unconnected state disables watchdog (internal 1.8V bias); toggling clears timeout timer. |
| MR | Manual Reset Input | Active-low input with internal 50–200µA pullup; asserts reset for ≥1µs pulse and holds 200ms after release. |
| CE IN | Chip-Enable Input | High-impedance during reset; series-gated to CE OUT with 2ns propagation delay to block spurious CE during power transients. |
| CE OUT | Chip-Enable Output | Passes CE signals during normal operation; pulled to higher of VCC/VBATT during reset to disable memory access. |
| PFO | Power-Fail Output | Active-low open-drain–compatible output; asserts when PFI < 2.265V; used for early preregulator fail detection. |
| BATT OK | Battery Status Flag | Active-high output indicating VBATT > 2.265V; valid only when VCC ≥ 4V - confirms backup battery readiness. |
Key Features
| Feature | Design Value |
|---|---|
| Dual RESET outputs | Simultaneous active-low and active-high signals eliminate need for external inverters in mixed-logic systems. |
| Integrated CE gating | 2ns propagation delay prevents erroneous writes to CMOS RAM during VCC brownout or power-up sequencing. |
| Low-line comparator | 52mV offset above reset threshold with ±1.5% accuracy enables deterministic NMI timing for safe shutdown routines. |
| Battery switchover control | Automatic VCC/BATT selection with <12Ω BATT-to-OUT resistance preserves RAM retention voltage under 20mA load. |
| Watchdog timer | Self-contained 1.6s timeout with edge-triggered WDI eliminates external RC timing components and reduces BOM count. |
| MaxCap®/SuperCap® compatibility | Supports high-capacitance backup storage without requiring external charge pumps or voltage clamps. |
Applications
| Industrial Controllers | Portable Medical Instruments |
|---|---|
Use Scenario: PLCs and motor controllers operating in environments with unstable 24VDC supplies subject to line sags and surges. IC Role / Device Role / Timing Role: Supervisory circuit asserting RESET during brownouts, generating LOW LINE NMI for graceful I/O freeze, and enabling CE gating to prevent corrupted register writes. Use Value: Prevents erratic actuator behavior and data loss by holding µP in reset until VCC recovers to 4.425V ±1.5%, with 200ms debounce. |
Use Scenario: Handheld ECG monitors powered by single-cell Li-ion batteries with tight voltage windows (3.0–4.2V). IC Role / Device Role / Timing Role: Battery switchover manager that transfers RAM supply from VCC to BATT at 4.175V (4.425V − 0.25V), while asserting BATT OK to confirm backup readiness. Use Value: Ensures continuous memory retention during hot-swap battery replacement or sudden AC adapter disconnection. |
| Intelligent Power Meters | Critical µP Data Loggers |
Use Scenario: Revenue-grade electricity meters exposed to grid transients and lightning-induced surges on mains input. IC Role / Device Role / Timing Role: Dual-threshold supervisor using PFI to monitor preregulated DC bus and LOW LINE to detect falling VCC before reset - enabling flash write completion. Use Value: Guarantees EEPROM write integrity by initiating NMI-driven save sequence ≥280µs before RESET assertion (tRP = 200ms). |
Use Scenario: Environmental sensors logging temperature/humidity every 10 seconds in remote locations with intermittent solar charging. IC Role / Device Role / Timing Role: Watchdog-enabled supervisor that forces system reset if firmware hangs during SD card write, using WDO→MR connection. Use Value: Eliminates field failures caused by silent µP lockups; 1.6s timeout ensures recovery before next scheduled measurement cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809SEUR+T | Simpler 3-pin SOT23 device; only active-low RESET output; no battery switchover, watchdog, or CE gating. | Basic reset-only use cases where power-fail warning, RAM backup, or memory protection are unnecessary. | Select MAX809SEUR+T only when design requires minimal footprint and supervision scope is limited to VCC monitoring. |
| TPS3808G18DBVR | TI part with 1.8V reset threshold; adjustable timeout (200ms fixed in MAX807MEWE+); no BATT input or LOW LINE output. | Low-voltage µP systems (e.g., ARM Cortex-M0+) where 4.425V reset is incompatible with 3.3V or 1.8V rails. | Choose TPS3808G18DBVR for 1.8V domain supervision; MAX807MEWE+ remains optimal for +5V systems needing full feature set. |
Compared with MAX809SEUR+T and TPS3808G18DBVR, the MAX807MEWE+ uniquely combines 4.425V precision reset, battery switchover, watchdog timer, and CE gating in one 16-pin TSSOP - making it irreplaceable in applications requiring coordinated power, memory, and firmware supervision.
Availability
MAX807MEWE+ is available at Aetrix Electronics and suitable for industrial controllers, portable medical instruments, intelligent power meters, and critical µP data loggers requiring stable component supply across extended temperature ranges (−40°C to +85°C).
Supply support for MAX807MEWE+ 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 MAX807 product line delivers full-featured µP supervision - integrating reset, watchdog, power-fail warning, and battery switchover - specifically for systems where data integrity, power resilience, and firmware reliability are mission-critical.
FAQ
What is the reset threshold voltage of the MAX807MEWE+ and how accurate is it?
The MAX807MEWE+ has a nominal reset threshold of 4.425V with ±1.5% accuracy over temperature (−40°C to +85°C). This precision ensures reliable hold-off of the microprocessor until the +5V supply stabilizes within specification, preventing premature execution during power-up or brownout recovery. The MAX807MEWE+ maintains this accuracy without external calibration or trimming components.
Does the MAX807MEWE+ support automatic battery switchover, and what are the voltage conditions?
Yes, the MAX807MEWE+ supports automatic battery switchover: when VCC falls below both the reset threshold (4.425V) and VBATT, the OUT pin disconnects from VCC and connects to BATT. The switchover occurs at VBATT − 0.25V (min), ensuring RAM remains powered even as VCC collapses. The BATT OK output confirms VBATT > 2.265V, validating backup readiness before switchover.
How does the MAX807MEWE+ implement chip-enable (CE) gating, and why is it important?
The MAX807MEWE+ uses an internal transmission gate between CE IN and CE OUT that disables during reset assertion. With a 2ns propagation delay (50Ω source, 50pF load), it blocks spurious CE signals during power transients - preventing corrupted writes to CMOS RAM or EEPROM. This gating is critical in systems where memory access must be frozen during brownout or power-up sequences.
Can the MAX807MEWE+ generate a non-maskable interrupt (NMI) before reset is asserted?
Yes, the MAX807MEWE+ provides a dedicated LOW LINE output that asserts low when VCC falls to 52mV above the reset threshold (i.e., at ~4.477V). This early warning signal can be routed to the µP's NMI pin, allowing firmware to execute an orderly shutdown - such as saving volatile data or disabling outputs - before the 200ms reset timeout completes and RESET is deasserted.
What is the watchdog timeout period of the MAX807MEWE+, and how is it triggered?
The MAX807MEWE+ watchdog timer has a typical timeout period of 1.6 seconds. It is triggered when the WDI input remains static (high or low) beyond this interval. A rising or falling edge on WDI clears the timer and keeps WDO high. If WDO is connected to MR, each timeout generates a 200ms reset pulse - providing autonomous recovery from µP lockups without host intervention.
MAX807MEWE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.575V
- Output:
- -
- 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-SOIC
MAX807MEWE+ FAQ
1.How can I place an order for MAX807MEWE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX807MEWE+ 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 MAX807MEWE+ reliable?
The price and inventory of MAX807MEWE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX807MEWE+ is usually 5 days.
3.What payment methods are accepted for MAX807MEWE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX807MEWE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX807MEWE+?
MAX807MEWE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX807MEWE+ 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 MAX807MEWE+?
For technical support, including MAX807MEWE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX807MEWE+ requirements.
6.How does Aetrix verify that MAX807MEWE+ is sourced from the original manufacturer or authorized distributors?
All MAX807MEWE+ 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 MAX807MEWE+ meets industry standards.
7.What is the process for return or replacement of MAX807MEWE+?
All MAX807MEWE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX807MEWE+, 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 MAX807MEWE+ part is unused and in its original packaging.
Return procedure for MAX807MEWE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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