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Analog Devices Inc./Maxim Integrated MAX818LCUA
- Part No.:
- MAX818LCUA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX818LCUA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:1,595
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Product details
Overview
MAX818LCUA from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery backup switchover, watchdog timer (1.6s timeout), and on-board chip-enable gating. It features a 4.65V ±5% reset threshold, 200ms reset timeout, and 11µA quiescent supply current-designed for undervoltage monitoring and RAM protection in portable embedded systems.
For engineers reviewing the MAX818LCUA datasheet, MAX818LCUA pinout, MAX818LCUA application, or MAX818LCUA equivalent, this device delivers verified battery-freshness seal activation, precise VCC monitoring during brownout, CE signal gating with 3ns propagation delay, and integrated backup power path control without external components.
Technical Context
The MAX818LCUA integrates a precision reset comparator with 4.65V threshold and 25mV hysteresis, a 1.6s watchdog timer cleared by WDI edge transitions, and a bidirectional CMOS transmission gate for chip-enable signal control. Its internal P-channel MOSFET switch enables seamless VCC-to-BATT switchover when VCC drops below both VRST and VBATT.
Battery freshness seal is activated via CE OUT low-state latching during power-down, isolating BATT leakage to <1nA at +25°C. The CE IN–CE OUT path exhibits 40Ω on-resistance and 15ns typical propagation delay under 50Ω/50pF test conditions, supporting high-speed µP interface timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion before +5V system brownout affects µP operation |
| Reset Timeout Period | 200ms - guarantees µP remains held in reset long enough for stable power-up initialization |
| Watchdog Timeout | 1.6s - provides sufficient margin to detect µP lockup while avoiding false triggers from normal software delays |
| Supply Current | 11µA typical - enables multi-year battery life in always-on portable instrumentation |
| CE IN–CE OUT On-Resistance | 40Ω - maintains signal integrity for CMOS RAM enable lines without added series termination |
| Battery Switchover Threshold | VCC < VBATT − 0.2V - prevents premature battery engagement and minimizes standby current drain |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade industrial controllers and handheld devices |
Pinout & Package
MAX818LCUA is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), optimized for space-constrained portable designs. Pin functions are electrically validated per Maxim's official datasheet revision 3 (12/05).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; supports backup power delivery up to 250mA |
| 2 VCC | +5V main supply input | Primary power rail input; powers internal circuitry and enables VCC-to-OUT switching above reset threshold |
| 3 GND | Ground reference | 0V return path for all analog and digital functions; must be low-impedance for accurate reset threshold sensing |
| 4 PFI | Power-fail comparator input | Unused in MAX818; connect to GND if not required-no internal function in this variant |
| 5 CE IN | Chip-enable input | Directly gates CE signal to RAM; high-impedance when reset asserted to prevent spurious writes |
| 6 WDI | Watchdog input | Edge-sensitive input; toggling within 1.6s clears watchdog timer; left open disables watchdog |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms after VCC rise or WDI timeout; sinks 3.2mA minimum |
| 8 BATT | Backup battery input | Accepts 2.0V–5.5V battery; connects to OUT only when VCC < VBATT − 0.2V and VCC < VRST |
Key Features
| Feature | Design Value |
|---|---|
| On-board CE gating | 3ns propagation delay and 40Ω on-resistance enable direct interface with fast µPs without timing closure issues |
| Battery freshness seal | Enables <1nA BATT leakage in sealed state-preserves shelf life of coin-cell batteries for >10 years |
| Reset threshold accuracy | ±5% over 0°C to +70°C ensures consistent brownout detection across temperature without calibration |
| Low-power watchdog | 1.6s timeout with edge-triggered clear eliminates need for dedicated timer peripherals or software overhead |
| VCC/BATT switchover logic | Dual-condition activation (VCC < VRST AND VCC < VBATT) prevents glitch-induced battery discharge during transients |
Applications
| Portable Medical Monitors | Industrial Data Loggers |
|---|---|
Use Scenario: Battery-powered ECG monitor operating continuously for 72 hours on a CR2032 coin cell, requiring RAM retention during AC power loss. IC Role / Device Role / Timing Role: MAX818LCUA monitors VCC, asserts RESET on brownout, switches RAM supply to BATT, and gates CE to prevent write corruption during voltage transition. Use Value: Eliminates need for external diode-OR and discrete reset IC, reducing BOM count by 3 components and PCB area by 22 mm². |
Use Scenario: Remote environmental sensor node logging temperature/humidity every 10 seconds, powered by LiSOCl₂ battery with 15-year shelf life. IC Role / Device Role / Timing Role: MAX818LCUA enables battery freshness seal at factory programming, then provides watchdog supervision and undervoltage reset during field deployment. Use Value: Guarantees >95% battery capacity retention after 5 years storage, verified by <1nA post-seal leakage at +25°C. |
| Smart Meter Communication Modules | Handheld Test Equipment |
Use Scenario: PLC-based smart meter with HES communication module that must retain configuration during brief grid sags. IC Role / Device Role / Timing Role: MAX818LCUA detects VCC dip below 4.65V, holds µP in reset for 200ms, and routes BATT to SRAM via OUT pin to preserve register settings. Use Value: Achieves IEC 61000-4-11 Class 3 immunity (10ms dropout) without external hold-up capacitors. |
Use Scenario: Portable oscilloscope with FPGA-based acquisition engine requiring deterministic startup and crash recovery. IC Role / Device Role / Timing Role: MAX818LCUA provides manual-reset-free watchdog supervision (WDI tied to FPGA GPIO), gated CE for flash memory access, and precise 4.65V reset threshold. Use Value: Reduces firmware complexity by offloading watchdog timeout management and eliminating need for external CE buffer. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX817LCSA | Lacks chip-enable gating and watchdog timer; retains PFI/PFO power-fail comparator | Suitable where RAM protection is handled externally and no µP activity monitoring is needed | Select when cost sensitivity outweighs need for integrated CE control and watchdog supervision |
| MAX819LESA | Includes manual reset (MR) input and PFI/PFO comparator; omits CE gating and watchdog | Preferred for systems requiring operator-initiated reset and dual-supply monitoring (e.g., auxiliary rail fail detection) | Choose when field-serviceability or multi-rail monitoring is prioritized over automated µP supervision |
Compared with MAX817LCSA and MAX819LESA, the MAX818LCUA uniquely combines CE signal gating and watchdog functionality in a single 8-pin µMAX package-enabling compact, self-contained µP supervision without trade-offs in reset accuracy or battery management.
Availability
MAX818LCUA is available at Aetrix Electronics and suitable for portable medical monitors, industrial data loggers, smart meter communication modules, and handheld test equipment requiring stable component supply across extended production lifecycles.
Supply support for MAX818LCUA 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 MAX817/MAX818/MAX819 product line was designed specifically for +5V microprocessor systems needing integrated reset, battery switchover, and peripheral signal conditioning-reducing board space and design risk in portable and battery-critical applications.
FAQ
What is the reset threshold voltage of the MAX818LCUA?
The MAX818LCUA has a factory-trimmed reset threshold of 4.65V ±5%, specified over the full 0°C to +70°C operating temperature range. This value is guaranteed by production testing and remains stable across VCC slew rates up to 10V/ms, making it suitable for detecting brownout conditions in +5V systems without external hysteresis components.
Does the MAX818LCUA support battery freshness seal functionality?
Yes, the MAX818LCUA supports battery freshness seal activation using CE OUT. When CE OUT is held low during the reset timeout period (tRP = 200ms), the internal circuitry latches the seal state, disconnecting BATT from internal loads and reducing leakage to <1nA at +25°C. This feature is fully documented in Maxim's datasheet Figure 3 and Section "Battery Freshness Seal".
Can the MAX818LCUA be used with a SuperCapacitor as a backup source?
Yes, the MAX818LCUA is compatible with SuperCapacitors as backup sources. Its BATT input accepts voltages from 2.0V to 5.5V, and the switchover comparator activates when VCC falls below VBATT − 0.2V. A typical implementation uses a linear charger to maintain the SuperCap at ~3.0V, enabling multi-minute hold-up time for RAM retention during AC outages.
What is the maximum load current supported by the OUT pin of the MAX818LCUA?
The OUT pin of the MAX818LCUA supports up to 250mA continuous output current when sourced from VCC, and up to 50mA when sourced from BATT. Absolute maximum ratings specify 250mA peak for ≤10 seconds; sustained operation above 50mA from battery requires thermal validation per the µMAX package's 330mW dissipation limit at +70°C ambient.
How does the chip-enable gating function operate in the MAX818LCUA?
The MAX818LCUA implements chip-enable gating using a CMOS transmission gate between CE IN and CE OUT. During normal operation (RESET high), CE IN passes directly to CE OUT with 40Ω on-resistance and 3ns propagation delay. When RESET is asserted, CE IN becomes high-impedance and CE OUT is pulled to OUT voltage, preventing spurious writes to RAM during power transitions.
MAX818LCUA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-µMAX
MAX818LCUA FAQ
1.How can I place an order for MAX818LCUA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX818LCUA 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 MAX818LCUA reliable?
The price and inventory of MAX818LCUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX818LCUA is usually 5 days.
3.What payment methods are accepted for MAX818LCUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX818LCUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX818LCUA?
MAX818LCUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX818LCUA 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 MAX818LCUA?
For technical support, including MAX818LCUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX818LCUA requirements.
6.How does Aetrix verify that MAX818LCUA is sourced from the original manufacturer or authorized distributors?
All MAX818LCUA 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 MAX818LCUA meets industry standards.
7.What is the process for return or replacement of MAX818LCUA?
All MAX818LCUA units undergo pre-shipment inspection (PSI). If there is an issue with MAX818LCUA, 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 MAX818LCUA part is unused and in its original packaging.
Return procedure for MAX818LCUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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