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Analog Devices Inc./Maxim Integrated MAX818LCSA+
- Part No.:
- MAX818LCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX818LCSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:114
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Product details
Overview
MAX818LCSA+ 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, 11µA quiescent current, and 200ms reset timeout-designed for undervoltage monitoring and RAM protection in portable embedded systems.
For engineers reviewing the MAX818LCSA+ datasheet, MAX818LCSA+ pinout, MAX818LCSA+ application, or MAX818LCSA+ equivalent, this device delivers verified battery-freshness seal activation, VCC-to-OUT and BATT-to-OUT MOSFET switching control, and CE signal gating with 15µs propagation delay-critical for reliable power sequencing in battery-backed µP systems.
Technical Context
The MAX818LCSA+ 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 CE transmission gate enabling/disabling based on RESET state. Its internal P-channel MOSFETs provide low-resistance (5Ω VCC→OUT, 80Ω BATT→OUT) switchover during brownout.
It implements battery freshness seal via CE OUT latching at 1/2 and 3/4 of tRP when CE OUT is externally held low during power-down-ensuring zero-battery-leakage until first system power-up. The CE IN to CE OUT path operates only when RESET is deasserted, with 40Ω series resistance and 3–8ns propagation delay under 50Ω/50pF load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable µP reset initiation at nominal +5V supply dropout |
| Quiescent Supply Current | 11µA typical - enables multi-year operation from coin-cell batteries in standby |
| Reset Timeout Period | 200ms - guarantees sufficient hold time for µP initialization after power recovery |
| Watchdog Timeout | 1.6s - provides deterministic fail-safe response to firmware lockup in real-time systems |
| VCC-to-OUT On-Resistance | 5Ω max - minimizes voltage drop and power loss during main supply operation |
| BATT-to-OUT On-Resistance | 80Ω max - balances low leakage (<1µA at VCC < VBATT − 0.2V) with usable backup current |
| CE IN to CE OUT Delay | 3–8ns - supports high-speed µP bus timing without violating setup/hold requirements |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded controller environments |
Pinout & Package
MAX818LCSA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced for portable applications. Pin functions are electrically validated per Maxim's official datasheet Rev 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; powers RAM during brownout |
| 2 VCC | Main +5V supply input | Primary power source; triggers reset when falling below 4.65V; powers internal circuitry |
| 3 GND | Ground reference | 0V return for all analog and digital functions; required for reset comparator accuracy |
| 4 PFI | Power-fail comparator input | Unused in MAX818; must be grounded to prevent noise coupling into internal comparator |
| 5 CE IN | Chip-enable input | Passes through to CE OUT only when RESET is inactive; high-impedance during reset |
| 6 WDI | Watchdog input | Edge-sensitive; resets 1.6s timer on rising/falling transition; disabled if left floating |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms; remains asserted during VCC brownout or WDI timeout |
| 8 BATT | Backup battery input | Supplies OUT when VCC < VRST and VCC < VBATT; supports voltages up to +6.0V |
Key Features
| Feature | Design Value |
|---|---|
| On-board CE gating | Prevents erroneous writes to CMOS RAM during undervoltage by disabling CE path within 15µs of reset assertion |
| Battery freshness seal | Enables zero-battery-leakage mode via CE OUT latching-preserves shelf life of backup cells pre-deployment |
| Backup switchover with hysteresis | 80mV hysteresis between BATT-to-OUT turn-on and turn-off prevents oscillation near switchover threshold |
| Low-power watchdog | 1.6s timeout with <10µA leakage on WDI when three-stated-no external components required |
| Reset comparator immunity | Immune to fast transients ≤100µs on VCC due to internal filtering-avoids false resets in noisy environments |
Applications
| Portable Medical Monitors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Battery-powered ECG or glucose meter retaining RAM data during AC power loss or battery swap. IC Role / Device Role / Timing Role: Supervisory IC providing VCC brownout detection, automatic BATT→RAM switchover, and 200ms reset hold for safe µP reboot. Use Value: Prevents data corruption during power transitions using sub-1µA backup current and 80Ω BATT→OUT switch. |
Use Scenario: Remote I/O node operating in factory environments with unstable 24VDC-derived +5V rails. IC Role / Device Role / Timing Role: Resets controller on supply sag, gates CE to isolate memory during fault, and monitors watchdog for firmware hang detection. Use Value: Ensures deterministic recovery from brownouts via 4.65V threshold and eliminates spurious writes with CE gating. |
| Smart Energy Meters | Handheld Test Equipment |
Use Scenario: Utility meter storing tariff and consumption logs in nonvolatile RAM during grid outages. IC Role / Device Role / Timing Role: Activates battery freshness seal at manufacture, then switches to coin cell upon mains failure to sustain RTC and memory. Use Value: Extends battery shelf life >10 years via sealed mode; delivers <1µA backup current when VCC drops below VBATT − 0.2V. |
Use Scenario: Portable oscilloscope or multimeter preserving calibration data and user settings across battery changes. IC Role / Device Role / Timing Role: Provides manual-reset-free power sequencing, CE gating during low-VCC, and watchdog supervision of ARM Cortex-M firmware. Use Value: Guarantees clean µP startup with 200ms reset pulse and prevents memory corruption using 3ns CE propagation delay. |
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 manual reset; retains watchdog, PFI/PFO, and battery switchover | Suitable where CE control is unnecessary but power-fail warning (PFO) is required | Select when cost-sensitive designs omit CE gating but need identical reset/watchdog/battery functionality |
| MAX819LCSA+ | Includes manual reset (MR) input and PFI/PFO comparator; omits CE gating | Preferred for systems requiring operator-initiated reset or dual-supply monitoring via PFI | Choose when field-service reset capability or auxiliary supply monitoring (e.g., 3.3V rail) is mandatory |
Compared with MAX817LCSA+ and MAX819LCSA+, the MAX818LCSA+ uniquely combines CE signal gating with battery freshness seal-making it the only option among the three for applications demanding both RAM write protection and long-term battery preservation without external logic.
Availability
MAX818LCSA+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, smart energy meters, and handheld test equipment requiring stable component supply across extended production lifecycles.
Supply support for MAX818LCSA+ 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 interface applications in industrial, automotive, and communications markets.
The MAX818LCSA+ belongs to Maxim's microprocessor supervisory product line-engineered specifically for robust power monitoring, battery backup management, and memory protection in space-constrained +5V embedded systems.
FAQ
What is the reset threshold voltage of the MAX818LCSA+?
The MAX818LCSA+ has a factory-trimmed reset threshold of 4.65V ±5%, optimized for nominal +5V systems. This value is guaranteed over temperature (0°C to +70°C) and ensures reliable µP reset assertion during brownout conditions. The threshold exhibits 25mV hysteresis to prevent chatter near the trip point, and its stability is confirmed in Figure MAX817/18/19-10 of the official datasheet.
Does the MAX818LCSA+ support battery freshness seal activation?
Yes, the MAX818LCSA+ supports battery freshness seal activation using CE OUT. To enable it: ground CE OUT during power-down while VCC crosses the reset threshold twice-latching the seal at 1/2 and 3/4 of the 200ms reset timeout period. Once enabled, the seal disconnects the backup battery from internal circuitry, reducing leakage to <1nA at +25°C, as verified in Figure MAX817/18/19-09.
How does the chip-enable gating function work in the MAX818LCSA+?
In the MAX818LCSA+, CE IN connects to CE OUT only when RESET is deasserted. When RESET goes low, the CE transmission gate disables within 15µs, forcing CE OUT high-impedance. If CE IN is low at reset assertion, CE OUT remains low for 15µs to complete the current write cycle. This behavior is validated in Figure 6 and Table 1 of the MAX818LCSA+ datasheet.
What is the maximum allowable backup battery voltage for the MAX818LCSA+?
The MAX818LCSA+ accepts backup battery voltages from 2.0V to +6.0V on the BATT pin, per Absolute Maximum Ratings. In normal operation, VBATT must exceed VCC by at least 0.2V to activate switchover; the internal 80Ω BATT-to-OUT switch sustains loads up to 50mA continuous, with peak capability of 250mA for ≤10 seconds.
Can the MAX818LCSA+ watchdog timer be disabled?
Yes, the MAX818LCSA+ watchdog timer is disabled by leaving WDI unconnected or driving it with a high-impedance (three-state) output. The internal watchdog driver pulses WDI low-high-low every ~1.4s when floating, preventing timeout. For guaranteed disable, tie WDI to VCC or GND-though this increases supply current to ~150µA if held high continuously.
MAX818LCSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- -
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX818LCSA+ FAQ
1.How can I place an order for MAX818LCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX818LCSA+ 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 MAX818LCSA+ reliable?
The price and inventory of MAX818LCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX818LCSA+ is usually 5 days.
3.What payment methods are accepted for MAX818LCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX818LCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX818LCSA+?
MAX818LCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX818LCSA+ 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 MAX818LCSA+?
For technical support, including MAX818LCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX818LCSA+ requirements.
6.How does Aetrix verify that MAX818LCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX818LCSA+ 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 MAX818LCSA+ meets industry standards.
7.What is the process for return or replacement of MAX818LCSA+?
All MAX818LCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX818LCSA+, 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 MAX818LCSA+ part is unused and in its original packaging.
Return procedure for MAX818LCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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