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Analog Devices Inc./Maxim Integrated MAX819LCUA
- Part No.:
- MAX819LCUA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX819LCUA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:614
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Product details
Overview
MAX819LCUA from Maxim Integrated is a +5V microprocessor supervisory circuit with manual reset input, active-low reset output, power-fail comparator, and battery backup switchover. It features 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent supply current, and operates in 0°C to +70°C temperature range. Designed for critical µP monitoring in portable equipment and embedded controllers.
For engineers reviewing the MAX819LCUA datasheet, MAX819LCUA pinout, MAX819LCUA application, or MAX819LCUA equivalent, this page delivers verified functional specifications, validated pin roles, confirmed battery-switchover behavior, and real-world timing constraints - all specific to the MAX819L variant in 8-pin µMAX package.
Technical Context
The MAX819LCUA integrates a precision reset comparator with 4.65V threshold and 25mV hysteresis, a manual reset input with internal 63kΩ pull-up, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold and 4mV hysteresis. Its reset generator guarantees 200ms minimum assertion time after VCC rise or MR release.
Battery switchover activates when VCC falls below both VRST (4.65V) and VBATT, connecting BATT to OUT via an 80Ω P-channel MOSFET switch; standby current drops to <1µA when VCC is >1V below VBATT. The device ignores fast transients on VCC and supports battery voltage exceeding VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion during +5V supply brownout down to 4.42V |
| Reset Timeout Period | 200ms typical - guarantees µP initialization stability after power-up or manual reset release |
| Supply Current | 11µA typical at +25°C - enables multi-year operation in battery-backed RAM applications |
| Manual Reset Input | Active-low with 63kΩ internal pull-up - supports direct switch-to-ground interface without external components |
| Power-Fail Comparator | 1.25V threshold on PFI - provides independent low-voltage warning for secondary supplies or battery monitoring |
| Battery Switchover | Activates when VCC < VRST and VCC < VBATT - preserves CMOS RAM data during main supply failure |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded controller and portable instrument use |
Pinout & Package
MAX819LCUA is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), compatible with space-constrained portable designs and offering thermal performance up to 330mW at +70°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; drives RAM VDD during main or backup power |
| 2 VCC | +5V main supply input | Primary power source; monitored for reset generation and used as reference for comparator thresholds |
| 3 GND | Ground reference | 0V return for all analog and digital functions; must be low-impedance for accurate reset threshold tracking |
| 4 PFI | Power-fail comparator input | Monitors external voltage divider; asserts PFO low when input falls below 1.25V threshold |
| 5 PFO | Power-fail comparator output | Open-drain output used for low-battery warning or cascaded reset triggering via MR connection |
| 6 WDI | Watchdog input | Not implemented in MAX819 - left unconnected or tied to VCC/GND; no watchdog timer functionality |
| 7 RESET | Active-low reset output | Drives µP reset pin; remains low for ≥200ms after VCC rise above 4.65V or MR release |
| 8 BATT | Backup battery input | Accepts 2.0V–6.0V battery; powers OUT and internal circuitry when VCC fails; supports voltage > VCC |
Key Features
| Feature | Design Value |
|---|---|
| Manual reset input (MR) | Logic-low trigger with internal 63kΩ pull-up - eliminates need for external resistor in pushbutton reset circuits |
| Power-fail comparator (PFI/PFO) | 1.25V threshold with 4mV hysteresis - enables precise undervoltage detection for auxiliary rails or battery health monitoring |
| Battery freshness seal | Enables via PFO grounding sequence - disconnects BATT from internal circuitry until first power-up, preserving shelf life |
| Reset threshold accuracy | ±5% over 0°C to +70°C - meets tight tolerance requirements for industrial-grade +5V µP systems |
| Low quiescent current | 11µA typical - extends battery life in always-on backup applications such as real-time clocks and configuration memory |
Applications
| Portable Medical Instrumentation | Industrial Data Logger |
|---|---|
Use Scenario: Handheld blood glucose meter with nonvolatile SRAM storing calibration history and usage logs. IC Role / Device Role / Timing Role: MAX819LCUA monitors main 5V supply and asserts RESET during battery swap; enables battery freshness seal to preserve backup coin cell for >5 years shelf life. Use Value: Prevents RAM corruption during hot-swap, guarantees deterministic reset timing, and eliminates premature battery discharge before first use. |
Use Scenario: Ruggedized environmental sensor node logging temperature/humidity to SPI flash, powered by Li-ion with backup supercap. IC Role / Device Role / Timing Role: MAX819LCUA detects main supply brownout and switches OUT to BATT; PFI monitors supercap voltage to trigger early warning via PFO. Use Value: Ensures uninterrupted logging during transient mains loss and provides predictive low-energy alert before data loss occurs. |
| Point-of-Sale Terminal | Smart Energy Meter |
Use Scenario: Credit card terminal with secure EEPROM storing encryption keys and transaction buffer. IC Role / Device Role / Timing Role: MAX819LCUA provides manual reset via front-panel button (MR) and active-low RESET to microcontroller; BATT maintains SRAM during AC outage. Use Value: Guarantees cryptographic state integrity during power interruption and enables field-serviceable reset without firmware intervention. |
Use Scenario: DIN-rail mounted electricity meter with metrology ASIC, RTC, and tamper-detection RAM. IC Role / Device Role / Timing Role: MAX819LCUA supervises 5V rail derived from isolated DC/DC converter; RESET holds metrology processor in known state during grid instability. Use Value: Meets IEC 62053-21 reset immunity requirements and prevents erroneous billing due to undervoltage-induced processor glitches. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX819MCPA | 4.40V reset threshold (±10%), 8-pin DIP package, same functionality | Suitable where lower reset voltage accommodates wider-tolerance 5V rails or legacy board layouts | Select when system brownout margin requires earlier reset assertion than 4.65V allows |
| MAX692ACSA+ | 4.63V reset threshold, includes watchdog timer, 8-pin SO package | Provides watchdog supervision missing in MAX819LCUA; lacks manual reset input and battery freshness seal | Choose when watchdog monitoring is mandatory and MR/PFO-based battery seal is not required |
Compared with MAX819MCPA, MAX819LCUA offers tighter reset threshold tolerance (±5% vs ±10%) and smaller µMAX footprint; compared with MAX692ACSA+, it trades watchdog capability for manual reset and battery seal - making it optimal for cost-sensitive, space-constrained, battery-sealed applications without watchdog needs.
Availability
MAX819LCUA is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial data loggers, point-of-sale terminals, and smart energy meters requiring stable component supply across extended production lifecycles.
Supply support for MAX819LCUA 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 MAX819LCUA belongs to the MAX817/MAX818/MAX819 family of +5V microprocessor supervisory circuits, engineered specifically for reliable power monitoring, battery backup control, and chip-enable gating in resource-constrained embedded systems.
FAQ
What is the reset threshold voltage of the MAX819LCUA?
The MAX819LCUA has a factory-trimmed reset threshold of 4.65V with ±5% tolerance over the 0°C to +70°C operating range. This value is guaranteed by design and tested during production; it triggers the active-low RESET output whenever VCC falls below this level, ensuring robust brownout protection for +5V microprocessor systems. The MAX819LCUA does not support adjustable or user-programmable reset thresholds.
Does the MAX819LCUA include a watchdog timer function?
No, the MAX819LCUA does not include a watchdog timer. Unlike the MAX817 and MAX818 variants, the MAX819 omits the WDI (watchdog input) functionality entirely - the WDI pin (Pin 6) is reserved and must be left unconnected or tied to VCC/GND. Watchdog supervision is available only in MAX817 and MAX818 devices; the MAX819LCUA instead emphasizes manual reset (MR) and power-fail comparator (PFI/PFO) capabilities.
How does the battery freshness seal work on the MAX819LCUA?
The battery freshness seal on the MAX819LCUA disconnects the BATT pin from internal circuitry until first power-up, preserving backup battery shelf life. To enable it: connect battery to BATT, ground PFO, bring VCC above 4.65V and hold until RESET deasserts (~200ms), then cycle VCC low. Once enabled, the seal remains active until VCC exceeds VRST again. MR must be high or open during enablement - connecting PFO to MR disables seal activation.
Can the MAX819LCUA monitor a secondary voltage rail using the PFI input?
Yes, the MAX819LCUA's PFI input supports external voltage monitoring via a resistor divider. With a fixed 1.25V internal reference, PFI detects when the divided voltage falls below threshold - for example, a 3.3V rail can be monitored using R1 = 100kΩ and R2 = 62kΩ to scale 3.3V to 1.25V. PFO asserts low on threshold breach and can drive an interrupt or be connected to MR for automatic reset, though doing so prevents battery freshness seal activation.
What is the maximum allowable battery voltage on the BATT pin of the MAX819LCUA?
The MAX819LCUA supports BATT voltages from 2.0V to 6.0V, per Absolute Maximum Ratings. In battery-backup mode, it safely handles VBATT exceeding VCC - enabling use with higher-voltage backup sources like 3.6V Li-ion cells or 5.5V supercapacitors. When VCC = 0V, BATT leakage current is <1µA, and the BATT-to-OUT on-resistance is typically 80Ω, ensuring efficient power delivery to attached RAM or RTC circuits.
MAX819LCUA 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:
- 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-uMAX/uSOP
MAX819LCUA FAQ
1.How can I place an order for MAX819LCUA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819LCUA 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 MAX819LCUA reliable?
The price and inventory of MAX819LCUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819LCUA is usually 5 days.
3.What payment methods are accepted for MAX819LCUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819LCUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819LCUA?
MAX819LCUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819LCUA 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 MAX819LCUA?
For technical support, including MAX819LCUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819LCUA requirements.
6.How does Aetrix verify that MAX819LCUA is sourced from the original manufacturer or authorized distributors?
All MAX819LCUA 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 MAX819LCUA meets industry standards.
7.What is the process for return or replacement of MAX819LCUA?
All MAX819LCUA units undergo pre-shipment inspection (PSI). If there is an issue with MAX819LCUA, 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 MAX819LCUA part is unused and in its original packaging.
Return procedure for MAX819LCUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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