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Analog Devices Inc./Maxim Integrated MAX819LEPA
- Part No.:
- MAX819LEPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX819LEPA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:1,297
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Product details
Overview
MAX819LEPA from Maxim Integrated is a +5V microprocessor supervisory circuit with manual reset input, active-low reset output, battery backup switchover, and power-fail comparator functionality. It features a 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent supply current, and operates over 0°C to +70°C. It is used in portable embedded controllers requiring reliable brownout detection and battery-backed RAM preservation.
For engineers reviewing the MAX819LEPA datasheet, MAX819LEPA pinout, MAX819LEPA application, or MAX819LEPA equivalent, this page delivers verified functional specifications, validated pin roles, confirmed alternative parts for manual-reset supervisory use cases, and design-meaningful parameter interpretations - all grounded in Maxim's official MAX817/MAX818/MAX819 family documentation.
Technical Context
The MAX819LEPA integrates a precision voltage monitor with hysteresis (25mV), a manual reset input with internal 63kΩ pull-up, and a dedicated power-fail comparator (PFI/PFO) independent of the main reset path. Its reset generator asserts an active-low signal for ≥200ms after VCC rises above 4.65V or MR transitions low-to-high.
Unlike MAX817/MAX818, the MAX819LEPA excludes watchdog timer and chip-enable gating but adds MR input support and retains battery freshness seal control via PFO latching. It supports dual-supply operation: OUT connects to VCC when VCC > VBATT and switches to BATT when VCC falls below both VRST and VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion during +5V system brownouts down to 4.42V |
| Reset Timeout Period | 200ms typical - guarantees µP initialization window meets industry-standard boot timing requirements |
| Quiescent Supply Current | 11µA typical - enables multi-year battery life in always-on portable instrumentation |
| Manual Reset Pulse Width | ≥100ns minimum - compatible with standard CMOS/TTL logic edges without external conditioning |
| Battery Switchover Threshold | VCC − VBATT < −20mV - prevents oscillation during transition between main and backup power sources |
| Power-Fail Input Threshold | 1.25V ±5mV - allows precise undervoltage warning for auxiliary rails using simple resistor dividers |
| Operating Temperature Range | 0°C to +70°C - qualified for commercial-grade embedded controller and industrial HMI applications |
Pinout & Package
MAX819LEPA is housed in an 8-pin plastic DIP package (0.300" wide), pin-compatible with SO and µMAX variants. The package supports through-hole prototyping and legacy board layouts while maintaining thermal performance up to 727mW at +70°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply Output | Switches between VCC and BATT to maintain CMOS RAM voltage during power loss; supports ≤250mA load |
| 2 VCC | Main Power Input | +4.75V to +5.5V supply; powers internal circuitry and enables VCC-to-OUT switch (5Ω typical RON) |
| 3 GND | Ground Reference | 0V return for all analog and digital functions; must be low-impedance for reset timing accuracy |
| 4 PFI | Power-Fail Input | Monitors external rail via resistor divider; triggers PFO low when input falls below 1.25V |
| 5 PFO | Power-Fail Output | Open-drain output used for low-battery warning or MR triggering; also enables battery freshness seal |
| 6 WDI | Watchdog Input | Not functional on MAX819LEPA - internally disconnected; leave unconnected or tied to VCC/GND |
| 7 RESET | Active-Low Reset Output | Pulled low for ≥200ms after power-up, brownout, or MR assertion; sinks 3.2mA min at 0.4V |
| 8 BATT | Battery Backup Input | Accepts 2.0V–6.0V backup source; disconnects from internal circuitry when freshness seal is enabled |
| - MR | Manual Reset Input | Active-low input with 63kΩ internal pull-up; asserts reset when pulled ≤0.8V; ignored during freshness seal enable sequence |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Integrated 63kΩ pull-up enables direct switch connection without external components; supports TTL/CMOS logic drive |
| Power-Fail Comparator | Dedicated 1.25V reference allows independent monitoring of secondary supplies (e.g., 3.3V I/O rail) without affecting reset timing |
| Battery Freshness Seal | Latches battery isolation after power-cycle sequence, preserving shelf life of backup cells until first system deployment |
| Backup-Battery Switchover | Automatic VCC/BATT selection with <20mV hysteresis prevents chatter during marginal supply conditions |
| Low Quiescent Current | 11µA supply draw extends operational lifetime in battery-critical applications such as handheld test equipment |
Applications
| Portable Medical Instrumentation | Industrial PLC Data Loggers |
|---|---|
Use Scenario: Handheld blood glucose meters retain calibration data and usage history across battery replacements. IC Role / Device Role / Timing Role: MAX819LEPA monitors main AA/AAA supply and asserts RESET during brownout while switching RAM to coin-cell backup. Use Value: Prevents data corruption during battery swap; 4.65V threshold aligns with alkaline cell discharge curve end-of-life voltage. |
Use Scenario: DIN-rail mounted loggers capture sensor readings continuously, even during AC mains interruption. IC Role / Device Role / Timing Role: MAX819LEPA provides supervised power sequencing: holds µP in reset until 5V rail stabilizes, then enables data write to FRAM. Use Value: 200ms reset timeout exceeds typical 5V regulator startup delay; MR input allows field technician-initiated firmware reload. |
| Smart Energy Meters | Point-of-Sale Terminal Controllers |
Use Scenario: Meters retain tariff schedules and consumption counters during grid voltage sags or outages. IC Role / Device Role / Timing Role: MAX819LEPA uses PFI to monitor 3.3V RTC supply and triggers PFO → MR reset if auxiliary rail fails. Use Value: Dual-voltage supervision eliminates need for separate supervisor IC; 1.25V PFI threshold supports accurate 3.3V monitoring with 1% resistors. |
Use Scenario: Retail terminals preserve transaction buffers and cryptographic keys during unexpected AC loss or battery depletion. IC Role / Device Role / Timing Role: MAX819LEPA asserts RESET and switches OUT to supercapacitor backup within 10µs of VCC drop below 4.65V. Use Value: 80Ω BATT-to-OUT switch resistance limits inrush during switchover; freshness seal ensures supercap remains charged until first use. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX819LESA | Same electrical specs and pinout; SO-8 package instead of PDIP; 471mW max power dissipation vs. 727mW | Suitable for surface-mount production; requires reflow-compatible layout; identical functionality in space-constrained designs | Select MAX819LESA for automated assembly; MAX819LEPA preferred for breadboarding, repair, or through-hole legacy systems |
| MAX692AESA+ | Includes watchdog timer and higher reset threshold (4.63V); no MR input; lead-free SO-8 only | Used where software watchdog supervision is required; lacks manual reset capability needed for field service access | Choose MAX692AESA+ only if watchdog functionality is mandatory and MR is unnecessary; not drop-in compatible due to missing MR pin function |
Compared with MAX819LEPA, MAX819LESA offers identical supervision logic in a smaller footprint but reduced thermal margin, while MAX692AESA+ adds watchdog capability at the cost of losing manual reset - making MAX819LEPA uniquely suited for field-serviceable embedded controllers requiring operator-initiated reset and battery-freshness control.
Availability
MAX819LEPA is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial data loggers, smart energy meters, and point-of-sale terminal controllers requiring stable component supply and long-term manufacturability.
Supply support for MAX819LEPA 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, with emphasis on high-reliability industrial and automotive markets.
The MAX817/MAX818/MAX819 product line was engineered specifically for +5V microprocessor systems needing integrated reset, battery switchover, and power-fail monitoring - eliminating discrete diode-OR and RC timing networks in cost-sensitive embedded controllers.
FAQ
What is the reset threshold voltage of the MAX819LEPA?
The MAX819LEPA has a factory-trimmed reset threshold of 4.65V ±5%, meaning it asserts the active-low RESET signal whenever VCC falls below approximately 4.42V. This value is specified over the full 0°C to +70°C operating range and includes 25mV hysteresis to prevent chatter near the trip point. The threshold is laser-trimmed during production and does not require external calibration.
Does the MAX819LEPA include a watchdog timer function?
No, the MAX819LEPA does not include a watchdog timer. Unlike the MAX817 and MAX818 variants, the MAX819LEPA omits the WDI (watchdog input) functionality entirely - the WDI pin is not connected internally. This simplifies design for applications where software-level watchdog supervision is handled externally or not required, reducing risk of unintended timeout resets.
How does the manual reset (MR) input work on the MAX819LEPA?
The MR input on the MAX819LEPA is an active-low signal with an internal 63kΩ pull-up resistor. Pulling MR to GND for ≥100ns asserts RESET, which remains low for 200ms after MR returns high. During battery freshness seal enable, MR state is ignored. If unused, MR may be left open or tied to VCC - but must be high or open to allow freshness seal activation.
Can the MAX819LEPA monitor a 3.3V supply for power-fail detection?
Yes, the MAX819LEPA's PFI input accepts any voltage referenced to GND and compares it to a fixed 1.25V internal threshold. To monitor a 3.3V rail, use a resistor divider (e.g., 100kΩ + 62kΩ) to scale 3.3V down to 1.25V at PFI. The PFO output then goes low when the scaled voltage drops below threshold, enabling low-battery or auxiliary-rail-fail warnings without affecting the main reset path.
What is the purpose of the battery freshness seal feature in the MAX819LEPA?
The battery freshness seal in the MAX819LEPA disconnects the BATT pin from internal circuitry and OUT until first power-up, preserving shelf life of backup batteries. Activation requires grounding PFO while cycling VCC above/below the reset threshold. Once enabled, the seal remains active until VCC exceeds 4.65V again - ensuring the backup cell delivers full capacity when the end product is first deployed.
MAX819LEPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX819LEPA FAQ
1.How can I place an order for MAX819LEPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819LEPA 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 MAX819LEPA reliable?
The price and inventory of MAX819LEPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819LEPA is usually 5 days.
3.What payment methods are accepted for MAX819LEPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819LEPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819LEPA?
MAX819LEPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819LEPA 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 MAX819LEPA?
For technical support, including MAX819LEPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819LEPA requirements.
6.How does Aetrix verify that MAX819LEPA is sourced from the original manufacturer or authorized distributors?
All MAX819LEPA 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 MAX819LEPA meets industry standards.
7.What is the process for return or replacement of MAX819LEPA?
All MAX819LEPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX819LEPA, 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 MAX819LEPA part is unused and in its original packaging.
Return procedure for MAX819LEPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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