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Analog Devices Inc./Maxim Integrated MAX819MEPA+
- Part No.:
- MAX819MEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX819MEPA+.pdf
- Description:
- IC SUPERVISOR MPU 5V 8-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,464
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Product details
Overview
MAX819MEPA+ 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 4.40V ±10% reset threshold, 200ms reset timeout, and 11µA quiescent supply current. Designed for portable and battery-powered µP systems, it ensures reliable reset assertion during brownout, power-up, and manual intervention events.
For engineers reviewing the MAX819MEPA+ datasheet, MAX819MEPA+ pinout, MAX819MEPA+ application, or MAX819MEPA+ equivalent, key selection considerations include its manual reset (MR) capability, battery-freshness seal enablement logic, PFI/PFO undervoltage monitoring interface, and compatibility with 5V µP systems requiring robust supply supervision and backup-power handover.
Technical Context
The MAX819MEPA+ integrates a precision voltage monitor with 4.40V reset threshold (±10%), a 200ms internal reset timeout timer, and a dedicated manual reset input (MR) with 63kΩ internal pull-up. Its power-fail comparator (PFI/PFO) operates independently of the reset generator and supports external low-battery or auxiliary supply monitoring.
Battery switchover occurs when VCC falls below both the reset threshold (4.40V) and VBATT, connecting BATT to OUT via an 80Ω PMOS switch; in backup mode, supply current drops below 1µA. The MR input asserts reset for as long as it is held low and for 200ms after release - a behavior unaffected by watchdog or power-fail activity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±10% - triggers reset when VCC falls below this level in +5V systems. |
| Reset Timeout Period | 200ms typical - guarantees minimum reset pulse width after VCC recovery or MR release. |
| Quiescent Supply Current | 11µA typical - enables ultra-low-power operation in portable and standby applications. |
| Manual Reset Input (MR) | Active-low with 63kΩ internal pull-up - accepts TTL/CMOS logic or momentary switch; no external components required. |
| Battery Switchover Threshold | VCC < VBATT and VCC < 4.40V - automatically connects BATT to OUT to preserve RAM during power loss. |
| Power-Fail Comparator Input (PFI) | 1.25V threshold - monitors external supplies; PFO asserts low when PFI falls below threshold or VCC drops below VBATT. |
| Operating Temperature Range | 0°C to +70°C - specified for commercial-grade embedded and industrial control environments. |
Pinout & Package
MAX819MEPA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), compatible with space-constrained portable designs. Pin assignments are validated per Maxim's official datasheet (Rev 3, 12/05).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply Output | Switches between VCC and BATT; delivers regulated +5V or backup battery voltage to CMOS RAM. |
| 2 VCC | Main Supply Input | +5V system rail input; powers internal circuitry and enables reset monitoring and switchover logic. |
| 3 GND | Ground Reference | 0V reference for all analog and digital functions; must be low-impedance for stable reset timing. |
| 4 PFI | Power-Fail Input | Analog input for external undervoltage detection; referenced to 1.25V internal bandgap. |
| 5 PFO | Power-Fail Output | Open-drain output asserting low on PFI threshold breach or VCC < VBATT; used for warning or MR triggering. |
| 6 WDI | Watchdog Input | Not functional in MAX819 - unused; must be left open or tied to VCC/GND per datasheet guidance. |
| 7 RESET | Active-Low Reset Output | Drives µP reset pin low for ≥200ms during brownout, power-up, or MR assertion; sinks/sourcing capable. |
| 8 BATT | Backup Battery Input | Accepts 2.0V–5.5V battery or SuperCap; connects to OUT when VCC fails, preserving volatile memory. |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Internally pulled up to VCC via 63kΩ resistor - eliminates external pull-up and enables direct switch or logic-level control. |
| Battery Freshness Seal | Enables OEM battery preservation - disconnects BATT from internal circuitry until first power cycle, extending shelf life. |
| Power-Fail Comparator (PFI/PFO) | Independent 1.25V threshold detector - supports dual-supply monitoring without interfering with reset generation. |
| Low-Power Backup Mode | <1µA supply current when VCC < VBATT − 0.2V - minimizes battery drain during extended standby. |
| Robust Transient Immunity | Immune to fast VCC transients ≤100µs at 4.40V overdrive - prevents false resets in noisy power environments. |
Applications
| Portable Medical Monitors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Battery-powered ECG or glucose meter requiring RAM retention and safe shutdown during main supply drop. IC Role / Device Role / Timing Role: Supervisory IC providing MR-triggered calibration reset, VCC brownout detection, and seamless BATT→OUT switchover within 10µs. Use Value: Prevents data corruption during field use; extends usable battery life via <1µA backup current and freshness seal. |
Use Scenario: DIN-rail mounted controller with isolated 24V DC input and onboard 5V µP subsystem needing fail-safe restart. IC Role / Device Role / Timing Role: Reset supervisor asserting 200ms pulse on input undervoltage or operator-initiated MR event; PFI monitors auxiliary 3.3V sensor rail. Use Value: Eliminates need for discrete reset generator + comparator + switch; reduces BOM count by 4 components. |
| Smart Utility Meters | Point-of-Sale Terminals |
Use Scenario: AMI meter with lithium primary battery backup and firmware update capability requiring controlled reset sequencing. IC Role / Device Role / Timing Role: Provides MR-gated firmware update reset, battery-freshness seal activation at factory programming, and PFO-driven tamper alert. Use Value: Ensures battery remains un-depleted until installation; enables secure, deterministic reset for OTA updates. |
Use Scenario: Handheld POS terminal with rechargeable Li-ion and real-time clock (RTC) RAM needing persistent state across charge cycles. IC Role / Device Role / Timing Role: Delivers clean 200ms reset on power-on, manages BATT→OUT handover at 4.40V, and isolates RTC supply during storage. Use Value: Guarantees RTC accuracy and transaction log integrity; eliminates cold-start failures due to marginal VCC ramp. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX819LEPA+ | 4.65V ±5% reset threshold instead of 4.40V ±10%; identical pinout, MR, PFI/PFO, and backup switchover. | Suitable for tighter-tolerance +5V systems where 4.65V trip better matches regulator dropout or noise margin. | Select MAX819LEPA+ when design requires higher reset threshold to avoid nuisance trips near 4.5V nominal rails. |
| MAX692AESA+ | Includes watchdog timer (1.6s timeout) and lacks MR input; same 4.40V reset threshold, 8-pin SO package, and battery switchover. | Applicable where software watchdog supervision is mandatory and manual reset is handled externally. | Choose MAX692AESA+ only if watchdog functionality is required and MR is implemented separately in system logic. |
Compared with MAX819MEPA+, MAX819LEPA+ offers tighter reset tolerance but less headroom for noisy 5V supplies, while MAX692AESA+ adds watchdog capability at the cost of losing MR - making MAX819MEPA+ optimal for manual-reset-critical, low-noise-margin portable systems.
Availability
MAX819MEPA+ is available at Aetrix Electronics and suitable for battery-powered computers, embedded controllers, and intelligent instruments requiring stable component supply, long-term lifecycle support, and lead-free compliance.
Supply support for MAX819MEPA+ 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, computing, and communications applications.
The MAX817/MAX818/MAX819 product line was designed specifically for +5V microprocessor systems needing integrated reset supervision, battery backup control, and auxiliary voltage monitoring - targeting portable, medical, and industrial embedded platforms.
FAQ
What is the reset threshold voltage of the MAX819MEPA+?
The MAX819MEPA+ has a factory-trimmed reset threshold of 4.40V ±10%, optimized for +5V systems with looser regulation margins. This value is confirmed in the Electrical Characteristics table under VRST (MAX81_M suffix), and applies across the full 0°C to +70°C operating range with 25mV hysteresis to prevent chatter near threshold.
Does the MAX819MEPA+ include a watchdog timer function?
No, the MAX819MEPA+ does not include a watchdog timer. Per the Selector Guide and Functional Diagram, watchdog input (WDI) is present but nonfunctional in the MAX819 variant. Watchdog capability is exclusive to MAX817 and MAX818. In MAX819MEPA+, WDI must be left open or tied to VCC/GND to avoid unintended behavior.
How does the manual reset (MR) input behave in the MAX819MEPA+?
In the MAX819MEPA+, the MR input is active-low with a 63kΩ internal pull-up resistor. Asserting MR low forces RESET low immediately and holds it for 200ms after MR returns high. During the reset timeout period, MR state is ignored if the battery freshness seal is enabled - ensuring seal integrity during initialization.
Can the MAX819MEPA+ monitor a secondary power supply?
Yes, the MAX819MEPA+ can monitor a secondary supply using its dedicated PFI input and PFO output. With PFI biased to 1.25V via resistor divider, it detects undervoltage conditions on auxiliary rails (e.g., 3.3V or 2.5V). When PFI falls below threshold, PFO pulls low - and can be connected directly to MR to generate a reset, as shown in Figure 9 of the datasheet.
What package type is used for the MAX819MEPA+?
The MAX819MEPA+ uses the 8-pin µMAX package (3mm × 3mm, 0.8mm height), a thermally enhanced, lead-free surface-mount package. This is confirmed in the Ordering Information table and Pin Configurations diagram. The "EPA" suffix explicitly denotes the µMAX package, distinguishing it from DIP (CPA) and SO (CSA) variants.
MAX819MEPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX819MEPA+ FAQ
1.How can I place an order for MAX819MEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819MEPA+ 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 MAX819MEPA+ reliable?
The price and inventory of MAX819MEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819MEPA+ is usually 5 days.
3.What payment methods are accepted for MAX819MEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819MEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819MEPA+?
MAX819MEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819MEPA+ 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 MAX819MEPA+?
For technical support, including MAX819MEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819MEPA+ requirements.
6.How does Aetrix verify that MAX819MEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX819MEPA+ 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 MAX819MEPA+ meets industry standards.
7.What is the process for return or replacement of MAX819MEPA+?
All MAX819MEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX819MEPA+, 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 MAX819MEPA+ part is unused and in its original packaging.
Return procedure for MAX819MEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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