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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 5V 8-UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:3,069
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Product details
Overview
The 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 functionality. It features a 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 battery-powered systems, it ensures reliable system initialization during power-up, brownout, and power-down events.
For engineers reviewing the MAX819LCUA+ datasheet, MAX819LCUA+ pinout, MAX819LCUA+ application, or MAX819LCUA+ equivalent, this device delivers verified manual reset control, precise 4.65V supply monitoring, battery-freshness seal enablement, and PFI/PFO-based low-voltage warning - all in an 8-pin µMAX package suitable for space-constrained embedded designs.
Technical Context
The MAX819LCUA+ integrates a precision voltage monitor with 4.65V reset threshold and 25mV hysteresis, a manual reset input (MR) with internal 63kΩ pull-up and 200ms post-release delay, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold referenced to VCC. Its reset generator asserts active-low RESET for ≥200ms after VCC exceeds VRST or MR transitions high.
Battery switchover occurs when VCC falls below both VRST (4.65V) and VBATT, connecting BATT to OUT via an 80Ω PMOS switch; in backup mode, supply current drops to <1µA when VCC < VBATT − 0.2V. The device ignores fast transients on VCC and supports battery freshness seal activation via controlled PFO grounding during power cycling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion before +5V supply drops into invalid operating range for most µPs. |
| Reset Timeout Period | 200ms typical - guarantees sufficient hold time for µP core and peripherals to stabilize after power-up or brownout recovery. |
| Quiescent Supply Current | 11µA typical - enables multi-year operation in battery-backed SRAM/RTC applications without significant drain. |
| Manual Reset Pulse Width | ≥100ns minimum - supports clean reset initiation from mechanical switches or logic-level signals without external debouncing. |
| Battery Switchover Threshold | VCC < VBATT by ≥20mV - triggers seamless transition to backup power while preventing shoot-through or oscillation during crossover. |
| Power-Fail Input Threshold | 1.25V ±5mV - allows accurate undervoltage detection of auxiliary rails (e.g., 3.3V, 2.5V) using simple resistor dividers. |
| Operating Temperature Range | 0°C to +70°C - validated for commercial-grade embedded controllers and portable instrumentation environments. |
Pinout & Package
MAX819LCUA+ uses an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad for improved power dissipation in compact layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply Output | Switches between VCC and BATT; connects to CMOS RAM VDD to maintain data during main supply loss. |
| 2 VCC | Main Supply Input | +5V system rail input; powers internal circuitry and enables VCC-to-OUT conduction above reset threshold. |
| 3 GND | Ground Reference | 0V reference for all analog comparators, reset logic, and battery switchover control. |
| 4 PFI | Power-Fail Input | Analog input for external undervoltage monitoring; compared against 1.25V internal reference. |
| 5 PFO | Power-Fail Output | Active-low open-drain output signaling PFI < 1.25V or VCC < VBATT; used to trigger MR or enable battery seal. |
| 6 WDI | Watchdog Input | Not implemented in MAX819 - pin is no-connect; differs from MAX817/MAX818 which use it for timeout supervision. |
| 7 RESET | Active-Low Reset Output | Drives µP reset pin low for ≥200ms after VCC rise, MR assertion, or brownout; sinks 3.2mA min. |
| 8 BATT | Backup Battery Input | Accepts 2.0V–5.5V battery or supercap; supplies OUT when VCC fails; leakage <1µA in backup mode. |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Internal 63kΩ pull-up enables direct switch connection; asserts RESET for duration of MR low + 200ms hold time. |
| Battery Freshness Seal | Disables BATT-to-OUT path until first power cycle completes; preserves shelf life of backup battery in shipped products. |
| Power-Fail Comparator (PFI/PFO) | Independent 1.25V threshold allows monitoring of secondary supplies (e.g., 3.3V, 2.5V) without affecting reset timing. |
| Low-Power Backup Mode | Draws <1µA from BATT when VCC < VBATT − 0.2V - extends multi-year operation in RTC/SRAM backup applications. |
| Transient-Immune Reset Detection | Ignores VCC spikes <100µs wide at up to 40mV overdrive - prevents false resets in noisy industrial or automotive environments. |
Applications
| Portable Medical Instrumentation | Industrial Data Logger |
|---|---|
Use Scenario: Handheld blood glucose meter with nonvolatile memory storing calibration history and usage logs. IC Role / Device Role / Timing Role: Supervises +5V main supply and enables battery-freshness seal to preserve CR2032 shelf life until first use. Use Value: Ensures deterministic µP reset at power-on and prevents RAM corruption during battery insertion or accidental disconnect. |
Use Scenario: Remote environmental sensor node logging temperature/humidity to SPI FRAM, powered by LiSOCl₂ battery. IC Role / Device Role / Timing Role: Monitors main supply rail and asserts RESET if VCC drops below 4.65V; switches RAM to BATT during brownout. Use Value: Guarantees 200ms reset hold time for safe FRAM write completion and eliminates data loss during intermittent solar charging. |
| Point-of-Sale Terminal | Smart Energy Meter |
Use Scenario: Battery-backed POS terminal retaining transaction buffer and encryption keys during AC power interruption. IC Role / Device Role / Timing Role: Provides manual reset via front-panel button (MR pin) and monitors VCC for graceful shutdown sequencing. Use Value: Enables field-serviceable reset without opening enclosure; maintains secure memory integrity during power failure. |
Use Scenario: Utility meter with real-time clock and tamper-detection EEPROM, requiring >10-year backup runtime. IC Role / Device Role / Timing Role: Uses PFI to monitor 3.3V RTC rail via resistor divider; triggers PFO→MR reset if auxiliary supply fails. Use Value: Prevents clock drift or configuration loss by asserting reset before RTC voltage enters invalid range. |
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 but in 8-pin SO package (3.9mm × 4.9mm); higher thermal resistance (471mW vs. 330mW). | Preferred where board rework or hand-soldering is required; less suitable for ultra-compact PCBs. | Select MAX819LESA+ only if µMAX assembly capability is unavailable or SO footprint already exists in design. |
| MAX692AESA+ | Includes watchdog timer (1.6s timeout) and lacks MR input; reset threshold fixed at 4.65V; same 8-pin SO package. | Suitable for systems needing watchdog supervision but not manual reset; incompatible for MR-driven diagnostics. | Choose MAX692AESA+ only if watchdog functionality is mandatory and MR is unused; not drop-in for MAX819LCUA+. |
Compared with MAX819LESA+, the MAX819LCUA+ offers superior board-area efficiency and thermal performance in µMAX; compared with MAX692AESA+, it trades watchdog capability for guaranteed manual reset control - making it optimal for field-serviceable or safety-critical reset initiation.
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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MAX817/MAX818/MAX819 product line was designed specifically for robust +5V microprocessor supervision in battery-critical systems - emphasizing low quiescent current, precise reset thresholds, and integrated battery management functions.
FAQ
What is the reset threshold voltage for MAX819LCUA+?
The MAX819LCUA+ has a factory-trimmed reset threshold of 4.65V ±5%, optimized for +5V systems. This value is guaranteed over 0°C to +70°C and provides reliable reset assertion before most microprocessors enter undefined operating regions. The threshold exhibits only ±2mV variation across temperature, as confirmed in the Typical Operating Characteristics graph (Figure MAX817/18/19-10).
Does MAX819LCUA+ include a watchdog timer function?
No, the MAX819LCUA+ does not include a watchdog timer. Unlike the MAX817 and MAX818 variants, the MAX819 family omits the WDI pin functionality - pin 6 is a no-connect. This is explicitly stated in the Selector Guide and Functional Diagram (Figure 1), where WDI is marked "THIS PIN FOR MAX819 ONLY" with no associated circuitry.
How is the battery freshness seal enabled on MAX819LCUA+?
The battery freshness seal on MAX819LCUA+ is enabled by grounding PFO while cycling VCC: (1) apply battery to BATT, (2) ground PFO, (3) bring VCC above 4.65V and hold until RESET deasserts (~200ms), then (4) lower VCC again. MR must be left open or pulled high during this sequence - connecting PFO to MR disables seal enablement per the Applications Information section.
What is the maximum allowable load capacitance on the MR pin of MAX819LCUA+?
The MR pin of MAX819LCUA+ supports direct connection to TTL/CMOS logic or momentary switches without external components. While the datasheet does not specify a maximum capacitive load, test conditions for MR pulse width (100ns minimum) and propagation delay (120ns MR-to-RESET) assume negligible pin capacitance. For long traces (>5cm), a 0.1µF capacitor to GND is recommended for noise immunity per the Detailed Description section.
Can MAX819LCUA+ monitor a 3.3V supply using the PFI input?
Yes, MAX819LCUA+ can monitor a 3.3V supply using PFI by scaling it with a resistor divider to match the 1.25V internal reference. For example, R1 = 165kΩ and R2 = 100kΩ yields VPFI = 1.25V at VIN = 3.3V. The PFI input draws only ±25nA, minimizing divider error, and the 4mV hysteresis ensures clean transition without chatter during slow supply ramps.
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:
- Obsolete
- 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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