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Analog Devices Inc./Maxim Integrated MAX819LEUA+
- Part No.:
- MAX819LEUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX819LEUA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:4,884
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Product details
Overview
MAX819LEUA+ from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, manual reset input (MR), battery backup switchover, and power-fail comparator (PFI/PFO). It features a 4.65V ±5% reset threshold, 200ms reset timeout, and 11µA quiescent current-designed for reliable brownout detection and RAM retention in portable 5V systems.
For engineers reviewing the MAX819LEUA+ datasheet, MAX819LEUA+ pinout, MAX819LEUA+ application, or MAX819LEUA+ equivalent, this device delivers verified manual reset control, battery-freshness seal enablement, and VCC/VBATT switchover logic critical for embedded controllers, intelligent instruments, and battery-powered computers requiring deterministic reset behavior under undervoltage conditions.
Technical Context
The MAX819LEUA+ integrates a precision reset comparator with 4.65V threshold and 25mV hysteresis, a manual reset input with internal 63kΩ pull-up and 200ms post-release delay, and a dedicated power-fail comparator (PFI input, PFO output) referenced to 1.25V. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) activated only when VCC falls below both VRST and VBATT.
Unlike MAX817/MAX818, the MAX819LEUA+ excludes watchdog timer and chip-enable gating but adds MR functionality and supports battery freshness seal activation via PFO latching during power-down sequencing-requiring MR high or open during enablement and remaining active until VCC exceeds VRST.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion before 5V supply drops below µP operational minimum. |
| Reset Timeout Period | 200ms typical - guarantees sufficient hold time for processor initialization after power-up or brownout recovery. |
| Quiescent Supply Current | 11µA typical - enables multi-year battery life in always-on backup applications. |
| Manual Reset Pulse Width | ≥100ns - supports clean reset initiation from mechanical switches or logic-level signals without external debouncing. |
| Battery Switchover Threshold | VCC < VBATT − 0.2V - prevents premature battery discharge while ensuring seamless RAM power continuity. |
| Power-Fail Input Threshold | 1.25V ±5mV - allows accurate monitoring of auxiliary supplies (e.g., 3.3V rails) using simple resistor dividers. |
| Operating Temperature Range | 0°C to +70°C - validated for commercial-grade industrial and portable equipment environments. |
Pinout & Package
MAX819LEUA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), compatible with space-constrained PCB layouts and reflow assembly. Pin functions are electrically isolated per functional block-no shared analog/digital paths compromise noise immunity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply Output | Switches between VCC and BATT to maintain CMOS RAM voltage; low-impedance path (5Ω/80Ω) minimizes dropout during switchover. |
| 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 comparators, reset logic, and output drivers; must be low-impedance for stable timing. |
| 4 PFI | Power-Fail Input | Analog input for external undervoltage monitoring; referenced to internal 1.25V bandgap-no external reference needed. |
| 5 PFO | Power-Fail Output | Open-drain output asserting low on PFI < 1.25V or VCC < VBATT; used for low-battery warning or MR triggering. |
| 6 WDI | Watchdog Input | Not functional in MAX819 - left unconnected or tied to VCC/GND; no internal watchdog timer present. |
| 7 RESET | Active-Low Reset Output | Drives µP reset pin low for ≥200ms; sinks 3.2mA at 0.4V - directly interfaces with TTL/CMOS inputs without pull-up. |
| 8 BATT | Backup Battery Input | Accepts 2.0V–6.0V battery or SuperCap; enables automatic switchover when VCC drops below VBATT − 0.2V. |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Internal 63kΩ pull-up enables switch-only reset; 200ms post-release hold ensures full µP reset cycle completion. |
| Battery Freshness Seal | Latches via PFO during controlled power-down - isolates BATT from leakage paths until first system power-up. |
| Power-Fail Comparator | Dedicated 1.25V reference allows independent monitoring of secondary rails (e.g., 3.3V, 2.5V) without affecting reset timing. |
| VCC/BATT Switchover Logic | Two-stage activation (VCC < VRST then VCC < VBATT − 0.2V) prevents false switching during transient dips. |
| Low-Power Design | 11µA supply current and <1µA battery standby draw extend shelf life of sealed portable devices. |
Applications
| Battery-Powered Computers | Embedded Controllers |
|---|---|
Use Scenario: Portable data loggers powered by Li-ion cells with nonvolatile RAM retention during main supply interruption. IC Role / Device Role / Timing Role: Supervisory circuit asserting RESET and switching OUT to BATT within 100µs of VCC falling below 4.65V. Use Value: Prevents RAM corruption during field-deployed brownouts; freshness seal ensures full battery capacity at first use. |
Use Scenario: Industrial PLC modules requiring deterministic reset on AC line sag or DC input ripple. IC Role / Device Role / Timing Role: Monitoring 5V DC-DC output and generating 200ms reset pulse synchronized to VCC recovery. Use Value: Eliminates need for external RC reset timers; PFI input monitors auxiliary 3.3V I/O rail independently. |
| Intelligent Instruments | Critical µP Monitoring |
Use Scenario: Handheld multimeters with real-time clock and calibration memory backed by coin cell. IC Role / Device Role / Timing Role: Enabling battery freshness seal at factory programming, then managing BATT-to-OUT switchover during battery replacement. Use Value: Guarantees >10-year shelf life; MR pin allows user-initiated recalibration reset without opening enclosure. |
Use Scenario: Medical diagnostic equipment where µP reset integrity is mandated by IEC 62304. IC Role / Device Role / Timing Role: Providing fail-safe reset with 4.65V threshold tolerance and 25mV hysteresis to reject EMI-induced glitches. Use Value: Meets Class C software safety requirements via hardware-enforced reset timing and MR override capability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX817LEUA+ | Lacks MR input; includes watchdog timer (1.6s timeout) and power-fail comparator - no manual reset capability. | Suitable for systems where firmware-controlled watchdog reset suffices and external reset button is unnecessary. | Select MAX817LEUA+ only if watchdog supervision is required and MR is unused; not drop-in compatible due to missing MR pin function. |
| MAX819TEUA+ | Same functionality but rated for -40°C to +85°C operating range; identical pinout and electrical specs except temperature grade. | Required for automotive or outdoor industrial deployments where extended temperature operation is mandatory. | Choose MAX819TEUA+ for harsh environments; MAX819LEUA+ is optimal for cost-sensitive commercial applications within 0°C–70°C. |
Compared with MAX817LEUA+, the MAX819LEUA+ trades watchdog functionality for guaranteed manual reset control-critical for test, service, and safety-critical restarts. Against MAX819TEUA+, it offers identical performance at lower cost for ambient-temperature applications, with no layout or sourcing changes needed.
Availability
MAX819LEUA+ is available at Aetrix Electronics and suitable for battery-powered computers, embedded controllers, intelligent instruments, and critical µP monitoring requiring stable component supply across commercial temperature ranges.
Supply support for MAX819LEUA+ 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 reliability and integration for embedded systems.
The MAX819LEUA+ belongs to the MAX817/MAX818/MAX819 family of +5V supervisory circuits engineered specifically for robust power-monitoring, battery backup, and reset control in portable and industrial µP systems.
FAQ
What is the reset threshold voltage of the MAX819LEUA+?
The MAX819LEUA+ has a factory-trimmed reset threshold of 4.65V ±5%, optimized for +5V systems. This value is specified over the full 0°C to +70°C operating range and includes 25mV hysteresis to prevent chatter during slow VCC ramps. The threshold is internally generated and does not require external components-ensuring consistent reset behavior across production units and temperature gradients.
Does the MAX819LEUA+ include a watchdog timer?
No, the MAX819LEUA+ does not include a watchdog timer. Unlike the MAX817LEUA+ and MAX818LEUA+, the MAX819LEUA+ omits the WDI pin and associated watchdog circuitry to prioritize manual reset functionality. The WDI pin (Pin 6) is a no-connect in the MAX819LEUA+ and must be left unconnected or tied to VCC/GND-no internal watchdog logic is present.
How does the battery freshness seal work on the MAX819LEUA+?
The MAX819LEUA+ enables the battery freshness seal by latching PFO low during a controlled power-down sequence: VCC must rise above 4.65V, then fall while PFO is held low (e.g., via external ground), with MR high or open. Once latched, the seal disconnects BATT from internal circuitry until VCC next exceeds VRST-preserving battery capacity for end-user deployment. MR state is irrelevant after latching.
Can the MAX819LEUA+ monitor a 3.3V supply using the PFI input?
Yes, the MAX819LEUA+ PFI input compares against a precise 1.25V internal reference, enabling direct monitoring of 3.3V supplies using a resistor divider (e.g., R1 = 16.5kΩ, R2 = 10kΩ). When the divided voltage drops below 1.25V, PFO asserts low-providing a clean power-fail signal independent of the main 5V reset path and usable for low-battery warnings or secondary rail supervision.
What is the maximum load current supported by the OUT pin of the MAX819LEUA+?
The OUT pin of the MAX819LEUA+ supports up to 250mA continuous output current when sourced from VCC, and up to 50mA when sourced from BATT. In battery-backup mode (VCC < VBATT − 0.2V), the BATT-to-OUT switch exhibits 80Ω on-resistance-limiting practical load to ≤10mA for ≤100mV dropout. For higher loads, external buffering is recommended to avoid excessive voltage drop or thermal stress.
MAX819LEUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX819LEUA+ FAQ
1.How can I place an order for MAX819LEUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819LEUA+ 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 MAX819LEUA+ reliable?
The price and inventory of MAX819LEUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819LEUA+ is usually 5 days.
3.What payment methods are accepted for MAX819LEUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819LEUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819LEUA+?
MAX819LEUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819LEUA+ 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 MAX819LEUA+?
For technical support, including MAX819LEUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819LEUA+ requirements.
6.How does Aetrix verify that MAX819LEUA+ is sourced from the original manufacturer or authorized distributors?
All MAX819LEUA+ 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 MAX819LEUA+ meets industry standards.
7.What is the process for return or replacement of MAX819LEUA+?
All MAX819LEUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX819LEUA+, 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 MAX819LEUA+ part is unused and in its original packaging.
Return procedure for MAX819LEUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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