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Analog Devices Inc./Maxim Integrated MAX819LCSA+
- Part No.:
- MAX819LCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX819LCSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:123
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Product details
Overview
MAX819LCSA+ 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 supply current-designed for reliable brownout protection and RAM retention in portable embedded systems.
For engineers reviewing the MAX819LCSA+ datasheet, MAX819LCSA+ pinout, MAX819LCSA+ application, or MAX819LCSA+ equivalent, this device delivers verified manual reset control, battery-freshness seal enablement, and VCC/VBATT switchover behavior critical for low-power µP systems requiring deterministic reset timing and backup power integrity.
Technical Context
The MAX819LCSA+ 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 input, PFO output) independent of reset logic. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) activated only when VCC < VRST and VCC < VBATT.
Unlike MAX817/MAX818, the MAX819LCSA+ excludes watchdog timer and chip-enable gating but adds MR functionality and retains full battery freshness seal operation-enabled only when MR is high or open and PFO is externally grounded during power cycling per Figure 3 timing sequence.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - guarantees reset assertion before +5V supply drops below safe µP operating margin. |
| Reset Timeout Period | 200ms typical - ensures µP remains held in reset long enough to stabilize clocks and peripherals after power recovery. |
| Supply Current | 11µA typical at +25°C - enables multi-year battery life in always-on monitoring applications. |
| Battery Switchover Threshold | VCC − VBATT < −20mV - prevents premature switchover during transient dips while ensuring seamless RAM backup when VCC collapses. |
| Manual Reset Pulse Width | ≥100ns - supports clean reset initiation from microcontroller GPIO or momentary switch without external debouncing. |
| PFO Output Drive | Sink capability ≥3.2mA at VOL ≤0.4V - allows direct interfacing with TTL/CMOS inputs or driving small LEDs for power-fail indication. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade industrial controllers and portable instrumentation. |
Pinout & Package
MAX819LCSA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), pin-compatible with SO and DIP variants. The µMAX package enables high-density PCB layouts while maintaining thermal performance suitable for battery-powered designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; provides uninterrupted power to backup memory during brownout. |
| 2 VCC | +5V main supply input | Primary power rail; powers internal circuitry and sources OUT when above reset threshold and VBATT. |
| 3 GND | Ground reference | 0V return path for all analog and digital functions; must be low-impedance for stable reset threshold accuracy. |
| 4 PFI | Power-fail comparator input | Monitors external voltage divider; asserts PFO low when input falls below 1.25V threshold-used for secondary supply monitoring. |
| 5 PFO | Power-fail comparator output | Open-drain output; pulled high by external resistor; used to trigger reset (when tied to MR) or signal low-battery condition. |
| 6 WDI | Watchdog input | No-connect (NC) on MAX819LCSA+ - function disabled; pin must be left floating or tied to VCC/GND per layout guidelines. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms after power-up, brownout, or MR assertion; sinks 3.2mA minimum. |
| 8 BATT | Backup battery input | Accepts 2.0V–6.0V battery or supercap; isolated from VCC via internal diode; enables freshness seal when grounded via PFO. |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Internal 63kΩ pull-up enables switch-only reset implementation; 100ns minimum pulse width supports fast µP-initiated resets. |
| Battery Freshness Seal | Enables OEM battery preservation by disconnecting BATT from internal circuitry until first power cycle-activated via timed PFO grounding sequence. |
| Power-Fail Comparator | Dedicated PFI/PFO pair with 1.25V threshold and 4mV hysteresis-supports independent monitoring of auxiliary rails without affecting reset timing. |
| Low-Power Switchover | Sub-µA battery standby current (<1µA when VCC < VBATT − 0.2V) extends shelf life of sealed battery-backed systems. |
| Reset Timing Accuracy | ±10% reset timeout tolerance over temperature ensures predictable µP initialization across 0°C–70°C range. |
Applications
| Portable Medical Monitors | Industrial Data Loggers |
|---|---|
Use Scenario: Battery-powered ECG monitor retaining real-time waveform data during AC power loss. IC Role / Device Role / Timing Role: Supervisory IC asserting RESET to halt µP execution and enabling BATT→OUT switchover to preserve SRAM contents. Use Value: 200ms guaranteed reset hold time prevents corrupted memory writes; 11µA quiescent current extends single-cell Li-ion runtime beyond 5 years in sleep mode. |
Use Scenario: Remote environmental sensor node logging temperature/humidity to flash memory during grid outages. IC Role / Device Role / Timing Role: Power-fail detection via PFI triggers PFO-driven interrupt to µP, initiating graceful shutdown and RAM-to-flash save before battery depletion. Use Value: Independent PFI comparator allows simultaneous monitoring of main +5V rail and backup battery voltage-no µP firmware overhead required. |
| Smart Meter Security Modules | Point-of-Sale Terminal Backups |
Use Scenario: Tamper-resistant electricity meter preserving cryptographic keys and billing counters during voltage sags. IC Role / Device Role / Timing Role: Battery freshness seal ensures sealed CR2032 remains unused until field deployment; MR pin enables secure factory test reset. Use Value: Seal activation requires precise VCC ramp-down sequence-prevents accidental discharge during manufacturing and shipping. |
Use Scenario: Retail terminal maintaining transaction buffer integrity during brief UPS switchover delays. IC Role / Device Role / Timing Role: Active-low RESET output holds ARM Cortex-M4 in reset while BATT powers SRAM, preventing partial write corruption during 10–50ms AC gap. Use Value: 5Ω VCC-to-OUT on-resistance limits voltage drop under 50mA load-ensures >4.75V at RAM VDD during transition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX819MCSA+ | 4.40V reset threshold (±10%) instead of 4.65V; identical pinout, timing, and feature set. | Suitable for +5V systems with looser supply tolerance (e.g., unregulated wall adapters); not interchangeable where 4.65V threshold is required for early brownout detection. | Select MAX819MCSA+ only if system VCC can dip to 4.4V without µP malfunction; verify compatibility with existing reset timing margins. |
| MAX692AESA+ | Includes watchdog timer and power-fail reset; lacks manual reset input and battery freshness seal; 4.65V threshold same. | Used where continuous µP activity monitoring is mandatory (e.g., safety-critical controllers); cannot replace MAX819LCSA+ in MR-dependent test or field service workflows. | Choose MAX692AESA+ only when watchdog supervision outweighs manual reset need; note different pin mapping (WDI replaces MR). |
Compared with MAX819MCSA+, the MAX819LCSA+ provides tighter reset threshold accuracy for robust early-brownout response; compared with MAX692AESA+, it trades watchdog functionality for field-serviceable manual reset and battery preservation-making it optimal for sealed, battery-backed instrumentation.
Availability
MAX819LCSA+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial data loggers, smart meter security modules, and point-of-sale terminal backups requiring stable component supply with guaranteed long-term availability.
Supply support for MAX819LCSA+ 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 management, sensing, and interface applications in industrial, automotive, and computing markets.
The MAX819LCSA+ belongs to Maxim's microprocessor supervisory product line-engineered specifically for deterministic reset generation, battery-backed memory retention, and power-fail warning in space-constrained, low-power embedded systems.
FAQ
What is the reset threshold voltage of the MAX819LCSA+ and how is it trimmed?
The MAX819LCSA+ has a factory-trimmed reset threshold of 4.65V ±5%, achieved via laser trimming of internal voltage-divider resistors during wafer sort. This value is specified over the full 0°C to +70°C operating range and exhibits only ±10mV drift across temperature, as shown in Figure MAX817/18/19-10. The 'L' suffix in MAX819LCSA+ explicitly denotes this 4.65V variant, distinguishing it from the 4.40V 'M' version.
How does the battery freshness seal work on the MAX819LCSA+ and what steps are required to enable it?
The battery freshness seal on the MAX819LCSA+ disconnects the BATT pin from internal circuitry until first use. To enable it: (1) connect a battery to BATT, (2) ground PFO, (3) bring VCC above 4.65V and hold until RESET deasserts after 200ms, then (4) lower VCC again. This sequence latches the seal-verified by <1µA BATT leakage in backup mode. MR must remain high or open during activation; once enabled, the seal persists until next full power cycle.
Can the MAX819LCSA+ be used with a supercapacitor instead of a battery at the BATT pin?
Yes-the MAX819LCSA+ supports supercapacitor backup at BATT, as confirmed in Applications Information section "Using a SuperCap™ as a Backup Power Source." With VBATT = 2.0V–6.0V and switchover hysteresis of −20mV, a 0.47F supercap charged to 5.0V provides ~120 seconds of RAM retention at 100µA load. Ensure charging circuit limits inrush current and maintains VBATT > VCC − 0.2V to avoid premature switchover.
What is the maximum load current the OUT pin can drive in battery-backup mode?
In battery-backup mode (VCC < VRST and VCC < VBATT), the MAX819LCSA+ OUT pin is driven by the BATT supply through an 80Ω internal PMOS switch. Electrical Characteristics specify BATT-to-OUT on-resistance as 80Ω typical, allowing up to 50mA continuous current per Absolute Maximum Ratings. At 50mA, worst-case voltage drop is 4.0V-so for 3.3V RAM, ensure VBATT ≥ 4.5V to maintain sufficient headroom.
Is the MAX819LCSA+ pin-compatible with other devices in the MAX817/MAX818/MAX819 family?
Yes-the MAX819LCSA+ shares identical 8-pin µMAX pinout with all MAX817/MAX818/MAX819 variants, including MAX817LCSA+, MAX818LCSA+, and MAX819MCSA+. However, functional differences exist: WDI (pin 6) is unused on MAX819LCSA+, while CE IN/CE OUT pins are absent. Layouts designed for any member of this family can accommodate MAX819LCSA+ without modification, though firmware must account for missing watchdog and CE gating features.
MAX819LCSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX819LCSA+ FAQ
1.How can I place an order for MAX819LCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819LCSA+ 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 MAX819LCSA+ reliable?
The price and inventory of MAX819LCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819LCSA+ is usually 5 days.
3.What payment methods are accepted for MAX819LCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819LCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819LCSA+?
MAX819LCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819LCSA+ 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 MAX819LCSA+?
For technical support, including MAX819LCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819LCSA+ requirements.
6.How does Aetrix verify that MAX819LCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX819LCSA+ 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 MAX819LCSA+ meets industry standards.
7.What is the process for return or replacement of MAX819LCSA+?
All MAX819LCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX819LCSA+, 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 MAX819LCSA+ part is unused and in its original packaging.
Return procedure for MAX819LCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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