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Analog Devices Inc./Maxim Integrated MAX819LCSA+T
- Part No.:
- MAX819LCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX819LCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,572
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Product details
Overview
MAX819LCSA+T 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 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent current, and operates in 0°C to +70°C temperature range. Designed for critical µP monitoring in portable and battery-powered systems.
For engineers reviewing the MAX819LCSA+T datasheet, MAX819LCSA+T pinout, MAX819LCSA+T application, or MAX819LCSA+T equivalent, this device delivers verified manual reset control, battery-freshness seal enablement, and precise undervoltage detection - key selection criteria for embedded controller power management and RAM retention designs.
Technical Context
The MAX819LCSA+T 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 activates when VCC falls below both VRST (4.65V) and VBATT, connecting BATT to OUT via an 80Ω PMOS switch.
Unlike MAX817/MAX818, the MAX819LCSA+T excludes watchdog timer and chip-enable gating but adds MR functionality and retains uncommitted PFI/PFO for low-battery or power-fail warning generation. The battery freshness seal is enabled only when MR is high or open and requires external 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 brownout affects µP operation |
| Reset Timeout Period | 200ms typical - guarantees sufficient hold time for µP initialization and memory stabilization |
| Supply Current | 11µA typical at +25°C - enables multi-year battery life in portable equipment with backup power |
| Manual Reset Pulse Width | ≥100ns minimum - supports clean reset initiation from mechanical switches or logic-level signals |
| Battery Switchover Threshold | VCC < VBATT by ≥20mV - prevents oscillation during transition and ensures seamless RAM power continuity |
| Power-Fail Input Threshold | 1.25V ±5mV - allows accurate monitoring of auxiliary supplies using simple resistor-divider networks |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded controllers and instrumentation |
Pinout & Package
MAX819LCSA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), compatible with space-constrained portable designs and offering thermal performance up to 330mW at +70°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply Output | Switches between VCC and BATT; connects to CMOS RAM VDD to maintain data during power loss |
| 2 VCC | Main Supply Input | +5V system rail input; powers internal circuitry and enables reset generation when above 4.65V |
| 3 GND | Ground Reference | 0V return path for all analog and digital functions; must be low-impedance for stable reset timing |
| 4 PFI | Power-Fail Input | Analog input for external voltage monitoring; triggers PFO low when below 1.25V threshold |
| 5 PFO | Power-Fail Output | Open-drain output used for low-battery warning or to drive MR on same device for cascaded reset |
| 6 WDI | Watchdog Input | Not functional in MAX819 - internally disabled; leave unconnected or tie to VCC/GND per layout best practice |
| 7 RESET | Active-Low Reset Output | Drives µP reset pin low for ≥200ms after power-up, brownout, or MR assertion; sinks 3.2mA min |
| 8 BATT | Backup Battery Input | Accepts 2.0V–5.5V battery or SuperCap; powers OUT and internal logic when VCC fails |
| - MR | Manual Reset Input | Active-low input with internal 63kΩ pull-up; asserts RESET when pulled low; required high/open for freshness seal |
Key Features
| Feature | Design Value |
|---|---|
| Manual Reset Input (MR) | Integrated active-low input with 63kΩ internal pull-up enables pushbutton reset without external components |
| Battery Freshness Seal | Disables BATT leakage (<1nA at +25°C) until first power cycle, preserving shelf life of backup batteries |
| Uncommitted Power-Fail Comparator | PFI/PFO pair provides flexible undervoltage detection for secondary rails or battery monitoring |
| Low-Power Operation | 11µA supply current enables >10-year battery life in always-on monitoring applications |
| Reset Timing Accuracy | 200ms timeout with ±20% variation over temperature ensures deterministic µP boot sequence |
Applications
| Portable Medical Monitors | Industrial PLC Controllers |
|---|---|
Use Scenario: Continuous vital-sign logging with nonvolatile RAM retention during AC power interruption. IC Role / Device Role / Timing Role: Supervisory IC providing active-low RESET to microcontroller and switching RAM supply from VCC to BATT within 10µs of brownout detection. Use Value: Prevents data corruption during transient line drops; 11µA quiescent current extends primary battery life beyond 5 years. |
Use Scenario: Remote I/O module operating in harsh factory environments with unstable 24VDC-to-5V conversion. IC Role / Device Role / Timing Role: Voltage monitor asserting RESET before 5V rail collapse, while PFI monitors 24V input for predictive failure alerts. Use Value: Enables graceful shutdown and fault logging; 4.65V reset threshold aligns with industrial +5V regulator dropout specifications. |
| Smart Energy Meters | Handheld Test Equipment |
Use Scenario: Tamper-resistant meter storing billing data in SRAM during utility power outages. IC Role / Device Role / Timing Role: Battery switchover controller maintaining VDD to real-time clock and SRAM; MR pin supports field calibration reset. Use Value: Guarantees 200ms RESET pulse for RTC initialization; battery freshness seal preserves 10-year backup battery shelf life. |
Use Scenario: Portable oscilloscope with flash-based firmware and configuration storage. IC Role / Device Role / Timing Role: Power supervisor asserting RESET on battery insertion and enabling manual recalibration via MR button. Use Value: Eliminates need for external reset IC and discrete PFI divider; µMAX package fits under 4-layer PCB height constraints. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX819MCSA+T | 4.40V reset threshold (±10%), otherwise identical pinout, timing, and feature set | Suitable for systems with looser +5V tolerance (e.g., legacy 5V regulators with ±10% spec) | Select MAX819MCSA+T when VCC nominal is 5.0V but may dip to 4.5V; MAX819LCSA+T preferred for tighter 4.75–5.25V rails. |
| MAX692AESA+ | Includes watchdog timer and no MR input; 4.63V reset threshold; SO-8 only | Lacks manual reset but adds watchdog supervision for software hang detection | Choose MAX692AESA+ when software reliability requires watchdog monitoring; MAX819LCSA+T when field-serviceable reset is mandatory. |
Compared with MAX819MCSA+T and MAX692AESA+, the MAX819LCSA+T uniquely balances precise 4.65V reset accuracy, integrated manual reset, and battery-freshness seal - making it optimal for portable instruments requiring long shelf life and user-initiated recovery.
Availability
MAX819LCSA+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC controllers, smart energy meters, and handheld test equipment requiring stable component supply across extended production lifecycles.
Supply support for MAX819LCSA+T 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 consumer applications.
The MAX819LCSA+T belongs to the MAX817/MAX818/MAX819 family of +5V microprocessor supervisory circuits, designed specifically for reliable power monitoring, battery backup control, and reset management in space- and power-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of the MAX819LCSA+T?
The MAX819LCSA+T has a factory-trimmed reset threshold of 4.65V with ±5% tolerance over temperature. This value is specified in the Electrical Characteristics table under "VRST" and is guaranteed across the full 0°C to +70°C operating range. The threshold remains stable with minimal drift - typically ±25mV from +25°C value - ensuring consistent brownout detection in +5V systems.
Does the MAX819LCSA+T include a watchdog timer function?
No, the MAX819LCSA+T does not include a watchdog timer. Per the Selector Guide and Functional Diagram in the datasheet, watchdog input (WDI) is present on the die but disabled in the MAX819 variant. The WDI pin must be left unconnected, tied to VCC, or grounded - it has no functional effect. Watchdog capability is exclusive to MAX817 and MAX818 variants.
How is the battery freshness seal enabled on the MAX819LCSA+T?
The battery freshness seal on the MAX819LCSA+T 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 remain high or open throughout; if MR is pulled low during this sequence, the seal will not activate. Once enabled, leakage drops to <1nA at +25°C.
Can the MAX819LCSA+T monitor a secondary voltage rail using PFI/PFO?
Yes, the MAX819LCSA+T's PFI input and PFO output form a standalone comparator with 1.25V reference. By connecting a resistor divider from a secondary rail (e.g., +3.3V or +12V) to PFI, users can generate a power-fail warning or trigger RESET via PFO-to-MR connection. The PFI threshold is 1.25V ±5mV, and PFO is open-drain - allowing direct interface with µP NMI or interrupt pins.
What is the maximum allowable load capacitance on the MR pin of the MAX819LCSA+T?
The MR pin of the MAX819LCSA+T supports up to 200pF total load capacitance when driven by a three-state buffer, as specified in Note 5 of the datasheet. Exceeding this capacitance risks violating the 100ns minimum MR pulse width requirement and may cause unreliable reset assertion. For long traces or noisy environments, a 0.1µF capacitor from MR to GND is recommended for noise immunity - but this counts toward the 200pF limit.
MAX819LCSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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+T FAQ
1.How can I place an order for MAX819LCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX819LCSA+T 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+T reliable?
The price and inventory of MAX819LCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX819LCSA+T is usually 5 days.
3.What payment methods are accepted for MAX819LCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX819LCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX819LCSA+T?
MAX819LCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX819LCSA+T 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+T?
For technical support, including MAX819LCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX819LCSA+T requirements.
6.How does Aetrix verify that MAX819LCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX819LCSA+T 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+T meets industry standards.
7.What is the process for return or replacement of MAX819LCSA+T?
All MAX819LCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX819LCSA+T, 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+T part is unused and in its original packaging.
Return procedure for MAX819LCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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