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Analog Devices Inc./Maxim Integrated MAX817LCUA+
- Part No.:
- MAX817LCUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX817LCUA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:100
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Product details
Overview
MAX817LCUA+ from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery backup switchover, and power-fail comparator 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 portable µP systems requiring reliable brownout protection and RAM backup control.
For engineers reviewing the MAX817LCUA+ datasheet, MAX817LCUA+ pinout, MAX817LCUA+ application, or MAX817LCUA+ equivalent, this device serves as a precision voltage monitor and system supervisor in battery-powered embedded controllers, intelligent instruments, and critical µP monitoring applications where low-power operation and fast transient immunity are essential.
Technical Context
The MAX817LCUA+ integrates a precision reset comparator with 25mV hysteresis, a 200ms internal reset timer, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold referenced to VCC. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) to maintain CMOS RAM supply during brownout.
It supports backup-battery operation with <1µA standby current when VCC < VBATT − 0.2V, and includes a battery freshness seal function enabled via PFO latching. Unlike MAX818/MAX819 variants, it lacks watchdog timer and manual reset inputs - confirmed by Selector Guide and Pin Description tables.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion before +5V supply drops below µP minimum operating voltage. |
| Reset Timeout Period | 200ms typical - guarantees sufficient hold time for µP initialization after power-up or brownout recovery. |
| Supply Current | 11µA typical at +25°C - enables multi-year battery life in portable equipment with infrequent wake cycles. |
| VCC-to-OUT On-Resistance | 5Ω max - minimizes voltage drop and power loss when supplying CMOS RAM from main +5V rail. |
| BATT-to-OUT On-Resistance | 80Ω max - balances low leakage (<1µA) and adequate current delivery for SRAM backup during extended outages. |
| Power-Fail Threshold | 1.25V on PFI input - allows flexible external resistor-divider configuration to monitor secondary supplies or low-battery conditions. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded systems without extended thermal requirements. |
Pinout & Package
MAX817LCUA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), pin-compatible with 8-pin SO and DIP variants. The µMAX package enables high-density PCB layouts in space-constrained portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | CMOS RAM supply output | Switches between VCC and BATT based on voltage comparison; drives SRAM VDD directly with low on-resistance. |
| 2 VCC | Main +5V supply input | Primary power source; powers internal circuitry and enables VCC-to-OUT switch when above reset threshold. |
| 3 GND | Ground reference | 0V return path for all analog and digital functions; must be low-impedance for accurate reset threshold sensing. |
| 4 PFI | Power-fail comparator input | Monitors external voltage divider; asserts PFO low when input falls below 1.25V - used for secondary supply monitoring. |
| 5 PFO | Power-fail comparator output | Open-drain output; pulled high externally; enables battery freshness seal when grounded during power cycle. |
| 6 WDI | Watchdog input | No functional connection in MAX817 - unused pin; must be left open or tied to GND per datasheet guidance. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up, brownout, or PFI-triggered event; sinks/sourcing capable. |
| 8 BATT | Backup battery input | Accepts 2.0V–6.0V battery or supercap; powers internal circuitry and OUT when VCC falls below VBATT and reset threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.65V reset threshold | ±5% tolerance over temperature ensures consistent µP reset timing across 0°C–70°C without external calibration. |
| 200ms reset timeout | Internally trimmed delay eliminates need for external RC network - reduces BOM count and layout area. |
| Battery switchover with <1µA standby | Enables multi-year shelf life in battery-backed instruments by minimizing parasitic drain when main supply is absent. |
| Uncommitted power-fail comparator | Independent of reset circuitry - allows simultaneous monitoring of auxiliary rails (e.g., +3.3V, +2.5V) without interfering with primary supervision. |
| Battery freshness seal | Latches battery isolation until first power-up - guarantees full battery capacity remains available at end-customer deployment. |
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 switches SRAM to coin-cell backup during battery replacement; asserts reset if supply dips during measurement. Use Value: Prevents memory corruption during hot-swap battery changes and ensures deterministic µP startup after low-power sleep mode. |
Use Scenario: Remote environmental sensor node logging temperature/humidity to SPI flash, powered by LiSOCl₂ battery. IC Role / Device Role / Timing Role: Monitors main supply voltage and triggers controlled shutdown before brownout; uses PFI to detect falling backup cell voltage. Use Value: Extends operational lifetime by enabling graceful data commit prior to power loss and preserving last valid readings in SRAM. |
| Point-of-Sale Terminal | Smart Energy Meter |
Use Scenario: Credit card reader with secure element and real-time clock, requiring tamper-proof memory retention during AC power interruption. IC Role / Device Role / Timing Role: Provides active-low reset to ARM Cortex-M0 and gates SRAM supply via OUT pin during mains dropout. Use Value: Eliminates need for discrete diode-OR and reset IC - reduces bill-of-materials while meeting IEC 61000-4-2 ESD immunity targets. |
Use Scenario: DIN-rail mounted electricity meter with metrology ASIC and RTC, operating continuously on utility-supplied +5V with supercap backup. IC Role / Device Role / Timing Role: Uses BATT-to-OUT switchover and battery freshness seal to preserve RTC and tariff data during grid outages up to 72 hours. Use Value: Achieves >10-year backup runtime with <1µA quiescent draw - meets ANSI C12.20 Class 0.2 accuracy requirements under intermittent power. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690ACPA+ | 4.65V reset threshold, 200ms timeout, but no power-fail comparator or battery switchover; requires external diode-OR for backup. | Lacks integrated BATT switching and PFI monitoring - suitable only where backup is handled externally or not required. | Select when cost sensitivity outweighs integration benefits and system already implements discrete backup control. |
| TPS3808G18DBVR | 4.63V reset threshold, 200ms timeout, 1.8µA supply current, but no BATT pin or PFI/PFO - single-supply reset only. | Cannot support RAM backup or secondary supply monitoring - limited to basic power-on reset in always-connected systems. | Choose for ultra-low-power applications where battery backup is unnecessary and footprint is constrained. |
Compared with MAX690ACPA+ and TPS3808G18DBVR, the MAX817LCUA+ uniquely combines precision reset, battery switchover, and uncommitted power-fail detection in one µMAX package - making it the only option among the three that fully satisfies portable instrumentation requirements for integrated backup and dual-rail monitoring.
Availability
MAX817LCUA+ 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 with long-term manufacturability assurance.
Supply support for MAX817LCUA+ 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 MAX817L/M series was designed specifically for +5V microprocessor systems needing integrated voltage monitoring, battery backup control, and power-fail warning - targeting portable and battery-critical embedded applications.
FAQ
What is the reset threshold voltage of the MAX817LCUA+?
The MAX817LCUA+ has a factory-trimmed reset threshold of 4.65V with ±5% tolerance over temperature. This value is fixed for the "L" suffix variant and ensures reliable reset assertion before the +5V supply falls below the minimum operating voltage of most 5V microprocessors. The threshold is internally generated and does not require external components for calibration.
Does the MAX817LCUA+ support battery backup switchover?
Yes, the MAX817LCUA+ supports automatic battery backup switchover via its BATT and OUT pins. When VCC falls below both the reset threshold (4.65V) and VBATT, the device disconnects VCC from OUT and connects the backup battery to maintain power to external CMOS RAM. The BATT-to-OUT on-resistance is 80Ω max, and standby current drops below 1µA when VCC < VBATT − 0.2V.
Can the MAX817LCUA+ monitor a secondary power supply?
Yes, the MAX817LCUA+ includes an uncommitted power-fail comparator with PFI and PFO pins. By connecting a resistor divider to PFI, users can configure the comparator to monitor any DC voltage - such as +3.3V or +2.5V rails - and assert PFO low when the monitored voltage falls below 1.25V. This function operates independently of the main reset circuitry.
Is the MAX817LCUA+ pin-compatible with other MAX817 variants?
Yes, the MAX817LCUA+ is pin-compatible with all MAX817 variants in µMAX, SO, and DIP packages, including MAX817M, MAX817CPA, and MAX817CSA. The "L" suffix denotes the 4.65V reset threshold, while the "CUA+" indicates the 8-pin µMAX package with lead-free finish - all share identical pinout and electrical behavior per the Selector Guide.
How does the battery freshness seal work on the MAX817LCUA+?
The battery freshness seal on the MAX817LCUA+ isolates the BATT pin from internal circuitry until first power-up. To enable it: ground PFO, bring VCC above 4.65V and hold until reset deasserts, then lower VCC. This latches the seal, preventing battery discharge during storage. Once enabled, the seal remains active until VCC exceeds VRST again - ensuring full battery capacity at end-customer deployment.
MAX817LCUA+ 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:
- 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
MAX817LCUA+ FAQ
1.How can I place an order for MAX817LCUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817LCUA+ 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 MAX817LCUA+ reliable?
The price and inventory of MAX817LCUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817LCUA+ is usually 5 days.
3.What payment methods are accepted for MAX817LCUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817LCUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817LCUA+?
MAX817LCUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817LCUA+ 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 MAX817LCUA+?
For technical support, including MAX817LCUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817LCUA+ requirements.
6.How does Aetrix verify that MAX817LCUA+ is sourced from the original manufacturer or authorized distributors?
All MAX817LCUA+ 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 MAX817LCUA+ meets industry standards.
7.What is the process for return or replacement of MAX817LCUA+?
All MAX817LCUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX817LCUA+, 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 MAX817LCUA+ part is unused and in its original packaging.
Return procedure for MAX817LCUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX817LCUA+ Tags
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MIC826SYMT-TR
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