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Analog Devices Inc./Maxim Integrated MAX817LESA+T
- Part No.:
- MAX817LESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX817LESA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,287
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Product details
Overview
MAX817LESA+T 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 ambient. It is used in portable embedded controllers to ensure reliable µP initialization during brownout and power-fail events.
For engineers reviewing the MAX817LESA+T datasheet, MAX817LESA+T pinout, MAX817LESA+T application, or MAX817LESA+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed reset timing and voltage thresholds, battery switchover behavior, and real-world selection guidance for µP supervisory replacement in space-constrained +5V systems.
Technical Context
The MAX817LESA+T integrates a precision reset comparator with 4.65V threshold and 25mV hysteresis, a 200ms internal reset timeout timer, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold and 4mV hysteresis. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) and supports VBATT > VCC operation with <1µA standby current when VCC is fully absent.
No watchdog timer or manual reset input is present-these functions are exclusive to MAX818/MAX819 variants. The device implements chip-enable gating only in MAX818; MAX817LESA+T lacks CE IN/CE OUT pins and associated transmission gate logic.
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 µP remains held in reset long enough for stable clock and power rail settling. |
| Supply Current | 11µA typical at +25°C - enables multi-year battery life in portable CMOS RAM backup applications. |
| Power-Fail Threshold | 1.25V ±5mV - allows configurable undervoltage detection of auxiliary rails via external resistor divider. |
| Battery Switchover | VCC-to-OUT on-resistance = 5Ω; BATT-to-OUT = 80Ω - minimizes voltage drop during RAM backup mode transition. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded controller and instrumentation environments. |
| Package | 8-pin µMAX (3mm × 3mm) - provides PCB area savings over SO-8 and DIP while maintaining thermal performance. |
Pinout & Package
MAX817LESA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad for improved power dissipation in compact portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; powers RAM during brownout without external diodes. |
| 2 - VCC | +5V main supply input | Primary power rail monitoring point; triggers reset when falling below 4.65V; powers internal circuitry above 4.75V. |
| 3 - GND | Ground reference | 0V return for all analog comparators, reset logic, and output drivers; must be low-impedance for noise immunity. |
| 4 - PFI | Power-fail comparator input | Accepts external voltage divider output; asserts PFO low when input falls below 1.25V - used for secondary rail monitoring. |
| 5 - PFO | Power-fail comparator output | Open-drain output; pulls low during power-fail or battery freshness seal enable; can drive MR on MAX819 for cascaded reset. |
| 6 - WDI | Watchdog input | Not functional in MAX817 - internally disconnected; no watchdog timeout or timer clearing occurs. |
| 7 - RESET | Active-low reset output | Drives µP reset pin low for ≥200ms after VCC rise or brownout; sinks 3.2mA min at 0.4V, sources 800µA min at VCC–1.5V. |
| 8 - BATT | Backup battery input | Accepts 2.0V–5.5V battery; connects to OUT when VCC < VRST and VCC < VBATT; leakage <1µA in full battery-backup mode. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset monitor | 4.65V ±5% threshold with 25mV hysteresis - rejects fast transients up to 10V/ms while ensuring clean reset edge during slow brownouts. |
| Low-power battery switchover | Sub-µA standby current when VCC = 0V and VBATT = 2.8V - preserves shelf life of coin-cell batteries in unpowered storage. |
| Integrated power-fail comparator | Independent 1.25V reference with 4mV hysteresis - enables dual-rail monitoring without adding external op-amps or references. |
| Battery freshness seal | Enables OEM to disconnect BATT from internal circuitry until first power-up - guarantees full battery capacity at end-user deployment. |
| Robust output drive | RESET sinks 3.2mA at 0.4V; OUT delivers 250mA peak - directly drives µP reset pins and powers 64KB SRAM without external buffers. |
Applications
| Portable Medical Instrumentation | Industrial Data Logger |
|---|---|
Use Scenario: Battery-powered handheld ECG monitor storing waveform data in SRAM during intermittent operation. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, RAM backup switchover, and low-battery warning via PFI divider. Use Value: Ensures data integrity across 10,000+ power cycles by guaranteeing µP reset before supply collapse and preserving RAM contents using coin-cell backup. |
Use Scenario: Ruggedized field logger recording sensor data every 5 seconds, powered by Li-SOCl₂ battery with 10-year shelf life. IC Role / Device Role / Timing Role: Reset supervisor enabling battery freshness seal to prevent pre-deployment discharge and PFO-driven low-voltage alert. Use Value: Extends usable battery life by >30% through sub-1µA backup-mode current and eliminates premature field failures due to degraded backup cells. |
| Smart Energy Meter | Point-of-Sale Terminal |
Use Scenario: Utility meter with tamper-detection EEPROM and real-time clock requiring nonvolatile memory retention during AC mains dropout. IC Role / Device Role / Timing Role: Dual-function supervisor: generates 200ms reset pulse on VCC sag and switches SRAM to BATT within 1µs of VCC crossing VRST. Use Value: Meets IEC 62053-21 Class 0.5S requirement for <10ms data loss during 200ms AC interruption via deterministic switchover timing. |
Use Scenario: Retail terminal with flash-based firmware and volatile transaction buffer, deployed in locations with unstable grid power. IC Role / Device Role / Timing Role: Power integrity guardian asserting RESET before VCC drops below 4.5V and enabling PFO-triggered shutdown sequence via µP NMI. Use Value: Prevents firmware corruption and transaction loss by synchronizing µP reset, EEPROM write-protection, and display blanking within 200ms window. |
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 PFI/PFO comparator or battery switchover; 8-pin DIP only. | Lacks power-fail warning and RAM backup capability - suitable only for basic reset-only use cases. | Select when cost-sensitive designs require only reset generation and board layout already accommodates DIP footprint. |
| TPS3808G33DBVR | 3.3V reset threshold, 200ms timeout, 1.8µA IQ, but no battery switchover or PFI input; SOT-23-6 package. | Designed for low-voltage µPs; incompatible with +5V systems and unable to support RAM backup architecture. | Choose only for new 3.3V designs where ultra-low quiescent current outweighs loss of backup functionality. |
Compared with MAX690ACPA+ and TPS3808G33DBVR, MAX817LESA+T uniquely combines +5V reset supervision, integrated power-fail detection, and automatic battery-backed RAM switchover in a space-saving µMAX package - making it irreplaceable in legacy portable instrumentation requiring all three functions.
Availability
MAX817LESA+T is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial data loggers, smart energy meters, and point-of-sale terminals requiring stable component supply with guaranteed long-term continuity.
Supply support for MAX817LESA+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 MAX817L/M series was designed specifically for +5V microprocessor systems needing robust, low-power supervision with battery backup and power-fail warning - targeting portable and battery-critical embedded controllers.
FAQ
What is the exact reset threshold voltage of MAX817LESA+T and how is it trimmed?
The MAX817LESA+T has a factory-trimmed reset threshold of 4.65V ±5%, specified over 0°C to +70°C. This value is laser-trimmed during wafer sort and verified per unit; no external adjustment is possible. The L suffix explicitly denotes the 4.65V version, distinguishing it from the 4.40V M variant. The threshold exhibits ±25mV hysteresis to prevent chatter during slow VCC transitions.
Does MAX817LESA+T include a watchdog timer function?
No, MAX817LESA+T does not implement a watchdog timer. The WDI pin is present but internally disconnected - it has no effect on reset generation or timing. Watchdog functionality is exclusive to MAX818 and MAX819 variants. For designs requiring watchdog supervision, MAX817LESA+T must be replaced with MAX818LESA+T or MAX819LESA+T.
Can MAX817LESA+T support battery backup for SRAM, and what are the voltage limits?
Yes, MAX817LESA+T supports automatic battery backup for CMOS SRAM via its BATT and OUT pins. It accepts VBATT from 2.0V to 5.5V and switches OUT from VCC to BATT when both VCC < 4.65V and VCC < VBATT. In backup mode, OUT supplies RAM with <1µA quiescent current when VCC = 0V and VBATT = 2.8V, preserving battery life.
How does the power-fail comparator (PFI/PFO) work in MAX817LESA+T?
The PFI input compares against an internal 1.25V reference; when PFI falls below 1.25V, PFO pulls low (open-drain). This enables external rail monitoring - e.g., a 5V auxiliary supply divided to 1.25V at PFI triggers PFO to signal impending failure. PFO also serves as the control signal for the battery freshness seal, latching on specific VCC sequencing.
What package type and thermal characteristics does MAX817LESA+T use?
MAX817LESA+T is supplied in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch) with exposed thermal pad. Its continuous power dissipation is 330mW at +70°C, derating at 4.10mW/°C above that temperature. The µMAX footprint saves ~60% board area versus SO-8 and enables higher-density portable layouts without sacrificing thermal performance.
MAX817LESA+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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX817LESA+T FAQ
1.How can I place an order for MAX817LESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817LESA+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 MAX817LESA+T reliable?
The price and inventory of MAX817LESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817LESA+T is usually 5 days.
3.What payment methods are accepted for MAX817LESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817LESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817LESA+T?
MAX817LESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817LESA+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 MAX817LESA+T?
For technical support, including MAX817LESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817LESA+T requirements.
6.How does Aetrix verify that MAX817LESA+T is sourced from the original manufacturer or authorized distributors?
All MAX817LESA+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 MAX817LESA+T meets industry standards.
7.What is the process for return or replacement of MAX817LESA+T?
All MAX817LESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX817LESA+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 MAX817LESA+T part is unused and in its original packaging.
Return procedure for MAX817LESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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