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Analog Devices Inc./Maxim Integrated MAX817LCSA
- Part No.:
- MAX817LCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX817LCSA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,094
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Product details
Overview
MAX817LCSA from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery 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. It is used in portable embedded systems requiring reliable brownout detection and RAM backup control.
For engineers reviewing the MAX817LCSA datasheet, MAX817LCSA pinout, MAX817LCSA application, or MAX817LCSA equivalent, this device serves as a precision voltage monitor and system supervisor for battery-backed µP systems - particularly where low-power operation, transient immunity, and integrated backup switching are required.
Technical Context
The MAX817LCSA integrates a precision reset comparator with 4.65V threshold and 25mV hysteresis, a 200ms internal reset timer, and a bidirectional battery switchover switch (VCC↔BATT→OUT) with <5Ω on-resistance from VCC and <80Ω from BATT. Its PFI/PFO comparator operates independently with 1.25V threshold and 4mV hysteresis.
It supports battery freshness seal activation via PFO latching during power cycling, ignores fast transients on VCC due to internal filtering, and delivers guaranteed RESET assertion for VCC < 4.65V down to 0V when VBATT > 1V. No watchdog or manual reset logic is present - distinguishing it from MAX818/MAX819 variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - triggers active-low RESET when VCC falls below this level; enables reliable brownout detection in +5V systems. |
| Reset Timeout Period | 200ms typical - ensures µP remains held in reset long enough to stabilize after power-up or recovery. |
| Supply Current | 11µA typical at +25°C - enables multi-year battery life in portable/standby applications. |
| Battery Switchover Threshold | VCC < VBATT - automatically connects BATT to OUT only when main supply drops below backup voltage. |
| Output Drive Capability | 250mA sink/source on OUT - directly powers CMOS RAM or small logic loads without external buffering. |
| Operating Temperature | 0°C to +70°C - suitable for commercial-grade embedded controllers and instrumentation. |
| PFO Comparator Threshold | 1.25V ±5mV - provides accurate low-battery or power-fail warning independent of reset circuitry. |
Pinout & Package
MAX817LCSA is housed in an 8-pin SO (Small Outline) package, surface-mount compatible, with 1.27mm lead pitch and JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output | Switches between VCC and BATT to maintain power to RAM; sinks/supplies up to 250mA. |
| 2 VCC | Main supply input | +5V system rail; powers internal circuitry and enables VCC→OUT path when above reset threshold. |
| 3 GND | Ground reference | 0V return for all analog and digital functions; must be low-impedance for noise immunity. |
| 4 PFI | Power-fail comparator input | Monitors external voltage divider; asserts PFO low when input falls below 1.25V. |
| 5 PFO | Power-fail comparator output | Open-drain output used for low-battery warning or battery freshness seal enable timing. |
| 6 WDI | Watchdog input | Not functional in MAX817 - left unconnected or tied to GND/VCC; no watchdog timer present. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up, brownout, or PFO-triggered events. |
| 8 BATT | Backup battery input | Accepts 2.0V–6.0V battery; connects to OUT only when VCC < VBATT and VCC < 4.65V. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset monitoring | 4.65V ±5% threshold with 25mV hysteresis ensures stable reset assertion without chatter during slow VCC ramps. |
| Battery switchover with low on-resistance | <5Ω VCC→OUT and <80Ω BATT→OUT paths minimize voltage drop and extend backup runtime. |
| Integrated power-fail comparator | Independent 1.25V reference allows flexible undervoltage monitoring of secondary rails or battery health. |
| Battery freshness seal support | PFO latching sequence enables OEMs to isolate BATT until first power-on, preserving shelf life. |
| Low-supply-current design | 11µA typical ICC extends operational lifetime in always-on portable instruments and controllers. |
Applications
| Portable Data Loggers | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Battery-powered field instrument recording sensor data over weeks without AC power. IC Role / Device Role / Timing Role: Supervises +5V rail, asserts RESET on brownout, and switches RAM to BATT to retain logs during power loss. Use Value: Prevents data corruption during intermittent power; 11µA supply current enables >5-year battery life with CR2032. |
Use Scenario: DIN-rail mounted controller maintaining real-time I/O state during factory line voltage sags. IC Role / Device Role / Timing Role: Monitors 5V backplane supply and triggers controlled shutdown/reset while preserving register contents via BATT. Use Value: Eliminates need for external reset generator and discrete MOSFET switchover, reducing BOM count by 3–4 components. |
| Medical Handheld Diagnostics | Smart Energy Meters |
Use Scenario: FDA-cleared handheld analyzer storing calibration history and patient measurements. IC Role / Device Role / Timing Role: Provides tamper-resistant power supervision and battery-backed memory retention during battery replacement. Use Value: Battery freshness seal ensures backup battery remains unused until first clinical use, guaranteeing full capacity at deployment. |
Use Scenario: ANSI C12.20-compliant meter retaining billing data across grid outages lasting hours. IC Role / Device Role / Timing Role: Detects AC loss via PFI divider, asserts RESET, and activates BATT→OUT path to sustain RTC and flash memory. Use Value: PFO comparator enables dual-threshold monitoring: one for early warning (PFI), one for hard reset (VCC). |
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. | Lacks backup power management - requires external diode-OR or MOSFET circuit for RAM retention. | Select when only basic reset supervision is needed and BATT functionality is handled externally. |
| TPS3808G18DBVR | 4.63V threshold, 200ms delay, 1.6µA IQ, but no battery switchover or PFI input; open-drain RESET only. | No integrated BATT path or power-fail warning - limited to single-rail reset generation. | Choose for ultra-low-power applications where backup switching is unnecessary and PCB space is constrained. |
Compared with MAX690ACPA and TPS3808G18DBVR, the MAX817LCSA uniquely combines reset supervision, battery switchover, and independent power-fail detection in a single 8-pin SO package - eliminating discrete support components and enabling true "single-chip" µP supervision in space- and power-constrained designs.
Availability
MAX817LCSA is available at Aetrix Electronics and suitable for portable equipment, embedded controllers, and intelligent instrumentation requiring stable component supply and long-term manufacturability.
Supply support for MAX817LCSA 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 computing markets.
The MAX817LCSA belongs to Maxim's microprocessor supervisory product line, designed specifically to replace discrete reset generators, battery switches, and voltage monitors in +5V µP systems - with emphasis on reliability, low power, and integration.
FAQ
What is the reset threshold voltage of the MAX817LCSA?
The MAX817LCSA has a factory-trimmed reset threshold of 4.65V ±5%, specified for operation with +5V systems. This value is guaranteed over temperature (0°C to +70°C) and ensures reliable brownout detection before µP operation becomes unstable. The threshold exhibits 25mV hysteresis to prevent oscillation during slow VCC ramps. This parameter is fixed for the 'L' suffix variant and cannot be adjusted externally.
Does the MAX817LCSA include a watchdog timer?
No, the MAX817LCSA does not include a watchdog timer. Watchdog functionality is exclusive to the MAX818 and MAX819 variants. The WDI pin on the MAX817LCSA is a no-connect - it may be left floating, tied to GND, or pulled to VCC without affecting operation. Attempting to drive WDI will not trigger reset behavior, as the internal watchdog circuitry is absent in the MAX817LCSA.
How does the battery switchover function work in the MAX817LCSA?
The MAX817LCSA automatically switches its OUT pin from VCC to BATT when two conditions are met: VCC falls below the 4.65V reset threshold *and* VCC drops below the BATT voltage. This dual-condition logic prevents premature switchover during minor transients. Once switched, OUT is driven from BATT through an ~80Ω internal PMOS switch, supporting up to 250mA load current while drawing <1µA from the battery when VCC is >1V below VBATT.
Can the MAX817LCSA be used with a supercapacitor as a backup source?
Yes, the MAX817LCSA is compatible with supercapacitors as backup sources. Its BATT input accepts voltages from 2.0V to 6.0V, and the switchover threshold depends only on relative VCC/VBATT levels - not absolute BATT voltage. When paired with a simple charging circuit (e.g., resistor + Schottky diode), a 0.47F supercap can provide minutes of backup runtime for CMOS RAM. Decoupling with a 0.1µF ceramic capacitor at BATT is recommended.
What is the purpose of the PFI and PFO pins on the MAX817LCSA?
The PFI (Power-Fail Input) and PFO (Power-Fail Output) pins implement an independent voltage comparator with a 1.25V threshold. PFI monitors an external voltage divider; when the divided voltage falls below 1.25V, PFO pulls low - signaling low battery or auxiliary supply failure. Unlike RESET, PFO is not affected by VCC brownouts unless VCC drops below VBATT. This allows simultaneous monitoring of multiple rails (e.g., 3.3V or 2.5V supplies) using a single MAX817LCSA.
MAX817LCSA 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:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- 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
MAX817LCSA FAQ
1.How can I place an order for MAX817LCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817LCSA 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 MAX817LCSA reliable?
The price and inventory of MAX817LCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817LCSA is usually 5 days.
3.What payment methods are accepted for MAX817LCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817LCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817LCSA?
MAX817LCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817LCSA 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 MAX817LCSA?
For technical support, including MAX817LCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817LCSA requirements.
6.How does Aetrix verify that MAX817LCSA is sourced from the original manufacturer or authorized distributors?
All MAX817LCSA 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 MAX817LCSA meets industry standards.
7.What is the process for return or replacement of MAX817LCSA?
All MAX817LCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX817LCSA, 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 MAX817LCSA part is unused and in its original packaging.
Return procedure for MAX817LCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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