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Analog Devices Inc./Maxim Integrated MAX817MCSA+T
- Part No.:
- MAX817MCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX817MCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,956
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Product details
Overview
The MAX817MCSA+T from Maxim Integrated is a +5V microprocessor supervisory circuit designed for power-supply monitoring, battery switchover, and active-low reset generation in embedded µP systems. It features a 4.40V ±10% reset threshold, 11µA quiescent supply current, 200ms reset timeout, and backup-battery switchover capability enabling seamless RAM retention during brownout. It is used in portable controllers and critical µP monitoring where low-power, transient-immune supervision is required.
For engineers reviewing the MAX817MCSA+T datasheet, MAX817MCSA+T pinout, MAX817MCSA+T application, or MAX817MCSA+T equivalent, key selection considerations include its M-suffix 4.40V reset threshold, µMAX-8 package compatibility, battery-freshness seal enablement sequence, and absence of watchdog timer or manual reset input-distinguishing it from MAX818/MAX819 variants.
Technical Context
The MAX817MCSA+T implements a precision voltage comparator with hysteresis (25mV) to monitor VCC against a trimmed 4.40V threshold, asserting RESET low for ≥200ms upon undervoltage detection. Its internal P-channel MOSFET switch enables automatic switchover from VCC to BATT when VCC falls below both VRST and VBATT, maintaining OUT at battery voltage with ≤80Ω on-resistance.
It integrates a power-fail comparator (PFI/PFO) with 1.25V threshold and 4mV hysteresis, independent of reset logic, allowing low-battery warning generation. The device ignores fast transients on VCC due to internal filtering and operates across 0°C to +70°C with guaranteed performance over VCC = +4.5V to +5.5V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±10% - sets brownout detection point for +5V systems; triggers reset when VCC drops below this level |
| Reset Timeout Period | 200ms typical - ensures µP remains held in reset long enough for stable power recovery before execution resumes |
| Supply Current | 11µA typical - enables multi-year operation in battery-backed portable equipment without significant drain |
| Battery Switchover Threshold | VCC < VBATT - activates automatic backup power path only when main supply fails and battery is present and valid |
| Power-Fail Comparator Threshold | 1.25V ±50mV - provides configurable undervoltage warning for auxiliary rails via external resistor divider |
| Operating Temperature Range | 0°C to +70°C - qualified for commercial-grade embedded controller and instrumentation applications |
| VCC Operating Range | +4.5V to +5.5V - supports standard +5V TTL/CMOS systems with ±10% tolerance |
Pinout & Package
MAX817MCSA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), surface-mount, lead-free compliant. Pin 1 is marked with a dot; pin numbering follows standard counter-clockwise orientation from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT automatically; delivers regulated backup power to memory during brownout |
| 2 VCC | Main +5V supply input | Primary power source; monitored for reset assertion and used as reference for all internal comparators |
| 3 GND | Ground reference | 0V return for all analog and digital functions; must be low-impedance connection for accurate threshold sensing |
| 4 PFI | Power-fail comparator input | Accepts external voltage divider for undervoltage detection on secondary rails; referenced to 1.25V internal bandgap |
| 5 PFO | Power-fail comparator output | Open-drain output that goes low when PFI < 1.25V; used for battery freshness seal enablement or system warning |
| 6 WDI | Watchdog input | Not functional in MAX817 - left unconnected or tied to VCC/GND; no watchdog timer present in this variant |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms on power-up, brownout, or PFO-triggered event; sinks 3.2mA minimum |
| 8 BATT | Backup battery input | Accepts 2.0V–6.0V battery; powers OUT and internal circuitry when VCC fails; supports battery freshness seal activation |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.40V reset threshold | ±10% tolerance over temperature - eliminates need for external resistor divider while ensuring reliable brownout detection in noisy +5V environments |
| Battery-freshness seal | Enables OEM battery preservation by disconnecting BATT from internal circuitry until first power cycle - extends shelf life and guarantees full capacity at deployment |
| Automatic VCC/BATT switchover | Sub-80Ω P-MOSFET switch with <1µA standby current - maintains RAM data integrity without external diodes or control logic |
| Power-fail comparator (PFI/PFO) | Independent 1.25V reference with 4mV hysteresis - allows flexible low-voltage warning on auxiliary supplies without interfering with reset timing |
| Transient-immune supervision | Internal filtering rejects fast VCC glitches up to 100µs duration - prevents spurious resets in electrically noisy industrial or automotive-adjacent systems |
Applications
| Portable Medical Monitors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Battery-powered ECG or glucose meter retaining real-time sensor data during brief AC dropout or battery swap. IC Role / Device Role / Timing Role: Supervisory circuit providing active-low RESET to ARM Cortex-M µP and switching RAM supply from main rail to coin cell via OUT pin. Use Value: Ensures zero data loss during 200ms brownout events; 11µA quiescent current extends single-CR2032 life to >5 years in sleep mode. |
Use Scenario: DIN-rail mounted remote I/O module operating in factory environments with unstable 24VDC-to-5V conversion. IC Role / Device Role / Timing Role: Voltage monitor asserting RESET on µP when 5V rail dips below 4.40V; PFI monitors 3.3V FPGA core rail for early warning. Use Value: Prevents firmware corruption during line sags; PFO-driven LED indicator gives maintenance staff advance notice of failing DC-DC converter. |
| Smart Energy Meters | Point-of-Sale Terminals |
Use Scenario: Revenue-grade electricity meter storing tariff data and timestamps during grid interruptions lasting seconds to minutes. IC Role / Device Role / Timing Role: Backup supervisor enabling battery-backed SRAM retention via OUT; battery freshness seal ensures 10-year shelf life before field installation. Use Value: Guarantees regulatory-compliant data integrity across power cycles; eliminates field failures due to prematurely depleted backup batteries. |
Use Scenario: Retail terminal using supercapacitor backup to preserve transaction logs during brief UPS switchover or AC loss. IC Role / Device Role / Timing Role: Switchover controller connecting supercap (BATT) to RAM supply (OUT) when 5V rail collapses; RESET holds µP in safe state until power stabilizes. Use Value: Enables use of cost-effective SuperCap™ instead of lithium battery; 200ms reset hold time aligns with typical UPS transfer delay specifications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX817LCSA+T | 4.65V ±5% reset threshold; tighter tolerance but higher trip point - less margin for noisy 5V rails | Suitable for systems with cleaner power and stricter reset timing requirements | Select when design requires earlier reset assertion (at 4.65V) and tighter voltage tolerance |
| MAX692ACSA+ | Includes watchdog timer and manual reset; 4.63V threshold; higher 25µA supply current | Required where µP activity monitoring or operator-initiated reset is mandatory | Choose only if watchdog or MR functionality is needed - not drop-in compatible due to pinout and feature set differences |
Compared with MAX817MCSA+T, the L-suffix variant offers higher reset accuracy at the cost of reduced noise immunity, while MAX692ACSA+ adds supervisory features but increases power and complexity - making MAX817MCSA+T optimal for cost-sensitive, low-power, battery-backed applications requiring only basic voltage monitoring and switchover.
Availability
MAX817MCSA+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, smart energy meters, and point-of-sale terminals requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for MAX817MCSA+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 computing applications.
The MAX817 family was designed specifically for low-power, space-constrained +5V microprocessor systems needing reliable power monitoring, battery switchover, and reset generation - targeting portable and battery-backed embedded controllers.
FAQ
What is the exact reset threshold voltage of the MAX817MCSA+T?
The MAX817MCSA+T has a factory-trimmed reset threshold of 4.40V with ±10% tolerance over temperature and supply variation. This value is specified in the Electrical Characteristics table under "VRST" for MAX81_M devices and is validated across the full 0°C to +70°C operating range. The M-suffix explicitly denotes the 4.40V version, distinguishing it from the 4.65V L-suffix variants.
Does the MAX817MCSA+T include a watchdog timer?
No, the MAX817MCSA+T does not include a watchdog timer. Watchdog functionality is exclusive to the MAX818 and MAX819 variants per the Selector Guide. The WDI pin on MAX817MCSA+T is a no-connect; leaving it unconnected or tying it to VCC/GND has no effect on operation. This simplifies design for applications requiring only voltage supervision and battery switchover.
How is the battery freshness seal enabled on the MAX817MCSA+T?
The battery freshness seal on MAX817MCSA+T is enabled by grounding PFO while cycling VCC: (1) apply battery to BATT, (2) ground PFO, (3) bring VCC above 4.40V and hold until RESET deasserts after 200ms, then (4) lower VCC again. Once enabled, the seal disconnects BATT from internal circuitry until next power-up above VRST - preserving battery shelf life. MR is not involved in this process for MAX817.
What package type and dimensions does the MAX817MCSA+T use?
The MAX817MCSA+T uses the 8-pin µMAX package (3.0mm × 3.0mm × 0.8mm body, 0.5mm pitch), a space-saving surface-mount solution with exposed pad for thermal performance. It is RoHS-compliant and lead-free, indicated by the "+T" suffix. This package is pin-compatible with other MAX817 variants in µMAX, SO, and DIP packages - though footprint and thermal design must match µMAX mechanical specs.
Can the MAX817MCSA+T monitor a secondary voltage rail like 3.3V?
Yes, the MAX817MCSA+T can monitor secondary rails using its dedicated PFI/PFO power-fail comparator. By connecting a resistor divider from the 3.3V rail to PFI, the internal 1.25V reference detects when the divided voltage falls below threshold - e.g., R1=1.69kΩ, R2=1.0kΩ yields trip at ~3.3V. PFO then asserts low, usable for warning or latching circuits, independent of the main reset function.
MAX817MCSA+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:
- 4.4V
- 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
MAX817MCSA+T FAQ
1.How can I place an order for MAX817MCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817MCSA+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 MAX817MCSA+T reliable?
The price and inventory of MAX817MCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817MCSA+T is usually 5 days.
3.What payment methods are accepted for MAX817MCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817MCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817MCSA+T?
MAX817MCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817MCSA+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 MAX817MCSA+T?
For technical support, including MAX817MCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817MCSA+T requirements.
6.How does Aetrix verify that MAX817MCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX817MCSA+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 MAX817MCSA+T meets industry standards.
7.What is the process for return or replacement of MAX817MCSA+T?
All MAX817MCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX817MCSA+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 MAX817MCSA+T part is unused and in its original packaging.
Return procedure for MAX817MCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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