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Analog Devices Inc./Maxim Integrated MAX816CSA+
- Part No.:
- MAX816CSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX816CSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,519
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Product details
Overview
MAX816CSA+ from Maxim Integrated is a ±1% accurate, low-power microprocessor supervisory circuit with adjustable reset threshold, power-fail monitoring, and manual reset input - designed for +3V systems (VCC = 3.06V to 5.5V), delivering 75µA max supply current and guaranteed RESET validity down to VCC = 1.0V. It serves as a system-level voltage monitor and reset controller in battery-powered instrumentation and embedded controllers.
For engineers reviewing the MAX816CSA+ datasheet, MAX816CSA+ pinout, MAX816CSA+ application, or MAX816CSA+ equivalent, this page provides verified functional identity, confirmed pin roles (including RESET IN, PFI, PFO), exact reset threshold adjustability via external divider, power-fail comparator reference (1.70V), and validated alternative options for 3V µP supervision.
Technical Context
The MAX816CSA+ uses a high-impedance (≤35nA leakage), 1.700V internal reference to monitor an externally divided voltage at the RESET IN pin - enabling precise, user-defined reset thresholds across 3V–5.5V VCC operation. Its power-fail comparator compares PFI against the same 1.70V reference, driving PFO low when PFI falls below threshold.
Unlike MAX814/MAX815, the MAX816CSA+ does not monitor VCC directly for reset assertion; instead, it relies entirely on the RESET IN signal path, supporting flexible monitoring of auxiliary rails or isolated supplies. It lacks watchdog functionality and LOW LINE output - distinguishing it from MAX814 and MAX815 variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Accuracy | ±1% worst-case - ensures reliable reset initiation across temperature, supply, and load variations in critical 3V systems. |
| Operating Voltage Range | VCC = 3.06V to 5.5V - supports dual-supply systems and brownout resilience down to 3.06V minimum. |
| Supply Current | 75µA max at +25°C - enables multi-year battery life in portable medical and handheld instruments. |
| RESET Validity Range | Guaranteed logic-low RESET output down to VCC = 1.0V - maintains deterministic reset state during deep brownout. |
| Power-Fail Reference | 1.70V fixed internal reference - allows early warning detection of failing 3.3V or 5V rails using simple resistor dividers. |
| RESET IN Input Leakage | ≤35nA max - permits use of megaohm-level resistive dividers without significant threshold error. |
| Reset Pulse Width | 140ms min after threshold crossing - satisfies µP reset timing requirements per Intel/ARM specifications. |
Pinout & Package
MAX816CSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free (+ suffix). Pin functions are electrically and physically distinct from MAX814/MAX815 - notably omitting WDI/WDO, LOW LINE, and dual RESET outputs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MR | Manual Reset Input | Active-low CMOS input with 150µA internal pullup; triggers reset when pulled <1.10V; compatible with open-drain logic or momentary switch to GND. |
| 2 VCC | Positive Supply Input | Primary power rail input (3.06V–5.5V); powers internal comparators and outputs but does NOT control reset - only RESET IN does. |
| 3 GND | Ground Reference | System ground return for all internal circuits and output drivers; must be low-impedance for noise immunity. |
| 4 PFI | Power-Fail Input | Analog input compared to 1.70V internal reference; used with external divider to detect undervoltage on any monitored rail. |
| 5 PFO | Power-Fail Output | Active-low open-drain output sinking ≥1.2mA; asserts when PFI <1.70V - suitable for µP interrupt or latch control. |
| 6 RESET IN | Adjustable Reset Comparator Input | High-Z input (≤35nA leakage) referenced to 1.70V; reset asserts when voltage falls below 1.70V, with 140ms minimum pulse width. |
| 7 RESET | Active-Low Reset Output | Push-pull output (not open-drain); sinks 3.2mA / sources 800µA; remains valid down to VCC = 1.0V. |
| 8 RESET | Active-High Reset Output | Inverted copy of pin 7; provides direct interface to µPs requiring active-high reset assertion. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset Threshold | Set via external resistor divider on RESET IN pin; achieves ±1.2% accuracy with 0.1% resistors - eliminates factory-trimmed variants. |
| 1.70V Power-Fail Reference | Fixed, stable reference shared by PFI comparator - enables consistent early-warning detection across temperature (-40°C to +85°C). |
| Guaranteed RESET Below 1V | RESET output remains logic-low and sink-capable down to VCC = 1.0V - prevents undefined µP state during severe brownout. |
| 75µA Max Supply Current | Ultra-low quiescent draw at +25°C - reduces battery drain in always-on portable equipment without compromising response time. |
| MR Input with Internal Pullup | 150µA internal CMOS pullup eliminates need for external resistor; supports direct switch-to-GND or logic-level drive. |
Applications
| Medical Instrumentation | Portable Data Loggers |
|---|---|
Use Scenario: Battery-powered handheld blood glucose meters requiring fail-safe startup and orderly shutdown before battery depletion. IC Role / Device Role / Timing Role: Supervisory circuit asserting RESET when main 3.3V rail drops below 2.9V, while PFO interrupts µP to save calibration data. Use Value: Prevents corrupted memory writes and ensures FDA-compliant deterministic boot sequence under marginal battery conditions. |
Use Scenario: Remote environmental sensor nodes powered by Li-ion cells, operating unattended for months. IC Role / Device Role / Timing Role: Monitors battery voltage via RESET IN divider; triggers reset at 3.0V threshold and signals PFO interrupt for EEPROM backup prior to cutoff. Use Value: Enables >2000 safe power cycles with zero data loss, leveraging 75µA supply current and 140ms reset hold time. |
| Industrial PLC I/O Modules | Smart Energy Meters |
Use Scenario: DIN-rail mounted I/O modules exposed to wide ambient temperature swings (-40°C to +85°C) and supply ripple. IC Role / Device Role / Timing Role: Provides ±1% reset accuracy over full temp range using RESET IN; PFI monitors isolated 5V auxiliary rail for early fault detection. Use Value: Eliminates field failures due to temperature-induced reset threshold drift - critical for SIL-2 compliant control systems. |
Use Scenario: Revenue-grade electricity meters with tamper detection and secure firmware update capability. IC Role / Device Role / Timing Role: Asserts RESET during AC dropout events; PFO triggers secure boot abort and cryptographic key wipe before voltage collapse. Use Value: Meets IEC 62053-21 anti-tampering requirements by guaranteeing reset assertion within 200µs of PFI threshold breach. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX814TSA+ | Fixed 3.03V reset threshold (±1%), no RESET IN pin; monitors VCC directly; includes LOW LINE output. | Suitable for simpler 3.3V systems where fixed threshold suffices and low-line warning is needed. | Select when design requires VCC-monitored reset with no external divider and needs early brownout warning via LOW LINE. |
| TPS3808G33DBVR | Fixed 3.3V threshold (±0.5%), 1.8µA quiescent current, push-pull RESET, no PFI/PFO; requires external capacitor for delay adjustment. | Better for ultra-low-power IoT sensors; lacks power-fail monitoring and manual reset input. | Select when minimizing sleep-mode current is paramount and power-fail warning is handled elsewhere in system. |
Compared with MAX816CSA+, MAX814TSA+ offers integrated low-line detection but sacrifices threshold flexibility, while TPS3808G33DBVR delivers lower quiescent current but removes both PFI monitoring and manual reset - making MAX816CSA+ uniquely suited for adjustable-threshold, dual-output, power-fail-aware 3V supervision.
Availability
MAX816CSA+ is available at Aetrix Electronics and suitable for medical instrumentation, portable data loggers, industrial PLC I/O modules, and smart energy meters requiring stable component supply with long-term lifecycle support.
Supply support for MAX816CSA+ 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) designs precision analog and mixed-signal ICs for demanding industrial, medical, and communications applications.
The MAX814/MAX815/MAX816 family was engineered specifically for high-accuracy, low-power microprocessor supervision in battery-critical and safety-relevant systems - with the MAX816CSA+ variant optimized for adjustable-threshold 3V operation.
FAQ
What is the exact reset threshold voltage of the MAX816CSA+?
The MAX816CSA+ has no fixed reset threshold - it is fully adjustable via an external resistor divider connected to the RESET IN pin. The internal reference is precisely 1.700V, and the trip point VRT is calculated as VRT = VRIT × (1 + R1/R2), where VRIT = 1.700V. With 0.1% resistors, the MAX816CSA+ achieves ±1.2% overall threshold accuracy across temperature and supply.
Does the MAX816CSA+ monitor VCC directly for reset generation?
No. Unlike the MAX814 and MAX815, the MAX816CSA+ does not use VCC as the reset sense input. Reset assertion is controlled exclusively by the voltage applied to the RESET IN pin, which is compared to the internal 1.700V reference. VCC only supplies power - it plays no role in the reset decision logic of the MAX816CSA+.
Can the MAX816CSA+ be used to monitor a negative voltage rail?
Yes - the PFI input can monitor negative rails using the circuit in Figure 12 of the MAX816CSA+ datasheet: a PNP transistor and two resistors convert negative-rail degradation into a positive-going signal at PFI. When the negative rail rises (becomes less negative), PFI voltage increases; crossing 1.70V triggers PFO low, enabling reset assertion for negative-supply fault detection.
What is the maximum recommended resistance for the RESET IN divider network?
The RESET IN input exhibits ≤35nA leakage current, allowing resistor values up to 10MΩ without introducing >0.35% threshold error. However, for noise immunity in industrial environments, total divider impedance is typically kept ≤1MΩ. For example, using R2 = 100kΩ and R1 = 680kΩ yields VRT ≈ 3.0V with <0.1% error contribution from leakage.
Is the MAX816CSA+ pin-compatible with other MAX814/MAX815 variants?
No. Although all three devices share the same 8-pin SO package outline, the MAX816CSA+ has a unique pinout: pin 6 is RESET IN (not LOW LINE or WDI), and pins 7–8 are dual active-low/active-high RESET outputs (not WDO or RESET-only). Swapping MAX816CSA+ into a MAX814 or MAX815 layout will cause functional failure due to misrouted signals.
MAX816CSA+ 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:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- Adjustable/Selectable
- Output:
- Push-Pull, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX816CSA+ FAQ
1.How can I place an order for MAX816CSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX816CSA+ 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 MAX816CSA+ reliable?
The price and inventory of MAX816CSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX816CSA+ is usually 5 days.
3.What payment methods are accepted for MAX816CSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX816CSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX816CSA+?
MAX816CSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX816CSA+ 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 MAX816CSA+?
For technical support, including MAX816CSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX816CSA+ requirements.
6.How does Aetrix verify that MAX816CSA+ is sourced from the original manufacturer or authorized distributors?
All MAX816CSA+ 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 MAX816CSA+ meets industry standards.
7.What is the process for return or replacement of MAX816CSA+?
All MAX816CSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX816CSA+, 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 MAX816CSA+ part is unused and in its original packaging.
Return procedure for MAX816CSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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