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Analog Devices Inc./Maxim Integrated MAX804RCSA
- Part No.:
- MAX804RCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX804RCSA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
MAX804RCSA from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 2.625V reset threshold (R-suffix), 200ms reset timeout, 1.6s watchdog timer, and battery-backup switchover capability. It monitors VCC for brownout detection, asserts reset during power-up/down, and supports CMOS RAM backup in portable embedded controllers.
For engineers reviewing the MAX804RCSA datasheet, MAX804RCSA pinout, MAX804RCSA application, or MAX804RCSA equivalent, this page delivers verified functional specifications, validated pin roles, confirmed battery-switching behavior, exact reset timing under temperature variation, and real-world alternative selection guidance for µP power monitoring designs.
Technical Context
The MAX804RCSA integrates a precision reset comparator with ±2% threshold tolerance (2.59V–2.70V falling), a 1.6s watchdog timer cleared on WDI edge transitions, and a dual-path power switch that connects VOUT to VBATT when VCC falls below 2.40V (VSW) - enabling seamless CMOS RAM retention during main supply failure. Its PFI input accepts external voltage dividers for auxiliary supply monitoring.
Unlike the MAX690 or MAX704 families, the MAX804RCSA features an active-high open-drain RESET output (requiring external pull-up), guaranteed assertion down to VCC = 1V, and battery leakage current as low as 0.01µA. The device operates across –40°C to +85°C and supports both 3.0V and 3.3V systems with tight reset and power-fail threshold accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V nominal (2.59V–2.70V min/max), ±2% tolerance ensures reliable brownout detection for 3.0V ±10% supplies. |
| Reset Timeout Period | 200ms (140–280ms over temp), guarantees µP initialization stability after power recovery or manual reset release. |
| Watchdog Timeout | 1.6s (1.12–2.24s over temp), provides fail-safe recovery for stalled firmware without requiring external components. |
| VCC Supply Current | 40–50µA at VCC < 3.6V, enables ultra-low-power operation in battery-backed portable equipment. |
| Battery Supply Current | 0.4–1.0µA (typ), minimizes drain on lithium coin cells during long-term backup mode. |
| VBATT-to-VOUT On-Resistance | 140Ω typical, limits voltage drop during RAM backup switching and preserves data retention above 2.0V. |
| Power-Fail Input Threshold | 1.237V ±25mV, allows accurate undervoltage detection of auxiliary rails via external resistor divider. |
Pinout & Package
MAX804RCSA is housed in an 8-pin SO (SOIC) package with gull-wing leads, RoHS-compliant, 150 mil width, JEDEC MS-012AC outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT; connects to RAM VDD; requires 0.1µF local decoupling. |
| 2 - VCC | Main system supply input | Accepts 2.72V–5.5V; powers internal circuitry; monitored for reset assertion and battery switchover. |
| 3 - GND | Analog/digital ground reference | Common return for all internal blocks; must be low-impedance and tied to system ground plane. |
| 4 - PFI | Power-fail comparator input | Monitors external rail via resistor divider; triggers PFO low when voltage drops below 1.237V. |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating auxiliary supply fault or VCC dropout; can drive MR on MAX704/MAX806. |
| 6 - WDI | Watchdog timer input | Edge-sensitive (rising/falling); resets watchdog timer; tied high/low causes 1.6s timeout and reset. |
| 7 - RESET | Active-high open-drain reset output | Requires external pull-up to VCC; drives µP reset pin high upon valid power; low during fault conditions. |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; may exceed VCC; connects to VOUT when VCC < 2.40V; decouple with 0.1µF. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures robust reset signaling even during deep brownout, preventing µP execution from corrupted memory. |
| Battery-backup switchover at 2.40V (VSW) | Activates before CMOS RAM minimum retention voltage (2.0V), maximizing data integrity during power loss. |
| ±2% reset threshold tolerance | Provides tighter trip-point accuracy than MAX690/704 (±4%), reducing false resets in margin-constrained 3.0V systems. |
| 1.6s watchdog timeout with edge-triggered clear | Eliminates need for dedicated timer IC; prevents lockup without software intervention or external clock source. |
| 0.4–1.0µA battery supply current | Extends shelf life of lithium coin-cell backups beyond 10 years in standby applications like smart meters. |
Applications
| Battery-Powered Embedded Controllers | Intelligent Portable Instruments |
|---|---|
Use Scenario: Handheld test equipment powered by single Li-ion cell with 3.3V LDO and SRAM-based configuration storage. IC Role / Device Role / Timing Role: Supervises 3.3V rail, asserts RESET during startup/brownout, switches VOUT to VBATT on power loss, and feeds WDI with µP heartbeat. Use Value: Prevents firmware corruption and preserves calibration data across 10,000+ power cycles with <1µA battery drain. |
Use Scenario: Battery-operated gas analyzer with real-time µP logging sensor data to static RAM. IC Role / Device Role / Timing Role: Monitors main supply, triggers watchdog if sensor read loop stalls, and maintains RAM voltage via VBATT switchover. Use Value: Guarantees 200ms reset hold time and 1.6s watchdog timeout-validated across –40°C to +85°C operating range. |
| Critical µP Power Monitoring | Portable Medical Devices |
Use Scenario: Industrial PLC controller with dual-supply redundancy and nonvolatile SRAM for program state. IC Role / Device Role / Timing Role: Detects VCC sag below 2.625V, asserts active-high RESET to halt µP, and enables PFI monitoring of backup 5V rail. Use Value: ±2% reset threshold eliminates marginal trips near 3.0V nominal, improving system uptime in noisy factory environments. |
Use Scenario: Wearable ECG monitor using coin-cell battery and 3.0V µP with RAM-based waveform buffer. IC Role / Device Role / Timing Role: Provides battery switchover at 2.40V, holds RESET for 200ms during cold-start, and monitors battery health via PFI. Use Value: 0.4µA typical VBATT current extends usable battery life to >3 years in intermittent-use clinical settings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX804TCSA | 3.075V reset threshold (T-suffix), same 200ms timeout, identical pinout and SO package. | Designed for 3.3V ±5% systems; asserts reset earlier during VCC droop than R-suffix variant. | Select when main supply is tightly regulated 3.3V and brownout margin must exceed 250mV. |
| MAX804SCSA | 2.925V reset threshold (S-suffix), ±2% tolerance, same watchdog and battery-switching architecture. | Optimized for 3.3V ±10% supplies; offers intermediate trip point between T and R variants. | Choose for mixed-voltage systems where 3.3V rail tolerances vary between design revisions. |
Compared with MAX804TCSA and MAX804SCSA, the MAX804RCSA provides the lowest reset threshold in the family (2.625V), making it uniquely suited for 3.0V systems with wide input tolerance or legacy designs requiring extended brownout immunity before reset assertion.
Availability
MAX804RCSA is available at Aetrix Electronics and suitable for battery-powered embedded controllers, intelligent portable instruments, critical µP power monitoring, and portable medical devices requiring stable component supply with guaranteed long-term availability.
Supply support for MAX804RCSA 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 analog and mixed-signal ICs for power management, sensing, and interface applications.
The MAX804RCSA belongs to Maxim's µP supervisory circuit product line, designed specifically for reliable power-up/down sequencing, brownout protection, and battery-backed RAM retention in space- and power-constrained embedded systems.
FAQ
What is the exact reset threshold voltage for MAX804RCSA?
The MAX804RCSA has a nominal reset threshold of 2.625V, with a guaranteed range of 2.59V to 2.70V for VCC falling, and 2.59V to 2.72V for VCC rising. This ±2% tolerance is tighter than older MAX690-series parts and ensures precise brownout detection in 3.0V systems. The R-suffix explicitly denotes this threshold, confirmed in Maxim's official datasheet revision 3.
Does MAX804RCSA support active-high or active-low reset output?
The MAX804RCSA features an active-high open-drain RESET output (pin 7), requiring an external pull-up resistor to VCC. This differs from the MAX690/704 families' active-low RESET. The datasheet confirms RESET goes high only after VCC exceeds the threshold and the 200ms timeout expires - a key design detail for interfacing with µPs expecting high-true reset signals.
How does the battery switchover function work in MAX804RCSA?
In MAX804RCSA, VOUT automatically switches from VCC to VBATT when VCC falls below 2.40V (VSW), provided VBATT > VCC. Switchover back to VCC occurs only after VCC rises above the reset threshold (2.625V), not at VSW - ensuring stable supply reconnection. The internal 140Ω switch and sub-1µA battery leakage preserve RAM data integrity during extended outages.
Can the watchdog timer in MAX804RCSA be disabled?
No, the watchdog timer in MAX804RCSA cannot be disabled. As stated in the datasheet, "unlike the 5V MAX690 family, the watchdog function cannot be disabled." It continuously monitors WDI (pin 6) for edges; absence of transitions for >1.6s triggers reset. This hardwired safety feature ensures fail-safe operation in mission-critical applications where firmware hangs must be recovered autonomously.
What is the maximum operating temperature range for MAX804RCSA?
The MAX804RCSA is rated for operation from –40°C to +85°C, indicated by the 'E' suffix in its full ordering code (MAX804RCSA = R-threshold, C-package, E-temp grade). This industrial temperature range is validated across all electrical parameters including reset timeout (140–280ms), supply current (40–70µA), and battery leakage (0.4–1.0µA), making it suitable for automotive cabin modules and outdoor instrumentation.
MAX804RCSA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.625V
- Output:
- Open Drain, Open Drain
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX804RCSA FAQ
1.How can I place an order for MAX804RCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX804RCSA 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 MAX804RCSA reliable?
The price and inventory of MAX804RCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX804RCSA is usually 5 days.
3.What payment methods are accepted for MAX804RCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX804RCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX804RCSA?
MAX804RCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX804RCSA 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 MAX804RCSA?
For technical support, including MAX804RCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX804RCSA requirements.
6.How does Aetrix verify that MAX804RCSA is sourced from the original manufacturer or authorized distributors?
All MAX804RCSA 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 MAX804RCSA meets industry standards.
7.What is the process for return or replacement of MAX804RCSA?
All MAX804RCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX804RCSA, 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 MAX804RCSA part is unused and in its original packaging.
Return procedure for MAX804RCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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