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Analog Devices Inc./Maxim Integrated MAX804TCSA+
- Part No.:
- MAX804TCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX804TCSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,856
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Product details
Overview
MAX804TCSA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 3.075V reset threshold (T-suffix), 200ms reset timeout, 1.6s watchdog timer, and battery-backup switchover capability for CMOS RAM retention. It monitors VCC supply integrity, detects power-fail conditions via PFI/PFO, and supports manual reset input - deployed in embedded controllers requiring reliable brownout protection and nonvolatile memory backup.
For engineers reviewing the MAX804TCSA+ datasheet, MAX804TCSA+ pinout, MAX804TCSA+ application, or MAX804TCSA+ equivalent, this page delivers verified electrical specifications, package-confirmed pin functions, real-world use cases in battery-powered systems, and two validated alternative parts with documented functional differences.
Technical Context
The MAX804TCSA+ integrates a precision reset comparator with ±2% threshold tolerance (3.075V), a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power switch: VCC-to-VOUT via 3Ω PMOS and VBATT-to-VOUT via 140Ω NMOS. Its battery switchover logic triggers at VSW = 2.40V (VBATT > VCC) and reverts to VCC only after VCC rises above VRST - ensuring stable power restoration before RAM reconnection.
It features an independent power-fail comparator (VPFT = 1.237V, ±20mV hysteresis), low-quiescent operation (40µA VCC supply current, 1µA battery current), and guaranteed RESET assertion down to VCC = 1V. The active-high RESET output requires external pull-up and is functionally inverted relative to MAX690/MAX704 series.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (±2%) - precisely targets 3.3V supplies with ±5% tolerance; asserts reset before VCC falls below 3.00V. |
| Reset Timeout Period | 200ms (140–280ms over temp) - ensures µP completes power-up initialization before release. |
| Watchdog Timeout | 1.6s (1.12–2.24s over temp) - detects firmware hangs without requiring software servicing. |
| VCC Supply Current | 40µA typical (VCC < 3.6V) - enables long-term operation in battery-backed systems. |
| Battery Supply Current | 1µA max (VBATT mode) - minimizes lithium cell drain during extended backup periods. |
| Power-Fail Threshold | 1.237V (±20mV hysteresis) - provides accurate undervoltage detection for auxiliary rails. |
| Operating Temp Range | 0°C to +70°C - qualified for commercial-grade embedded applications. |
Pinout & Package
MAX804TCSA+ is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package with standard 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and moisture sensitivity level (MSL) 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); connects to RAM VDD. |
| 2 - VCC | Main system supply input | Primary 3.0V/3.3V power source; powers internal circuitry and enables VOUT sourcing. |
| 3 - GND | Ground reference | Common return path for all analog/digital functions; must be low-impedance. |
| 4 - PFI | Power-fail input | Monitors auxiliary rail voltage; trips PFO when input falls below 1.237V. |
| 5 - PFO | Power-fail open-drain output | Asserts low on PFI undervoltage or VCC dropout; used for interrupt or MR triggering. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; cannot be disabled. |
| 7 - RESET | Active-high open-drain reset output | Requires external pull-up; drives µP reset high upon fault; inverse of MAX690 RESET. |
| 8 - VBATT | Backup battery input | Accepts up to 6V; powers VOUT during VCC brownout; may exceed VCC in normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, preventing undefined µP state. |
| Battery switchover with 2.40V threshold | Triggers backup before VOUT drops below 2.0V - preserving CMOS RAM data integrity. |
| ±2% reset threshold accuracy | Tighter tolerance than MAX690 (±4%) - reduces false resets in margin-constrained 3.3V designs. |
| 1.6s watchdog timeout with edge-clearing | Eliminates need for dedicated timer peripheral; immune to static WDI states (tie-high/tie-low). |
| 1µA battery supply current | Extends lithium coin-cell life to >10 years in standby - critical for maintenance-free devices. |
Applications
| Battery-Powered Embedded Controller | Intelligent Industrial Instrument |
|---|---|
Use Scenario: Portable data logger with RTC and SRAM, powered by 3.3V Li-ion battery and backed by 3.6V coin cell. IC Role / Device Role / Timing Role: Supervises main supply, asserts RESET on brownout, switches RAM to VBATT, and triggers watchdog if firmware stalls. Use Value: Prevents data corruption during battery swap or low-voltage events; enables 10+ year coin-cell backup life. |
Use Scenario: Handheld multimeter with EEPROM calibration storage and LCD controller. IC Role / Device Role / Timing Role: Monitors 3.3V rail for sensor ADC stability, generates PFO interrupt on auxiliary 5V supply failure, and holds µP in reset until clean power resumes. Use Value: Eliminates spurious measurements during power transients; ensures calibration data retention across power cycles. |
| Critical µP Power Monitoring | Portable Medical Device |
Use Scenario: Infusion pump MCU operating from regulated 3.3V DC-DC converter with backup supercapacitor. IC Role / Device Role / Timing Role: Detects VCC sag below 3.075V, initiates 200ms reset hold-off, and activates VBATT switchover to maintain RAM and safety-critical state. Use Value: Meets IEC 62304 Class C requirements for deterministic reset behavior and zero-data-loss power transition. |
Use Scenario: Wearable ECG monitor using 3.0V coin cell and flash-based firmware storage. IC Role / Device Role / Timing Role: Provides manual reset via pushbutton (MR), monitors battery voltage decay via PFI, and asserts RESET before VCC drops below safe operating range. Use Value: Enables user-initiated recovery without full power cycle; prevents firmware execution in undervoltage condition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805TCSA+ | Active-low RESET output (push-pull), identical reset threshold, same pinout and timing. | Direct replacement where µP requires active-low reset signal; no PCB change needed. | Select MAX805TCSA+ when interfacing with legacy µPs lacking internal pull-up on reset input. |
| MAX706TCSA+ | No battery switchover or WDI; adds PFI hysteresis control pin; 200ms reset only; 3.085V threshold. | Suitable for cost-sensitive, non-battery-backed systems needing basic reset + power-fail warning. | Choose MAX706TCSA+ when backup RAM is unnecessary and watchdog functionality is not required. |
Compared with MAX804TCSA+, MAX805TCSA+ offers identical supervision features but with inverted reset polarity, while MAX706TCSA+ removes battery management and watchdog to reduce cost and complexity - making it appropriate only for simpler, single-supply applications.
Availability
MAX804TCSA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, critical µP power monitoring, and portable equipment requiring stable component supply and long-term industrial availability.
Supply support for MAX804TCSA+ 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 MAX804TCSA+ belongs to Maxim's 3.0V/3.3V microprocessor supervisory family, designed specifically for robust power monitoring, battery-backed RAM retention, and watchdog-based firmware reliability in space- and power-constrained embedded systems.
FAQ
What is the reset threshold voltage of the MAX804TCSA+?
The MAX804TCSA+ has a nominal reset threshold voltage of 3.075V, with ±2% tolerance over temperature and supply voltage. This value is specified for VCC falling and rising conditions, and is optimized for 3.3V systems with ±5% supply tolerance. The T-suffix explicitly denotes this 3.075V threshold per Maxim's ordering guide.
Does the MAX804TCSA+ support battery backup for CMOS RAM?
Yes, the MAX804TCSA+ provides automatic battery-backup switchover for CMOS RAM via its VOUT pin. When VCC falls below the 2.40V switch threshold (VSW) and VBATT exceeds VCC, the device connects VBATT to VOUT through a 140Ω internal switch - maintaining RAM power without external circuitry. VBATT may safely exceed VCC during normal operation.
How does the watchdog timer function on the MAX804TCSA+?
The MAX804TCSA+ incorporates a 1.6s watchdog timer that triggers reset if the WDI pin remains static (high or low) beyond timeout. The timer clears on any WDI edge transition and cannot be disabled. Unlike older families, this watchdog operates independently of reset state and remains active even during VCC brownout if VBATT is present.
What is the purpose of the PFI and PFO pins on the MAX804TCSA+?
The PFI (Power-Fail Input) pin accepts an external voltage for undervoltage monitoring, comparing it to a 1.237V internal reference. When PFI falls below this threshold, the open-drain PFO (Power-Fail Output) pulls low - enabling use as a general-purpose voltage monitor or as a trigger for manual reset (e.g., connecting PFO to MR on compatible variants). PFI hysteresis is ±20mV.
Is the MAX804TCSA+ pin-compatible with other devices in the MAX80x family?
Yes, the MAX804TCSA+ shares identical 8-pin SOIC packaging and pinout with MAX802TCSA+, MAX805TCSA+, and MAX806TCSA+. All variants maintain consistent VOUT, VCC, GND, PFI, PFO, WDI, RESET/RESET, and VBATT assignments. Functional differences (e.g., RESET polarity, MR presence) do not affect physical layout or PCB footprint.
MAX804TCSA+ 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:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Open Drain, Open Drain
- 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
MAX804TCSA+ FAQ
1.How can I place an order for MAX804TCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX804TCSA+ 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 MAX804TCSA+ reliable?
The price and inventory of MAX804TCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX804TCSA+ is usually 5 days.
3.What payment methods are accepted for MAX804TCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX804TCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX804TCSA+?
MAX804TCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX804TCSA+ 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 MAX804TCSA+?
For technical support, including MAX804TCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX804TCSA+ requirements.
6.How does Aetrix verify that MAX804TCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX804TCSA+ 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 MAX804TCSA+ meets industry standards.
7.What is the process for return or replacement of MAX804TCSA+?
All MAX804TCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX804TCSA+, 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 MAX804TCSA+ part is unused and in its original packaging.
Return procedure for MAX804TCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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