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Analog Devices Inc./Maxim Integrated MAX804REPA+
- Part No.:
- MAX804REPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX804REPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:224
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Product details
Overview
MAX804REPA+ 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, watchdog timer (1.6s), and battery-backup switchover-designed for reliable power monitoring in battery-powered embedded controllers and CMOS RAM retention systems.
For engineers reviewing the MAX804REPA+ datasheet, MAX804REPA+ pinout, MAX804REPA+ application, or MAX804REPA+ equivalent, this page delivers verified functional specifications, validated pin roles, confirmed operating conditions across -40°C to +85°C, and real-world substitution guidance for industrial and portable µP systems.
Technical Context
The MAX804REPA+ integrates a precision reset comparator with ±2% tolerance on the 2.625V threshold, a dedicated power-fail comparator (VPFT = 1.237V, ±10mV hysteresis), and a non-disableable watchdog timer that triggers reset upon 1.6s WDI inactivity. Its dual-supply architecture enables seamless VCC-to-VBATT switchover at VSW = 2.40V (typ) while supporting VBATT > VCC operation.
It features an open-drain active-high RESET output requiring external pull-up, a manual reset input (MR) with internal 70µA pull-up, and guaranteed RESET assertion down to VCC = 1V. The device operates from 2.72V to 5.5V VCC and supports battery backup with <1µA VBATT supply current in standby.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V (VCC falling), ±2% tolerance - ensures reliable brownout detection for 3.0V ±10% supplies before data corruption occurs. |
| Reset Timeout Period | 200ms (typ), 140–280ms range - provides sufficient deassertion delay for µP power stabilization after VCC recovery. |
| Watchdog Timeout | 1.6s (typ), 1.12–2.24s range - detects µP lockup without requiring software intervention or external timing components. |
| VCC Supply Current | 40–50µA (VCC < 3.6V), 50–65µA (VCC < 5.5V) - enables ultra-low-power operation in always-on battery-backed systems. |
| VBATT Supply Current | 0.4–1µA (C/E grade) - minimizes battery drain during extended backup mode, extending lithium cell life beyond 10 years. |
| Battery Switch Threshold | VSW = 2.40V (typ), 25mV hysteresis - initiates switchover before VOUT drops below 2.0V, preserving CMOS RAM data integrity. |
| Power-Fail Input Threshold | VPFT = 1.237V ±10mV - supports accurate undervoltage detection of auxiliary rails via external resistor divider. |
Pinout & Package
MAX804REPA+ is supplied in an 8-pin plastic DIP (PDIP) package with lead-free finish (+ suffix), RoHS-compliant, and rated for -40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT; connects to VBATT (via 140Ω switch) when VCC < VSW, ensuring uninterrupted RAM power. |
| 2 - VCC | Main system supply input | Accepts 2.72V–5.5V; powers internal circuitry and sources VOUT when above reset threshold. |
| 3 - GND | Analog/digital ground reference | Common return path for all internal comparators, timers, and output drivers; must be low-impedance. |
| 4 - PFI | Power-fail comparator input | Monitors auxiliary voltage via external divider; asserts PFO low when input falls below 1.237V. |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating PFI undervoltage or VCC < VSW; can drive MR on compatible devices (e.g., MAX704). |
| 6 - WDI | Watchdog timer input | Rising/falling edge clears 1.6s timer; static high/low for >1.6s triggers reset - no disable option. |
| 7 - RESET | Active-high open-drain reset output | Requires external pull-up to VCC; goes high-impedance when asserted low, enabling bidirectional µP reset I/O interfacing. |
| 8 - VBATT | Backup battery input | Supports voltages exceeding VCC (e.g., 3.6V Li-cell); powers VOUT during main supply failure. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset initiation even during deep brownout, preventing µP execution from corrupted memory. |
| ±2% reset threshold tolerance | Tighter than MAX690/MAX704 families - reduces false resets in noisy 3.0V systems with wide supply tolerances. |
| Battery switchover with 25mV hysteresis | Prevents oscillation during VCC recovery near VSW; maintains stable VOUT during transition. |
| 1.6s watchdog timeout with edge-triggered clear | Eliminates need for periodic software pulses - hardware-level lockup recovery independent of firmware state. |
| 0.4–1µA VBATT supply current | Enables decade-scale battery life in static RAM backup applications without compromising switchover speed. |
Applications
| Battery-Powered Embedded Controllers | Intelligent Portable Instruments |
|---|---|
Use Scenario: Industrial handheld meter with flash memory and SRAM retaining calibration data during battery swaps. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, watchdog supervision, and automatic VBATT switchover to preserve RAM contents. Use Value: Prevents data loss during hot battery replacement by asserting RESET only when VCC drops below 2.625V and switching VOUT to VBATT before VOUT falls below 2.0V. |
Use Scenario: Battery-operated medical sensor logging vital signs to local SRAM before wireless upload. IC Role / Device Role / Timing Role: Power monitor generating PFO interrupt on auxiliary sensor rail undervoltage and triggering watchdog reset if firmware hangs. Use Value: Enables early warning of power degradation via PFI/PFO while guaranteeing system recovery from lockup within 1.6s. |
| Critical µP Power Monitoring | Portable Computing Peripherals |
Use Scenario: USB-powered IoT gateway with ARM Cortex-M4, external SRAM, and Li-ion backup. IC Role / Device Role / Timing Role: Dual-role supervisor: RESET generator during AC adapter disconnect and watchdog enforcer for communication stack stability. Use Value: 200ms reset timeout ensures µP completes power-down sequence; open-drain RESET allows safe sharing with bidirectional µP reset pins. |
Use Scenario: Wireless barcode scanner with sleep/wake cycles and volatile configuration storage. IC Role / Device Role / Timing Role: Low-quiescent supervisor managing VCC/VBATT arbitration and issuing timed reset pulses on wake-up initialization failure. Use Value: 40µA VCC supply current extends battery runtime; MR input enables user-initiated reset without PCB layout changes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX804SEPA+ | 2.925V reset threshold (S-suffix), same package and pinout | Suitable for 3.3V ±10% systems where higher trip point prevents nuisance resets during nominal ripple | Select when system VCC nominal is 3.3V and brownout margin must exceed 2.925V. |
| MAX804TEPA+ | 3.075V reset threshold (T-suffix), identical timing and interface | Optimized for 3.3V systems with ±5% tolerance; tighter alignment with 3.3V rail regulation limits | Choose for new 3.3V designs requiring highest immunity to transient dips near 3.1V. |
Compared with MAX804SEPA+ and MAX804TEPA+, the MAX804REPA+ offers the lowest reset threshold (2.625V), making it uniquely suited for 3.0V systems or applications requiring maximum brownout depth tolerance before reset assertion-critical for legacy low-voltage µPs or marginal power designs.
Availability
MAX804REPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply across industrial temperature ranges.
Supply support for MAX804REPA+ 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, mixed-signal, and power management ICs for industrial, computing, and communications markets.
The MAX804 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power monitoring, watchdog supervision, and battery-backed RAM retention in portable and embedded 3.0V/3.3V systems.
FAQ
What is the reset threshold voltage of the MAX804REPA+?
The MAX804REPA+ has a nominal reset threshold of 2.625V (R-suffix), with ±2% tolerance over temperature. This value applies to VCC falling; the rising threshold is 2.635V (min) to 2.72V (max). It is optimized for 3.0V ±10% power supplies and guarantees reset assertion before VCC falls below 2.59V.
Does the MAX804REPA+ support battery backup with VBATT exceeding VCC?
Yes, the MAX804REPA+ explicitly supports VBATT > VCC operation-such as a 3.6V lithium coin cell with a 3.3V main supply. The internal battery switchover circuit activates when VCC falls below VSW = 2.40V (typ), connecting VBATT to VOUT through a 140Ω switch while isolating VCC.
Is the watchdog timer on the MAX804REPA+ disableable?
No, the watchdog timer on the MAX804REPA+ cannot be disabled. It times out after 1.6 seconds (typ) if the WDI pin remains static (high or low); the timer resets only on rising or falling edges. This design ensures continuous lockup protection without reliance on firmware configuration.
What is the function of the RESET pin on the MAX804REPA+?
The RESET pin on the MAX804REPA+ is an active-high, open-drain output. It requires an external pull-up resistor to VCC. During reset assertion, RESET is pulled low (sinking up to 1.2mA); otherwise, it presents high impedance. This allows safe interfacing with bidirectional µP reset I/O pins using a series resistor.
Can the MAX804REPA+ operate without a backup battery?
Yes, but VBATT and VOUT must both be connected to VCC if no battery is used. Leaving VBATT floating or unconnected may cause undefined behavior. For battery-less applications, alternatives like the MAX706R or MAX708R are also available-but the MAX804REPA+ remains functional with proper pin tying.
MAX804REPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX804REPA+ FAQ
1.How can I place an order for MAX804REPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX804REPA+ 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 MAX804REPA+ reliable?
The price and inventory of MAX804REPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX804REPA+ is usually 5 days.
3.What payment methods are accepted for MAX804REPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX804REPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX804REPA+?
MAX804REPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX804REPA+ 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 MAX804REPA+?
For technical support, including MAX804REPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX804REPA+ requirements.
6.How does Aetrix verify that MAX804REPA+ is sourced from the original manufacturer or authorized distributors?
All MAX804REPA+ 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 MAX804REPA+ meets industry standards.
7.What is the process for return or replacement of MAX804REPA+?
All MAX804REPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX804REPA+, 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 MAX804REPA+ part is unused and in its original packaging.
Return procedure for MAX804REPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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