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Analog Devices Inc./Maxim Integrated MAX704RCSA
- Part No.:
- MAX704RCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704RCSA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:160
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Product details
Overview
MAX704RCSA from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-low RESET output, manual reset input (MR), watchdog timer (1.6s timeout), precision voltage monitor (2.625V reset threshold), and battery-backup switchover capability. It ensures reliable power-up, brownout, and watchdog-initiated reset for embedded controllers and battery-powered systems.
For engineers reviewing the MAX704RCSA datasheet, MAX704RCSA pinout, MAX704RCSA application, or MAX704RCSA equivalent, this device delivers guaranteed RESET assertion down to VCC = 1V, 200ms reset timeout, ±4% reset threshold accuracy, low 40µA VCC supply current, and integrated power-fail warning via PFI/PFO - critical for robust µP system initialization and data retention.
Technical Context
The MAX704RCSA integrates a precision reset comparator with 2.625V nominal threshold (±4% tolerance), a 1.6s watchdog timer that clears on WDI edge transitions, and a bidirectional battery switchover circuit enabling VBATT > VCC operation. Its internal 70µA MR pull-up eliminates external components for manual reset.
It features dual independent comparators: one for reset (VCC vs. VRST) and one for power-fail detection (PFI vs. 1.237V reference), each with 10mV typical hysteresis. The RESET output remains asserted during VCC < VRST, MR low, or watchdog timeout - with 200ms deassertion delay after recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V (nominal), ±4% tolerance - sets precise brownout detection point for 3.0V systems with ±10% supply tolerance. |
| Reset Timeout Period | 200ms (typical) - guarantees minimum reset pulse width for reliable µP initialization after power-up or fault recovery. |
| VCC Supply Current | 40µA (typical, VCC < 3.6V) - enables ultra-low-power operation in battery-backed embedded systems. |
| Watchdog Timeout | 1.6s (typical) - provides fail-safe recovery window for µP firmware hangs without requiring external timing components. |
| Battery Switch Threshold | VSW = 2.40V (typical) - triggers automatic switchover from VCC to VBATT before CMOS RAM voltage drops below 2.0V retention level. |
| PFO Input Threshold | 1.237V (typical) - enables accurate power-fail or low-battery warning using external resistor divider on PFI pin. |
| Operating Voltage Range | VCC = 2.72V to 5.5V - supports wide input range while maintaining supervision functionality down to brownout conditions. |
Pinout & Package
MAX704RCSA is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package with standard 1.27mm pitch, RoHS-compliant lead-free finish (indicated by '+' suffix in ordering code).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC and VBATT based on voltage thresholds; connects to VCC if no battery used. |
| 2 - VCC | Main power supply input | Primary 3.0V/3.3V system supply; powers internal circuitry and defines reset comparator reference. |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT. |
| 4 - PFI | Power-fail input | Monitors external supply via resistor divider; asserts PFO low when voltage falls below 1.237V. |
| 5 - PFO | Power-fail output | Open-drain active-low signal indicating undervoltage condition on PFI or VCC falling below VSW. |
| 6 - WDI | Watchdog input | Edge-sensitive input; clearing 1.6s timer on rising/falling transition prevents unwanted reset assertion. |
| 7 - RESET | Active-low reset output | Drives µP reset pin low during power-up, brownout, MR assertion, or watchdog timeout; guaranteed valid to VCC = 1V. |
| 8 - VBATT | Backup battery input | Accepts lithium cell up to 6.0V; enables seamless RAM backup when VCC drops below 2.40V (VSW). |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic reset behavior even during deep brownout, preventing undefined µP state. |
| Battery can exceed VCC in normal operation | Allows use of standard 3.6V lithium coin cells without series diode or regulator, simplifying backup design. |
| 200ms reset time delay | Meets µP minimum reset pulse width requirements across temperature and voltage ranges. |
| 40µA VCC supply current | Minimizes quiescent power draw in always-on monitoring applications, extending battery life. |
| 1µA battery supply current | Reduces self-discharge of backup source, preserving RAM data for months during main power loss. |
| Watchdog timer with edge-triggered clear | Eliminates need for periodic software toggling; single WDI transition resets timer, supporting low-duty-cycle firmware. |
Applications
| Battery-Powered Embedded Controller | Critical µP Power Monitoring |
|---|---|
Use Scenario: Portable medical sensor with ARM Cortex-M0+ MCU and SRAM retaining calibration data during battery swaps. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, manual reset button interface, and automatic VBATT-to-VCC switchover for RAM retention. Use Value: Prevents data corruption during 3.0V supply sag below 2.625V and enables hot-swap battery replacement without system reset. |
Use Scenario: Industrial PLC module requiring guaranteed µP startup sequence and immunity to 40µs VCC glitches. IC Role / Device Role / Timing Role: Precision voltage monitor asserting RESET for ≥200ms until stable 3.3V rail is confirmed. Use Value: Eliminates need for discrete RC reset circuits; ±4% threshold accuracy ensures consistent trip point across temperature. |
| Intelligent Instrumentation | Portable Test Equipment |
Use Scenario: Handheld multimeter with EEPROM configuration storage and real-time clock powered by CR2032. IC Role / Device Role / Timing Role: Dual-function supervisor generating PFO interrupt on main supply droop and asserting RESET on VCC failure. Use Value: Enables graceful shutdown and clock backup via PFO-triggered firmware save before VBATT takeover. |
Use Scenario: Battery-operated oscilloscope front-end with FPGA configuration memory and analog front-end biasing. IC Role / Device Role / Timing Role: Watchdog-enabled supervisor detecting FPGA lockup and forcing hard reset via RESET line. Use Value: 1.6s watchdog timeout prevents hung state without requiring FPGA-side timer management logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SCSA | Higher reset threshold (2.925V) with same 8-SO package and pinout. | Suitable for 3.3V ±10% systems where brownout detection must occur above 2.85V. | Select when system supply tolerance requires earlier reset assertion than MAX704RCSA's 2.625V threshold. |
| MAX805RCSA | Tighter reset threshold tolerance (±2% vs. ±4%) and improved PFI accuracy (±2% vs. ±4%). | Better suited for high-precision power monitoring in automotive or industrial control where voltage drift must be minimized. | Choose when enhanced accuracy justifies cost premium and compatibility with existing MAX704RCSA layout is verified. |
Compared with MAX704RCSA, MAX704SCSA offers earlier reset activation for higher-voltage systems, while MAX805RCSA provides superior threshold stability at the expense of higher cost - both retain identical pinout and core functionality for drop-in evaluation.
Availability
MAX704RCSA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, and critical µP power monitoring applications requiring stable component supply and long-term lifecycle support.
Supply support for MAX704RCSA 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 power management, sensing, and connectivity in industrial, automotive, and computing applications.
The MAX704 family targets 3.0V/3.3V microprocessor systems needing integrated reset, watchdog, and battery switchover - optimized for reliability in portable and mission-critical embedded environments.
FAQ
What is the exact reset threshold voltage for MAX704RCSA?
The MAX704RCSA has a nominal reset threshold voltage of 2.625V, with a specified tolerance of ±4% over temperature and supply variations. This value applies to both rising and falling VCC transitions, though hysteresis ensures stable operation during voltage recovery. The threshold is factory-trimmed and guaranteed per datasheet Electrical Characteristics table.
Does MAX704RCSA support battery voltage higher than VCC?
Yes, MAX704RCSA explicitly supports VBATT exceeding VCC - a key feature enabling direct connection of standard 3.6V lithium batteries without diode drops or regulators. The internal battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT while isolating VCC, ensuring uninterrupted RAM power.
How does the watchdog timer in MAX704RCSA operate?
The MAX704RCSA watchdog timer has a fixed 1.6s timeout period and is cleared only by edges (rising or falling) on the WDI pin. Unlike some variants, it cannot be disabled. If WDI remains static beyond 1.6s, RESET is asserted for 200ms. The timer restarts immediately upon deassertion of RESET, ensuring continuous supervision of µP activity.
Can MAX704RCSA be used without a backup battery?
Yes, MAX704RCSA can operate without a backup battery: connect VBATT and VOUT directly to VCC. However, battery-switchover and PFO-based low-battery warning functions become inactive. For pure reset-only applications without backup needs, alternatives like MAX706RCSA may offer lower cost and reduced feature set.
What is the maximum allowable VCC transient duration that will not trigger reset in MAX704RCSA?
According to the MAX704RCSA datasheet Figure 7, a negative-going VCC transient of 100mV below the reset threshold (i.e., 2.525V for MAX704RCSA) will not cause reset assertion if its duration is ≤40µs. Immunity decreases as overdrive increases - e.g., a 200mV overdrive allows only ~10µs. A 100nF bypass capacitor near VCC improves noise rejection.
MAX704RCSA 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:
- Push-Pull, Totem Pole
- 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
MAX704RCSA FAQ
1.How can I place an order for MAX704RCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704RCSA 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 MAX704RCSA reliable?
The price and inventory of MAX704RCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704RCSA is usually 5 days.
3.What payment methods are accepted for MAX704RCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704RCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704RCSA?
MAX704RCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704RCSA 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 MAX704RCSA?
For technical support, including MAX704RCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704RCSA requirements.
6.How does Aetrix verify that MAX704RCSA is sourced from the original manufacturer or authorized distributors?
All MAX704RCSA 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 MAX704RCSA meets industry standards.
7.What is the process for return or replacement of MAX704RCSA?
All MAX704RCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX704RCSA, 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 MAX704RCSA part is unused and in its original packaging.
Return procedure for MAX704RCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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