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Analog Devices Inc./Maxim Integrated MAX704SCSA
- Part No.:
- MAX704SCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704SCSA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:1,331
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Product details
Overview
MAX704SCSA from Maxim Integrated is a 3.3V/3.0V microprocessor supervisory circuit with active-low RESET output, manual reset input (MR), watchdog timer (1.6s timeout), precision voltage monitoring (2.925V reset threshold), and battery-backup switchover-designed for embedded controllers and battery-powered systems requiring reliable power-up/down sequencing and brownout protection.
For engineers reviewing the MAX704SCSA datasheet, MAX704SCSA pinout, MAX704SCSA application, or MAX704SCSA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in RAM backup and power-fail warning, and validated alternative parts with documented functional differences.
Technical Context
The MAX704SCSA integrates a precision reset comparator with ±4% threshold tolerance (2.925V nominal), a 200ms reset timeout timer, and a non-disableable watchdog circuit triggered by WDI inactivity exceeding 1.6s. Its battery switchover logic activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT via a 140Ω internal switch while isolating VCC.
It features dual supply monitoring: VCC supervision for µP reset assertion down to 1V, and independent PFI/PFO comparator (1.237V threshold, ±20mV hysteresis) for external power-fail detection. The MR input includes a 70µA internal pull-up and guarantees reset assertion for ≥100ns low pulses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (±4%) - ensures reset assertion before 3.3V supply drops below system-safe 2.85V margin |
| Reset Timeout Period | 200ms (140–280ms over temp) - provides sufficient hold time for µP initialization after power stabilization |
| Watchdog Timeout | 1.6s (1.12–2.24s over temp) - detects µP lockup without requiring software intervention |
| VCC Supply Current | 40µA (typ) at VCC < 3.6V - enables ultra-low-power operation in battery-backed standby mode |
| Battery Supply Current | 0.4–1µA - minimizes drain on lithium backup cells during extended offline periods |
| VBATT-to-VOUT On-Resistance | 140Ω (typ) - limits voltage drop during RAM backup, supporting >2.0V retention under load |
| Power-Fail Input Threshold | 1.237V (±20mV hysteresis) - allows accurate monitoring of auxiliary rails via external resistor divider |
Pinout & Package
MAX704SCSA is housed in an 8-pin SOIC package (SO) with gull-wing leads, RoHS-compliant, 3.9mm × 4.9mm body, 1.27mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT based on VSW; connects to RAM VDD to maintain data during brownout |
| 2 - VCC | Main system supply input | Primary 3.0V/3.3V power rail input; powers internal circuitry and sources VOUT when above VSW |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT |
| 4 - PFI | Power-fail comparator input | Accepts divided-down voltage from auxiliary rail; triggers PFO low when input falls below 1.237V |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating undervoltage condition on PFI or VCC falling below VSW |
| 6 - WDI | Watchdog timer input | Rising/falling edge clears 1.6s timer; static high/low for >1.6s forces reset assertion |
| 7 - RESET | Active-low reset output | Open-drain output asserted low during power-up, brownout, MR activation, or watchdog timeout |
| 8 - VBATT | Backup battery input | Accepts 2.0–6.0V lithium cell; powers VOUT when VCC drops below VSW (2.40V) or 1.75V |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | 2.925V ±4% - matches 3.3V ±10% supply tolerance, preventing spurious resets during normal ripple |
| Guaranteed RESET assertion to VCC = 1V | Ensures µP remains held in reset even during deep brownout, avoiding undefined execution |
| Battery switchover with 2.40V VSW | Activates backup before VOUT drops below 2.0V RAM retention threshold, maximizing data integrity |
| 200ms reset timeout with restart-on-brownout | Each VCC dip below VRST restarts timer - prevents premature release during unstable power recovery |
| 1.6s watchdog with edge-triggered clear | Eliminates need for dedicated watchdog clock; toggling WDI from µP GPIO suffices for supervision |
Applications
| Battery-Powered Embedded Controller | RAM Data Retention System |
|---|---|
Use Scenario: Portable industrial controller operating on lithium coin cell with intermittent 3.3V main supply. IC Role / Device Role / Timing Role: Supervises VCC for safe boot/reset, switches RAM to VBATT during mains loss, asserts RESET until stable VCC returns. Use Value: Prevents firmware corruption during power transitions and preserves configuration memory for >10 years on 220mAh cell. |
Use Scenario: CMOS SRAM module in medical diagnostic device requiring zero-data-loss during AC outage. IC Role / Device Role / Timing Role: Monitors VCC, initiates switchover at 2.40V, maintains VOUT ≥2.0V via 140Ω switch, holds RESET until VCC recovers above 2.925V. Use Value: Guarantees RAM retention across 200ms+ outages without external LDO or diode-OR circuitry. |
| Power-Fail Warning System | Watchdog-Protected µP Platform |
Use Scenario: Smart meter detecting AC line sag before complete failure using auxiliary 5V rail. IC Role / Device Role / Timing Role: PFI monitors divided 5V rail; PFO pulls MR low to trigger controlled shutdown sequence upon undervoltage. Use Value: Enables 50ms early-warning interrupt before VCC collapse, allowing EEPROM save and graceful halt. |
Use Scenario: Automotive body control module where µP must recover autonomously after EMI-induced lockup. IC Role / Device Role / Timing Role: WDI connected to µP GPIO; missing edge within 1.6s forces hardware RESET, bypassing frozen firmware. Use Value: Eliminates need for external watchdog IC or complex software timers; meets ISO 26262 ASIL-B fault coverage requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TCSA | Reset threshold 3.075V (±4%), higher trip point for tighter 3.3V ±5% supplies | Suitable for systems where brownout must be detected earlier, e.g., high-speed µP with narrow VCC margin | Select when design requires reset assertion above 2.925V to accommodate lower noise immunity or stricter supply regulation |
| MAX706SCSA | No watchdog timer; no WDI pin; adds PFI hysteresis option and improved PFO drive strength | Used where only reset + power-fail warning is needed, and watchdog supervision is handled externally or in firmware | Choose when reducing BOM count is critical and µP-level watchdog is already implemented, eliminating redundant timing logic |
Compared with MAX704SCSA, MAX704TCSA offers earlier reset assertion for tighter supply tolerances, while MAX706SCSA removes watchdog functionality to simplify design where software-based supervision suffices-both share identical SO-8 packaging and battery switchover capability.
Availability
MAX704SCSA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instruments requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for MAX704SCSA 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 interface applications in industrial, automotive, and computing markets.
The MAX704 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power monitoring and fail-safe reset generation in 3.0V/3.3V µP systems with battery backup requirements.
FAQ
What is the exact reset threshold voltage of the MAX704SCSA?
The MAX704SCSA has a nominal reset threshold voltage of 2.925V, with a tolerance of ±4% over temperature (–40°C to +85°C). This value is specified for VCC falling conditions and ensures reset assertion before the 3.3V supply drops below 2.85V, aligning with typical 3.3V ±10% system requirements. The rising threshold is 2.935V (min) to 3.02V (max), incorporating 10mV hysteresis to prevent oscillation.
Does the MAX704SCSA support battery voltage higher than VCC?
Yes, the MAX704SCSA explicitly supports VBATT exceeding VCC during normal operation. Its battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω internal switch. This design accommodates standard 3.6V lithium cells used in backup applications, and the device remains functional with VBATT up to 6.0V regardless of VCC level.
How does the watchdog timer in the MAX704SCSA operate?
The MAX704SCSA watchdog timer has a fixed 1.6s timeout period and cannot be disabled. It clears on any rising or falling edge at the WDI pin and triggers RESET if WDI remains static (high or low) for longer than 1.6s. During RESET assertion, the timer is held cleared; it resumes counting only after RESET deasserts. This behavior ensures automatic recovery from µP lockup without software dependency.
Can the MAX704SCSA be used without a backup battery?
Yes, the MAX704SCSA can operate without a backup battery: connect both VBATT and VOUT pins directly to VCC. In this configuration, the battery switchover function is disabled, but all other features-including RESET generation, manual reset (MR), watchdog (WDI), and power-fail detection (PFI/PFO)-remain fully functional. No external components are required for basic supervision.
What is the maximum allowable VCC transient duration that will not trigger reset on the MAX704SCSA?
According to the MAX704SCSA datasheet, a negative-going VCC transient will not cause a reset pulse if its duration is within the limit defined by reset-comparator overdrive. For example, a 100mV overdrive (i.e., VCC dropping 100mV below the 2.925V threshold) allows transients up to ~40µs without triggering reset. This immunity is enhanced by a 0.1µF bypass capacitor placed near the VCC pin, which suppresses short-duration glitches.
MAX704SCSA 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:
- 2.925V
- 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
MAX704SCSA FAQ
1.How can I place an order for MAX704SCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704SCSA 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 MAX704SCSA reliable?
The price and inventory of MAX704SCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704SCSA is usually 5 days.
3.What payment methods are accepted for MAX704SCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704SCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704SCSA?
MAX704SCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704SCSA 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 MAX704SCSA?
For technical support, including MAX704SCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704SCSA requirements.
6.How does Aetrix verify that MAX704SCSA is sourced from the original manufacturer or authorized distributors?
All MAX704SCSA 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 MAX704SCSA meets industry standards.
7.What is the process for return or replacement of MAX704SCSA?
All MAX704SCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX704SCSA, 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 MAX704SCSA part is unused and in its original packaging.
Return procedure for MAX704SCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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