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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 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:280
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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, 2.925V reset threshold (S-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover. It monitors VCC supply integrity, asserts reset during power-up/brownout/watchdog timeout, and switches CMOS RAM to VBATT when VCC drops below 2.40V - used in embedded controllers and portable equipment requiring reliable power sequencing.
For engineers reviewing the MAX704SCSA+ datasheet, MAX704SCSA+ pinout, MAX704SCSA+ application, or MAX704SCSA+ equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, ±4% reset threshold accuracy, 40µA VCC supply current, and compatibility with lithium backup batteries exceeding VCC voltage.
Technical Context
The MAX704SCSA+ integrates a precision reset comparator with 2.925V nominal threshold (±4%), a 200ms internal reset timeout timer, and a non-disableable 1.6s watchdog timer cleared by WDI transitions. Its battery switchover circuit uses a PMOS switch (3Ω on-resistance from VCC-to-VOUT) and a 140Ω VBATT-to-VOUT switch, activated when VCC falls below VSW = 2.40V while VBATT > VCC.
It features dual-supply monitoring: VCC powers the core logic and RESET generation, while VBATT supplies VOUT during brownout. The PFI input enables external power-fail detection with 1.237V threshold and 10mV hysteresis, and MR provides manual reset with 70µA internal pull-up and 200ms deassertion delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (nominal), ±4% tolerance - ensures reset assertion before VCC drops below 2.85V in 3.3V ±10% systems |
| Reset Timeout Period | 200ms (typical) - guarantees minimum reset pulse width for reliable µP initialization after power-up or brownout |
| VCC Supply Current | 40µA (typical, VCC < 3.6V) - enables ultra-low-power operation in battery-backed embedded systems |
| Watchdog Timeout | 1.6s (typical) - detects µP lockup without requiring software intervention or external timing components |
| Battery Switch Threshold | VSW = 2.40V (typical) - triggers switchover to VBATT before VOUT falls below 2.0V, preserving CMOS RAM data |
| PFO Input Threshold | 1.237V (typical), ±25mV - supports accurate external undervoltage detection via resistor divider on PFI |
| Operating Temperature | -40°C to +85°C - qualified for industrial-grade embedded controller and portable equipment environments |
Pinout & Package
MAX704SCSA+ is housed in an 8-pin SOIC package (SO) with gull-wing leads, RoHS-compliant (indicated by '+' suffix), footprint compatible with standard 8-SO land pattern 90-0096.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch); must be decoupled with 0.1µF capacitor |
| 2 - VCC | Main supply input | Accepts 3.02V–5.5V; powers internal logic and RESET generator; absolute max = +6.0V |
| 3 - GND | Ground reference | Common return for VCC, VBATT, and all I/O; requires low-inductance connection to system ground plane |
| 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; can be tied to MR on MAX704 to trigger reset on external supply failure |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; cannot be disabled; 0.3×VCC/0.7×VCC logic thresholds |
| 7 - RESET | Active-low reset output | Pulled low during power-up, brownout, or watchdog timeout; remains low ≥200ms after recovery |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; may exceed VCC; connects to VOUT during brownout; leakage <1µA at -40°C to +85°C |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for retaining µP state in low-voltage conditions |
| Battery-backup switchover with VBATT > VCC support | Enables use of standard 3.6V lithium coin cells without level-shifting; eliminates need for external diode OR-ing |
| 200ms reset time delay with internal timer | Removes requirement for external RC timing network, reducing BOM count and layout complexity |
| 1.6s watchdog timeout with edge-triggered clear | Prevents spurious resets from noise; allows µP to service watchdog with minimal GPIO overhead |
| 40µA VCC supply current (typical) | Extends battery life in always-on portable instrumentation; 25× lower than discrete supervisor solutions |
| ±4% reset threshold accuracy | Meets tight margin requirements for 3.3V ±10% systems without calibration or trimming components |
Applications
| Battery-Powered Embedded Controller | Portable Medical Instrument |
|---|---|
Use Scenario: A handheld glucose meter operates from a single 3.3V Li-ion cell and retains calibration data in battery-backed SRAM during sleep mode. IC Role / Device Role / Timing Role: MAX704SCSA+ monitors VCC for brownout, asserts RESET to halt µP execution, and switches VOUT to VBATT to preserve SRAM contents when VCC drops below 2.40V. Use Value: Prevents data corruption during battery discharge; eliminates need for external switchover MOSFET and timing resistors. |
Use Scenario: A portable ECG monitor uses a 3.0V supply and requires guaranteed reset during power-up and low-battery warning before shutdown. IC Role / Device Role / Timing Role: MAX704SCSA+ generates 200ms reset pulse at power-on, monitors VCC with 2.925V threshold, and uses PFI/PFO to signal low-battery condition to µP via interrupt. Use Value: Ensures deterministic boot sequence and early warning of end-of-life battery voltage (e.g., <2.85V). |
| Industrial PLC Remote I/O Module | Smart Sensor Node with SuperCap Backup |
Use Scenario: A DIN-rail mounted I/O module powered from 3.3V DC supply must survive brief AC line sags without losing communication state. IC Role / Device Role / Timing Role: MAX704SCSA+ detects VCC sag below 2.925V, holds µP in reset for 200ms, and activates watchdog to recover from firmware hangs caused by transient noise. Use Value: Maintains operational continuity during 10–50ms grid disturbances; reduces field failure rate due to unhandled brownouts. |
Use Scenario: A wireless temperature sensor node uses a 3.3V supply and 0.47F SuperCap for backup during mains outage. IC Role / Device Role / Timing Role: MAX704SCSA+ connects SuperCap to VOUT when VCC falls, leveraging VBATT > VCC capability; WDI monitors µP heartbeat to prevent false resets during cap recharge. Use Value: Enables >24-hour backup without battery replacement; avoids diode voltage drop losses in traditional backup architectures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706SCSA+ | No watchdog timer; only RESET and PFI/PFO functions; same 2.925V threshold and 200ms timeout | Suitable where watchdog functionality is unnecessary or implemented in firmware | Select MAX706SCSA+ to reduce cost and complexity when system-level watchdog is available |
| MAX803SCSA+ | Single-function reset IC: no WDI, no PFI/PFO, no battery switchover; 2.93V threshold, 240ms timeout | Targeted at basic reset-only applications with no backup power or power-fail monitoring needs | Choose MAX803SCSA+ only if battery backup, watchdog, and power-fail alert are not required |
Compared with MAX704SCSA+, MAX706SCSA+ removes watchdog capability but retains identical reset behavior and battery switchover, while MAX803SCSA+ sacrifices all auxiliary functions for lowest possible BOM cost and footprint - making MAX704SCSA+ the optimal choice when integrated supervision with backup power management is essential.
Availability
MAX704SCSA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instruments requiring stable component supply and long-term industrial lifecycle support.
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 high-performance analog and mixed-signal semiconductor solutions for industrial, communications, computing, and consumer markets.
The MAX704 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power-monitoring and battery-backup control in 3.0V/3.3V embedded systems with stringent reliability requirements.
FAQ
What is the reset threshold voltage of the MAX704SCSA+?
The MAX704SCSA+ has a nominal reset threshold voltage of 2.925V with ±4% tolerance over temperature. This value is specified for VCC falling conditions and ensures reset assertion before VCC drops below 2.85V in 3.3V ±10% systems. The S-suffix explicitly denotes this 2.925V variant, distinct from T (3.075V) and R (2.625V) versions.
Does the MAX704SCSA+ support battery voltages higher than VCC?
Yes, the MAX704SCSA+ supports VBATT exceeding VCC - a key design feature enabling direct connection of standard 3.6V lithium coin cells without external level-shifting. The internal battery switchover circuit activates when VCC falls below VSW = 2.40V (typical) and VBATT > VCC, connecting VBATT to VOUT through a 140Ω switch.
Can the watchdog timer in the MAX704SCSA+ be disabled?
No, the watchdog timer in the MAX704SCSA+ cannot be disabled. It is a fixed-function 1.6s timeout circuit that clears only upon detection of a rising or falling edge on the WDI pin or during active RESET assertion. This hardwired behavior ensures fail-safe operation even if firmware fails to initialize or configure the watchdog.
What is the maximum continuous VCC supply current for the MAX704SCSA+?
The MAX704SCSA+ draws a typical VCC supply current of 40µA when VCC < 3.6V and MR = VCC, with a maximum of 65µA across full temperature range. This ultra-low quiescent current is critical for extending battery life in portable and remote sensing applications where the device remains powered continuously.
How does the MAX704SCSA+ handle manual reset input (MR)?
The MAX704SCSA+ features an active-low MR input with 70µA internal pull-up current. A logic-low pulse on MR asserts RESET for the duration of the low signal plus 200ms after MR returns high. MR accepts TTL/CMOS logic levels and can be driven directly by a microcontroller GPIO or momentary switch to ground - no external pull-up or debounce circuitry required.
MAX704SCSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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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