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Analog Devices Inc./Maxim Integrated MAX704RCSA+T
- Part No.:
- MAX704RCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704RCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,029
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Product details
Overview
MAX704RCSA+T from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-low RESET output, 2.625V reset threshold (R-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover capability. It monitors VCC for brownout and power-fail conditions while supporting CMOS RAM backup via VOUT/VBATT switching in embedded controllers and portable equipment.
For engineers reviewing the MAX704RCSA+T datasheet, MAX704RCSA+T pinout, MAX704RCSA+T application, or MAX704RCSA+T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, ±4% reset threshold accuracy, 40µA VCC supply current, battery-switching hysteresis (25mV), and compatibility with lithium coin-cell backup sources.
Technical Context
The MAX704RCSA+T integrates a precision voltage monitor with 2.625V nominal reset threshold (VCC falling), 200ms internal reset timeout timer, and a non-disableable 1.6s watchdog timer cleared by WDI edges. Its battery switchover circuit uses a 140Ω VBATT-to-VOUT switch activated when VCC falls below 2.40V (VSW) and VBATT > VCC, ensuring reliable CMOS RAM retention during brownout.
It features dual-supply monitoring: PFI input compares against 1.237V reference for external power-fail detection, while RESET remains asserted until VCC exceeds the rising-threshold (2.635V) and the 200ms timer expires. The device operates across 0°C to +70°C and supports both leaded and RoHS-compliant packaging (indicated by '+' suffix).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VCC falling) | 2.55V to 2.70V (nominal 2.625V); ensures reset assertion before 3.0V supply drops below system minimum operating voltage |
| Reset Timeout Period | 140ms to 280ms (typical 200ms); guarantees sufficient hold time for µP initialization after power-up or brownout recovery |
| VCC Supply Current | 40µA typical (VCC < 3.6V); enables ultra-low-power operation in battery-backed portable systems |
| VBATT Supply Current | 0.4µA to 1µA; minimizes battery drain during long-term backup mode |
| Watchdog Timeout | 1.12s to 2.24s (typical 1.6s); provides robust software hang detection without requiring external timing components |
| Battery Switch Threshold (VSW) | 2.30V to 2.50V (typical 2.40V); initiates switchover to VBATT before VOUT drops below 2.0V required for CMOS RAM data retention |
| PFO Input Threshold | 1.187V to 1.287V (typical 1.237V); allows accurate external power-rail monitoring via resistor divider |
Pinout & Package
MAX704RCSA+T is housed in an 8-pin SOIC package (S8+4 outline, 21-0041), RoHS-compliant ('+' suffix), with 1.27mm pitch and surface-mount footprint (land pattern 90-0096). Pin functions are validated per Maxim's official pin description table and block diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Supply output for CMOS RAM | Switches between VCC and VBATT; connects to VCC when VCC > VSW, to VBATT when VCC < VSW and VBATT > VCC |
| VCC | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and defines reset comparator reference |
| GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT |
| PFI | Power-fail input | Monitors external rail via resistor divider; asserts PFO low when input falls below 1.237V |
| PFO | Power-fail output | Open-drain logic-low signal indicating PFI undervoltage or VCC < VSW; can drive MR on same-family parts |
| WDI | Watchdog input | Edge-sensitive input; clears 1.6s timer on rising/falling transitions; cannot be disabled |
| RESET | Active-low reset output | Guaranteed low for VCC < 2.625V; stays low 200ms after VCC rises above threshold or MR release |
| VBATT | Backup-battery input | Accepts up to 6.0V; enables seamless switchover to lithium cell (e.g., 3.6V) without diode drop |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for deterministic µP startup in low-voltage systems |
| 200ms reset timeout with hysteresis | Prevents oscillation during slow VCC ramp-up; eliminates need for external RC timing network |
| Battery switchover with 25mV hysteresis | Stabilizes VOUT during VCC transition near VSW, extending battery life and preventing RAM corruption |
| 40µA VCC supply current (typ) | Reduces quiescent load on primary supply, enabling longer runtime in always-on embedded applications |
| 1.6s watchdog timer with edge-triggered clear | Enables robust firmware supervision without dedicated clock source or configuration registers |
| 1.237V PFI reference with ±20mV tolerance | Supports accurate monitoring of auxiliary rails (e.g., 5V, -12V) using standard resistor dividers |
Applications
| Battery-Powered Portable Equipment | Embedded Controller Power Monitoring |
|---|---|
Use Scenario: Handheld medical devices requiring persistent RAM state across battery swaps and intermittent charging. IC Role / Device Role / Timing Role: Supervisory IC providing VCC brownout detection, manual reset, and automatic VBATT switchover to preserve SRAM contents. Use Value: Enables zero-data-loss hot-swap capability using a 3.6V lithium coin cell, with guaranteed RESET down to VCC = 1V during transition. |
Use Scenario: Industrial PLC modules operating from 3.3V SMPS with risk of line sags and transient overloads. IC Role / Device Role / Timing Role: Primary power supervisor asserting RESET during VCC dips below 2.625V and triggering watchdog reset if firmware hangs. Use Value: Prevents erratic behavior by enforcing 200ms minimum reset pulse and 1.6s software watchdog timeout. |
| Intelligent Instrumentation | Critical µP Power Monitoring |
Use Scenario: Precision test equipment with real-time clock and calibration memory powered by 3.0V rail. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main VCC for brownout and uses PFI to track auxiliary 5V analog supply via resistor divider. Use Value: Single-chip solution replaces discrete comparators and timers, reducing BOM count while maintaining ±4% reset accuracy. |
Use Scenario: Aerospace-grade avionics subsystem where µP must never execute invalid code due to marginal supply. IC Role / Device Role / Timing Role: Fail-safe reset generator with guaranteed assertion at VCC = 1V and 200ms timeout, independent of temperature or aging. Use Value: Meets DO-254 reliability requirements via internal hysteresis, no external components, and validated -40°C to +85°C operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SCSA+T | Higher reset threshold (2.925V vs. 2.625V); identical pinout, timing, and feature set | Suitable for 3.3V ±10% systems where brownout detection must occur later in VCC droop | Select when system requires earlier reset assertion during deeper voltage sags |
| MAX706RCSA+T | No watchdog timer; no manual reset (MR); PFI/PFO only; 2.63V reset threshold; 350ms timeout | Targeted at simpler systems needing only power-fail warning and reset, without software supervision | Choose for cost-sensitive designs where watchdog functionality is unnecessary |
Compared with MAX704RCSA+T, MAX704SCSA+T offers higher reset voltage for less aggressive brownout response, while MAX706RCSA+T removes watchdog and MR to reduce complexity and cost-making it suitable only for basic reset-and-warning applications.
Availability
MAX704RCSA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instrumentation requiring stable component supply across industrial temperature ranges and long-lifecycle programs.
Supply support for MAX704RCSA+T 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 ICs for power, sensing, and connectivity applications.
The MAX704RCSA+T belongs to Maxim's microprocessor supervisory family, engineered specifically for reliable power monitoring and battery backup in 3.0V/3.3V µP systems with stringent uptime and data-integrity requirements.
FAQ
What is the exact reset threshold voltage for MAX704RCSA+T?
The MAX704RCSA+T has a nominal reset threshold of 2.625V (R-suffix), with guaranteed range of 2.55V to 2.70V for VCC falling. This value is specified at temperature extremes and ensures reset assertion before a 3.0V supply drops below 2.59V, aligning with ±10% system tolerance requirements.
Does MAX704RCSA+T support battery backup with lithium cells exceeding VCC?
Yes, MAX704RCSA+T explicitly supports VBATT > VCC operation-lithium coin cells (e.g., 3.6V) may exceed the 3.0V/3.3V VCC rail. Its internal 140Ω VBATT-to-VOUT switch activates when VCC falls below 2.40V, ensuring seamless switchover without diode losses or external components.
Can the watchdog timer in MAX704RCSA+T be disabled?
No, the watchdog timer in MAX704RCSA+T cannot be disabled. It is a fixed-function 1.6s timeout (1.12s–2.24s range) cleared only by edges on the WDI pin or during RESET assertion. This design ensures continuous firmware supervision without configuration overhead or failure modes from accidental disablement.
What is the function of the PFI and PFO pins on MAX704RCSA+T?
PFI is a dedicated input compared to a 1.237V internal reference; when PFI falls below this threshold, PFO (an open-drain output) pulls low. This allows monitoring of auxiliary supplies (e.g., 5V, -12V) via resistor dividers. PFO can also be connected to MR on MAX704RCSA+T to trigger reset on external supply failure.
Is MAX704RCSA+T compatible with manual reset switches and TTL/CMOS logic?
Yes, MAX704RCSA+T's MR pin is an active-low input with a 70µA internal pull-up, allowing direct connection to TTL/CMOS outputs or a momentary switch to GND. Reset remains asserted for 200ms after MR returns high, eliminating need for external debounce circuitry in pushbutton implementations.
MAX704RCSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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+T FAQ
1.How can I place an order for MAX704RCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704RCSA+T 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+T reliable?
The price and inventory of MAX704RCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704RCSA+T is usually 5 days.
3.What payment methods are accepted for MAX704RCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704RCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704RCSA+T?
MAX704RCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704RCSA+T 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+T?
For technical support, including MAX704RCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704RCSA+T requirements.
6.How does Aetrix verify that MAX704RCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX704RCSA+T 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+T meets industry standards.
7.What is the process for return or replacement of MAX704RCSA+T?
All MAX704RCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX704RCSA+T, 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+T part is unused and in its original packaging.
Return procedure for MAX704RCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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