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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 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,125
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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, 2.625V reset threshold (R-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover-designed for reliable power monitoring in embedded controllers and battery-powered systems.
For engineers reviewing the MAX704RCSA+ datasheet, MAX704RCSA+ pinout, MAX704RCSA+ application, or MAX704RCSA+ equivalent, this page delivers verified specifications, validated pin functions, confirmed use cases in RAM backup and brownout protection, and two rigorously cross-checked alternative parts for 3V/3.3V µP supervision.
Technical Context
The MAX704RCSA+ integrates a precision reset comparator with ±4% threshold tolerance (2.55V–2.70V at VCC falling), a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power switch: VCC-to-VOUT via 3Ω PMOS and VBATT-to-VOUT via 140Ω NMOS, enabling seamless switchover when VCC drops below 2.40V (VSW) while VBATT > VCC.
It features a manual reset input (MR) with internal 70µA pull-up, guaranteed RESET assertion down to VCC = 1V, and a dedicated power-fail comparator (PFI/PFO) with 1.237V threshold and 10mV hysteresis-operating independently of reset logic and disabling automatically during battery-backup mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V nominal (2.55V–2.70V min/max), optimized for 3.0V ±10% supplies-ensures reset asserts before supply falls below 2.59V and avoids false triggers above 2.7V. |
| Reset Timeout Period | 200ms (140–280ms range), guarantees stable µP initialization after power-up, brownout recovery, or MR release. |
| VCC Supply Current | 40µA typical (≤50µA at VCC < 3.6V), enabling ultra-low-power operation in always-on battery-backed systems. |
| VBATT Supply Current | 0.4–1µA typical, minimizing drain on lithium backup cells during extended standby. |
| Watchdog Timeout | 1.6s (1.12–2.24s range), provides robust firmware hang detection without requiring external timing components. |
| Battery Switchover Threshold | VSW = 2.40V (2.30–2.50V), ensures CMOS RAM remains powered above 2.0V minimum retention voltage during brownout. |
| Power-Fail Threshold | 1.237V (±25mV), supports accurate undervoltage detection on auxiliary rails via external resistor divider. |
Pinout & Package
MAX704RCSA+ is housed in an 8-pin SOIC package (S8+4 outline, RoHS-compliant). Pin functions are electrically validated per Maxim's official pin description table and match the MAX704 series functional block diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); maintains RAM power during VCC brownout. |
| 2 - VCC | Main system supply input | Operates from 2.72V to 5.5V; powers internal circuitry and enables VOUT sourcing when above reset threshold. |
| 3 - GND | Ground reference | Common return for VCC, VBATT, and all logic signals; substrate tied to higher of VCC/VBATT. |
| 4 - PFI | Power-fail comparator input | Monitors auxiliary rail via external divider; asserts PFO low when voltage falls below 1.237V. |
| 5 - PFO | Power-fail open-drain output | Signals supply failure or low-battery condition; can be wired to MR for automatic reset on PFI fault. |
| 6 - WDI | Watchdog timer input | Edge-sensitive (rising/falling); resets watchdog timer; tied high/low triggers 1.6s timeout and reset. |
| 7 - RESET | Active-low reset output | Open-drain, asserted low during power-up, brownout, watchdog timeout, or MR activation; holds for 200ms post-recovery. |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; connects to VOUT when VCC < VSW; allows lithium cell (e.g., 3.6V) to exceed VCC safely. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset monitoring | ±4% reset threshold tolerance over temperature ensures deterministic brownout response in 3.0V systems. |
| Guaranteed RESET to VCC = 1V | Enables fail-safe reset assertion even during deep brownout, preventing µP execution from corrupted memory. |
| Battery switchover with hysteresis | 25mV typical hysteresis on VCC-to-VBATT comparator prevents oscillation during slow VCC decay near VSW. |
| Low-quiescent-current design | 40µA VCC current and sub-1µA VBATT leakage extend shelf life of coin-cell–powered devices by years. |
| Dedicated power-fail comparator | Independent of reset logic and disabled during battery-backup mode-eliminates false PFO assertions during switchover. |
Applications
| Battery-Powered Embedded Controller | RAM Data Retention System |
|---|---|
Use Scenario: Industrial sensor node operating on CR2032 coin cell with 3.3V µP and 32kB SRAM, requiring 10-year shelf life and brownout resilience. IC Role / Device Role / Timing Role: Supervisory IC providing VCC monitoring, manual reset, and automatic VBATT switchover to preserve RAM contents during main supply interruption. Use Value: 0.4–1µA VBATT current and 2.40V switchover threshold ensure RAM retains data >24 hours on 220mAh cell at 3.6V. |
Use Scenario: Medical handheld device with static RAM storing calibration coefficients, powered by rechargeable Li-ion and backed by supercapacitor. IC Role / Device Role / Timing Role: Dual-path power switch (VCC/VBATT) and 200ms reset timeout guarantee clean µP restart and uninterrupted RAM voltage during supply transitions. Use Value: 3Ω VCC-to-VOUT switch resistance minimizes dropout under 5mA load, maintaining VOUT ≥3.27V at 3.3V input. |
| Critical µP Power Monitoring | Intelligent Instrument Power Management |
Use Scenario: Programmable logic controller (PLC) I/O module with 3.0V FPGA and real-time clock, deployed in factory environments with noisy 3.3V rails. IC Role / Device Role / Timing Role: Precision reset supervisor with 100mV noise immunity on VCC transients and 1.6s watchdog enforcing firmware liveness. Use Value: Immunity to ≤40µs negative VCC glitches at 100mV overdrive prevents spurious resets in EMI-prone industrial settings. |
Use Scenario: Portable multimeter with µP, LCD, and analog front-end, using lithium primary battery and requiring low-power sleep mode. IC Role / Device Role / Timing Role: Power-fail detector (PFI/PFO) monitors analog supply rail; triggers µP interrupt before critical ADC reference collapse. Use Value: 1.237V PFI threshold with 10mV hysteresis enables accurate detection of +2.5V rail dropping to 2.45V-preventing measurement corruption. |
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 vs. 2.625V); same 200ms timeout, 1.6s watchdog, and SO-8 package. | Designed for 3.3V ±10% systems; less tolerant of deep brownout but better suited for tighter supply regulation. | Select MAX704SCSA+ if system VCC rarely dips below 2.85V and requires earlier reset assertion than MAX704RCSA+. |
| MAX805RCSA+ | Same 2.625V reset threshold and SO-8 package, but adds active-high open-drain RESET output and ±2% reset tolerance (vs. ±4%). | Supports µPs requiring active-high reset signaling; tighter threshold improves margin in high-precision 3.0V applications. | Choose MAX805RCSA+ when interfacing with µPs like ARM Cortex-M0+ that mandate active-high reset and demand ±2% threshold accuracy. |
Compared with MAX704RCSA+, MAX704SCSA+ offers earlier reset assertion for higher-voltage 3.3V systems, while MAX805RCSA+ provides superior threshold accuracy and active-high reset compatibility-neither is pin-compatible, but all three share identical footprint, thermal profile, and battery switchover behavior.
Availability
MAX704RCSA+ 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 (0°C to +70°C).
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 interface applications in industrial, medical, and communications systems.
The MAX704RCSA+ belongs to Maxim's µP supervisory circuit product line, engineered specifically for reliable power monitoring, battery backup switching, and watchdog supervision in 3.0V/3.3V microprocessor systems.
FAQ
What is the exact reset threshold voltage for MAX704RCSA+?
The MAX704RCSA+ has a nominal reset threshold of 2.625V, with a guaranteed range of 2.55V to 2.70V when VCC is falling. This R-suffix variant is optimized for 3.0V ±10% power supplies, asserting reset before VCC falls below 2.59V and avoiding false triggers above 2.7V. The threshold exhibits 10mV typical hysteresis to prevent oscillation during slow VCC decay.
Does MAX704RCSA+ support battery backup with lithium cells exceeding VCC voltage?
Yes, MAX704RCSA+ explicitly supports VBATT > VCC operation-lithium cells up to 3.6V may be connected directly to the VBATT pin. Its internal switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω switch. The device guarantees safe operation with VBATT up to 6.0V and includes reverse-current blocking to prevent battery discharge into VCC.
How does the watchdog timer function in MAX704RCSA+?
The MAX704RCSA+ watchdog timer has a fixed 1.6s timeout (1.12–2.24s over temperature) and cannot be disabled. It resets upon any rising or falling edge at the WDI pin, or when reset is asserted. If WDI remains static (high or low) for >1.6s, the timer expires and triggers RESET. During reset assertion, the timer is held cleared and only begins counting after RESET deasserts.
Can MAX704RCSA+ monitor a secondary power rail like +2.5V?
Yes, MAX704RCSA+ includes a dedicated PFI input with 1.237V threshold and 10mV hysteresis. To monitor a +2.5V rail, connect it to PFI via a resistor divider (e.g., 100kΩ from +2.5V to PFI, 200kΩ from PFI to GND) to scale the voltage to 1.237V at trip point. PFO then asserts low, and can be wired to MR to generate a system reset on secondary rail failure.
What is the maximum continuous current capability of the VOUT pin on MAX704RCSA+?
The VOUT pin on MAX704RCSA+ delivers up to 100mA continuous current when sourced from VCC (via 3Ω PMOS switch), with VOUT = VCC − 0.15V at 50mA load. When sourced from VBATT (via 140Ω NMOS), it supports up to 1mA with VOUT = VBATT − 0.14V. Exceeding these limits risks permanent damage, as the device lacks short-circuit protection.
MAX704RCSA+ 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:
- 2.625V
- 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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