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Analog Devices Inc./Maxim Integrated MAX704CSA+
- Part No.:
- MAX704CSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704CSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:161
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Product details
Overview
MAX704CSA+ from Maxim Integrated is a microprocessor supervisory circuit designed for power-supply monitoring and battery-backup switching in +5V μP systems. It provides active-low reset assertion below 4.40V, battery switchover with 40mV hysteresis, 1.25V power-fail comparator input, and debounced manual reset - enabling reliable RAM retention during brownout in embedded controllers and intelligent instruments.
For engineers reviewing the MAX704CSA+ datasheet, MAX704CSA+ pinout, MAX704CSA+ application, or MAX704CSA+ equivalent, key selection criteria include its guaranteed RESET assertion down to VCC = 1V, 200ms reset pulse width, 50nA battery-backup quiescent current, and SO-8 package compatibility with industrial temperature range (0°C to +70°C).
Technical Context
The MAX704CSA+ integrates four core functions in a single SO-8 IC: precision supply-voltage monitoring (4.40V ±40mV hysteresis), battery-backed VOUT switching via p-channel MOSFETs (5Ω on-resistance in VCC mode, 80Ω in VBATT mode), a dedicated 1.25V reference-based power-fail comparator with PFI/PFO interface, and TTL/CMOS-compatible manual reset with internal 250µA pullup.
Its reset generator asserts RESET low during power-up, brownout, or power-down until VCC exceeds 4.40V and holds low for 200ms thereafter; in battery-backup mode, RESET remains low, VOUT connects to VBATT, and PFI/PFO are disabled - ensuring deterministic behavior during extended power loss.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±0.15V - guarantees reliable reset initiation before +5V supply dropout affects μP operation |
| Reset Pulse Width | 200ms typical - ensures μP completes full initialization before release from reset state |
| Supply Current (Active) | 200–350µA - enables low-power system monitoring without burdening main supply |
| Quiescent Current (Battery Mode) | 50nA - preserves lithium battery life for multi-year RAM backup in unpowered systems |
| VOUT Switch Resistance | 5Ω (VCC mode), 80Ω (VBATT mode) - minimizes voltage drop during switchover while limiting inrush |
| Power-Fail Comparator Threshold | 1.25V ±0.05V - supports accurate undervoltage detection of auxiliary supplies or unregulated rails |
| Operating Temperature Range | 0°C to +70°C - qualified for commercial-grade embedded instrumentation and controller applications |
Pinout & Package
MAX704CSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant with lead(Pb)-free finish (indicated by "+" suffix), footprint compatible with standard SOIC-8 land pattern 90-0096.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Switched Power Output | Connects to CMOS RAM VDD; sourced from VCC (via 5Ω switch) or VBATT (via 80Ω switch) depending on supply status |
| 2 - VCC | +5V Supply Input | Main system supply input; monitored for reset generation and used as substrate reference |
| 3 - GND | Ground Reference | Common return path for all internal circuits and external loads; substrate connection point |
| 4 - PFI | Power-Fail Input | Analog input compared to 1.25V reference; triggers PFO low when voltage falls below threshold |
| 5 - PFO | Power-Fail Output | Open-drain output asserting low on PFI undervoltage; disabled in battery-backup mode |
| 6 - MR | Manual Reset Input | Active-low TTL/CMOS-compatible input with 250µA internal pullup; debounced by 200ms reset timer |
| 7 - RESET | Reset Output | Active-low open-drain reset signal asserted during VCC brownout, power-up, or MR activation |
| 8 - VBATT | Battery Backup Input | Backup supply input; enables automatic switchover to preserve RAM when VCC drops below 4.40V |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.40V Reset Threshold | Guaranteed over 0°C to +70°C; enables robust brownout protection for +5V systems with ±10% tolerance |
| Automatic Battery Switchover | Seamless transition to VBATT with 40mV hysteresis prevents oscillation during slow VCC decay |
| 1.25V Precision Reference Comparator | Supports external undervoltage monitoring of non-+5V rails (e.g., unregulated DC, negative supplies) |
| 200ms Debounced Manual Reset | Eliminates need for external RC timing components; ensures clean reset pulse regardless of switch bounce |
| 50nA Battery-Backup Quiescent Current | Extends shelf life of 3V lithium coin cells beyond 10 years in standby RAM retention applications |
Applications
| Industrial Controller Monitoring | Embedded Instrument Power Management |
|---|---|
|
Use Scenario: Continuous operation of PLC I/O modules powered from switched-mode +5V supplies subject to line transients and brownouts. IC Role / Device Role / Timing Role: Supervisory circuit asserting RESET to halt processor execution and enable safe state capture before supply collapse. Use Value: Prevents corrupted firmware writes and data loss during unstable mains conditions using guaranteed 4.40V threshold and 200ms hold time. |
Use Scenario: Portable handheld test equipment requiring nonvolatile RAM retention during battery swaps or AC adapter disconnection. IC Role / Device Role / Timing Role: Battery switchover controller routing power from main supply to lithium backup cell without interrupting RAM VDD. Use Value: Achieves zero-interruption RAM backup with <50nA quiescent draw and 80Ω VBATT switch resistance. |
| Intelligent Power Metering | Critical μP Power Monitoring |
|
Use Scenario: Smart electricity meters monitoring utility voltage quality and logging outage events using on-chip RTC and SRAM. IC Role / Device Role / Timing Role: Dual-role supervisor providing both VCC brownout detection (RESET) and unregulated DC rail monitoring (PFI/PFO). Use Value: Enables early warning of impending supply failure via PFO interrupt while maintaining μP reset integrity. |
Use Scenario: Medical diagnostic equipment where unexpected reset must be avoided unless supply falls below safe operating margin. IC Role / Device Role / Timing Role: Primary power integrity monitor asserting RESET only when VCC drops below 4.40V, with validity guaranteed down to VCC = 1V. Use Value: Eliminates false resets during marginal supply conditions while ensuring fail-safe behavior at true under-voltage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX703CSA+ | 4.65V reset threshold (vs. 4.40V); identical pinout, timing, and feature set | Suitable for +5V systems with tighter supply tolerance (±5%) where earlier reset assertion is required | Select MAX703CSA+ when design uses regulated +5V ±5% supply and requires reset at higher voltage threshold |
| MAX708CSA+ | No battery backup; adds active-high RESET and BATT ON outputs; same 4.40V threshold | Used where RAM backup is handled externally or unnecessary, but high-assertion reset and battery-status signaling are needed | Choose MAX708CSA+ when battery switchover is not required but system demands complementary reset polarity and battery presence indication |
Compared with MAX704CSA+, MAX703CSA+ offers earlier reset initiation for tighter supply margins, while MAX708CSA+ removes battery switching but adds active-high reset and BATT ON signaling - making each optimal for distinct power architecture requirements.
Availability
MAX704CSA+ is available at Aetrix Electronics and suitable for industrial controller monitoring, embedded instrument power management, intelligent power metering, and critical μP power monitoring requiring stable component supply across commercial temperature range.
Supply support for MAX704CSA+ 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 industrial, communications, and computing applications, with emphasis on reliability and integration.
The MAX703/MAX704 family delivers cost-effective, single-chip solutions for μP power supervision and battery backup - targeting space-constrained embedded systems needing deterministic reset and long-term RAM retention.
FAQ
What is the guaranteed reset assertion voltage for MAX704CSA+ over temperature?
The MAX704CSA+ guarantees reset assertion when VCC falls below 4.25V (minimum) and releases reset when VCC rises above 4.50V (maximum), with 40mV hysteresis - fully specified over 0°C to +70°C. This ensures consistent brownout protection across the commercial temperature range without derating.
Can MAX704CSA+ operate with a 3.0V lithium battery on VBATT while VCC is at +5V?
Yes, the MAX704CSA+ supports 3.0V lithium batteries on VBATT with VCC at +5V. Its internal switchover circuitry disables VBATT conduction when VCC exceeds the reset threshold, preventing reverse current flow. Diode D1 in the internal substrate path blocks battery discharge into VCC under normal operation.
How does the power-fail comparator behave during battery-backup mode in MAX704CSA+?
In battery-backup mode (VCC < 4.40V), the MAX704CSA+ disables the power-fail comparator entirely: PFI input is disconnected from the reference, and PFO is forced logic-low regardless of PFI voltage. This eliminates spurious interrupts and reduces current draw to <1µA during extended backup operation.
What is the maximum allowable VBATT voltage for MAX704CSA+ when used with a ±10% +5V supply?
The MAX704CSA+ allows up to 4.55V on VBATT when used with a ±10% +5V supply (i.e., VCC min = 4.5V). This limit prevents excessive forward bias across internal diode D1 during switchover and avoids substrate current injection that could compromise reliability or increase quiescent current.
Does MAX704CSA+ require external components to generate a valid reset signal down to VCC = 0V?
No - the MAX704CSA+ guarantees RESET assertion down to VCC = 1V, but below that, RESET becomes high-impedance. To ensure valid low state down to 0V, a 100kΩ pulldown resistor on the RESET pin is recommended per Maxim's Figure 6, preventing floating inputs in CMOS systems during deep undervoltage.
MAX704CSA+ 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:
- 4.4V
- 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
MAX704CSA+ FAQ
1.How can I place an order for MAX704CSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704CSA+ 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 MAX704CSA+ reliable?
The price and inventory of MAX704CSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704CSA+ is usually 5 days.
3.What payment methods are accepted for MAX704CSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704CSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704CSA+?
MAX704CSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704CSA+ 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 MAX704CSA+?
For technical support, including MAX704CSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704CSA+ requirements.
6.How does Aetrix verify that MAX704CSA+ is sourced from the original manufacturer or authorized distributors?
All MAX704CSA+ 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 MAX704CSA+ meets industry standards.
7.What is the process for return or replacement of MAX704CSA+?
All MAX704CSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX704CSA+, 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 MAX704CSA+ part is unused and in its original packaging.
Return procedure for MAX704CSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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