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Analog Devices Inc./Maxim Integrated MAX704CSA+T
- Part No.:
- MAX704CSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704CSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,598
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Product details
Overview
MAX704CSA+T from Maxim Integrated is a microprocessor supervisory circuit providing precision supply-voltage monitoring, battery-backup switching, power-fail warning, and manual reset functionality in +5V systems. It asserts an active-low RESET output for 200ms when VCC drops below 4.40V, switches VOUT to VBATT during brownout, and features a 1.25V PFI threshold detector. Used in critical μP power monitoring for embedded controllers and intelligent instruments.
For engineers reviewing the MAX704CSA+T datasheet, MAX704CSA+T pinout, MAX704CSA+T application, or MAX704CSA+T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 50nA quiescent current in battery-backup mode, 200ms reset pulse width, and 8-pin SO package compatibility with lead-free assembly.
Technical Context
The MAX704CSA+T integrates four core functions: a precision voltage monitor with 4.40V ±40mV hysteresis reset threshold, a battery switchover circuit using p-channel MOSFETs (5Ω in VCC mode, 80Ω in VBATT mode), a 1.25V reference-based power-fail comparator with TTL/CMOS-compatible PFO output, and a debounced manual reset input with 250µA internal pullup.
Its architecture ensures reliable reset generation during power-up, brownout, and power-down events while maintaining valid RESET output even as VCC falls to 1V. In battery-backup mode, it disables the PFI comparator, forces PFO low, disconnects VCC from VOUT, and powers internal circuitry from VBATT - all with <1µA supply current when VCC is >1V below VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±40mV - guarantees reset assertion before +5V supply collapse affects μP operation |
| Reset Pulse Width | 200ms typical - provides sufficient time for μP initialization and peripheral stabilization |
| Quiescent Current | 200µA at VCC = 5V - enables low-power system monitoring without burdening main supply |
| Battery-Backup Current | 50nA at VCC = 0V, VBATT = 2.8V - preserves lithium battery life for years in standby |
| PFI Threshold | 1.25V ±50mV - supports accurate power-fail or low-battery detection via external divider |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path) - minimizes voltage drop during RAM backup under load |
| Operating Temp Range | 0°C to +70°C - qualified for commercial-grade industrial and computing applications |
| Package | 8-pin SO (Small Outline) - surface-mount compatible with automated PCB assembly |
Pinout & Package
MAX704CSA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant with lead-free finish indicated by the "+" suffix. The package measures 4.9mm × 6.0mm with 1.27mm pitch, suitable for high-density layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 5Ω p-MOSFET) and VBATT (via 80Ω p-MOSFET) based on reset threshold crossing |
| 2 - VCC | +5V main supply input | Primary power source; monitored for reset generation and used to bias internal circuitry |
| 3 - GND | Ground reference | Common return for all analog and digital functions; substrate connection point |
| 4 - PFI | Power-fail comparator input | Compares external voltage to 1.25V reference; triggers PFO low when input falls below threshold |
| 5 - PFO | Power-fail comparator output | Active-low open-drain output; disabled and forced low during 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 push-pull output asserted for ≥140ms; guaranteed functional down to VCC = 1V |
| 8 - VBATT | Backup-battery input | Source for VOUT during brownout; requires ≥2.0V and >20mV above VCC to engage switchover |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET to VCC = 1V | Ensures deterministic reset behavior during deep brownout, preventing μP lockup |
| 40mV reset threshold hysteresis | Prevents oscillatory reset assertion during slow VCC ramp-down or noise-induced dips |
| 50nA battery-backup quiescent current | Extends 3V lithium battery life beyond 10 years in always-on memory retention applications |
| Debounced MR input with 200ms pulse | Eliminates need for external RC debounce circuitry; simplifies pushbutton interface design |
| VBATT switchover with 20mV turn-on/turn-off thresholds | Provides clean, bounce-free transition between main and backup supplies without chatter |
| Internal 1.25V precision reference | Enables accurate power-fail or low-battery detection without external voltage reference IC |
Applications
| Industrial Controllers | Embedded Data Loggers |
|---|---|
Use Scenario: PLCs and motion controllers requiring nonvolatile RAM retention during AC mains interruption. IC Role / Device Role / Timing Role: Supervisory circuit providing battery-backed VOUT and brownout-triggered RESET to preserve state and prevent corrupted writes. Use Value: Enables seamless failover to lithium backup without software intervention or external switch control logic. | Use Scenario: Remote environmental sensors logging data to static RAM during extended field deployments. IC Role / Device Role / Timing Role: Power-monitoring and switchover controller ensuring RAM integrity across intermittent solar/battery power cycles. Use Value: 50nA battery-backup current extends 3.6V coin-cell life to >15 years at 25°C, reducing maintenance frequency. |
| Medical Diagnostic Terminals | Point-of-Sale (POS) Systems |
Use Scenario: Portable ultrasound or ECG units needing instant resume after brief power loss. IC Role / Device Role / Timing Role: Reset generator and RAM power manager asserting RESET until stable VCC is confirmed, then enabling fast recovery. Use Value: 200ms reset pulse width exceeds μP minimum reset hold time requirements per Intel/ARM specifications. | Use Scenario: Retail kiosks operating from unregulated wall adapters subject to line sags and surges. IC Role / Device Role / Timing Role: Dual-threshold supervisor detecting both VCC brownout (4.40V) and auxiliary supply failure (via PFI). Use Value: 1.25V PFI comparator allows early warning of DC-DC converter degradation before main rail collapse. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704ESA+ | Extended temperature range (-40°C to +85°C) vs. MAX704CSA+T (0°C to +70°C); identical electrical specs and pinout | Suitable for automotive under-hood or outdoor industrial enclosures where ambient exceeds 70°C | Select MAX704ESA+ when operating temperature exceeds +70°C; otherwise MAX704CSA+T offers cost advantage for commercial environments |
| MAX706CPA+ | No battery backup; 4.40V reset threshold; 1.6s watchdog timeout; 8-pin PDIP package | Used where RAM backup is unnecessary but watchdog supervision is required for firmware crash recovery | Choose MAX706CPA+ only if watchdog functionality is mandatory and battery switchover is not needed |
Compared with MAX704ESA+, MAX704CSA+T trades extended temperature capability for lower cost in commercial applications; compared with MAX706CPA+, it adds battery backup and removes watchdog - making it optimal for pure power-monitoring and RAM-retention use cases without crash-recovery needs.
Availability
MAX704CSA+T is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, medical diagnostic terminals, and point-of-sale systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX704CSA+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 precision analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.
The MAX703/MAX704 product line delivers low-cost, integrated supervisory solutions focused on reliable power monitoring, battery-backed RAM retention, and deterministic reset generation in +5V μP systems.
FAQ
What is the guaranteed minimum reset pulse width for MAX704CSA+T?
The MAX704CSA+T guarantees a reset pulse width of at least 140ms, with a typical value of 200ms and maximum of 280ms. This timing is generated by an internal timer that starts when VCC rises above 4.40V or when the manual reset input (MR) transitions from low to high. The pulse width ensures compliance with most microprocessor reset hold-time requirements, including those of Intel 80x86 and ARM Cortex-M families. The MAX704CSA+T maintains this specification across its full 0°C to +70°C operating temperature range.
Can MAX704CSA+T operate with a 3.3V main supply?
No, the MAX704CSA+T is specified only for +5V systems, with VCC operating range from +4.5V to +5.5V. Its 4.40V reset threshold and internal circuitry are optimized for 5V rails. Attempting to use it with 3.3V will result in immediate and continuous RESET assertion, as VCC remains below the threshold. For 3.3V applications, consider the MAX6326 series or MAX708, which offer 3.08V or adjustable reset thresholds. The MAX704CSA+T must be used with a regulated +5V supply to function correctly.
How does MAX704CSA+T handle battery replacement without causing a system reset?
The MAX704CSA+T allows safe battery replacement while VCC remains valid because it enters battery-backup mode only when VCC falls below 4.40V. As long as VCC stays above the reset threshold, the device ignores VBATT voltage changes and keeps VOUT connected to VCC. Even if VBATT floats near VCC during replacement, no switchover occurs. This behavior prevents spurious resets common in older switchover ICs. The MAX704CSA+T's design ensures that battery removal or insertion has zero impact on system operation when main power is stable.
What is the maximum allowable VBATT voltage for MAX704CSA+T?
The maximum allowable VBATT voltage for MAX704CSA+T is 4.55V, as specified in Table 2 of the datasheet. Exceeding this voltage risks forward-biasing the internal substrate diode (D1 in Figure 3) when VCC is near its reset threshold, causing unwanted current flow from VBATT into the substrate and potential latch-up or increased quiescent current. This limit accounts for worst-case tolerances in both VCC and VBATT. For lithium batteries, use cells with nominal 3.0–3.6V output; avoid 4.2V fully charged Li-ion unless actively regulated to ≤4.55V. The MAX704CSA+T relies on this voltage ceiling to ensure robust, long-term reliability.
Does MAX704CSA+T provide watchdog timer functionality?
No, the MAX704CSA+T does not include a watchdog timer. It provides only power-supply monitoring, battery switchover, power-fail warning, and manual reset - four dedicated supervisory functions without timeout-based firmware supervision. Watchdog capability is found in other members of the MAX70x family such as the MAX705 (with 1.6s watchdog) or MAX791 (with programmable watchdog). If your design requires periodic CPU heartbeat monitoring to recover from software hangs, you must select a different part. The MAX704CSA+T is purpose-built for deterministic power-event response, not runtime fault detection.
MAX704CSA+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:
- 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+T FAQ
1.How can I place an order for MAX704CSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704CSA+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 MAX704CSA+T reliable?
The price and inventory of MAX704CSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704CSA+T is usually 5 days.
3.What payment methods are accepted for MAX704CSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704CSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704CSA+T?
MAX704CSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704CSA+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 MAX704CSA+T?
For technical support, including MAX704CSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704CSA+T requirements.
6.How does Aetrix verify that MAX704CSA+T is sourced from the original manufacturer or authorized distributors?
All MAX704CSA+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 MAX704CSA+T meets industry standards.
7.What is the process for return or replacement of MAX704CSA+T?
All MAX704CSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX704CSA+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 MAX704CSA+T part is unused and in its original packaging.
Return procedure for MAX704CSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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