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Analog Devices Inc./Maxim Integrated MAX704CPA
- Part No.:
- MAX704CPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX704CPA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,279
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Product details
Overview
MAX704CPA from Maxim Integrated is a microprocessor supervisory circuit in 8-pin PDIP package, providing active-low reset (4.40V threshold), battery-backup switching, 1.25V power-fail detection, and debounced manual reset input. It ensures reliable μP startup and brownout recovery in embedded systems with CMOS RAM retention.
For engineers reviewing the MAX704CPA datasheet, MAX704CPA pinout, MAX704CPA application, or MAX704CPA equivalent, key selection criteria include reset voltage accuracy (±150mV), 200ms reset pulse width, 50nA battery-backup quiescent current, guaranteed RESET assertion down to VCC = 1V, and compatibility with +5V ±10% supplies.
Technical Context
The MAX704CPA integrates four core functions: a precision bandgap-based supply monitor with 4.40V reset threshold and 40mV hysteresis; a p-channel MOSFET switchover circuit (5Ω on-resistance in VCC mode, 80Ω in VBATT mode); a 1.25V reference comparator for PFI/PFO power-fail signaling; and TTL/CMOS-compatible MR input with internal 250µA pullup.
Its battery-switchover logic activates only when VCC falls below the reset threshold and VBATT exceeds VCC by ≥20mV, with 40mV hysteresis preventing chatter during slow VCC decay. In battery-backup mode, internal circuitry powers from VBATT, disabling PFI/PFO and asserting RESET low while VOUT connects to VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V (min 4.25V, max 4.50V) - ensures reset assertion before +5V supply drops below safe μP operating margin |
| Reset Pulse Width | 200ms (min 140ms, max 280ms) - provides sufficient time for μP initialization and peripheral stabilization |
| Supply Current | 200–350µA at VCC = 4.5–5.5V - enables low-power operation without compromising reset timing accuracy |
| Battery-Backup Current | 50nA (typ) at VCC = 0V, VBATT = 2.8V - preserves lithium battery life for multi-year RAM backup |
| VOUT Output Voltage | VCC − 0.025V (at 5mA) - minimizes voltage drop to CMOS RAM during main supply operation |
| PFI Threshold | 1.25V (min 1.20V, max 1.30V) - enables precise undervoltage detection of auxiliary rails or unregulated inputs |
| MR Input Threshold | 0.8V (low), 2.0V (high) - ensures robust noise immunity and compatibility with TTL/CMOS logic levels |
Pinout & Package
MAX704CPA uses an 8-pin plastic dual in-line package (PDIP) with 0.3-inch body width and standard through-hole footprint. Pin 1 is VOUT, pin 8 is VBATT, and all pins follow JEDEC MS-001AC outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 5Ω p-MOSFET) and VBATT (via 80Ω p-MOSFET) based on reset state and voltage comparison |
| 2 - VCC | +5V main supply input | Primary power source; monitored for reset generation and used as substrate reference |
| 3 - GND | Ground reference | Common return for all internal circuits and external loads; must be low-impedance for stable reset timing |
| 4 - PFI | Power-fail comparator input | Compares external voltage divider output to 1.25V reference; triggers PFO low when input < 1.25V |
| 5 - PFO | Power-fail comparator output | Active-low open-drain output; sinks current when PFI < 1.25V; disabled in battery-backup mode |
| 6 - MR | Manual reset input | Active-low TTL/CMOS-compatible input with internal 250µA pullup; debounced by 200ms reset timer |
| 7 - RESET | μP reset output | Active-low push-pull output; asserted low during power-up, brownout, or MR activation; guaranteed to VCC = 1V |
| 8 - VBATT | Battery backup input | Accepts 2.8–4.55V lithium battery; sources VOUT during VCC failure with automatic hysteresis-controlled switchover |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures valid reset signal even during deep brownout, preventing μP lockup when supply collapses slowly |
| 40mV reset threshold hysteresis | Prevents oscillatory reset assertion during marginal VCC conditions, eliminating system instability near trip point |
| 80Ω VBATT-to-VOUT switch resistance | Minimizes voltage drop under typical RAM load (≤250µA), preserving data integrity during extended backup |
| 50nA quiescent current in battery mode | Extends 3V lithium battery life beyond 10 years in standby, critical for industrial logging and metering applications |
| Debounced MR input with 200ms hold time | Eliminates need for external RC debounce circuitry, reducing BOM count and PCB area in space-constrained designs |
Applications
| Industrial Programmable Logic Controllers (PLCs) | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Maintaining SRAM contents during AC mains interruption or fuse blow in field-mounted PLCs. IC Role / Device Role / Timing Role: Supervisory circuit providing battery-backed VOUT and synchronized RESET to prevent program corruption during power transitions. Use Value: Enables deterministic restart after power restoration without firmware reload, meeting IEC 61131-2 reliability requirements. | Use Scenario: Preserving calibration data and patient history in portable ultrasound units during battery swap. IC Role / Device Role / Timing Role: Switchover controller ensuring continuous RAM power from backup cell while main supply is disconnected. Use Value: Eliminates data loss risk during hot-swap maintenance, satisfying FDA 21 CFR Part 11 audit trail integrity mandates. |
| Automotive Engine Control Units (ECUs) | Smart Energy Meters |
Use Scenario: Securing flash configuration registers during vehicle ignition cycle transients and battery voltage sag. IC Role / Device Role / Timing Role: Precision voltage monitor asserting RESET before VCC drops below 4.40V, synchronizing with ECU boot sequence. Use Value: Prevents erroneous sensor readings or actuator commands during cold-crank events, supporting ISO 16750-2 compliance. | Use Scenario: Retaining tariff schedules and consumption logs during grid outage in residential smart meters. IC Role / Device Role / Timing Role: Dual-function supervisor generating reset pulse and switching supercapacitor backup to VOUT upon AC loss. Use Value: Guarantees >10-year data retention with single 3.6V lithium cell, meeting ANSI C12.20 Class 0.2 accuracy requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704CSA | Same electrical specs, 8-pin SO package (surface-mount) | Requires rework of PCB layout for SMT assembly; no through-hole compatibility | Select for automated production where board space and thermal performance outweigh hand-soldering needs |
| MAX706CPA | 4.40V reset threshold, no battery backup, adds watchdog timer and CE write-protect | Cannot retain RAM during power loss; suited for systems with external backup or non-volatile memory | Choose when watchdog supervision is required and battery switchover is unnecessary or handled externally |
Compared with MAX704CSA, MAX704CPA offers identical supervision functionality but in through-hole PDIP for prototyping and legacy repair; compared with MAX706CPA, it trades watchdog capability for essential battery backup-critical where RAM data persistence is non-negotiable.
Availability
MAX704CPA is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, automotive ECUs, and smart energy meters requiring stable component supply across extended product lifecycles.
Supply support for MAX704CPA 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 industrial, communications, and computing applications.
The MAX703/MAX704 family was engineered specifically for cost-sensitive μP systems needing integrated power monitoring, battery switchover, and reset generation in a single 8-pin package.
FAQ
What is the minimum VCC voltage at which MAX704CPA guarantees valid RESET output?
The MAX704CPA guarantees RESET output validity down to VCC = 1V during falling VCC conditions. Below 1V, the RESET pin becomes high-impedance and requires an external pulldown resistor (e.g., 100kΩ to GND) to maintain a defined logic-low state. This specification ensures deterministic behavior during deep brownout scenarios where other supervisors may release reset prematurely.
Can MAX704CPA be used with a 3.3V microprocessor system?
No, MAX704CPA is designed exclusively for +5V systems with VCC operating range of +4.5V to +5.5V. Its 4.40V reset threshold, internal 1.25V reference, and VOUT switching architecture assume a nominal 5V rail. For 3.3V systems, consider the MAX6326 series or MAX708, which offer 3.08V or adjustable reset thresholds compatible with lower-voltage logic.
What is the maximum allowable VBATT voltage for MAX704CPA?
The maximum allowable VBATT voltage for MAX704CPA is 4.55V, as specified in Table 2 of the datasheet. Exceeding this voltage risks excessive current flow through internal substrate diode D1 when VCC approaches the reset threshold, potentially causing latch-up or accelerated battery discharge. Lithium cells (3.0–3.6V) and properly regulated supercaps are within safe operating limits.
How does MAX704CPA handle manual reset debouncing?
MAX704CPA implements hardware debouncing via its fixed 200ms reset pulse width timer. When the MR pin is pulled low (below 0.8V), the internal timer initiates a full 200ms RESET assertion regardless of MR pin duration-even if the pushbutton is released after 10ms. This eliminates need for external RC networks or firmware debounce routines, simplifying design and improving reliability.
Does MAX704CPA provide power-fail warning during battery-backup mode?
No, the power-fail comparator (PFI/PFO) is disabled during battery-backup mode. When VCC falls below the reset threshold and VBATT takes over VOUT, PFO is forced low and PFI input is inactive. This design prevents false warnings during backup operation and conserves battery current. Power-fail signaling is only functional during normal VCC-powered operation.
MAX704CPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX704CPA FAQ
1.How can I place an order for MAX704CPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704CPA 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 MAX704CPA reliable?
The price and inventory of MAX704CPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704CPA is usually 5 days.
3.What payment methods are accepted for MAX704CPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704CPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704CPA?
MAX704CPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704CPA 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 MAX704CPA?
For technical support, including MAX704CPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704CPA requirements.
6.How does Aetrix verify that MAX704CPA is sourced from the original manufacturer or authorized distributors?
All MAX704CPA 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 MAX704CPA meets industry standards.
7.What is the process for return or replacement of MAX704CPA?
All MAX704CPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX704CPA, 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 MAX704CPA part is unused and in its original packaging.
Return procedure for MAX704CPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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