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Analog Devices Inc./Maxim Integrated MAX703CPA
- Part No.:
- MAX703CPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX703CPA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,620
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Product details
Overview
MAX703CPA from Maxim Integrated is an 8-pin PDIP microprocessor supervisory circuit providing precision supply-voltage monitoring, battery-backup switching, power-fail warning, and manual reset functionality. It asserts active-low RESET when VCC drops below 4.65V, delivers 200ms reset pulse width, consumes only 200µA quiescent current, and supports CMOS RAM backup during brownout. It is used in critical μP power monitoring for industrial controllers and intelligent instruments.
For engineers reviewing the MAX703CPA datasheet, MAX703CPA pinout, MAX703CPA application, or MAX703CPA equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 1.25V PFI threshold accuracy, battery switchover hysteresis of 40mV, and compatibility with +5V ±5% supplies in commercial-temperature systems.
Technical Context
The MAX703CPA integrates a precision bandgap-based voltage monitor (4.65V ±150mV threshold), a debounced TTL/CMOS-compatible manual reset input with 250µA internal pullup, and a p-channel MOSFET-based battery switchover circuit with 5Ω on-resistance in VCC mode and 80Ω in VBATT mode. Its power-fail comparator compares PFI to a stable 1.25V reference and forces PFO low in battery-backup mode.
RESET output remains valid down to VCC = 1V and features guaranteed low-state sinking capability (3.2mA) and high-impedance open-drain behavior below that level. The device enters ultra-low-power battery-backup mode (<1µA) when VCC falls >1V below VBATT, disabling MR, PFI, and PFO while maintaining RESET low and connecting VBATT to VOUT via the 80Ω switch.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - ensures reliable μP reset initiation before +5V supply dropout |
| Reset Pulse Width | 200ms typical - provides sufficient time for μP initialization after power recovery |
| Quiescent Current | 200µA max at +25°C - enables low-power system monitoring without burdening main supply |
| Battery-Backup Current | 50nA typical - preserves lithium battery life for years in standby applications |
| PFI Threshold | 1.25V ±50mV - enables accurate power-fail or low-battery detection using external resistor dividers |
| VBATT Switch Hysteresis | 40mV - prevents oscillatory switching during slow VCC decay near switchover point |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded control and instrumentation |
| Package | 8-pin PDIP - compatible with through-hole prototyping and legacy industrial PCB assembly |
Pinout & Package
MAX703CPA is housed in an 8-pin plastic dual in-line package (PDIP) with 0.3-inch body width and standard DIP footprint. Pin 1 is marked by a notch or dot; pins are numbered counterclockwise from top-left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Supply output for CMOS RAM | Switches between VCC (5Ω path) and VBATT (80Ω path) based on reset threshold crossing; maintains RAM power during brownout |
| VCC (Pin 2) | +5V main supply input | Primary power source; monitored for reset generation and used to bias internal circuitry and switches |
| GND (Pin 3) | Ground reference | Common return for all analog and digital functions; substrate connection point |
| PFI (Pin 4) | Power-fail comparator input | Monitors external voltage divider; triggers PFO low when input falls below 1.25V |
| PFO (Pin 5) | Power-fail comparator output | Open-drain output asserted low during PFI undervoltage or battery-backup mode |
| MR (Pin 6) | Manual reset input | Active-low TTL/CMOS-compatible input with 250µA internal pullup; debounced by 200ms reset timer |
| RESET (Pin 7) | Reset output | Active-low open-drain output held low during VCC < 4.65V or MR assertion; guaranteed operation down to VCC = 1V |
| VBATT (Pin 8) | Backup-battery input | Accepts 2.8V–4.8V lithium or supercap source; powers VOUT and internal logic when VCC fails |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic reset state even during deep brownout, preventing μP lockup |
| 200ms minimum reset pulse width | Meets μP minimum reset hold-time requirements without external timing components |
| 50nA quiescent current in battery-backup mode | Extends 3V lithium battery life beyond 10 years in always-on monitoring applications |
| Internal 1.25V precision reference for PFI | Enables accurate, temperature-stable power-fail detection without external references |
| 80Ω VBATT-to-VOUT switch with 40mV hysteresis | Prevents chattering during marginal VCC recovery and minimizes voltage drop under 250µA load |
| Debounced MR input with 250µA pullup | Eliminates need for external RC debounce network and supports direct pushbutton interface |
Applications
| Industrial Controllers | Intelligent Instruments |
|---|---|
Use Scenario: PLC I/O modules requiring nonvolatile RAM retention during AC line sags or fuse interruptions. IC Role / Device Role / Timing Role: Supervisory circuit providing brownout-triggered battery switchover and synchronized reset to prevent firmware corruption. Use Value: Maintains SRAM data integrity and guarantees clean μP restart within 200ms of supply recovery, eliminating field resets. | Use Scenario: Portable multimeters and calibration equipment needing long-term parameter storage without external backup power management. IC Role / Device Role / Timing Role: Voltage monitor and battery switch enabling zero-maintenance memory retention during battery replacement or charging cycles. Use Value: Eliminates external diode-OR circuits and reduces BOM count by integrating switchover, reset, and power-fail warning in one 8-pin IC. |
| Critical μP Power Monitoring | Computers |
Use Scenario: Embedded BIOS watchdog systems where supply instability must trigger immediate reset before instruction execution errors occur. IC Role / Device Role / Timing Role: Primary reset generator asserting active-low signal within 250ns of MR activation or VCC droop below 4.65V. Use Value: Provides deterministic reset timing independent of μP clock domain, meeting JEDEC JESD84-A44 reliability requirements. | Use Scenario: Legacy desktop motherboard power sequencing where +5V rail stability must be verified prior to CPU enable. IC Role / Device Role / Timing Role: Standalone supervisor verifying VCC monotonic rise and holding RESET until 200ms after threshold crossing. Use Value: Replaces discrete reset IC + Schmitt trigger + battery diode solution, reducing layout area by 65% and improving thermal margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704CPA | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and feature set | Suitable for +5V ±10% supplies; not interchangeable without verifying system VCC tolerance | Select MAX704CPA only if design uses wider-tolerance regulators or requires earlier reset assertion |
| MAX705CPA | No battery backup; adds CE write-protect and watchdog timeout; 4.65V reset; same 8-pin SO/PDIP packages | Used where memory protection or watchdog supervision is required instead of RAM backup | Choose MAX705CPA when system needs write-protection or timeout-based recovery, not battery switchover |
Compared with MAX704CPA, MAX703CPA offers higher reset threshold for tighter +5V regulation compliance; compared with MAX705CPA, it trades watchdog/CE features for integrated battery switching-making it optimal for cost-sensitive, battery-backed RAM applications without watchdog requirements.
Availability
MAX703CPA is available at Aetrix Electronics and suitable for industrial controllers, intelligent instruments, critical μP power monitoring, and legacy computer systems requiring stable component supply across extended production lifecycles.
Supply support for MAX703CPA 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.
The MAX703/MAX704 product line was engineered specifically for cost-effective, single-chip μP supervision with integrated battery backup-targeting systems where RAM data retention during power loss is essential but watchdog or write-protect features are unnecessary.
FAQ
What is the guaranteed minimum reset pulse width for MAX703CPA?
The MAX703CPA guarantees a minimum reset pulse width of 140ms, with a typical value of 200ms and maximum of 280ms. This timing ensures μPs with longer reset-hold requirements-such as Intel 80C188 or ARM7TDMI derivatives-are fully initialized before release. The pulse starts when VCC rises above 4.65V or MR transitions from low to high, and is generated internally without external components. MAX703CPA's 200ms typical value meets or exceeds JEDEC-standard reset timing for commercial-grade microprocessors.
Can MAX703CPA operate with a 3.3V main supply?
No, MAX703CPA is specified only for +5V systems: its VCC operating range is 4.75V to 5.5V, and its 4.65V reset threshold is designed to detect dropout in regulated +5V rails. Applying 3.3V to VCC will prevent proper reset assertion and may cause undefined behavior in the internal comparators and switches. For 3.3V supervision, consider the MAX6326 series or MAX706R; MAX703CPA must be used exclusively in +5V applications per its datasheet limits.
How does MAX703CPA handle battery replacement without causing a system reset?
MAX703CPA allows safe battery replacement while VCC remains valid because it only enters battery-backup mode when VCC falls below 4.65V. As long as VCC stays above the reset threshold, the VBATT pin is effectively isolated from the reset logic and switchover circuit-floating VBATT cannot trigger RESET. This behavior differs from older switchover ICs that assert reset when VBATT ≈ VCC. MAX703CPA's architecture ensures uninterrupted operation during maintenance, making it ideal for field-serviceable instrumentation where battery swaps occur without powering down.
What is the maximum allowable backup battery voltage for MAX703CPA?
The maximum allowable backup battery voltage for MAX703CPA is 4.80V, 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 the reset threshold, causing unintended current flow from VBATT into the substrate and potential latch-up or increased quiescent current. Lithium cells (3.0–3.6V) and properly sized supercaps charged to ≤4.8V meet this limit safely. MAX703CPA's 4.80V ceiling directly supports common 3.6V LiSOCl₂ and 4.2V LiPo configurations with margin.
Does MAX703CPA provide power-fail interrupt capability?
Yes, MAX703CPA provides power-fail interrupt capability via its PFI/PFO pair: when the voltage at PFI drops below 1.25V, PFO is driven low (open-drain), which can be connected to a μP's NMI or GPIO interrupt pin. This allows the system to execute controlled shutdown routines-such as saving registers or flushing buffers-before VCC collapses below operational levels. In battery-backup mode, PFO is forced low regardless of PFI, ensuring consistent interrupt signaling during extended outages. MAX703CPA's 1.25V reference and nanoscale PFI input current (<25nA) ensure minimal loading on external divider networks.
MAX703CPA 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:
- 4.65V
- 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
MAX703CPA FAQ
1.How can I place an order for MAX703CPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX703CPA 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 MAX703CPA reliable?
The price and inventory of MAX703CPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX703CPA is usually 5 days.
3.What payment methods are accepted for MAX703CPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX703CPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX703CPA?
MAX703CPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX703CPA 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 MAX703CPA?
For technical support, including MAX703CPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX703CPA requirements.
6.How does Aetrix verify that MAX703CPA is sourced from the original manufacturer or authorized distributors?
All MAX703CPA 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 MAX703CPA meets industry standards.
7.What is the process for return or replacement of MAX703CPA?
All MAX703CPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX703CPA, 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 MAX703CPA part is unused and in its original packaging.
Return procedure for MAX703CPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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