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Analog Devices Inc./Maxim Integrated MAX703ESA+
- Part No.:
- MAX703ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX703ESA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:518
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Product details
Overview
MAX703ESA+ 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 at 4.65V supply threshold, 200ms reset pulse width, 1.25V power-fail comparator input, and automatic switchover to backup battery (VBATT) when VCC drops below reset threshold - used in industrial controllers and critical embedded systems requiring reliable power sequencing.
For engineers reviewing the MAX703ESA+ datasheet, MAX703ESA+ pinout, MAX703ESA+ application, or MAX703ESA+ equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 50nA quiescent current in battery-backup mode, 8-pin SO package compatibility, and precise 4.65V supply-monitoring threshold with 40mV hysteresis.
Technical Context
The MAX703ESA+ integrates four core functions in a single IC: a precision voltage monitor with fixed 4.65V reset threshold, a battery-switchover circuit using p-channel MOSFET switches (5Ω in VCC mode, 80Ω in VBATT mode), a 1.25V reference-based power-fail comparator (PFI/PFO), and a debounced TTL/CMOS-compatible manual reset input (MR) with internal 250µA pullup.
Its reset generator asserts active-low RESET for ≥140ms (typ. 200ms) after VCC rises above threshold or MR transitions low-to-high; during brownout, the internal timer restarts continuously, ensuring sustained reset until VCC remains stable above threshold. In battery-backup mode (VCC < VRST), RESET is held low, PFI/PFO are disabled, and VOUT connects to VBATT through an 80Ω switch while substrate bias shifts to VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - ensures reliable μP reset initiation before +5V supply dropout affects code execution. |
| Reset Pulse Width | 140–280ms - guarantees sufficient hold time for μP initialization and peripheral stabilization after power recovery. |
| Supply Current (Active) | 200–500µA - enables low-power operation in industrial temperature range (-40°C to +85°C). |
| Battery-Backup Quiescent Current | 5.0µA max - preserves lithium battery life for years in CMOS RAM retention applications. |
| Power-Fail Comparator Threshold | 1.25V ±50mV - supports accurate undervoltage detection of auxiliary supplies or unregulated rails via external divider. |
| VOUT Switch Resistance | 5Ω (VCC mode), 80Ω (VBATT mode) - limits voltage drop under load while maintaining RAM data integrity during switchover. |
| Operating Voltage Range | VCC/VBATT: 0–5.5V - accommodates wide input tolerance and supercapacitor-based backup sources. |
Pinout & Package
MAX703ESA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with standard 1.27mm pitch and JEDEC MS-012AC outline. Pin 1 is marked by a beveled corner or dot.
| 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 and hysteresis. |
| 2 (VCC) | +5V main supply input | Primary power source; monitored for reset generation and used as substrate reference unless in battery-backup mode. |
| 3 (GND) | Ground reference | Common return for all analog and digital circuitry; must be low-impedance for accurate comparator operation. |
| 4 (PFI) | Power-fail comparator input | Accepts divided-down voltage; triggers PFO low when input falls below 1.25V - used for early warning of supply collapse. |
| 5 (PFO) | Power-fail comparator output | Open-drain active-low output; disabled and forced low during battery-backup mode to prevent false interrupts. |
| 6 (MR) | Manual reset input | Active-low TTL/CMOS-compatible input with internal 250µA pullup; debounced by 200ms reset timer. |
| 7 (RESET) | Reset output | Active-low open-drain output; asserted when VCC < 4.65V or MR pulled low; guaranteed functional down to VCC = 1V. |
| 8 (VBATT) | Backup-battery input | Accepts 2.8–4.8V lithium or supercap source; powers VOUT and internal circuitry when VCC fails. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.65V supply monitor | Guaranteed threshold with 40mV hysteresis prevents chatter during slow VCC droop or rise. |
| Automatic battery switchover | Seamless transition to VBATT with 20mV switchover threshold and 40mV hysteresis avoids oscillation near crossover. |
| 200ms minimum reset pulse width | Ensures μP and peripherals fully initialize before release, eliminating race conditions in multi-chip systems. |
| 50nA battery-backup quiescent current | Enables >10-year lithium battery life in static RAM retention without compromising switchover speed. |
| 1.25V reference-based PFI comparator | Supports flexible monitoring of non-+5V rails (e.g., -5V, +3.3V) via resistor dividers with predictable trip points. |
Applications
| Industrial Controllers | Embedded Data Loggers |
|---|---|
Use Scenario: PLCs and motor controllers operating in harsh environments with fluctuating 5V supplies. IC Role / Device Role / Timing Role: Supervisory circuit providing fail-safe reset and RAM backup during brownouts or mains interruptions. Use Value: Prevents corrupted firmware execution and preserves configuration registers via guaranteed RESET assertion down to VCC = 1V and sub-µA battery drain. | Use Scenario: Remote environmental sensors logging data to SRAM during extended power outages. IC Role / Device Role / Timing Role: Battery switchover controller maintaining VOUT to SRAM while disabling non-critical circuitry. Use Value: Enables >5-year field deployment with coin-cell batteries by limiting backup-mode current to 5µA max. |
| Medical Diagnostic Equipment | Test & Measurement Instruments |
Use Scenario: Portable ultrasound or ECG devices requiring deterministic boot-up and patient data retention. IC Role / Device Role / Timing Role: Power integrity guardian asserting RESET until regulated +5V stabilizes, then enabling safe μP startup. Use Value: Eliminates boot failures caused by undershoot on power rails, verified across -40°C to +85°C operating range. | Use Scenario: Benchtop oscilloscopes and spectrum analyzers with volatile calibration memory. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main supply for reset and uses PFI to detect auxiliary rail faults before system lockup. Use Value: Provides early warning via PFO interrupt, allowing graceful shutdown and nonvolatile save of calibration coefficients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704ESA+ | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and features. | Suitable for systems with tighter +5V tolerance (±10%) or lower dropout margins. | Select MAX704ESA+ only if design requires reset at 4.40V; otherwise MAX703ESA+ ensures earlier intervention for standard ±5% supplies. |
| MAX705CSA+ | No battery backup; adds watchdog timer and CE write-protect; 4.65V reset; same 8-SO package. | Used where RAM backup is unnecessary but system-level fault detection (watchdog timeout) is required. | Choose MAX705CSA+ when watchdog supervision outweighs battery retention needs; not a functional replacement for backup functionality. |
Compared with MAX704ESA+, MAX703ESA+ triggers reset earlier (4.65V vs. 4.40V), improving margin against supply collapse in nominal +5V systems; compared with MAX705CSA+, it retains battery switchover capability but omits watchdog and write-protect - making it optimal for cost-sensitive, RAM-critical applications without runtime monitoring needs.
Availability
MAX703ESA+ is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, medical diagnostic equipment, and test & measurement instruments requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX703ESA+ 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 power, sensing, interface, and reliability-critical applications.
The MAX703/MAX704 family targets cost-sensitive microprocessor systems needing robust power monitoring and battery-backed RAM retention - optimized for simplicity, low quiescent current, and guaranteed operation over industrial temperature ranges.
FAQ
What is the guaranteed minimum reset pulse width for MAX703ESA+?
The MAX703ESA+ guarantees a reset pulse width of at least 140ms, with a typical value of 200ms and maximum of 280ms. This timing is internally generated and independent of external components, ensuring consistent μP initialization across temperature and supply variations. The pulse begins when VCC rises above 4.65V or when the manual reset input (MR) transitions from low to high, and is critical for reliable boot sequencing in MAX703ESA+ applications.
Does MAX703ESA+ support lithium battery backup, and what is the maximum allowable VBATT voltage?
Yes, MAX703ESA+ supports lithium battery backup with a maximum allowable VBATT voltage of 4.80V, as specified in Table 2 of the datasheet. This limit prevents excessive current flow into the substrate diode (D1) when VCC is near the 4.65V reset threshold. Typical use cases employ 3.0V–3.6V lithium cells, which connect directly without regulation. Exceeding 4.80V risks substrate conduction and potential latch-up, so MAX703ESA+ designs must respect this absolute maximum rating.
How does the power-fail comparator (PFI/PFO) behave during battery-backup mode in MAX703ESA+?
In battery-backup mode (activated when VCC falls below 4.65V), the power-fail comparator inside MAX703ESA+ is disabled and PFO is forced logic-low regardless of PFI voltage. This prevents spurious interrupts during backup operation and conserves power. The PFI input becomes high-impedance, and no current flows into it. Once VCC rises above the reset threshold and exits backup mode, the comparator resumes normal operation - meaning MAX703ESA+ inherently isolates PFO functionality from backup state transitions.
Can MAX703ESA+ operate with VCC as low as 1V, and what happens to RESET output at that level?
Yes, MAX703ESA+ guarantees RESET assertion functionality down to VCC = 1V, as explicitly stated in the Absolute Maximum Ratings and Detailed Description sections. Below 1V, the RESET output stops sinking current and becomes high-impedance (open-circuit). To maintain a valid logic-low state in such deep brownout conditions, a 100kΩ pulldown resistor is recommended on the RESET line - a design practice confirmed in Figure 6 of the MAX703ESA+ datasheet to prevent floating inputs in downstream CMOS logic.
What is the quiescent current of MAX703ESA+ in battery-backup mode, and how is it measured?
The MAX703ESA+ draws ≤5.0µA quiescent current in battery-backup mode (VCC = 0V, VBATT = 2.8V, TA = TMIN to TMAX), per Electrical Characteristics table. This value includes current for internal biasing, RESET output stage in low state, and leakage through the 80Ω VOUT switch. At +25°C, typical current is 0.05µA - effectively 50nA - enabling multi-year operation on small lithium cells. The specification is measured with VCC disconnected and VBATT supplying only the MAX703ESA+ die, confirming ultra-low standby consumption essential for MAX703ESA+ longevity in always-on backup applications.
MAX703ESA+ 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:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX703ESA+ FAQ
1.How can I place an order for MAX703ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX703ESA+ 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 MAX703ESA+ reliable?
The price and inventory of MAX703ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX703ESA+ is usually 5 days.
3.What payment methods are accepted for MAX703ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX703ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX703ESA+?
MAX703ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX703ESA+ 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 MAX703ESA+?
For technical support, including MAX703ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX703ESA+ requirements.
6.How does Aetrix verify that MAX703ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX703ESA+ 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 MAX703ESA+ meets industry standards.
7.What is the process for return or replacement of MAX703ESA+?
All MAX703ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX703ESA+, 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 MAX703ESA+ part is unused and in its original packaging.
Return procedure for MAX703ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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