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Analog Devices Inc./Maxim Integrated MAX704ESA+
- Part No.:
- MAX704ESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX704ESA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,421
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Product details
Overview
MAX704ESA+ from Maxim Integrated is a microprocessor supervisory circuit providing active-low reset, battery-backup switching, 1.25V power-fail detection, and manual reset input for +5V systems. It asserts reset below 4.40V with 200ms pulse width, supports CMOS RAM backup via VOUT, and operates over –40°C to +85°C in 8-pin SO package.
For engineers reviewing the MAX704ESA+ datasheet, MAX704ESA+ pinout, MAX704ESA+ application, or MAX704ESA+ equivalent, key selection criteria include reset threshold accuracy (4.40V ±150mV), battery switchover hysteresis (40mV), quiescent current in backup mode (50nA), and guaranteed RESET assertion down to VCC = 1.2V.
Technical Context
The MAX704ESA+ integrates four core functions on a single die: a precision bandgap-based voltage monitor for VCC reset assertion, a dedicated 1.25V reference comparator for PFI/PFO power-fail signaling, a p-channel MOSFET-based battery switchover circuit with 5Ω (VCC→VOUT) and 80Ω (VBATT→VOUT) on-resistance paths, and a debounced TTL/CMOS-compatible MR input with 250µA internal pullup.
Its reset generator uses an internal timer to guarantee 200ms (min) reset pulse width after VCC rise or MR release; the battery switchover logic activates only when VCC falls below 4.40V and VBATT exceeds VCC by ≥20mV, with 40mV hysteresis preventing oscillation during slow VCC decay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±150mV - ensures reliable μP reset initiation before +5V supply brownout causes code corruption |
| Reset Pulse Width | 200ms typical - provides sufficient time for μP initialization and peripheral stabilization after power recovery |
| Supply Current | 200µA typical at +25°C - enables low-power system monitoring without significant load on main +5V rail |
| Battery-Backup Current | 50nA max - preserves lithium battery life for years in standby RAM retention applications |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path) - limits voltage drop to ≤250mV at 50mA load, ensuring stable RAM supply |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, instrumentation, and embedded computing environments |
| PFI Threshold | 1.25V ±50mV - enables accurate power-fail warning for unregulated supplies via external resistor divider |
Pinout & Package
MAX704ESA+ is housed in an 8-pin SO (Small Outline) package with standard 150mil body width and 0.050" lead pitch. Pin 1 is marked with a beveled corner or dot; the package is RoHS-compliant (lead-free), indicated by the "+" suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VOUT | Switched output supply | Delivers regulated +5V or backup battery voltage to CMOS RAM; connects to VCC or VBATT based on switchover logic |
| 2 VCC | Main +5V supply input | Primary power source; monitored for reset generation and used as substrate reference |
| 3 GND | Analog/digital ground | Common return for all internal circuits and external decoupling; must be low-impedance |
| 4 PFI | Power-fail comparator input | Accepts divided-down voltage for early warning of supply droop; referenced to internal 1.25V bandgap |
| 5 PFO | Power-fail comparator output | Active-low open-drain signal indicating PFI < 1.25V; disabled during battery-backup mode |
| 6 MR | Manual reset input | Active-low TTL/CMOS-compatible trigger; internally pulled up to VCC with 250µA current |
| 7 RESET | Reset output | Active-low push-pull output asserted when VCC < 4.40V or MR low; guaranteed valid down to VCC = 1.2V |
| 8 VBATT | Backup battery input | Accepts 2.8V–4.55V lithium cell; powers internal circuitry and VOUT during main supply failure |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1.2V | Ensures deterministic reset behavior even during deep brownout, preventing μP lockup |
| 200ms reset pulse width | Meets μP minimum reset timing requirements without external RC timing components |
| 50nA quiescent current in battery-backup mode | Extends 3V lithium battery life beyond 10 years in static RAM retention applications |
| 40mV battery switchover hysteresis | Prevents rapid VOUT source toggling during slow VCC decay, eliminating RAM supply glitches |
| Debounced MR input with 250µA pullup | Enables direct pushbutton connection without external debounce circuitry or pullup resistors |
Applications
| Industrial Controllers | Embedded Instrumentation |
|---|---|
Use Scenario: PLCs and motor controllers requiring nonvolatile RAM retention during AC mains interruption. IC Role / Device Role / Timing Role: Supervisory circuit providing seamless switchover from +5V rail to lithium backup battery and asserting reset to halt processor execution during undervoltage. Use Value: Prevents data corruption in configuration registers and real-time clocks by maintaining VOUT > 2.7V for >10 years on a single CR2032 cell. | Use Scenario: Portable multimeters and oscilloscopes needing persistent calibration data storage during battery replacement. IC Role / Device Role / Timing Role: Voltage monitor and battery switch enabling hot-swap of main power without resetting the measurement engine. Use Value: Allows battery replacement while VCC remains valid, avoiding loss of active measurements or calibration state due to unintended reset. |
| Computing Peripherals | Critical μP Power Monitoring |
Use Scenario: USB-to-serial adapters and PCIe endpoint devices requiring BIOS parameter retention across host power cycles. IC Role / Device Role / Timing Role: Reset generator and RAM power manager ensuring consistent device enumeration and configuration after host reboot. Use Value: Eliminates need for external EEPROM by preserving 256-byte SRAM contents using integrated switchover and ultra-low 50nA backup current. | Use Scenario: Medical infusion pumps where firmware integrity must be verified before each dose delivery. IC Role / Device Role / Timing Role: Primary power supervisor asserting reset if +5V drops below 4.40V for >200ms, blocking unsafe operation during power anomaly. Use Value: Provides fail-safe hardware-enforced reset window that cannot be bypassed by software, meeting IEC 62304 Class C 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 functionality but rated for 0°C to +70°C commercial temperature range | Suitable for office equipment or consumer electronics with controlled ambient | Select MAX704CSA for cost-sensitive commercial designs where extended temperature operation is unnecessary |
| MAX706ESA+ | No battery backup; includes watchdog timer and active-high reset output | Used where RAM retention is not required but system-level fault recovery via watchdog timeout is critical | Choose MAX706ESA+ when supervisory function focuses on runtime error detection rather than power-fail response |
Compared with MAX704ESA+, MAX704CSA offers identical electrical performance but reduced thermal qualification, while MAX706ESA+ trades battery switchover for watchdog capability-making it suitable for applications prioritizing runtime reliability over data retention during power loss.
Availability
MAX704ESA+ is available at Aetrix Electronics and suitable for industrial controllers, embedded instrumentation, and critical μP power monitoring requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX704ESA+ 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, automotive, and communications markets.
The MAX703/MAX704 family was engineered specifically for cost-sensitive microprocessor systems needing integrated reset, battery backup, and power-fail warning without external components.
FAQ
What is the guaranteed minimum reset pulse width for MAX704ESA+?
The MAX704ESA+ guarantees a minimum reset pulse width of 140ms, with a typical value of 200ms and maximum of 280ms. This timing is generated by an internal oscillator and timer circuit, ensuring consistent μP initialization regardless of external capacitor tolerances or temperature drift. The 200ms typical value meets or exceeds the reset timing requirements of most 8-bit and 16-bit microprocessors, including Intel 80Cxx and Motorola 68HCxx families. The MAX704ESA+ maintains this specification across its full –40°C to +85°C operating range.
Can MAX704ESA+ operate with a 3.3V main supply?
No, the MAX704ESA+ is designed exclusively for +5V systems and requires VCC between +4.5V and +5.5V for proper operation. Its 4.40V reset threshold and internal bandgap reference are optimized for 5V rails; applying 3.3V to VCC will prevent reset assertion and disable internal circuitry. For 3.3V applications, consider the MAX6326 series or MAX809, which feature 3.08V or adjustable thresholds. The MAX704ESA+ datasheet explicitly states VCC operating range as +4.5V to +5.5V, and absolute maximum ratings cap VCC at +6.0V.
How does MAX704ESA+ handle battery switchover during slow VCC decay?
The MAX704ESA+ uses a 40mV hysteresis in its battery switchover comparator to prevent oscillation during slow VCC decay. When VCC falls below the reset threshold (4.40V), switchover initiates only if VBATT exceeds VCC by ≥20mV; once activated, VCC must rise ≥20mV above VBATT to revert to main supply. This 40mV total hysteresis eliminates repeated VOUT source toggling that could cause RAM supply glitches. The MAX704ESA+ datasheet confirms this behavior in the "Battery Switchover Hysteresis" parameter (40mV) and Figure 3 block diagram, ensuring clean transitions even with <10mV/ms VCC ramp rates.
What is the maximum allowable backup battery voltage for MAX704ESA+?
The maximum allowable backup battery voltage for MAX704ESA+ is 4.55V, as specified in Table 2 of the official datasheet. Exceeding this voltage risks forward-biasing internal substrate diodes (D1 in Figure 3), causing current leakage from VBATT into the VCC substrate when VCC is near the reset threshold. This condition can degrade reset accuracy and increase quiescent current. Lithium coin cells (3.0V–3.6V) and supercapacitors charged to ≤4.55V comply safely; higher-voltage sources require series regulation. The MAX704ESA+ datasheet explicitly lists "MAXIMUM BACKUP-BATTERY VOLTAGE (V)" as 4.55 for MAX704 parts.
Does MAX704ESA+ provide active-high reset output?
No, the MAX704ESA+ provides only an active-low reset output (pin 7, RESET). It lacks an active-high variant in this package; the RESET pin is a push-pull driver that sinks current when asserted (low) and sources current when deasserted (high). For active-high reset functionality, designers must use external inversion (e.g., a single NPN transistor or inverter gate) or select alternative parts like the MAX707/MAX708 series, which integrate complementary active-high outputs. The MAX704ESA+ datasheet's Pin Description and Electrical Characteristics sections confirm RESET is active-low with VOH and VOL specifications defined accordingly.
MAX704ESA+ 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX704ESA+ FAQ
1.How can I place an order for MAX704ESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704ESA+ 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 MAX704ESA+ reliable?
The price and inventory of MAX704ESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704ESA+ is usually 5 days.
3.What payment methods are accepted for MAX704ESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704ESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704ESA+?
MAX704ESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704ESA+ 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 MAX704ESA+?
For technical support, including MAX704ESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704ESA+ requirements.
6.How does Aetrix verify that MAX704ESA+ is sourced from the original manufacturer or authorized distributors?
All MAX704ESA+ 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 MAX704ESA+ meets industry standards.
7.What is the process for return or replacement of MAX704ESA+?
All MAX704ESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX704ESA+, 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 MAX704ESA+ part is unused and in its original packaging.
Return procedure for MAX704ESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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