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Analog Devices Inc./Maxim Integrated MAX703ESA-T
- Part No.:
- MAX703ESA-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX703ESA-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,313
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Product details
Overview
MAX703ESA-T from Maxim Integrated is a microprocessor supervisory circuit designed for power-supply monitoring and battery-backup switching in embedded 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 requiring reliable brownout protection and CMOS RAM retention.
For engineers reviewing the MAX703ESA-T datasheet, MAX703ESA-T pinout, MAX703ESA-T application, or MAX703ESA-T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 50nA quiescent current in battery-backup mode, ±40mV reset threshold hysteresis, and compatibility with lithium batteries (3.0–3.6V) and supercapacitor backup sources.
Technical Context
The MAX703ESA-T integrates four core functions in a single 8-pin SO package: a precision voltage monitor with fixed 4.65V reset threshold, a debounced TTL/CMOS-compatible manual reset input (MR), a 1.25V reference-based power-fail comparator (PFI/PFO), and bidirectional battery switchover logic that connects VBATT to VOUT when VCC falls below threshold - with 40mV hysteresis to prevent oscillation during slow VCC decay.
Its internal architecture includes a p-channel MOSFET switch (5Ω on-resistance in VCC mode, 80Ω in VBATT mode), a reset timer with guaranteed 140–280ms pulse width, and substrate isolation during battery-backup mode to eliminate leakage paths - enabling valid RESET output even as VCC collapses to 1V while maintaining <1μA supply current when VCC is >1V below VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - asserts active-low RESET when VCC drops below this level, ensuring deterministic μP initialization during brownout. |
| Reset Pulse Width | 200ms typical - guarantees sufficient hold time for μP boot sequence after power recovery, with 140–280ms guaranteed range. |
| Power-Fail Threshold | 1.25V ±50mV - enables precise undervoltage detection of auxiliary supplies via PFI pin for early warning before main supply collapse. |
| Quiescent Current | 200µA max (VCC powered), 50nA max (battery-backup mode) - minimizes standby drain on backup source, extending lithium battery life beyond 10 years. |
| Battery Switchover Hysteresis | 40mV - prevents chattering during marginal VCC transitions by requiring 20mV rise above VBATT to re-engage VCC path. |
| Operating Temperature | -40°C to +85°C - qualified for industrial environments where thermal cycling impacts long-term reliability of power-monitoring circuits. |
| VOUT Output Voltage Drop | VCC − 0.025V @ 5mA - ensures minimal voltage loss to connected CMOS RAM during normal operation, preserving data integrity. |
Pinout & Package
MAX703ESA-T is housed in an 8-pin SO (Small Outline) package with standard 1.27mm pitch, RoHS-compliant lead-free finish (denoted by "+" suffix), and JEDEC MS-012AC outline. The package supports surface-mount assembly and provides thermal performance suitable for industrial PCBs with moderate airflow.
| 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 state; delivers regulated backup power without external diodes. |
| 2 - VCC | +5V main supply input | Primary power rail monitored for reset generation; must be ≥4.65V for normal operation; powers internal circuitry unless in battery-backup mode. |
| 3 - GND | Ground reference | Common return for all analog and digital functions; substrate connection is isolated during battery-backup mode to prevent VBATT leakage. |
| 4 - PFI | Power-fail comparator input | Compares external voltage (e.g., unregulated DC) against 1.25V internal reference; triggers PFO low when input falls below threshold. |
| 5 - PFO | Power-fail comparator output | Active-low open-drain output signaling power-fail condition; disabled and forced low during battery-backup mode to conserve current. |
| 6 - MR | Manual reset input | Active-low TTL/CMOS-compatible input with 250µA internal pullup; generates 200ms reset pulse when pulled below 0.8V. |
| 7 - RESET | Reset output | Active-low push-pull output asserted when VCC < 4.65V or MR is active; remains low for full 200ms after recovery, ensuring μP reset completion. |
| 8 - VBATT | Backup-battery input | Accepts 2.8–4.8V lithium or supercap source; automatically powers VOUT when VCC fails; draws <1µA when VCC is >1V below VBATT. |
Key Features
| Feature | Design Value |
|---|---|
| Precision Reset Threshold | 4.65V with ±150mV tolerance and 40mV hysteresis - eliminates need for external resistor dividers or trimming, reducing BOM count and layout area. |
| Battery-Backup Switchover Logic | Automatic, low-leakage switching between VCC and VBATT with substrate isolation - preserves RAM data during extended outages without external FETs or diodes. |
| Guaranteed RESET Assertion to VCC = 1V | RESET remains valid and sinks current down to VCC = 1V - ensures robust reset behavior during deep brownouts where competing supervisors fail. |
| Ultra-Low Battery-Backup Current | 50nA typical quiescent current in VBATT-only mode - enables >10-year backup life with standard CR2032 lithium coin cells. |
| Debounced Manual Reset Input | 250µA internal pullup and 200ms minimum pulse width - eliminates need for external RC debounce networks or firmware debouncing routines. |
Applications
| Industrial PLC Controllers | Medical Diagnostic Equipment |
|---|---|
Use Scenario: Maintaining volatile configuration memory and real-time clock during AC mains interruption or brownout events in programmable logic controllers. IC Role / Device Role / Timing Role: Supervisory IC providing dual-role power monitoring (VCC reset) and seamless battery-backed RAM supply (VOUT switchover). Use Value: Prevents loss of ladder logic programs and calibration data by asserting RESET only when VCC is truly invalid and sustaining VOUT from VBATT within 100ns of VCC collapse. | Use Scenario: Preserving patient parameter history and system calibration settings during brief power interruptions in portable ultrasound or ECG devices. IC Role / Device Role / Timing Role: Power-fail detector (PFI/PFO) coupled with battery-backed RAM supply (VOUT) and hard-reset generator (RESET). Use Value: Enables uninterrupted data logging by triggering NMI interrupt via PFO before main supply collapse and retaining SRAM contents using 3.6V lithium cell with <50nA standby drain. |
| Point-of-Sale Terminals | Smart Energy Meters |
Use Scenario: Securing transaction logs and encryption keys during unexpected power loss in retail payment terminals deployed in unstable grid environments. IC Role / Device Role / Timing Role: Microprocessor supervisor with manual reset (MR) for field service and battery-backed VOUT for nonvolatile SRAM retention. Use Value: Guarantees atomic write completion for financial records by holding μP in RESET until stable VCC returns and delivering clean 4.95V to RAM from VCC (not VBATT) during normal operation. | Use Scenario: Retaining billing cycle data, tamper logs, and time-of-use registers during grid outages in ANSI C12.20-compliant electricity meters. IC Role / Device Role / Timing Role: Dual-threshold supervisor (4.65V reset + 1.25V PFI) enabling both main supply monitoring and auxiliary DC rail supervision. Use Value: Supports dual-voltage monitoring - VCC for 5V logic rail and PFI for 3.3V RTC/EEPROM supply - with independent PFO interrupt signaling for predictive maintenance alerts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704ESA-T | 4.40V reset threshold (vs. 4.65V), identical pinout, timing, and features | Suitable for systems with tighter VCC tolerance (±10%) or lower nominal supply rails | Select MAX704ESA-T when main supply is 5V ±10% or when interfacing with 4.5V-tolerant μPs. |
| MAX705CSA+ | No battery backup, 4.65V reset, integrated watchdog timer, CE write-protect output | Lacks VBATT/VOUT functionality but adds watchdog timeout and memory write protection | Choose MAX705CSA+ when system requires watchdog supervision and memory protection but does not need RAM backup. |
Compared with MAX704ESA-T, the MAX703ESA-T offers higher reset threshold for improved noise margin in noisy 5V systems; compared with MAX705CSA+, it trades watchdog capability for essential battery-switchover functionality required in data-retention-critical applications.
Availability
MAX703ESA-T is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic equipment, point-of-sale terminals, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX703ESA-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 high-performance analog and mixed-signal ICs for industrial, communications, computing, and consumer applications, with emphasis on power management, interface, and sensing solutions.
The MAX703/MAX704 product line was engineered specifically for cost-sensitive microprocessor systems needing reliable power monitoring and battery-backed memory retention - targeting applications where discrete reset generators and backup switches would increase board area and failure risk.
FAQ
What is the guaranteed reset threshold voltage for MAX703ESA-T?
The MAX703ESA-T has a guaranteed reset threshold of 4.65V, with a minimum of 4.50V and maximum of 4.75V across the full -40°C to +85°C operating temperature range. This threshold is factory-trimmed and specified in the Electrical Characteristics table of the official datasheet. The MAX703ESA-T asserts its active-low RESET output whenever VCC falls below this value, and holds RESET low for at least 140ms after VCC rises above the threshold - ensuring robust initialization of connected microprocessors under varying load and temperature conditions.
Does MAX703ESA-T support lithium battery backup, and what voltage range is allowed?
Yes, MAX703ESA-T supports direct connection of lithium batteries to the VBATT pin, with a maximum allowable voltage of 4.80V as specified in Table 2 of the datasheet. Standard 3.0V to 3.6V lithium coin cells (e.g., CR2032) are fully compatible and require no external regulation. The device automatically switches VOUT to VBATT when VCC drops below 4.65V, and draws only 50nA in battery-backup mode - enabling multi-year data retention. Exceeding 4.80V risks substrate conduction through internal diode D1, so voltage clamping or regulation is required for higher-voltage sources.
How does the power-fail comparator (PFI/PFO) function in MAX703ESA-T?
The MAX703ESA-T's PFI pin compares an external voltage against an internal 1.25V reference; when PFI falls below this threshold, the open-drain PFO output goes low to signal impending power failure. This allows early warning before VCC collapse - for example, monitoring unregulated DC input to trigger μP save routines. PFO is disabled and forced low during battery-backup mode to minimize current draw. The comparator features low input current (<25nA) and can be enhanced with external hysteresis resistors (R1/R2/R3) to reject noise near the trip point, as shown in Figure 7 of the datasheet.
Can MAX703ESA-T operate with VCC as low as 1V, and what happens to RESET output?
Yes, MAX703ESA-T guarantees RESET assertion down to VCC = 1V, meaning the active-low RESET output remains functional and capable of sinking current even as the main supply collapses. Below 1V, RESET becomes high-impedance (open-circuit), which may cause floating logic inputs. To ensure a defined low state in deep brownout, the datasheet recommends adding a 100kΩ pulldown resistor from RESET to GND (Figure 6). This design choice distinguishes MAX703ESA-T from many competitors whose RESET outputs become invalid well above 1V, making it suitable for ultra-robust industrial power monitoring.
What is the quiescent current of MAX703ESA-T in normal and battery-backup modes?
In normal operation (VCC powered, VBATT inactive), MAX703ESA-T draws ≤350µA typical supply current (200–500µA over temperature). In battery-backup mode (VCC = 0V, VBATT = 2.8V), quiescent current drops to ≤1.0µA over temperature, with a typical value of 50nA at +25°C - verified in the Electrical Characteristics table. This ultra-low standby current enables decade-long backup operation with standard lithium coin cells. The transition between modes is fully automatic and requires no external control signals or configuration.
MAX703ESA-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:
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX703ESA-T FAQ
1.How can I place an order for MAX703ESA-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX703ESA-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 MAX703ESA-T reliable?
The price and inventory of MAX703ESA-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX703ESA-T is usually 5 days.
3.What payment methods are accepted for MAX703ESA-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX703ESA-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX703ESA-T?
MAX703ESA-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX703ESA-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 MAX703ESA-T?
For technical support, including MAX703ESA-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX703ESA-T requirements.
6.How does Aetrix verify that MAX703ESA-T is sourced from the original manufacturer or authorized distributors?
All MAX703ESA-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 MAX703ESA-T meets industry standards.
7.What is the process for return or replacement of MAX703ESA-T?
All MAX703ESA-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX703ESA-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 MAX703ESA-T part is unused and in its original packaging.
Return procedure for MAX703ESA-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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