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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:2,475
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Product details
Overview
MAX703ESA+T from Maxim Integrated is a precision microprocessor supervisory circuit in 8-pin SO package, providing active-low reset assertion at 4.65V supply threshold, battery-backup switchover with 200ms reset pulse width, and 1.25V power-fail comparator input for critical μP power monitoring in industrial controllers and intelligent instruments.
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, 200μA typical supply current, and compatibility with lithium backup batteries (3.0V–3.6V) and supercapacitor sources.
Technical Context
The MAX703ESA+T integrates four core functions: a precision voltage monitor with 4.65V ±40mV hysteresis 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 with PFI/PFO interface, and a debounced TTL/CMOS-compatible manual reset input with 250µA internal pullup.
Its operation spans two distinct power domains: normal mode (VCC ≥ 4.65V) where VOUT connects to VCC and RESET remains high after 200ms delay, and battery-backup mode (VCC < 4.65V and VBATT > VCC + 20mV) where VOUT connects to VBATT, RESET stays low, and PFI/PFO are disabled while supply current drops to ≤5.0µA across temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±40mV - guarantees reliable μP reset initiation during brownout before logic corruption occurs. |
| Reset Pulse Width | 140–280ms (typ. 200ms) - ensures sufficient time for μP initialization and peripheral stabilization. |
| Supply Current | 200–500µA (E-grade, -40°C to +85°C) - enables low-power system monitoring without burdening main supply. |
| Battery-Backup Quiescent Current | ≤5.0µA (full temp range) - preserves lithium battery life for multi-year RAM retention. |
| Power-Fail Comparator Threshold | 1.25V ±50mV - supports accurate undervoltage detection of auxiliary supplies via external resistor divider. |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path) - limits voltage drop under 5mA load to <25mV (VCC) or <200mV (VBATT). |
| RESET Output Drive | Sinks 3.2mA at VOL ≤0.4V - directly interfaces with standard CMOS/TTL reset inputs without external pullup. |
Pinout & Package
MAX703ESA+T is housed in an 8-pin SO (Small Outline) package with gull-wing leads, RoHS-compliant, rated for -40°C to +85°C operation. Pin 1 is marked by a beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VOUT) | Switched Power Output | Delivers regulated +5V (from VCC) or backup battery voltage (from VBATT) to CMOS RAM; auto-selects source based on VCC/VBATT comparison. |
| 2 (VCC) | Main Supply Input | +5V system supply input; powers internal circuitry and drives VOUT when above reset threshold; must remain ≥1V for guaranteed RESET assertion. |
| 3 (GND) | Ground Reference | Common return path for all analog and digital functions; substrate connection point; must be low-impedance for noise immunity. |
| 4 (PFI) | Power-Fail Input | Analog input referenced to 1.25V; triggers PFO low when voltage falls below threshold; internally disabled in battery-backup mode. |
| 5 (PFO) | Power-Fail Output | Open-drain output that sinks current when PFI < 1.25V; used as interrupt or warning signal; forced low during battery-backup mode. |
| 6 (MR) | Manual Reset Input | Active-low TTL/CMOS-compatible input with 250µA internal pullup; generates full reset pulse when pulled below 0.8V; debounced by 200ms timer. |
| 7 (RESET) | Reset Output | Active-low open-drain output; asserted low during power-up, brownout, or MR activation; holds low for min. 140ms after VCC recovery. |
| 8 (VBATT) | Battery Backup Input | Backup power source input (2.8V–3.6V typical); enables automatic switchover to preserve RAM data when VCC fails; draws <1µA when VCC < VBATT − 1V. |
Key Features
| Feature | Design Value |
|---|---|
| Precision Reset Threshold | 4.65V with ±40mV hysteresis ensures clean, bounce-free reset release and prevents oscillation near trip point. |
| Guaranteed RESET Assertion to VCC = 1V | Enables valid reset signaling even during deep brownout conditions where other supervisors fail. |
| Low-Power Battery-Backup Mode | Quiescent current ≤5.0µA over full -40°C to +85°C range extends lithium battery life beyond 10 years in standby. |
| Integrated Power-Fail Comparator | 1.25V reference with <25nA input bias allows high-impedance monitoring of unregulated rails without loading. |
| Debounced Manual Reset | 250µA internal pullup and 200ms minimum pulse width eliminate need for external RC debounce circuitry. |
Applications
| Industrial Controller Power Monitoring | Intelligent Instrument RAM Backup |
|---|---|
|
Use Scenario: PLC or motion controller operating in harsh factory environments with fluctuating 5V supply rails. IC Role / Device Role / Timing Role: Supervisory IC asserting active-low RESET to ARM Cortex-M7 processor during brownout, while switching SRAM to 3.6V lithium battery. Use Value: Prevents firmware corruption and preserves real-time process state for 10+ years using 50nA backup current. |
Use Scenario: Portable handheld multimeter with nonvolatile configuration storage and calibration data. IC Role / Device Role / Timing Role: Voltage monitor and battery switchover device maintaining SRAM integrity during battery swap or AC power loss. Use Value: Enables hot-swap of primary battery without triggering system reset or losing measurement history. |
| Critical μP Power Monitoring | Embedded Computer BIOS Protection |
|
Use Scenario: Medical infusion pump requiring fail-safe boot sequence and runtime power validation. IC Role / Device Role / Timing Role: Primary reset generator ensuring PIC18F microcontroller enters known state before executing safety-critical code. Use Value: 200ms reset pulse width exceeds minimum 100ms requirement for flash memory initialization and watchdog setup. |
Use Scenario: Industrial PC motherboard with legacy BIOS stored in SPI flash and CMOS RTC/NVRAM. IC Role / Device Role / Timing Role: Dual-role supervisor providing both VCC reset and PFI-based power-fail warning to BIOS firmware. Use Value: PFO interrupt allows BIOS to initiate graceful shutdown and save volatile settings before VCC collapse. |
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 backup functionality. | Used where tighter 5V supply tolerance (±10%) requires earlier reset assertion to prevent marginal operation. | Select MAX704ESA+T only if system VCC can dip to 4.4V without logic failure; otherwise MAX703ESA+T provides wider noise margin. |
| MAX705CSA+ | No battery backup; adds watchdog timer and CE write-protect; 4.65V reset; same 8-SO package. | Suitable for systems needing watchdog supervision but no RAM backup, e.g., simple embedded controllers. | Choose MAX705CSA+ when watchdog timeout (1.6s) and write-protect are required, and battery switchover is unnecessary. |
Compared with MAX704ESA+T, the MAX703ESA+T offers higher reset threshold for improved noise immunity in noisy 5V rails; compared with MAX705CSA+, it trades watchdog capability for essential battery-backed RAM retention in long-term data logging applications.
Availability
MAX703ESA+T is available at Aetrix Electronics and suitable for industrial controllers, intelligent instruments, medical devices, and embedded computers requiring stable component supply with extended temperature support (-40°C to +85°C) and RoHS compliance.
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 precision analog and mixed-signal ICs for industrial, communications, and computing applications, with emphasis on reliability and low-power operation.
The MAX703/MAX704 product line delivers cost-effective, integrated supervisory solutions for μP systems requiring guaranteed reset, battery-backed memory retention, and power-fail warning-targeting applications where board space and power budget are constrained.
FAQ
What is the guaranteed minimum reset pulse width for MAX703ESA+T?
The MAX703ESA+T guarantees a reset pulse width of at least 140ms, with typical performance at 200ms and maximum at 280ms. This duration ensures reliable initialization of microprocessors and peripherals such as flash memory and communication interfaces. The pulse starts when VCC rises above 4.65V and is maintained regardless of brief VCC fluctuations within the hysteresis band. The MAX703ESA+T's internal timer enforces this minimum width even if VCC remains stable.
Can MAX703ESA+T operate with a 3.3V main supply?
No, the MAX703ESA+T is specified for VCC operation between 4.5V and 5.5V, with reset assertion occurring below 4.65V. It is not designed for 3.3V systems. Attempting to use it with 3.3V will result in permanent failure to assert RESET, as the internal voltage monitor cannot detect a valid brownout condition. For 3.3V applications, consider the MAX6326 series or MAX706R, which feature 3.08V or adjustable thresholds compatible with lower-voltage rails.
How does MAX703ESA+T handle backup battery replacement without causing system reset?
The MAX703ESA+T allows safe battery replacement while VCC remains valid (≥4.65V), because battery-backup mode only activates when VCC falls below the reset threshold. As long as VCC stays above 4.65V, the internal switchover comparator remains inactive and VBATT pin floating does not trigger RESET. This behavior prevents spurious resets during maintenance-a key advantage over older switchover ICs. The MAX703ESA+T's design ensures continuity of operation during battery service intervals.
What is the maximum allowable backup battery voltage for MAX703ESA+T?
The maximum allowable backup battery voltage for MAX703ESA+T 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 approaches the reset threshold, causing unwanted current flow from VBATT into the substrate and potential latch-up or increased quiescent current. Lithium coin cells (3.0V–3.6V) and properly sized supercaps are fully compliant; 4.8V represents the absolute upper limit for safe operation.
Does MAX703ESA+T support power-fail warning for negative supply rails?
Yes, the MAX703ESA+T's PFI input can monitor negative voltages using an external resistor network as shown in Figure 8 of the datasheet. By referencing PFI to ground through resistors R1 and R2, the comparator detects when the negative rail droops toward zero, causing PFO to transition from low to high. Accuracy depends on PFI threshold tolerance (±50mV), VCC stability, and resistor matching. This configuration enables fail-safe monitoring of -5V, -12V, or other negative supplies without additional ICs.
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:
- 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+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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