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Analog Devices Inc./Maxim Integrated MAX703CSA-T
- Part No.:
- MAX703CSA-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX703CSA-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,446
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Product details
Overview
MAX703CSA-T from Maxim Integrated is a low-cost microprocessor supervisory circuit providing precision 4.65V supply-voltage monitoring, active-low reset with 200ms pulse width, battery-backup switchover for CMOS RAM, and 1.25V power-fail comparator functionality in an 8-pin SO package. It ensures reliable μP startup and brownout protection in embedded controllers and intelligent instruments.
For engineers reviewing the MAX703CSA-T datasheet, MAX703CSA-T pinout, MAX703CSA-T application, or MAX703CSA-T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, 50nA quiescent current in battery-backup mode, and precise 40mV hysteresis on the reset threshold - critical for stable operation in industrial power-monitoring designs.
Technical Context
The MAX703CSA-T integrates four core functions: a precision bandgap-based voltage monitor with 4.65V ±150mV threshold, a p-channel MOSFET-based battery switchover circuit with 20mV turn-on/turn-off thresholds and 40mV hysteresis, a dedicated 1.25V reference comparator for PFI/PFO, and a debounced TTL/CMOS-compatible manual reset input with internal 250µA pullup.
Its reset generator asserts active-low RESET during power-up, brownout (VCC < 4.65V), and power-down, holding the output low for a guaranteed minimum 140ms and typical 200ms after VCC rises above threshold. In battery-backup mode (VCC < VRST), internal circuitry powers from VBATT, disconnecting VCC from VOUT and forcing RESET low, PFO low, and disabling MR and PFI.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - guarantees reliable μP reset initiation before +5V supply dropout affects logic integrity |
| Reset Pulse Width | 140–280ms - ensures sufficient time for μP initialization and peripheral stabilization after power recovery |
| Supply Current (Active) | 200–350µA - enables low-power system monitoring without burdening main +5V rail |
| Quiescent Current (Battery Mode) | 50nA - preserves lithium battery life for years in memory-retention applications |
| Power-Fail Threshold | 1.25V ±50mV - provides accurate undervoltage warning for unregulated supplies via external resistor divider |
| Battery Switchover Hysteresis | 40mV - prevents oscillatory switching during slow VCC decay near VBATT voltage |
| RESET Assertion Down to VCC | 1V - maintains valid reset signal even during deep brownout, preventing undefined μP states |
Pinout & Package
MAX703CSA-T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with standard 1.27mm pitch and gull-wing leads. The package supports surface-mount assembly and meets JEDEC MS-012 specifications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VOUT) | RAM Supply Output | Switches between VCC (via 5Ω p-MOSFET) and VBATT (via 80Ω p-MOSFET) based on reset state and relative voltage levels |
| 2 (VCC) | +5V Main Supply Input | Primary power source; monitored for reset generation and used as substrate reference when active |
| 3 (GND) | Ground Reference | Common return path for all internal circuits and external loads; must be low-impedance for noise immunity |
| 4 (PFI) | Power-Fail Comparator Input | High-impedance (±25nA) node comparing external voltage to internal 1.25V reference; disabled in battery mode |
| 5 (PFO) | Power-Fail Comparator Output | Open-drain output sinking up to 3.2mA; forced low during battery-backup mode regardless of PFI |
| 6 (MR) | Manual Reset Input | Active-low TTL/CMOS-compatible input with internal 250µA pullup; debounced by reset timer |
| 7 (RESET) | Reset Output | Active-low open-drain output asserting during VCC brownout, power-up, and manual trigger; sinks 3.2mA min |
| 8 (VBATT) | Battery Backup Input | Accepts 2.0–4.8V backup source; powers internal circuitry and VOUT when VCC falls below reset threshold |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.65V Reset Threshold | Guaranteed ±150mV tolerance ensures deterministic reset timing across temperature and supply variations |
| 200ms Reset Pulse Width | Internally timed delay prevents premature μP release before power rails stabilize post-brownout |
| 50nA Battery-Backup Quiescent Current | Enables multi-year data retention in CMOS RAM using standard 3V lithium coin cells |
| Guaranteed RESET Assertion to VCC = 1V | Maintains functional reset signaling even during severe undervoltage conditions where other supervisors fail |
| 40mV Battery Switchover Hysteresis | Eliminates chatter during gradual VCC collapse, ensuring clean transition to backup power |
Applications
| Industrial PLC Controllers | Medical Diagnostic Instruments |
|---|---|
Use Scenario: Monitoring +5V supply integrity in programmable logic controller CPU modules during factory floor voltage fluctuations. IC Role / Device Role / Timing Role: Supervisory circuit asserting active-low RESET to hold μP in known state during brownout, while switching SRAM to lithium backup to preserve configuration data. Use Value: Prevents spurious program execution and memory corruption during transient line sags, meeting IEC 61000-4-11 immunity requirements. | Use Scenario: Ensuring safe shutdown and data retention in portable ultrasound imaging devices during battery swap or AC adapter disconnection. IC Role / Device Role / Timing Role: Detecting VCC drop below 4.65V to initiate controlled firmware save sequence, then enabling VBATT-to-VOUT switchover within 200ms. Use Value: Guarantees uninterrupted RAM contents for patient scan history and calibration settings, supporting FDA 21 CFR Part 11 data integrity mandates. |
| Point-of-Sale Terminals | Smart Energy Meters |
Use Scenario: Maintaining transaction log integrity in retail terminals subjected to frequent power cycling and unstable wall adapters. IC Role / Device Role / Timing Role: Providing 200ms reset pulse on power-up and brownout, while backing up real-time clock and sales buffer memory via 3.0V lithium cell. Use Value: Eliminates lost sale records and clock drift during brief outages, satisfying PCI DSS requirement for non-volatile transaction logging. | Use Scenario: Preserving tariff schedules and consumption registers in utility meters during grid instability or battery depletion events. IC Role / Device Role / Timing Role: Using PFI to monitor auxiliary 3.3V rail for early power-fail warning, triggering EEPROM write before VCC drops below 4.65V. Use Value: Enables deterministic data commit prior to full power loss, complying with ANSI C12.22 secure metering protocol. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX703CPA | Same electrical specs and function, but in 8-pin PDIP package with through-hole mounting | Suitable for prototyping, legacy board rework, or high-reliability military-grade assemblies requiring leaded solder compatibility | Select MAX703CPA only when through-hole assembly or MIL-STD-883 processing is required; MAX703CSA-T offers superior thermal performance and smaller footprint for modern SMT production. |
| MAX705CSA-T | Lacks battery-backup switching; adds watchdog timer and CE write-protect output; reset threshold same (4.65V) | Used where system-level watchdog supervision and flash memory protection are needed, not RAM backup | Choose MAX705CSA-T if watchdog timeout and hardware write-protection are mandatory; MAX703CSA-T is optimal when battery-backed SRAM retention is the primary requirement. |
Compared with MAX703CPA, MAX703CSA-T delivers identical supervisory functionality in a space- and thermally optimized SO package, while MAX705CSA-T trades battery switchover for watchdog and memory protection - making MAX703CSA-T the sole choice when long-term RAM data retention under power failure is critical.
Availability
MAX703CSA-T is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, point-of-sale terminals, and smart energy meters requiring stable component supply, long-lifecycle support, and guaranteed RoHS compliance.
Supply support for MAX703CSA-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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MAX703/MAX704 product line was designed specifically for cost-sensitive microprocessor systems needing reliable power-supply monitoring and battery-backed memory retention without external discrete components.
FAQ
What is the guaranteed reset threshold voltage for MAX703CSA-T?
The MAX703CSA-T has a guaranteed reset threshold voltage of 4.65V with a tolerance of ±150mV (4.50V to 4.75V) over the 0°C to +70°C operating temperature range. This specification ensures consistent reset activation across all units and environmental conditions, directly supporting deterministic μP initialization in +5V systems.
Does MAX703CSA-T support battery-backup operation with lithium coin cells?
Yes, MAX703CSA-T supports battery-backup operation with standard 3.0V to 3.6V lithium coin cells. Its 50nA quiescent current in battery-backup mode enables multi-year data retention in CMOS RAM, and its 4.80V maximum allowable VBATT voltage (per Table 2) ensures safe interface with common CR2032 and BR2032 batteries without external regulation.
How does the manual reset input (MR) function on MAX703CSA-T?
The MR input on MAX703CSA-T is an active-low, TTL/CMOS-compatible pin with an internal 250µA pullup current. Pulling MR below 0.8V generates a full 200ms reset pulse, independent of VCC level. The internal debounce eliminates switch bounce issues, and leaving MR floating disables manual reset functionality entirely - no external pullup required.
Can MAX703CSA-T monitor negative supply voltages?
Yes, MAX703CSA-T can monitor negative supply voltages using an external resistor network that references the PFI input to ground. As shown in Figure 8 of the datasheet, connecting the negative rail through resistors R1 and R2 to PFI allows detection of negative supply droop, causing PFO to transition from low to high - enabling use in dual-rail systems with ±12V or ±15V supplies.
What is the maximum allowable backup battery voltage for MAX703CSA-T?
The maximum allowable backup battery voltage for MAX703CSA-T is 4.80V, as specified in Table 2 of the datasheet. Exceeding this voltage risks forward-biasing internal substrate diodes (D1 in Figure 3), potentially causing unintended current flow from VBATT to VCC and compromising reliability in battery-backup mode.
MAX703CSA-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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX703CSA-T FAQ
1.How can I place an order for MAX703CSA-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX703CSA-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 MAX703CSA-T reliable?
The price and inventory of MAX703CSA-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX703CSA-T is usually 5 days.
3.What payment methods are accepted for MAX703CSA-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX703CSA-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX703CSA-T?
MAX703CSA-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX703CSA-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 MAX703CSA-T?
For technical support, including MAX703CSA-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX703CSA-T requirements.
6.How does Aetrix verify that MAX703CSA-T is sourced from the original manufacturer or authorized distributors?
All MAX703CSA-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 MAX703CSA-T meets industry standards.
7.What is the process for return or replacement of MAX703CSA-T?
All MAX703CSA-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX703CSA-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 MAX703CSA-T part is unused and in its original packaging.
Return procedure for MAX703CSA-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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