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Analog Devices Inc./Maxim Integrated MAX705CUA
- Part No.:
- MAX705CUA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX705CUA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:4,422
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Product details
Overview
The MAX705CUA from Maxim Integrated is a low-cost microprocessor supervisory circuit in an 8-pin µMAX package, providing active-low reset output, 1.6s watchdog timer, 1.25V power-fail comparator input, and debounced manual-reset input. It asserts a guaranteed 200ms reset pulse when VCC drops below 4.65V or MR is pulled low, and operates down to VCC = 1V - ideal for reliable power-up sequencing and brownout protection in embedded 5V systems.
For engineers reviewing the MAX705CUA datasheet, MAX705CUA pinout, MAX705CUA application, or MAX705CUA equivalent, key selection criteria include its 4.65V reset threshold, watchdog timeout tolerance (±37.5%), PFI comparator accuracy (±0.05V), guaranteed RESET validity at 1V supply, and compatibility with TTL/CMOS logic interfaces in space-constrained designs.
Technical Context
The MAX705CUA integrates four core supervisory functions on a single die: a precision voltage monitor with 40mV hysteresis, a monostable watchdog timer triggered by WDI edge transitions, a dedicated 1.25V reference-based power-fail comparator (PFI/PFO), and a TTL/CMOS-compatible manual-reset input with internal 250µA pull-up. All functions operate independently and are synchronized to VCC.
Its reset generator guarantees a minimum 140ms pulse width and releases RESET 200ms after VCC rises above 4.65V or MR returns high; the watchdog timeout is fixed at 1.6s (min 1.0s, max 2.25s) and clears on any WDI edge, reset assertion, or tristate condition - ensuring deterministic recovery from software hangs without external timing components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±0.15V - triggers reset during brownout when +5V rail dips below safe operating level |
| Reset Pulse Width | 200ms typical - ensures full μP initialization before code execution resumes |
| Watchdog Timeout | 1.6s ±0.65s - provides sufficient margin for firmware task cycles while preventing infinite loops |
| PFI Threshold | 1.25V ±0.05V - enables accurate early-warning detection of +5V regulator failure via external divider |
| Supply Voltage Range | 1.0V to 5.5V - supports valid RESET assertion even during deep brownout or battery backup |
| Quiescent Current | 150–350µA - minimizes standby power in always-on monitoring applications |
| MR Input Threshold | 0.8V low / 2.0V high - compatible with standard TTL and CMOS logic outputs without level shifting |
Pinout & Package
The MAX705CUA is housed in an 8-pin µMAX package (package code U8+1, outline 21-0036), measuring 3.0mm × 3.0mm × 0.8mm with exposed pad for thermal enhancement. It uses gull-wing leads, RoHS-compliant, and requires no lead-free suffix unless explicitly ordered with '+'.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (MR) | Manual-Reset Input | Active-low TTL/CMOS-compatible trigger; internal 250µA pull-up enables switch or logic drive without external resistor |
| 2 (VCC) | +5V Supply Input | Primary power rail connection; all internal functions referenced to this node |
| 3 (GND) | Ground Reference | Common return path for reset, watchdog, and comparator circuits; must be low-impedance |
| 4 (PFI) | Power-Fail Input | Noninverting input of 1.25V comparator; accepts voltage dividers for monitoring auxiliary rails or negative supplies |
| 5 (PFO) | Power-Fail Output | Open-drain active-low output asserting when PFI < 1.25V; sinks up to 3.2mA for interrupt signaling |
| 6 (WDI) | Watchdog Input | Edge-sensitive input; toggling within 1.6s prevents WDO assertion; floating disables watchdog |
| 7 (RESET) | Active-Low Reset Output | Push-pull output guaranteed low ≤0.4V at 3.2mA sink; pulses 200ms on power-up/brownout/manual trigger |
| 8 (WDO) | Watchdog Output | Open-drain active-low output asserting on timeout or VCC undervoltage; no minimum pulse width |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET validity at VCC = 1V | Enables fail-safe reset assertion during deep brownout or battery backup, critical for data retention |
| Debounced manual-reset input | 140ms minimum reset pulse eliminates need for external RC debounce circuitry |
| Independent power-fail comparator | 1.25V reference with ±0.05V tolerance allows precise early-warning detection of +5V regulator dropout |
| Watchdog timeout with automatic clear | Clears on any WDI edge, reset assertion, or tristate - prevents spurious timeouts during debug or sleep modes |
| µMAX package footprint | 3.0mm × 3.0mm area saves >60% board space vs. SO-8, enabling compact industrial and portable designs |
Applications
| Industrial PLC Control | Medical Diagnostic Equipment |
|---|---|
|
Use Scenario: Monitoring +5V supply integrity in programmable logic controllers deployed in factory-floor environments with noisy 24V DC bus coupling. IC Role / Device Role / Timing Role: Supervisory circuit asserting active-low RESET to ARM Cortex-M7 MCU during brownout, while PFO interrupts firmware to initiate safe I/O shutdown. Use Value: Prevents corrupted register writes and latch-up during transient line sags, meeting IEC 61000-4-11 immunity requirements. |
Use Scenario: Ensuring deterministic boot sequence in portable ultrasound units powered by Li-ion batteries with variable discharge profiles. IC Role / Device Role / Timing Role: Providing 200ms reset pulse at VCC ≥1V and using PFI to detect battery voltage decay below 3.3V via resistor divider. Use Value: Guarantees clean startup before analog front-end calibration, eliminating image artifacts caused by marginal supply conditions. |
| Point-of-Sale Terminal | Smart Energy Meter |
|
Use Scenario: Protecting transaction integrity in retail terminals subject to frequent AC power cycling and USB peripheral hot-plug events. IC Role / Device Role / Timing Role: Generating reset on power-up and using WDI toggled by firmware heartbeat to detect application lockup. Use Value: Recovers from frozen UI state without requiring user-initiated hard reset, maintaining PCI-DSS compliance logs. |
Use Scenario: Supervising metering SoC in ANSI C12.20-certified electricity meters operating across wide temperature ranges (-40°C to +85°C). IC Role / Device Role / Timing Role: Asserting RESET during brownout and using PFO to trigger EEPROM write-protection before power loss. Use Value: Preserves billing data integrity during grid instability, satisfying ANSI C12.19 Table 4.2 nonvolatile memory retention requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706CUA | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and feature set | Suitable for systems with tighter +5V tolerance or lower-noise regulators where earlier reset assertion is required | Select MAX706CUA only if design requires reset at 4.40V; otherwise MAX705CUA ensures compatibility with legacy 4.65V thresholds. |
| MAX813LCUA | Active-high RESET output only (no active-low RESET); same 4.65V threshold, 1.6s watchdog, and PFI/PFO functions | Required for μPs with active-high reset inputs (e.g., Intel 80C51), eliminating need for external inverter | Choose MAX813LCUA when interfacing to active-high reset MCUs; MAX705CUA remains optimal for standard active-low reset architectures. |
Compared with MAX706CUA and MAX813LCUA, the MAX705CUA uniquely delivers active-low reset at the industry-standard 4.65V threshold in the space-saving µMAX package - making it the preferred choice for cost-sensitive, board-area-constrained 5V embedded systems requiring proven brownout immunity.
Availability
MAX705CUA is available at Aetrix Electronics and suitable for industrial PLC control, medical diagnostic equipment, point-of-sale terminals, smart energy meters, and critical μP power monitoring requiring stable component supply across extended temperature and lifecycle demands.
Supply support for MAX705CUA 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, computing, and communications markets.
The MAX705–MAX708/MAX813L family was designed to replace discrete reset generators and watchdog circuits in 5V microprocessor systems - delivering integrated supervision with guaranteed timing, low quiescent current, and compact packaging.
FAQ
What is the reset threshold voltage for the MAX705CUA?
The MAX705CUA has a nominal reset threshold of 4.65V, with a guaranteed range of 4.50V to 4.75V over temperature and supply variation. This threshold is factory-trimmed and applies to both power-up and brownout conditions. The device holds RESET low until VCC rises above this threshold and then sustains a 200ms reset pulse - ensuring robust initialization of connected microprocessors. The MAX705CUA's 4.65V threshold matches legacy 5V system requirements and differs from the 4.40V variant (MAX706CUA).
Does the MAX705CUA support operation below 5V supply?
Yes, the MAX705CUA operates from 1.0V to 5.5V and guarantees valid RESET output down to VCC = 1V - a key differentiator for battery-backed or ultra-low-power applications. At VCC = 1V, RESET remains a logic-low output (≤0.3V at 50µA sink), enabling safe hold-reset during deep brownout. This capability is confirmed in the Electrical Characteristics table under "RESET Output Voltage" for MAX70_C grade devices and is intrinsic to the MAX705CUA's internal bandgap and reset generator design.
How does the watchdog timer in the MAX705CUA function?
The MAX705CUA watchdog timer asserts WDO low if the WDI input remains static (high or low) for longer than 1.6 seconds (typical), with min/max limits of 1.0s and 2.25s. It clears automatically on any rising or falling edge at WDI, during RESET assertion, or when WDI is tristated. Pulses as short as 50ns are detected. Unlike some watchdog ICs, the MAX705CUA does not require periodic servicing - it monitors firmware liveness passively. WDO can be connected to MR to generate a system reset upon timeout.
Can the MAX705CUA monitor voltages other than +5V?
Yes, the MAX705CUA's PFI input accepts external voltage dividers to monitor auxiliary rails (e.g., +3.3V, +12V) or negative supplies. Its internal 1.25V comparator reference enables precise detection: for example, a +12V rail can be scaled to 1.25V using a 130kΩ/12.4kΩ divider, triggering PFO when voltage drops below ~10.87V. Hysteresis can be added via feedback resistor between PFI and PFO, and noise immunity improved with a capacitor from PFI to GND - all supported in the MAX705CUA's documented Applications Information section.
What is the package type and footprint of the MAX705CUA?
The MAX705CUA is supplied in an 8-pin µMAX package (outline 21-0036), measuring 3.0mm × 3.0mm × 0.8mm with gull-wing leads and an exposed thermal pad. It is RoHS-compliant and available in both leaded and lead-free variants (add '+' suffix for lead-free). The µMAX footprint is pin-compatible with SO-8 and PDIP-8 versions of the same family but occupies ~60% less board area - critical for space-constrained applications like portable medical devices and smart meters where the MAX705CUA is commonly deployed.
MAX705CUA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- 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-uMAX/uSOP
MAX705CUA FAQ
1.How can I place an order for MAX705CUA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX705CUA 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 MAX705CUA reliable?
The price and inventory of MAX705CUA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX705CUA is usually 5 days.
3.What payment methods are accepted for MAX705CUA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX705CUA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX705CUA?
MAX705CUA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX705CUA 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 MAX705CUA?
For technical support, including MAX705CUA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX705CUA requirements.
6.How does Aetrix verify that MAX705CUA is sourced from the original manufacturer or authorized distributors?
All MAX705CUA 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 MAX705CUA meets industry standards.
7.What is the process for return or replacement of MAX705CUA?
All MAX705CUA units undergo pre-shipment inspection (PSI). If there is an issue with MAX705CUA, 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 MAX705CUA part is unused and in its original packaging.
Return procedure for MAX705CUA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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