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Analog Devices Inc./Maxim Integrated MAX825REXK-T
- Part No.:
- MAX825REXK-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
MAX825REXK-T.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:11,978
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Product details
Overview
MAX825REXK-T from Maxim Integrated is a 5-pin SC70-packaged microprocessor supervisory circuit with manual reset input and complementary active-high reset output, designed for precise power-supply monitoring in embedded systems. It features a 2.63V reset threshold, 140ms minimum reset timeout, guaranteed RESET validity down to VCC = 1V, 2µA supply current (SC70), and operates over –40°C to +85°C for battery-powered instrumentation.
For engineers reviewing the MAX825REXK-T datasheet, MAX825REXK-T pinout, MAX825REXK-T application, or MAX825REXK-T equivalent, key selection criteria include reset threshold accuracy, manual reset timing behavior, SC70 thermal performance, and compatibility with bidirectional µP reset pins requiring ≤1.2mA sink capability at VCC = 2.7V.
Technical Context
The MAX825REXK-T implements a precision voltage comparator with 40ppm/°C temperature coefficient and internal hysteresis (5mV) to reject noise-induced false resets. Its reset generator uses an RC-based timer ensuring 140–280ms timeout, while the manual reset path includes a 52kΩ internal pullup and 1µs minimum MR pulse width tolerance.
Unlike the MAX823/MAX824 variants, the MAX825REXK-T omits watchdog functionality but adds an active-high RESET output synchronized to the active-low RESET signal - enabling direct interface to logic families requiring high-asserted reset signals without external inverters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.63V ±15mV (TA = –40°C to +85°C); ensures reliable brownout detection for 2.7V–3.6V systems |
| Supply Current | 2µA typical (SC70 package, TA = +25°C); enables multi-year operation in coin-cell–powered devices |
| Reset Timeout | 140ms min / 280ms max; provides sufficient hold time for µP initialization across voltage ramps |
| Operating Range | VCC = 2.7V to 3.6V; matches nominal 3.0V/3.3V rail tolerances without external regulation |
| RESET Validity | Guaranteed low/high state down to VCC = 1V; supports graceful shutdown during deep brownout |
| MR Input Logic | VIL ≤ 0.3×VCC, VIH ≥ 0.7×VCC; compatible with standard CMOS drivers and open-drain switches |
| Output Drive | RESET sinks 1.2mA @ VCC = 2.7V, VOL ≤ 0.3V; interfaces directly with µP bidirectional reset pins |
Pinout & Package
MAX825REXK-T is housed in a 5-pin SC70-5 package (2.0mm × 2.1mm × 0.9mm, 0.65mm pitch), optimized for space-constrained portable designs and offering 247mW power dissipation at +70°C ambient.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low open-drain reset output; asserts low during power-up, brownout, or MR activation |
| 2 | GND | Analog/digital ground reference; must be connected to system ground plane for comparator stability |
| 3 | MR | Manual reset input; logic-low assertion forces reset for ≥1µs; internal 52kΩ pullup allows floating if unused |
| 4 | RESET | Active-high push-pull reset output; inverse of Pin 1; drives high when VCC > 2.63V and MR inactive |
| 5 | VCC | Positive supply input; accepts 2.7V–3.6V; requires local 0.1µF ceramic bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| 2.63V Precision Reset Threshold | Enables accurate supervision of 2.7V/3.0V rails without external resistor dividers or calibration |
| Complementary RESET Outputs | Eliminates need for external inverters when interfacing with both active-low and active-high reset logic |
| 1µA-Level Quiescent Current | Extends battery life in always-on monitoring applications such as smart sensors and wearables |
| MR Noise Immunity | Rejects pulses <100ns wide; prevents spurious resets from ESD or switching noise on manual reset lines |
| VCC Transient Immunity | Withstands negative-going glitches down to 2.25V for ≤1µs without triggering reset (per VRST–VCC overdrive curve) |
Applications
| Portable Medical Sensors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Continuous glucose monitor powered by CR2032 coin cell with firmware update capability via BLE. IC Role / Device Role / Timing Role: Supervises 3.0V LDO output; asserts reset during battery voltage sag below 2.63V and on user-initiated firmware recovery. Use Value: Prevents corrupted memory writes during brownout and enables safe reinitialization after manual reset button press. | Use Scenario: DIN-rail mounted analog input module operating in factory environments with 24VDC-derived 3.3V rail. IC Role / Device Role / Timing Role: Monitors isolated 3.3V supply; triggers dual-reset outputs to simultaneously reset ARM Cortex-M4 MCU and FPGA configuration logic. Use Value: Ensures deterministic startup sequence across heterogeneous logic domains using single supervisory IC. |
| Automotive Body Control Units | Smart Energy Meters |
Use Scenario: Door module with LIN transceiver, EEPROM, and wake-on-RF circuitry exposed to load-dump transients. IC Role / Device Role / Timing Role: Provides reset assertion during cold-crank (VCC dip to 2.5V) and validates power integrity before CAN controller initialization. Use Value: Guarantees µP remains held in reset until stable 2.7V+ supply is confirmed, avoiding bus arbitration errors. | Use Scenario: ANSI C12.22-compliant meter with real-time clock, metrology ASIC, and RF mesh radio. IC Role / Device Role / Timing Role: Supervises backup supercapacitor-charged 3.0V rail; asserts reset when voltage decays below 2.63V during AC mains failure. Use Value: Preserves RTC timekeeping integrity and initiates controlled shutdown of non-volatile memory writes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX825SEUK-T | SOT23-5 package, –40°C to +125°C rating, same 2.93V threshold and functional pinout | Higher temperature range suits under-hood automotive use; larger footprint increases board area by 2.3× | Select when extended temperature operation or legacy SOT23 layout reuse is required |
| TPS3808G33DBVR | TI device with 3.08V threshold, 350ms reset timeout, 1.6µA quiescent current, and no complementary reset output | Lacks active-high RESET pin; requires external inverter for dual-signal systems; higher reset delay reduces µP boot margin | Choose only when 3.08V threshold better matches system rail or TI supply-chain preference dominates |
Compared with MAX825REXK-T, MAX825SEUK-T offers identical supervision logic in a thermally robust SOT23 package but sacrifices space efficiency, while TPS3808G33DBVR trades complementary outputs and tighter threshold tolerance for ultra-low current and broader vendor support - making MAX825REXK-T optimal for compact, dual-output 2.7V–3.6V systems demanding precision and layout simplicity.
Availability
MAX825REXK-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive body control units, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX825REXK-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 power, sensing, and connectivity applications in industrial, automotive, and computing markets.
The MAX823/MAX824/MAX825 family delivers integrated reset, watchdog, and manual reset functions in ultra-small packages to simplify power-management architecture in space- and power-constrained embedded systems.
FAQ
What is the exact reset threshold voltage for MAX825REXK-T and how tightly is it specified?
The MAX825REXK-T has a nominal reset threshold of 2.63V, with a guaranteed range of 2.59V to 2.66V over the full operating temperature range (–40°C to +85°C). This specification is validated per the Reset Threshold Table in the official Maxim datasheet, and the device exhibits only 40ppm/°C temperature coefficient - ensuring minimal drift across environmental conditions. The MAX825REXK-T maintains this accuracy without external components or calibration.
Does MAX825REXK-T include a watchdog timer function?
No, the MAX825REXK-T does not include a watchdog timer. Per the Selector Guide and Functional Diagram in the Maxim datasheet, the MAX825 variant provides manual reset input (MR) and complementary active-high reset output (RESET), but explicitly omits the WDI (watchdog input) pin and associated timing circuitry present in MAX823/MAX824 versions. The MAX825REXK-T pinout contains only VCC, GND, MR, RESET (active-low), and RESET (active-high).
What is the maximum allowable VCC transient duration that will not trigger a reset on MAX825REXK-T?
According to the Typical Operating Characteristics graph "Maximum VCC Transient Duration vs. Reset Threshold Overdrive", a negative-going VCC transient of 100mV below the 2.63V threshold (i.e., to 2.53V) can last up to approximately 1.2µs without asserting reset. At 200mV overdrive (VCC = 2.43V), the maximum allowable duration drops to ~0.3µs. These values are measured under SC70 conditions and assume proper 0.1µF local bypassing as recommended in the MAX825REXK-T application circuit.
Can MAX825REXK-T drive a microcontroller's bidirectional reset pin directly?
Yes, the MAX825REXK-T can directly interface with bidirectional µP reset pins such as those found on the 68HC11 or STM32 series. Its active-low RESET output sinks up to 1.2mA at VCC = 2.7V with VOL ≤ 0.3V, while its maximum pullup current is 400µA - well within the 200–800µA range expected by most bidirectional reset inputs. This eliminates need for external pullup resistors or level-shifting circuitry in standard 3.0V/3.3V systems.
What is the function of Pin 4 on MAX825REXK-T, and how does it differ from Pin 1?
Pin 1 of the MAX825REXK-T is the active-low open-drain RESET output, while Pin 4 is the complementary active-high push-pull RESET output. When VCC rises above 2.63V and MR is inactive, Pin 1 goes high-impedance (requiring external pullup), and Pin 4 actively drives high (~VCC). During reset assertion, Pin 1 pulls low and Pin 4 pulls low - providing simultaneous assertion of both logic polarities. This dual-output architecture enables direct connection to mixed-signaling systems without discrete inverters or additional supervision ICs.
MAX825REXK-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.63V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-5
MAX825REXK-T FAQ
1.How can I place an order for MAX825REXK-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX825REXK-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 MAX825REXK-T reliable?
The price and inventory of MAX825REXK-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX825REXK-T is usually 5 days.
3.What payment methods are accepted for MAX825REXK-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX825REXK-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX825REXK-T?
MAX825REXK-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX825REXK-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 MAX825REXK-T?
For technical support, including MAX825REXK-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX825REXK-T requirements.
6.How does Aetrix verify that MAX825REXK-T is sourced from the original manufacturer or authorized distributors?
All MAX825REXK-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 MAX825REXK-T meets industry standards.
7.What is the process for return or replacement of MAX825REXK-T?
All MAX825REXK-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX825REXK-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 MAX825REXK-T part is unused and in its original packaging.
Return procedure for MAX825REXK-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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