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Analog Devices Inc./Maxim Integrated MAX812SEUS+
- Part No.:
- MAX812SEUS+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX812SEUS+.pdf
- Description:
- MAX812 4-PIN MICRO PROCESSOR VOL
- Quantity:
- Payment:
- Shipping:
Inventory:4,889
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Product details
Overview
MAX812SEUS+ from Maxim Integrated is an active-high microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor 3.08V supply rails with ±1.5% threshold accuracy over -40°C to +85°C. It asserts RESET for ≥140ms after VCC rises above threshold, features 6µA quiescent current, and includes debounced manual reset (MR) input with 20kΩ internal pull-up-used in battery-powered instrumentation and embedded controllers requiring reliable power-on reset.
For engineers reviewing the MAX812SEUS+ datasheet, MAX812SEUS+ pinout, MAX812SEUS+ application, or MAX812SEUS+ equivalent, this page delivers verified electrical parameters, thermal behavior, MR timing constraints, reset timeout stability, and real-world interface guidance for µP reset line conditioning and brownout immunity design.
Technical Context
The MAX812SEUS+ implements a precision bandgap-based voltage comparator with hysteresis-free threshold detection and an internal monostable timer controlling reset assertion duration. Its active-high RESET output remains high during undervoltage or MR assertion and sustains that state for ≥140ms after recovery, independent of VCC slew rate.
It integrates transient immunity against negative-going VCC glitches ≤40µs at 125mV overdrive (for L/M variants) or ≤20µs (for R/S/T), and guarantees valid RESET output down to VCC = 1V when sinking 1.2mA-critical for deterministic reset sequencing in low-voltage microcontroller systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08V nominal, ±1.5% over temperature - ensures reliable trip point for 3.3V ±5% supplies before system ICs drop below minimum operating voltage. |
| Supply Current | 6µA typical at +25°C - enables multi-year operation in coin-cell–powered portable instruments without compromising supervision integrity. |
| Reset Timeout | ≥140ms after VCC rise - meets JEDEC JESD78 requirement for minimum reset pulse width to guarantee full µP initialization. |
| MR Minimum Pulse Width | 10µs - allows clean reset initiation from short-duration switch closures or logic pulses without external debounce. |
| RESET Output Drive | 1.2mA sink capability at VCC = VTH(MIN) - sufficient to directly drive TTL/CMOS inputs and withstand PCB trace capacitance up to 50pF. |
| Operating Temp Range | -40°C to +85°C - qualified for industrial-grade embedded control and automotive body electronics environments. |
| Reset Threshold Tempco | 30ppm/°C - limits threshold drift to <±12mV across full temperature range, preserving margin against false resets. |
Pinout & Package
MAX812SEUS+ uses a 4-pin SOT143 (also referenced as SOT-143B) surface-mount package measuring 4.0 × 2.0 × 1.75 mm, with gull-wing leads and standard EIA-481-1 marking layout. Pin 1 is marked by a dot or beveled edge.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC | Positive Supply Input | Accepts 1.0V to 6.0V; powers internal comparator and timer; must be decoupled with 0.1µF ceramic capacitor placed within 2mm of pin. |
| MR | Manual Reset Input | Active-low; internally pulled up to VCC via 20kΩ resistor; logic-low pulse ≥10µs initiates reset; open-circuit default is inactive. |
| RESET | Active-High Reset Output | Drives high during normal operation and for ≥140ms after VCC recovery; sinks 1.2mA at VTH(MIN); requires no external pull-up for most µP interfaces. |
| GND | Ground Reference | System ground return for all internal circuitry; must connect to low-impedance analog/digital ground plane with shortest possible trace. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 3.08V Threshold | Factory-trimmed to ±1.5% tolerance across -40°C to +85°C - eliminates need for external resistor dividers or calibration in 3.3V systems. |
| 140ms Guaranteed Reset Pulse | Monostable timeout unaffected by VCC ramp rate or noise - ensures µP completes internal POR and clock stabilization before release. |
| Integrated MR Debounce | No external RC network required; 10µs MR glitch immunity and 180ms post-release hold time prevent spurious resets from mechanical switch bounce. |
| Low 6µA Quiescent Current | Enables always-on supervision in energy-constrained devices such as handheld meters and sensor nodes without measurable battery drain. |
| VCC Transient Immunity | Rejects negative VCC glitches ≤20µs at 125mV overdrive - prevents false resets caused by switching regulator ripple or ESD-induced supply dips. |
Applications
| Portable Medical Instrumentation | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Handheld blood glucose meters powered by CR2032 coin cells require guaranteed reset during battery insertion and voltage sag under load. IC Role / Device Role / Timing Role: MAX812SEUS+ monitors 3.3V rail derived from boost converter; asserts RESET until stable VCC > 3.08V and holds for 140ms to allow ADC reference settling and µC boot ROM validation. Use Value: Eliminates external reset IC and RC network, reducing BOM count by two components while maintaining JESD78-compliant reset timing across -20°C to +60°C operating range. |
Use Scenario: DIN-rail mounted I/O modules operate in electrically noisy factory environments with frequent 24V supply transients coupling into 3.3V logic rails. IC Role / Device Role / Timing Role: MAX812SEUS+ detects brownout on isolated 3.3V domain; generates clean active-high reset pulse synchronized to VCC recovery, overriding noise on MR from adjacent relay coils. Use Value: 20µs glitch immunity and 30ppm/°C tempco prevent false resets during 48V surge events, improving system uptime versus generic supervisor ICs with ±3% thresholds. |
| Smart Energy Meters | Automotive Body Control Units |
|
Use Scenario: Electricity meters with dual-supply architecture (main AC-derived 3.3V + backup supercapacitor 3.0V) must maintain deterministic reset during mains dropout. IC Role / Device Role / Timing Role: MAX812SEUS+ supervises the 3.3V rail; its 1.2mA RESET sink drives opto-isolated µP reset line directly, eliminating level-shifter requirements. Use Value: Valid RESET output down to VCC = 1V ensures controlled shutdown sequence even as supercap drops below 2.0V, preventing EEPROM corruption during last-second write cycles. |
Use Scenario: BCM modules powered from vehicle battery (9V–16V) with LDO-regulated 3.3V domain experience cold-crank dips to 6V and load-dump spikes. IC Role / Device Role / Timing Role: MAX812SEUS+ monitors post-LDO 3.3V rail; ignores sub-20µs transients induced by alternator switching while asserting reset during sustained dips below 3.08V. Use Value: 6µA supply current minimizes standby loss in always-on CAN nodes; SOT143 footprint supports automated optical inspection and reflow compatibility with AEC-Q200 board assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS3123E18DBVR | Fixed 1.8V threshold, 200ms reset timeout, 1.8V–5.5V operating range, 1.6µA ICC. | Designed for ultra-low-voltage SoCs; lacks manual reset input and 3.08V threshold option. | Select when supervising 1.8V core domains where longer timeout and lower ICC outweigh missing MR functionality. |
| ADM6806-3ARTZ-RL7 | 3.08V threshold, 200ms timeout, -40°C to +125°C rating, 12µA ICC, no MR input. | Higher temperature grade suits under-hood automotive use; higher ICC and no MR limit use in portable equipment. | Choose for extended-temp industrial controls where 125°C operation is mandatory and MR is handled externally. |
Compared with TPS3123E18DBVR and ADM6806-3ARTZ-RL7, the MAX812SEUS+ uniquely combines 3.08V precision threshold, integrated manual reset, 6µA ICC, and 140ms timeout in a 4-pin SOT143-making it optimal for cost-sensitive, space-constrained 3.3V portable and industrial systems requiring both power and user-initiated reset control.
Availability
MAX812SEUS+ is available at Aetrix Electronics and suitable for portable medical instrumentation, industrial PLC I/O modules, smart energy meters, and automotive body control units requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for MAX812SEUS+ 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, mixed-signal, and power management ICs for industrial, communications, computing, and consumer applications.
The MAX812SEUS+ belongs to the MAX811/MAX812 family of micropower voltage supervisors-engineered specifically for reliable, low-component-count reset generation in battery-powered and noise-prone embedded systems.
FAQ
What is the exact reset threshold voltage of the MAX812SEUS+?
The MAX812SEUS+ has a nominal reset threshold of 3.08V, with guaranteed accuracy of ±1.5% over the full -40°C to +85°C temperature range. This value is factory-trimmed and specified in the Electrical Characteristics table under "Reset Threshold (VTH)" for the 'T' suffix variant. The threshold remains stable with 30ppm/°C tempco, ensuring minimal drift across operating conditions.
Does the MAX812SEUS+ provide manual reset functionality, and how is it implemented?
Yes, the MAX812SEUS+ includes a dedicated manual reset (MR) input. It is an active-low pin with an internal 20kΩ pull-up resistor, allowing direct connection to a normally open pushbutton switch tied to GND. A logic-low pulse ≥10µs on MR initiates reset, which remains asserted for 180ms after MR returns high-eliminating need for external debounce circuitry in most applications.
How does the MAX812SEUS+ behave when VCC falls below 1V?
For the MAX812SEUS+, the RESET output remains valid and actively driven high down to VCC = 1V. Below 1V, the output transitions to a high-impedance state. To ensure RESET stays defined near 0V, a 100kΩ pull-up resistor to VCC is recommended-unlike the MAX811, which requires a pull-down. This behavior is documented in the "Ensuring a Valid RESET Output Down to VCC = 0V" section of the datasheet.
Can the MAX812SEUS+ be used with microcontrollers that have bidirectional reset pins?
Yes, but interface conditioning is required. When connecting the MAX812SEUS+ to µPs like the Motorola 68HC11 with bidirectional reset I/O, contention may occur. The recommended solution is a 4.7kΩ series resistor between the MAX812SEUS+ RESET pin and the µP reset pin-this isolates drive sources while preserving signal integrity and enabling buffered distribution to other system components.
What is the maximum VCC transient duration the MAX812SEUS+ can ignore without asserting reset?
The MAX812SEUS+ ('T'/'S'/'R' variants) rejects negative-going VCC transients ≤20µs in duration when the overdrive (VTH – VCC) is 125mV. This immunity is confirmed in the Typical Operating Characteristics plots and applies to fast supply glitches from switching regulators or ESD events. A 0.1µF ceramic capacitor placed at the VCC pin further enhances robustness against higher-energy transients.
MAX812SEUS+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- -
- Type:
- Power Supply Monitor
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.93V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-4
MAX812SEUS+ FAQ
1.How can I place an order for MAX812SEUS+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX812SEUS+ 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 MAX812SEUS+ reliable?
The price and inventory of MAX812SEUS+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX812SEUS+ is usually 5 days.
3.What payment methods are accepted for MAX812SEUS+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX812SEUS+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX812SEUS+?
MAX812SEUS+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX812SEUS+ 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 MAX812SEUS+?
For technical support, including MAX812SEUS+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX812SEUS+ requirements.
6.How does Aetrix verify that MAX812SEUS+ is sourced from the original manufacturer or authorized distributors?
All MAX812SEUS+ 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 MAX812SEUS+ meets industry standards.
7.What is the process for return or replacement of MAX812SEUS+?
All MAX812SEUS+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX812SEUS+, 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 MAX812SEUS+ part is unused and in its original packaging.
Return procedure for MAX812SEUS+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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