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STMicroelectronics STM1812LWX7F
- Part No.:
- STM1812LWX7F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
STM1812LWX7F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,464
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Product details
Overview
STM1812LWX7F from STMicroelectronics is an active-high, push-pull reset supervisor IC designed to monitor 3.3 V or 3.0 V supply rails in microcontroller-based systems. It asserts a high-level reset signal when VCC drops below 3.06 V (typ.), maintains reset for ≥100 ms after VCC recovers, draws only 4 µA typical supply current, and operates across –40 °C to +105 °C - enabling reliable power-up sequencing in portable embedded controllers.
For engineers reviewing the STM1812LWX7F datasheet, STM1812LWX7F pinout, STM1812LWX7F application, or STM1812LWX7F equivalent, key selection criteria include its active-high push-pull output configuration, factory-trimmed 3.06 V threshold, guaranteed operation down to VCC = 1.0 V, and SOT23-3 footprint compatibility with DS181x/MXD181x families.
Technical Context
The device integrates a precision voltage reference, comparator, and reset timer to detect brownout conditions on VCC. Its reset assertion logic is triggered solely by VCC falling below the 3.06 V threshold (±2.5% over temperature), with no internal watchdog or windowing function.
Reset deassertion occurs only after VCC rises above threshold and remains stable for ≥100 ms (trec), with no manual reset input capability - distinguishing it from STM1813/1818 variants. The push-pull output drives high actively and sinks low without external pull-up components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.06 V (typ.), ±2.5% accuracy from –40 °C to +105 °C - ensures consistent brownout detection across industrial temperature range |
| Reset Pulse Width | ≥100 ms - guarantees MCU reset hold time sufficient for full core initialization and memory stabilization |
| Supply Current | 4 µA (typ.) at 25 °C - enables multi-year battery life in always-on supervisory applications |
| Operating Voltage Range | 1.0 V to 5.5 V - supports valid reset assertion even during deep brownout down to 1.0 V |
| Output Type | Active-high, push-pull - eliminates need for external pull-up resistor and provides strong drive into MCU reset pin |
| Temperature Range | –40 °C to +105 °C - qualified for automotive under-hood and industrial control environments |
| Package | SOT23-3 (WX) - 2.9 mm × 1.3 mm footprint compatible with high-density PCB layouts |
Pinout & Package
The STM1812LWX7F is housed in a 3-pin SOT23-3 (WX) package with gull-wing leads, JEDEC MO-178AC compliant, 1.45 mm max height, and RoHS-compliant ECOPACK® construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RST | Active-high reset output | Push-pull driver that sources current when asserted (high) and sinks current when deasserted (low); directly interfaces MCU reset pin without external components |
| 2 - VCC | Supply voltage input | Monitored rail input and power source for internal circuitry; valid operation supported from 1.0 V to 5.5 V |
| 3 - VSS | Ground reference | System ground connection required for comparator reference and output stage return path |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed 3.06 V threshold | Eliminates external resistor network calibration and reduces BOM count in 3.3 V system designs |
| 100 ms minimum reset timeout | Ensures sufficient hold time for ARM Cortex-M and PIC microcontrollers to complete internal PLL lock and flash initialization |
| 4 µA typical quiescent current | Enables integration into energy-harvesting nodes and coin-cell-powered IoT sensors without compromising battery lifetime |
| VCC transient immunity | Rejects negative-going glitches ≤20 µs at 100 mV overdrive - prevents spurious resets during switching regulator noise events |
| Guaranteed operation down to 1.0 V | Provides deterministic reset behavior during severe brownout, avoiding undefined MCU states before shutdown |
Applications
| Industrial PLC I/O Module | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Power monitoring during cold-cranking when battery voltage dips to 6–9 V while engine cranks. IC Role / Device Role / Timing Role: Reset supervisor asserting active-high signal to ARM-based MCU upon 3.3 V rail collapse. Use Value: Prevents firmware corruption by holding MCU in reset until 3.3 V rail stabilizes post-crank, leveraging 100 ms trec and 1.0 V operational floor. | Use Scenario: Supervising 3.3 V domain powering CAN transceiver and microcontroller in door module. IC Role / Device Role / Timing Role: Brownout detector ensuring MCU reset during load-dump-induced rail sag. Use Value: 3.06 V threshold aligns with 3.3 V LDO dropout margin; ±2.5% accuracy avoids false triggers across –40 °C to +105 °C ambient. |
| Portable Medical Sensor Hub | Smart Energy Meter MCU Subsystem |
Use Scenario: Battery-powered glucose meter requiring guaranteed reset during Li-ion discharge from 4.2 V to 2.8 V. IC Role / Device Role / Timing Role: Low-power supervisor monitoring regulated 3.3 V rail derived from buck converter. Use Value: 4 µA supply current extends single-CR2032 battery life beyond 5 years in standby; SOT23-3 footprint saves board space. | Use Scenario: Reset coordination between metrology ASIC and host MCU during AC mains interruption. IC Role / Device Role / Timing Role: Primary reset generator for dual-core ARM processor subsystem. Use Value: Active-high push-pull output drives both MCU and ASIC reset pins simultaneously without level-shifting or buffering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar reset supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809TRD2T | 3.08 V threshold (±2%), 140 ms reset timeout, 1.2 µA supply current, SOT23-3 | Lacks guaranteed operation below 1.8 V; not rated for full –40 °C to +105 °C range | Select when ultra-low current dominates over brownout robustness and extended temperature coverage |
| TPS3808G30DBVR | 3.0 V threshold (±0.5%), 200 ms timeout, 16 µA supply current, SOT23-6 | Requires external capacitor for timeout adjustment; larger 6-pin package increases layout area | Select when higher threshold accuracy and programmable delay justify added component and footprint cost |
Compared with MAX809TRD2T and TPS3808G30DBVR, STM1812LWX7F uniquely balances industrial temperature coverage, 1.0 V operational floor, and minimal 3-pin footprint - making it optimal for space-constrained, wide-temperature embedded controllers where deterministic brownout response is critical.
Availability
STM1812LWX7F is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and portable medical sensor hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for STM1812LWX7F 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering silicon solutions for automotive, industrial, and consumer markets since 1987.
The STM181x series was developed specifically as low-power, precision reset supervisors for microcontroller-based embedded systems - emphasizing supply voltage monitoring fidelity, minimal footprint, and robustness against power rail transients.
FAQ
What is the exact reset threshold voltage for STM1812LWX7F?
The STM1812LWX7F has a factory-trimmed nominal reset threshold of 3.06 V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40 °C to +105 °C. This value is specified in ST's official datasheet (Doc ID11464 Rev 8, Table 9) and applies to the 3.3 V/3.0 V supply monitoring variant within the STM181x family.
Does STM1812LWX7F support manual reset via the RST pin?
No. STM1812LWX7F does not include manual reset detection functionality. Unlike STM1813/1818 variants, its RST pin is output-only and lacks push-button debounce circuitry. Pulling RST low externally will not trigger a reset pulse; the device responds exclusively to VCC voltage drops below its 3.06 V threshold.
Can STM1812LWX7F be used with a 5 V supply rail?
Yes - the device supports VCC inputs from 1.0 V to 5.5 V per absolute maximum ratings (Table 7). However, its 3.06 V threshold is optimized for 3.3 V/3.0 V systems. Using it on a 5 V rail would result in premature reset assertion unless the 5 V rail is regulated down to ~3.3 V first; for native 5 V supervision, STM1810/1815 variants with 4.37 V/4.62 V thresholds are recommended.
Is STM1812LWX7F pin-compatible with DS1812?
Yes. STM1812LWX7F is fully compatible with the Dallas/Maxim DS1812 in pinout, function, and timing - both are active-high, push-pull reset supervisors in SOT23-3 packages with 100 ms minimum reset timeout and similar threshold tolerances. ST explicitly states "fully compatible with DS181x and MXD181x products" in the datasheet introduction.
STM1812LWX7F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.62V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 100ms Minimum
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
STM1812LWX7F FAQ
1.How can I place an order for STM1812LWX7F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM1812LWX7F 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 STM1812LWX7F reliable?
The price and inventory of STM1812LWX7F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM1812LWX7F is usually 5 days.
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STM1812LWX7F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM1812LWX7F 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 STM1812LWX7F?
For technical support, including STM1812LWX7F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM1812LWX7F requirements.
6.How does Aetrix verify that STM1812LWX7F is sourced from the original manufacturer or authorized distributors?
All STM1812LWX7F 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 STM1812LWX7F meets industry standards.
7.What is the process for return or replacement of STM1812LWX7F?
All STM1812LWX7F units undergo pre-shipment inspection (PSI). If there is an issue with STM1812LWX7F, 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 STM1812LWX7F part is unused and in its original packaging.
Return procedure for STM1812LWX7F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM1812LWX7F Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
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