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STMicroelectronics STM819LM6E
- Part No.:
- STM819LM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM819LM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,375
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Product details
Overview
STM819LM6E from STMicroelectronics is a 5 V microprocessor supervisory IC with battery switchover, active-low and active-high reset outputs, manual reset input (MR), power-fail comparator (PFI/PFO), and battery freshness seal - designed for non-volatile SRAM backup in industrial embedded systems requiring guaranteed RST assertion down to VCC = 1.0 V and trec = 200 ms (typ).
For engineers reviewing the STM819LM6E datasheet, STM819LM6E pinout, STM819LM6E application, or STM819LM6E equivalent, this device serves as a precision voltage-monitoring supervisor with dual-reset signaling, battery-backed LPSRAM support, and industrial-grade operation from –40 °C to +85 °C.
Technical Context
The STM819LM6E implements a dual-comparator architecture: one monitors VCC against VRST (reset threshold) to assert RST/RST during brownout or power-up, while a second compares PFI against VPFI (2.4 V typ) or detects VCC < VSO to drive PFO low for early power-fail warning. Reset timing is controlled by an internal trec generator ensuring ≥200 ms minimum pulse width.
It features a dedicated MR input with internal 40 kΩ pull-up, enabling push-button reset without external components; VOUT automatically switches between VCC and VBAT via a P-channel MOSFET when VCC falls below VSO (lesser of VRST or VBAT), supporting seamless SRAM backup with ≤100 Ω on-resistance and 0.4 µA battery supply current (typ).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC operating voltage | 5 V nominal; supports stable supervision across full industrial range without external regulation. |
| Reset threshold (VRST) | 4.63 V (typ); guarantees RST assertion until VCC rises above threshold plus hysteresis. |
| Reset timeout (trec) | 200 ms (typ); ensures sufficient MCU initialization time after power-up or recovery. |
| Battery supply current | 0.4 µA (typ); minimizes drain on backup battery during extended VCC loss. |
| Power-fail detection threshold | 2.4 V (typ) on PFI; triggers PFO low before critical system voltage collapse. |
| Operating temperature | –40 °C to +85 °C; qualified for industrial environments without derating. |
| Reset output type | Push-pull RST and RST; eliminates need for external pull-ups in most MCU interfaces. |
Pinout & Package
STM819LM6E is housed in an SO8 (Small Outline 8-pin) package with standard 1.27 mm pitch, RoHS-compliant lead-free finish, and surface-mount compatibility for automated PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-high reset output; drives high during valid VCC and asserts low only during fault conditions. |
| 2 | VOUT | Switched output supplying external LPSRAM; auto-selects VCC or VBAT based on switchover logic. |
| 3 | PFO | Push-pull power-fail output; goes low when PFI < 2.4 V or VCC < VSO, signaling impending supply loss. |
| 4 | VBAT | Backup battery input; enables automatic switchover to preserve SRAM data during main supply failure. |
| 5 | PFI | Power-fail input; monitors auxiliary rail or scaled VCC to trigger early PFO warning. |
| 6 | MR | Manual reset input; active-low with internal 40 kΩ pull-up; debounced internally for push-button use. |
| 7 | VSS | Ground reference; common return path for all analog and digital functions. |
| 8 | VCC | Main supply input; powers internal comparators, timers, and output drivers at 5 V nominal. |
Key Features
| Feature | Design Value |
|---|---|
| Battery freshness seal | Enables factory-sealed battery installation; prevents discharge during storage/shipment until first VCC power-up. |
| Dual reset signaling | Simultaneous RST (active-low) and RST (active-high) outputs simplify interface to diverse MCU reset architectures. |
| Automatic VCC/VBAT switchover | VOUT transitions within 10 µs (typ) when VCC drops below VSO, preserving SRAM state without software intervention. |
| Low-power battery mode | 0.4 µA (typ) VBAT supply current extends backup runtime in long-duration outage scenarios. |
| Integrated power-fail comparator | Dedicated PFI/PFO path provides deterministic early-warning signal independent of reset threshold logic. |
Applications
| Industrial PLC Memory Backup | Smart Meter Data Retention |
|---|---|
|
Use Scenario: Maintaining real-time energy logging data in smart meters during grid outages. IC Role / Device Role / Timing Role: Supervises 5 V system rail, asserts RST to halt CPU writes, and switches VOUT to backup battery to sustain SRAM. Use Value: Guarantees >10-year data integrity using low-leakage VBAT path and 0.4 µA standby current. |
Use Scenario: Preserving configuration and tariff tables in utility meters during brownouts. IC Role / Device Role / Timing Role: Monitors VCC and PFI simultaneously; triggers PFO 50 ms before RST to initiate graceful shutdown sequence. Use Value: Enables deterministic firmware save-to-flash before power collapse, preventing corruption. |
| Medical Diagnostic Equipment | Factory Automation HMI |
|
Use Scenario: Securing patient parameter history in portable ultrasound devices during battery swaps. IC Role / Device Role / Timing Role: Provides trec = 200 ms reset hold-off and VOUT switchover to maintain SRAM contents during brief main supply interruption. Use Value: Eliminates need for external supercapacitor or complex power-path ICs, reducing BOM count. |
Use Scenario: Retaining operator session state and alarm logs in human-machine interface panels. IC Role / Device Role / Timing Role: Uses MR input for front-panel hard reset and PFO to trigger EEPROM write-back on detected AC loss. Use Value: Supports Class I industrial safety requirements with guaranteed RST assertion down to VCC = 1.0 V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM805LWY6F | Lacks MR input and PFI/PFO; single active-high RST only; no battery switchover. | Suitable only for basic reset generation without backup or power-fail warning. | Select when cost sensitivity outweighs need for SRAM backup or early power-loss detection. |
| MAX6361KA29+T | Higher reset threshold (2.93 V); no VOUT switching; includes watchdog timer (absent in STM819). | Designed for 3.3 V systems; incompatible with 5 V LPSRAM backup architecture. | Choose only for 3.3 V designs requiring watchdog supervision but not battery switchover. |
Compared with STM805LWY6F and MAX6361KA29+T, the STM819LM6E uniquely integrates MR, PFI/PFO, and VOUT battery switchover in a single 5 V supervisor - enabling complete SRAM data retention, manual reset, and predictive power-fail response without external components.
Availability
STM819LM6E is available at Aetrix Electronics and suitable for industrial PLC memory backup, smart meter data retention, medical diagnostic equipment, and factory automation HMI requiring stable component supply across extended product lifecycles.
Supply support for STM819LM6E 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 specializing in automotive, industrial, and power management solutions, with over 45 years of analog and mixed-signal IC design expertise.
The STM8xx supervisor family targets industrial and metering applications requiring robust, low-power, battery-backed memory protection and deterministic reset behavior under wide voltage and temperature ranges.
FAQ
What is the function of the MR pin on STM819LM6E?
The MR (Manual Reset) pin is an active-low input with internal 40 kΩ pull-up that directly asserts both RST and RST outputs when pulled low. It remains asserted for trec (200 ms typ) after MR returns high, enabling reliable push-button reset without external debounce circuitry. MR may be left floating if unused.
Does STM819LM6E include a watchdog timer?
No. The STM819LM6E does not include a watchdog timer - this feature is explicitly excluded per datasheet Section 2.3 ("Watchdog input NOT available on STM703/704/819"). Devices in the same family offering watchdog functionality include STM690A, STM692A, STM802, STM805, and STM817.
How does the battery freshness seal operate on STM819LM6E?
The battery freshness seal prevents VBAT discharge during storage by disabling the VOUT switch until VCC first exceeds VRST (4.63 V). Once powered, the seal is activated; subsequent VCC removal does not re-enable it unless the procedure in Section 2.12 of the datasheet is followed - ensuring zero battery drain pre-deployment.
Can VBAT exceed VCC on STM819LM6E?
Yes. VBAT may safely exceed VCC, as confirmed in Section 1.1.6 of the datasheet. When VCC falls below VSO (lesser of VRST or VBAT), the internal P-channel MOSFET connects VBAT to VOUT. This allows use of higher-voltage backup sources (e.g., 3.6 V Li-ion) while maintaining 5 V system operation.
STM819LM6E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
STM819LM6E FAQ
1.How can I place an order for STM819LM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM819LM6E 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 STM819LM6E reliable?
The price and inventory of STM819LM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM819LM6E is usually 5 days.
3.What payment methods are accepted for STM819LM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM819LM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM819LM6E?
STM819LM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM819LM6E 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 STM819LM6E?
For technical support, including STM819LM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM819LM6E requirements.
6.How does Aetrix verify that STM819LM6E is sourced from the original manufacturer or authorized distributors?
All STM819LM6E 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 STM819LM6E meets industry standards.
7.What is the process for return or replacement of STM819LM6E?
All STM819LM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM819LM6E, 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 STM819LM6E part is unused and in its original packaging.
Return procedure for STM819LM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM819LM6E Tags
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MIC826SYMT-TR
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