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STMicroelectronics STM805LM6E
- Part No.:
- STM805LM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM805LM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,199
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Product details
Overview
STM805LM6E from STMicroelectronics is a 5 V microprocessor supervisory IC with battery switchover, active-high reset output, watchdog timer, and power-fail comparator - designed for non-volatile SRAM backup in industrial embedded systems. It guarantees RST assertion down to VCC = 1.0 V, features 200 ms typical reset timeout (trec), 1.6 s typical watchdog timeout, and consumes only 40 µA typical supply current.
For engineers reviewing the STM805LM6E datasheet, STM805LM6E pinout, STM805LM6E application, or STM805LM6E equivalent, this page delivers verified functional identity, SO8 package mapping, confirmed pin roles (RST, WDI, PFI, VOUT, etc.), battery switchover behavior, and real-world use cases in SRAM-backed data loggers, PLCs, and energy metering systems.
Technical Context
The STM805LM6E integrates a precision voltage reference and comparator monitoring VCC against a fixed reset threshold (VRST ≈ 4.63 V), triggering RST assertion on undervoltage, watchdog timeout, or manual reset. Its dual-supply architecture enables seamless switchover from VCC to VBAT (≥1 V) on VOUT when VCC drops below the lesser of VRST or VBAT - ensuring continuous LPSRAM bias during main power loss.
It implements a 1.6 s typ watchdog timer cleared by WDI edge transitions, push-pull RST/RST outputs, and a dedicated power-fail comparator (PFI/PFO) with 2.4 V threshold - all operating across –40 °C to +85 °C without external components. The device lacks chip-enable gating (not STM818), confirming its role as a core supervisor-not memory controller interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 5 V nominal; operates over full industrial range with no external regulation required. |
| Reset threshold (VRST) | 4.63 V (typ); ensures reliable MCU reset before critical logic voltage margin is violated. |
| Reset timeout (trec) | 200 ms (typ); provides sufficient hold time for full system initialization after power-up or recovery. |
| Watchdog timeout (tWD) | 1.6 s (typ); detects firmware lockup in real-time control loops without false triggers. |
| Supply current (ICC) | 40 µA (typ); minimizes main rail loading in always-on monitoring subsystems. |
| Battery current (IBAT) | 0.4 µA (typ); extends shelf life of backup coin cells beyond 10 years in storage. |
| Operating temperature | –40 °C to +85 °C; qualified for industrial automation, smart grid, and factory floor deployment. |
Pinout & Package
STM805LM6E is housed in an industry-standard 8-pin SO8 (Small Outline) package (ECOPACK® compliant, RoHS-compliant, 150 mil body width), with gull-wing leads and 1.27 mm pitch - compatible with automated SMT assembly and IPC-7351B land patterns.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-high reset output; push-pull, asserted high during VCC undervoltage, watchdog timeout, or MR low. |
| 2 | VOUT | Switched output supplying external LPSRAM; automatically routes to VCC or VBAT based on switchover logic. |
| 3 | PFO | Power-fail output; push-pull, goes low when VCC < 2.4 V or PFI < VPFI - signals imminent brownout. |
| 4 | VBAT | Backup battery input; enables VOUT switchover when VCC fails; accepts up to 5.5 V; connect to VCC if unused. |
| 5 | PFI | Power-fail input; monitors external voltage rail; asserts PFO when input falls below VPFI (≈2.4 V). |
| 6 | MR | Manual reset input; active-low, internally pulled up; debounced via trec delay - no external RC needed. |
| 7 | WDI | Watchdog input; edge-sensitive (rising/falling); resets internal timer on transition; float to disable. |
| 8 | VCC | Main supply input; powers all internal circuitry and drives VOUT when above switchover threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RST assertion down to VCC = 1.0 V | Ensures deterministic reset even during deep brownout, preserving MCU state integrity. |
| Automatic battery switchover on VOUT | Enables zero-intervention SRAM backup using coin cell or supercapacitor without external MOSFET or diode. |
| Integrated power-fail comparator (PFI/PFO) | Provides early warning of supply collapse - allows firmware to save critical data before reset occurs. |
| Push-pull RST and RST outputs | Eliminates need for external pull-up resistors; drives standard CMOS/TTL inputs directly. |
| Low 40 µA supply current | Reduces thermal load and extends battery runtime in portable or energy-harvested systems. |
Applications
| Industrial Data Logger | Smart Energy Meter |
|---|---|
|
Use Scenario: Continuous logging of voltage/current waveforms into external LPSRAM during mains outage. IC Role / Device Role: Supervisor and SRAM power manager - maintains VOUT from VBAT while asserting RST to halt CPU and preserve RAM contents. Use Value: Enables >10-year coin-cell-backed data retention without volatile cache loss or external power-path ICs. |
Use Scenario: Tamper-resistant energy measurement with secure SRAM storage of billing registers and event logs. IC Role / Device Role: Dual-role supervisor - triggers immediate RST on brownout while activating PFO to flag power anomaly to metrology ASIC. Use Value: Meets IEC 62053-21 tamper requirements via synchronized reset + power-fail alert within single SO8 footprint. |
| Programmable Logic Controller (PLC) | Factory Floor HMI |
|
Use Scenario: Preserving I/O configuration and process state in SRAM during brief AC line dips (<50 ms). IC Role / Device Role: Real-time voltage monitor and watchdog - asserts RST only when VCC breaches 4.63 V or firmware hangs. Use Value: Prevents spurious reboots during transient noise; eliminates need for redundant reset supervisors. |
Use Scenario: Maintaining display buffer and user settings in LPSRAM during scheduled power cycling or UPS switchover. IC Role / Device Role: Battery-backed VOUT source + active-high RST generator - ensures clean UI restart without corrupted frame buffers. Use Value: Delivers zero-glitch GUI recovery by synchronizing SRAM bias continuity with reset timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809SEUR+T | No battery switchover, no PFI/PFO, no watchdog; only active-high reset at 4.63 V. | Limited to basic reset-only use; cannot support SRAM backup or power-fail warning. | Select only if system uses separate battery management and requires minimal BOM cost. |
| TPS3808G12DBVR | Adjustable reset threshold (via resistor divider), no VOUT switchover, no PFI/PFO, watchdog only. | Requires external components for SRAM bias; lacks integrated power-fail signaling. | Choose when precise threshold tuning is mandatory and backup power path is handled externally. |
Compared with MAX809SEUR+T and TPS3808G12DBVR, STM805LM6E uniquely integrates battery switchover, power-fail detection, and watchdog in one SO8 package - reducing board area, eliminating external discretes, and enabling certified data retention in safety-critical industrial designs.
Availability
STM805LM6E is available at Aetrix Electronics and suitable for industrial data loggers, smart energy meters, and programmable logic controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.
Supply support for STM805LM6E 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, specializing in automotive, industrial, and power management ICs with broad manufacturing scale and AEC-Q100/IEC 60730 certification expertise.
The STM805 belongs to ST's legacy supervisor product line targeting industrial-grade microprocessor monitoring - emphasizing robustness, low-power operation, and integrated backup power management for mission-critical embedded systems.
FAQ
What is the reset threshold voltage for STM805LM6E?
The STM805LM6E has a fixed reset threshold (VRST) of 4.63 V (typical), with guaranteed operation from 4.55 V to 4.71 V over temperature and supply variation. This threshold is factory-trimmed and does not require external resistors - ensuring consistent reset behavior across batches and operating conditions without calibration.
Does STM805LM6E support automatic switchover to backup battery?
Yes - when VCC falls below the switchover voltage (VSO), defined as the lesser of VRST (4.63 V) or VBAT, the internal P-channel MOSFET connects VBAT to VOUT. This occurs with ≤100 Ω on-resistance and no external components, enabling direct LPSRAM bias from coin cell or supercapacitor during main power loss.
Can the watchdog timer be disabled on STM805LM6E?
Yes - the watchdog function is disabled when the WDI pin is left floating or tri-stated, provided leakage current remains below 10 µA and load capacitance stays under 200 pF. No register write or strap pin is required; disabling is purely analog and hardware-based per datasheet Section 2.3.
Is STM805LM6E pin-compatible with other devices in the STM8xx family?
No - STM805LM6E uses the same SO8 pinout as STM690A/692A/703/704/802/817 (per Table 3), but differs from STM818 (which adds E/ECON pins) and STM819 (which replaces WDI with MR). Pin compatibility is limited to the STM805/STM802/STM703/STM704 group; cross-replacement requires verification of RST polarity and feature set.
STM805LM6E 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 High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
STM805LM6E FAQ
1.How can I place an order for STM805LM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM805LM6E 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 STM805LM6E reliable?
The price and inventory of STM805LM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM805LM6E is usually 5 days.
3.What payment methods are accepted for STM805LM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM805LM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM805LM6E?
STM805LM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM805LM6E 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 STM805LM6E?
For technical support, including STM805LM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM805LM6E requirements.
6.How does Aetrix verify that STM805LM6E is sourced from the original manufacturer or authorized distributors?
All STM805LM6E 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 STM805LM6E meets industry standards.
7.What is the process for return or replacement of STM805LM6E?
All STM805LM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM805LM6E, 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 STM805LM6E part is unused and in its original packaging.
Return procedure for STM805LM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM805LM6E Tags
-
MIC826SYMT-TR
Microchip Technology
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APX803S-31SA-7
Diodes Incorporated
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APX803L20-29SA-7
Diodes Incorporated
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TPS3828-33DBVR
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V6340RSP3B+
EM Microelectronic
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EM6325CXSP5B-2.9+
EM Microelectronic
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MCP120T-300I/TT
Microchip Technology
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MCP130T-315I/TT
Microchip Technology
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MCP120T-475I/TT
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MCP111T-300E/TT
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MCP120T-315I/TT
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MCP809T-315I/TT
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