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STMicroelectronics STM817LM6E
- Part No.:
- STM817LM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM817LM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,596
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Product details
Overview
STM817LM6E from STMicroelectronics is a 5 V microprocessor supervisor IC with integrated battery switchover, power-fail comparator (PFI/PFO), and watchdog timer (1.6 s typ). It provides active-low RST and active-high RST outputs, guarantees reset assertion down to VCC = 1.0 V, and supports external low-power SRAM backup via VOUT. Used in industrial embedded systems requiring reliable power monitoring and non-volatile memory retention during main supply loss.
For engineers reviewing the STM817LM6E datasheet, STM817LM6E pinout, STM817LM6E application, or STM817LM6E equivalent, key selection considerations include guaranteed reset assertion at 1.0 V VCC, 200 ms typical reset timeout (trec), automatic VCC-to-VBAT switchover with 100 Ω switch resistance, and push-pull PFO output for early power-fail warning in battery-backed systems.
Technical Context
The STM817LM6E implements dual-reset architecture with independent active-low and active-high outputs, both push-pull, asserted when VCC falls below VRST (4.63 V typ), on MR assertion, or after watchdog timeout. Its internal precision voltage reference monitors VCC against a fixed threshold and triggers trec-limited reset pulses with no external components required.
It integrates a dedicated power-fail comparator comparing PFI against VPFI (1.25 V typ) and asserting PFO low upon violation - independent of VCC status - enabling preemptive system shutdown before brownout. Battery switchover occurs at VSO (lesser of VBAT and VRST), ensuring maximal VCC utilization before backup activation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC operating voltage | 5 V nominal; supports full functionality across 1.0–5.5 V range for robust brownout tolerance. |
| Reset threshold (VRST) | 4.63 V (typ); ensures reset assertion before MCU operational failure during VCC sag. |
| Reset timeout (trec) | 200 ms (typ); provides sufficient hold time for complete MCU initialization after power recovery. |
| Watchdog timeout | 1.6 s (typ); detects firmware lockup without requiring external timing components. |
| Battery supply current | 0.4 µA (typ); enables multi-year backup operation from coin-cell batteries. |
| Power-fail comparator threshold (VPFI) | 1.25 V (typ); allows early detection of failing auxiliary supplies or battery discharge. |
| VCC-to-VBAT switchover resistance | 100 Ω (typ); limits inrush current and voltage drop during transition to backup power. |
| Operating temperature | –40 °C to +85 °C; qualified for industrial-grade embedded applications without derating. |
Pinout & Package
STM817LM6E is housed in an 8-pin SO8 (Small Outline) package with standard 1.27 mm pitch, RoHS-compliant, and lead-free. Pin layout follows JEDEC MS-012AC, suitable for automated PCB assembly and thermal reliability in industrial environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: RST | Active-high reset output | Push-pull output asserted high during reset condition; compatible with MCUs requiring active-high reset input. |
| 2: VOUT | SRAM supply output | Switched output connected to VCC or VBAT; powers external LPSRAM during main supply loss. |
| 3: PFO | Power-fail output | Push-pull output driven low when PFI < 1.25 V or VCC < 2.4 V; signals imminent power collapse. |
| 4: ECON | Conditioned chip-enable output | Low only when E = low and reset not asserted; gates LPSRAM access during reset or disable. |
| 5: PFI | Power-fail input | Monitors auxiliary supply voltage; triggers PFO when below 1.25 V threshold. |
| 6: MR | Manual reset input | Active-low input with internal 40 kΩ pull-up; initiates reset pulse on button press or logic low. |
| 7: WDI | Watchdog input | Edge-sensitive input; toggling within 1.6 s prevents reset; floating disables watchdog. |
| 8: VCC | Main supply input | Primary 5 V power rail; monitored for reset generation and switchover control. |
| VSS | Ground | Reference node for all analog comparators and digital logic; must be low-impedance. |
| VBAT | Battery backup input | Connects to coin cell or supercap; automatically powers VOUT when VCC drops below VSO. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset down to 1.0 V VCC | Ensures deterministic reset behavior even during deep brownout, critical for data integrity in SRAM-backed systems. |
| Automatic battery switchover with 100 Ω switch | Minimizes voltage droop and transition delay when switching to backup power, preserving SRAM state. |
| Independent PFI/PFO power-fail comparator | Provides early warning of auxiliary supply failure before VCC collapse, enabling graceful shutdown. |
| 200 ms reset timeout with no external capacitor | Eliminates BOM cost and board space for RC timing networks while guaranteeing reliable MCU boot sequencing. |
| 0.4 µA battery supply current | Extends coin-cell life beyond 10 years in standby, supporting long-life industrial and metering applications. |
| Push-pull RST and RST outputs | Drives heavy capacitive loads directly without external pull-ups, simplifying interface to diverse MCU families. |
Applications
| Smart Energy Metering | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Meters retain tariff data and time-of-use logs during grid outages using battery-backed SRAM. IC Role / Device Role / Timing Role: STM817LM6E monitors mains voltage, asserts RST on brownout, switches VOUT to VBAT, and triggers PFO to initiate EEPROM save before power loss. Use Value: Guarantees SRAM data retention for ≥10 years on CR2032 via 0.4 µA battery current and 100 Ω low-loss switchover path. |
Use Scenario: PLC modules maintain I/O configuration and diagnostic history during factory power interruptions. IC Role / Device Role / Timing Role: Provides dual RST outputs to reset CPU and FPGA simultaneously; uses WDI to detect firmware hang in real-time control loops. Use Value: 1.6 s watchdog timeout and 200 ms trec ensure deterministic recovery without manual intervention or external timers. |
| Medical Infusion Pumps | Building Automation Controllers |
|
Use Scenario: Critical therapy parameters stored in SRAM must survive brief AC line dips or battery swaps. IC Role / Device Role / Timing Role: Monitors VCC and PFI (for internal DC-DC rail); asserts RST at 4.63 V to halt motor control before undervoltage-induced fault. Use Value: Reset threshold accuracy ±1.5% and –40 °C to +85 °C operation ensure reliability across clinical environments. |
Use Scenario: HVAC controllers log sensor trends and schedule events in SRAM during nightly utility cycling. IC Role / Device Role / Timing Role: Uses MR for field-service reset, PFO to trigger cloud alert on sustained low-battery condition, and VOUT to sustain RTC/SRAM. Use Value: Integrated PFI/PFO eliminates need for discrete comparator and saves 3 passive components per node. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX692AESA+ | Single RST output (active-low only); no PFI/PFO; 2.63 V reset threshold; 140 ms trec. | Lacks dual-reset and power-fail warning; suited for simpler 3.3 V systems without battery backup. | Select when only basic reset supervision is needed and VCC is ≤3.3 V; avoid for 5 V SRAM backup designs. |
| TPS3808G33DBVR | Adjustable reset threshold (via resistor divider); no battery switchover or PFI/PFO; 3.3 V fixed option. | Requires external components for threshold setting; no VOUT/VBAT path - unsuitable for SRAM backup. | Choose for flexible threshold tuning in 3.3 V domains; reject for any application requiring automatic VCC/VBAT handoff. |
Compared with MAX692AESA+ and TPS3808G33DBVR, STM817LM6E uniquely combines 5 V operation, dual RST outputs, integrated battery switchover, and PFI/PFO in one SO8 package - making it irreplaceable for industrial SRAM-retention systems where power continuity and early failure warning are mandatory.
Availability
STM817LM6E is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical devices, and building automation controllers requiring stable component supply across extended product lifecycles.
Supply support for STM817LM6E 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 microcontrollers, power management, and analog/mixed-signal ICs for industrial, automotive, and consumer markets.
The STM69x/70x/80x/81x supervisor family was designed specifically for robust, low-power, battery-backed microprocessor systems requiring guaranteed reset behavior, early power-fail detection, and seamless SRAM supply switchover - targeting industrial and medical applications with stringent reliability requirements.
FAQ
What is the function of the ECON pin on STM817LM6E?
ECON is a conditioned chip-enable output that goes low only when both the E input is low and reset is not asserted. It remains low for 15 µs or until E returns high if reset is asserted during E deactivation. In disabled mode, ECON is pulled up to VOUT, enabling controlled gating of external LPSRAM access during reset or power transitions without external logic.
Can STM817LM6E operate without a backup battery?
Yes - VBAT can be tied directly to VCC if no battery is used. In this configuration, VOUT remains connected to VCC, and all supervisor functions (reset, watchdog, PFI/PFO) operate normally. The device guarantees RST assertion down to VCC = 1.0 V even without battery, ensuring reliable reset during brownout conditions.
How does the power-fail comparator (PFI/PFO) interact with VCC monitoring?
The PFI/PFO comparator operates independently of VCC monitoring: PFO asserts low when PFI falls below 1.25 V (typ), regardless of VCC level. However, PFO also asserts if VCC drops below 2.4 V or the switchover voltage VSO - providing dual-path early warning for either auxiliary supply failure or main rail collapse.
Is the watchdog timer enabled by default on STM817LM6E?
No - the watchdog timer is enabled only when WDI is actively toggled (rising or falling edge) within the 1.6 s timeout window. If WDI is left floating or held static (high or low), the watchdog triggers reset every ~1.8 s (tWD + trec). To disable it permanently, WDI must be floated with leakage <10 µA and load capacitance <200 pF, per datasheet Section 2.3.
STM817LM6E 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
STM817LM6E FAQ
1.How can I place an order for STM817LM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM817LM6E 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 STM817LM6E reliable?
The price and inventory of STM817LM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM817LM6E is usually 5 days.
3.What payment methods are accepted for STM817LM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM817LM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM817LM6E?
STM817LM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM817LM6E 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 STM817LM6E?
For technical support, including STM817LM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM817LM6E requirements.
6.How does Aetrix verify that STM817LM6E is sourced from the original manufacturer or authorized distributors?
All STM817LM6E 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 STM817LM6E meets industry standards.
7.What is the process for return or replacement of STM817LM6E?
All STM817LM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM817LM6E, 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 STM817LM6E part is unused and in its original packaging.
Return procedure for STM817LM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM817LM6E Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
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EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
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MCP130T-315I/TT
Microchip Technology
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MCP120T-475I/TT
Microchip Technology
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MCP111T-300E/TT
Microchip Technology
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MCP120T-315I/TT
Microchip Technology
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MCP809T-315I/TT
Microchip Technology
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