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STMicroelectronics STM806RM6F
- Part No.:
- STM806RM6F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM806RM6F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,876
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Product details
Overview
STM806RM6F from STMicroelectronics is a 3 V microprocessor supervisory IC with battery switchover, active-low push-pull RST output, manual reset (MR) input, power-fail comparator (PFI/PFO), and guaranteed reset assertion down to VCC = 1.0 V. It features 200 ms typical reset timeout (trec), 0.4 µA typical battery supply current, and operates from –40 °C to +85 °C for industrial embedded systems requiring reliable power monitoring and non-volatile SRAM backup.
For engineers reviewing the STM806RM6F datasheet, STM806RM6F pinout, STM806RM6F application, or STM806RM6F equivalent, key selection criteria include its MR-triggered reset behavior, VCC/VBAT switchover at 2.4 V, PFI threshold accuracy, trec timing stability over temperature, and compatibility with external LPSRAM retention during main supply failure.
Technical Context
The STM806RM6F implements a precision voltage monitor with a fixed 2.4 V switchover threshold (VSW) and a reset threshold (VRST) of 2.63 V (typ), both with hysteresis. Its internal comparator continuously monitors VCC against VRST to assert RST when undervoltage occurs, and independently compares PFI against VPFI (1.25 V typ) to drive PFO low on power-fail detection.
Unlike watchdog-equipped variants (e.g., STM802/804), the STM806RM6F omits WDI functionality but integrates dedicated MR logic with 40 kΩ internal pull-up and trec-based deassertion timing. Its VOUT switch uses a P-channel MOSFET with <100 Ω on-resistance, enabling seamless transition between VCC and VBAT (up to 5.5 V) while maintaining regulated output for external LPSRAM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VRST) | 2.63 V (typ); guarantees RST assertion until VCC rises ≥2.63 V + hysteresis, ensuring clean MCU boot after brownout recovery. |
| Switchover Voltage (VSW) | 2.4 V (typ); triggers automatic VOUT source switch from VCC to VBAT, preserving SRAM data before system shutdown. |
| Reset Timeout (trec) | 200 ms (typ); holds RST low for minimum 200 ms after VCC rise or MR release, meeting ARM Cortex-M and legacy MCU reset timing requirements. |
| Battery Supply Current | 0.4 µA (typ); enables multi-year backup operation from coin-cell batteries without significant drain during VCC loss. |
| Power-Fail Input Threshold (VPFI) | 1.25 V (typ); provides early warning of VCC decay by asserting PFO when PFI falls below 1.25 V, allowing firmware-controlled save operations. |
| Operating Temperature | –40 °C to +85 °C; qualified for industrial environments including factory automation controllers and metering hardware. |
| VCC Range | 1.0 V to 5.5 V; supports reset assertion even at ultra-low VCC (e.g., capacitor discharge scenarios), critical for fail-safe shutdown. |
Pinout & Package
STM806RM6F is housed in an SO8 (Small Outline 8-pin) package per JEDEC MS-012, with 1.27 mm pitch and surface-mount footprint. Pin functions are validated per ST's DocID10519 Rev 10 Figure 5 and Table 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: PFO | Power-fail output | Push-pull output asserted low when PFI < 1.25 V or VCC < 2.4 V; drives interrupt lines or status LEDs directly without external pull-up. |
| 2: VOUT | Supply output for LPSRAM | Switched output sourced from VCC (≥2.4 V) or VBAT (<2.4 V); delivers up to 75 mA to retain external low-power SRAM during main supply loss. |
| 3: VCC | Main supply input | Primary 3 V system rail input; monitored for reset generation and switchover control; accepts 1.0–5.5 V range. |
| 4: RST | Active-low reset output | Push-pull output asserted low during VCC undervoltage, MR activation, or power-up; meets TTL/CMOS reset input thresholds. |
| 5: VSS | Ground reference | Common return path for all internal comparators, timers, and output drivers; requires low-impedance PCB connection. |
| 6: MR | Manual reset input | Active-low input with 40 kΩ internal pull-up; debounced via trec timer-no external RC needed; compatible with momentary switches. |
| 7: PFI | Power-fail input | Analog input referenced to VSS; monitors auxiliary rail (e.g., 3.3 V or 5 V) for early power-loss detection independent of VCC. |
| 8: VBAT | Backup battery input | Accepts 1.0–5.5 V backup source; isolated from VCC until switchover condition met; prevents battery discharge during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset down to VCC = 1.0 V | Ensures deterministic MCU reset even during deep brownout or capacitor discharge, preventing undefined processor states. |
| Automatic battery switchover at 2.4 V | Enables zero-interruption SRAM retention by switching VOUT to VBAT before VCC drops below MCU operating voltage. |
| 0.4 µA typical battery current | Extends coin-cell life beyond 10 years in standby, supporting long-life industrial logging and smart meter applications. |
| Integrated 200 ms reset timeout generator | Eliminates need for external RC timing components, reducing BOM count and layout area while improving temperature stability. |
| Push-pull PFO and RST outputs | Drives interrupts and reset lines directly-no external pull resistors required-simplifying interface design and improving noise immunity. |
Applications
| Industrial PLC Controller | Smart Electricity Meter |
|---|---|
Use Scenario: Main 3.3 V rail collapses during grid fluctuation while backup supercapacitor sustains SRAM. IC Role / Device Role / Timing Role: STM806RM6F monitors VCC, asserts RST to halt CPU, switches VOUT to VBAT within 1 µs, and signals PFO to trigger firmware save sequence. Use Value: Prevents meter data corruption during 10–500 ms outages; maintains timekeeping and tariff logs without NVRAM write cycles. |
Use Scenario: Tamper event causes intentional VCC interruption; coin-cell battery must preserve tamper flags and last-read kWh value. IC Role / Device Role / Timing Role: Detects VCC drop below 2.4 V, activates VOUT→VBAT path, holds RST low for 200 ms to freeze CPU state, and asserts PFO to log event timestamp. Use Value: Guarantees forensic integrity of tamper records with sub-10 µs switchover latency and zero data loss across 100,000+ power cycles. |
| Factory Automation HMI | Medical Infusion Pump Controller |
Use Scenario: Dust-induced connector arcing causes intermittent VCC dropout; system must recover without rebooting UI state. IC Role / Device Role / Timing Role: Monitors VCC with 2.63 V threshold and hysteresis; asserts RST only on sustained undervoltage (>200 ms), ignoring transients. Use Value: Avoids nuisance resets from ESD or contact bounce; preserves touchscreen calibration and session context during brief dips. |
Use Scenario: Battery-backed real-time clock and therapy history must survive AC power loss during infusion delivery. IC Role / Device Role / Timing Role: Supplies 3 V to RTC and SRAM via VOUT during mains failure; asserts RST to pause motor control until safe shutdown completes. Use Value: Meets IEC 62304 Class C safety requirement for uninterrupted therapy data logging and time-critical alarm generation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690EPA+ | Fixed 4.65 V reset threshold; no PFI/PFO; no battery switchover; 200 ms trec. | Lacks VCC/VBAT management and power-fail warning-suitable only for simple reset-only use cases. | Select only if system uses single-rail 5 V supply and does not require SRAM backup or early power-loss detection. |
| TPS3808G33DBVR | Adjustable reset threshold (via external resistor); 200 ms trec; no MR input; no battery switchover; 2.5 µA quiescent current. | Requires external components for threshold setting; higher battery drain eliminates long-term coin-cell viability. | Prefer when precise reset voltage tuning is needed and backup battery is omitted or managed externally. |
Compared with MAX690EPA+ and TPS3808G33DBVR, the STM806RM6F uniquely integrates battery switchover, MR input, and PFI/PFO in a single SO8 package-enabling compact, self-contained SRAM supervision without external FETs or comparators.
Availability
STM806RM6F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart electricity meters, factory HMI terminals, and medical infusion pump controllers requiring stable component supply and long-term lifecycle support.
Supply support for STM806RM6F 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, designing and manufacturing microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.
The STM690/704/806 family was engineered specifically for robust microprocessor supervision in harsh industrial environments, emphasizing low-power battery backup, precise voltage monitoring, and integrated power-fail signaling without external components.
FAQ
What is the function of the MR pin on STM806RM6F?
The MR (manual reset) pin is an active-low input with a 40 kΩ internal pull-up resistor. Driving MR low asserts the RST output for the duration of the low signal plus the 200 ms reset timeout (trec). It supports direct connection to a momentary switch to ground-no external debounce circuitry is required. MR remains functional even when VCC drops below 1.0 V, provided VBAT > 1 V.
Does STM806RM6F include a watchdog timer?
No. The STM806RM6F does not include a watchdog timer function. According to ST's DocID10519 Rev 10 Section 2.3, watchdog input (WDI) is explicitly excluded from STM704 and STM806 variants. This distinguishes it from STM802/804/805, which integrate a 1.6 s typical watchdog timeout. Designers requiring watchdog capability must select those alternatives or add external supervision.
How does the VOUT/VBAT switchover operate during power failure?
VOUT automatically switches from VCC to VBAT when VCC falls below the 2.4 V switchover threshold (VSW). The internal P-channel MOSFET connects VBAT to VOUT with <100 Ω on-resistance, sustaining external LPSRAM. Switchover occurs within 1 µs, and VOUT remains stable as long as VBAT ≥ 1.0 V. When VCC recovers above VSW + hysteresis (~2.46 V), VOUT reconnects to VCC.
Can PFI be used to monitor a 5 V auxiliary rail while VCC is 3.3 V?
Yes. PFI is a dedicated analog input referenced to VSS-not to VCC-so it can monitor any DC voltage rail (e.g., 5 V, 12 V) using a resistor divider to scale the signal below VPFI's 1.25 V threshold. When PFI drops below 1.25 V, PFO asserts low regardless of VCC level, enabling independent early-warning detection of auxiliary supply faults without affecting primary reset behavior.
STM806RM6F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.625V
- 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
STM806RM6F FAQ
1.How can I place an order for STM806RM6F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM806RM6F 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 STM806RM6F reliable?
The price and inventory of STM806RM6F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM806RM6F is usually 5 days.
3.What payment methods are accepted for STM806RM6F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM806RM6F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM806RM6F?
STM806RM6F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM806RM6F 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 STM806RM6F?
For technical support, including STM806RM6F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM806RM6F requirements.
6.How does Aetrix verify that STM806RM6F is sourced from the original manufacturer or authorized distributors?
All STM806RM6F 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 STM806RM6F meets industry standards.
7.What is the process for return or replacement of STM806RM6F?
All STM806RM6F units undergo pre-shipment inspection (PSI). If there is an issue with STM806RM6F, 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 STM806RM6F part is unused and in its original packaging.
Return procedure for STM806RM6F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM806RM6F Tags
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MIC826SYMT-TR
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APX803L20-29SA-7
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