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STMicroelectronics STM805SM6E
- Part No.:
- STM805SM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM805SM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,688
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Product details
Overview
STM805SM6E from STMicroelectronics is a 3 V supply voltage supervisor IC with automatic battery switchover, active-high open-drain RST output, power-fail comparator (PFI/PFO), and manual reset (MR) input. It guarantees reset assertion down to VCC = 1.0 V, delivers 200 ms typical reset timeout (trec), and draws only 40 µA typical supply current. It is used in microcontroller-based systems requiring nonvolatile SRAM backup and early power-fail warning.
For engineers reviewing the STM805SM6E datasheet, STM805SM6E pinout, STM805SM6E application, or STM805SM6E equivalent, key selection criteria include its open-drain active-high reset architecture, 2.4 V switchover threshold (VSW), 1.6 s watchdog timeout (tWD), and compatibility with external LPSRAM backup via VOUT/VBAT switching.
Technical Context
The STM805SM6E integrates a precision voltage reference and comparator to monitor VCC against a 2.4 V switchover threshold (VSW) and a reset threshold (VRST). When VCC falls below VRST or MR is asserted, it drives its open-drain RST output high for ≥200 ms (trec), ensuring reliable MCU reset initiation.
It features a dedicated PFI input and push-pull PFO output for early power-fail detection, and supports seamless VOUT supply switching between VCC and VBAT using an internal P-channel MOSFET. Unlike STM704/795/806, it includes watchdog timer functionality with 1.6 s timeout and edge-sensitive WDI input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Output Type | Active-high, open-drain RST - enables flexible pull-up configuration and direct interface to MCU reset pins requiring high-level assertion. |
| Reset Timeout (trec) | 200 ms (typ) - ensures sufficient hold time for full microprocessor initialization after power-up or fault recovery. |
| Watchdog Timeout (tWD) | 1.6 s (typ) - provides deterministic system recovery window if MCU firmware hangs or fails to toggle WDI. |
| VCC Switchover Threshold (VSW) | 2.4 V - triggers automatic VOUT sourcing from VBAT before main supply collapse, preserving SRAM data integrity. |
| Supply Current (ICC) | 40 µA (typ) - minimizes system standby power draw during normal operation without compromising supervision accuracy. |
| Battery Supply Current (IBAT) | 0.4 µA (typ) - extends backup battery life during extended power-loss events while maintaining VOUT regulation. |
| Operating Temperature | –40 °C to +85 °C - supports industrial-grade deployment in embedded control, metering, and automation equipment. |
Pinout & Package
STM805SM6E is housed in an SO8 (Small Outline 8-pin) package, compliant with JEDEC MS-012, with 1.27 mm pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: PFO | Power-fail output | Push-pull output asserting low when PFI < VPFI or VCC < VSW - provides immediate system-level power-fail interrupt signal. |
| 2: VOUT | Supply output voltage | Switched output sourcing from VCC (when VCC > VSW) or VBAT (when VCC < VSW) - directly powers external LPSRAM during brownout. |
| 3: VCC | Main supply input | Primary 3 V system rail input - monitored for reset assertion and switchover logic; valid operating range: 1.0 V to 5.5 V. |
| 4: RST | Active-high reset output | Open-drain output pulled high externally - asserts logic high during reset condition, compatible with MCUs requiring active-high reset input. |
| 5: VSS | Ground | Reference node for all internal comparators and outputs - must be connected to system ground plane with low-impedance path. |
| 6: MR | Manual reset input | Active-low input with internal 40 kΩ pull-up - initiates reset on button press; debounced internally, no external RC required. |
| 7: WDI | Watchdog input | Edge-sensitive input - toggling (rising/falling) clears watchdog timer; static high/low triggers reset every ~1.8 s. |
| 8: PFI | Power-fail input | Analog input monitoring external supply rail - compared to VPFI (~1.25 V) to generate preemptive PFO assertion before VCC collapse. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic battery switchover | VOUT switches from VCC to VBAT at 2.4 V (VSW) with hysteresis - eliminates need for external diode-or or PMOS control circuitry. |
| Guaranteed reset down to 1.0 V | RST remains valid even as VCC collapses to 1.0 V (with VBAT > 1 V) - ensures last-chance reset before complete power loss. |
| Low-power supervision | 40 µA ICC (typ) and 0.4 µA IBAT (typ) - enables multi-year battery-backed operation in energy-constrained IoT and metering nodes. |
| Integrated power-fail comparator | Dedicated PFI/PFO pair with 1.25 V threshold - delivers early warning of supply decay, allowing graceful shutdown or data save. |
| Watchdog timer with edge sensitivity | 1.6 s timeout cleared by any WDI edge (≥50 ns pulse) - detects both firmware lockup and communication stall without requiring clocked toggling. |
Applications
| Industrial PLC Controller | Smart Electricity Meter |
|---|---|
Use Scenario: Maintains real-time clock and tariff data in SRAM during AC mains interruption. IC Role / Device Role / Timing Role: Supervisor IC providing VOUT battery switchover, PFO-triggered data save, and RST-driven safe boot on restoration. Use Value: Prevents SRAM data corruption during sub-second outages; enables <100 ms recovery without EEPROM wear. |
Use Scenario: Preserves billing registers and tamper logs during utility power dips or battery replacement. IC Role / Device Role / Timing Role: Monitors VCC and PFI to assert PFO before brownout, triggering flash write and disabling peripherals via RST. Use Value: Meets IEC 62053-21 data retention requirements with zero external components beyond backup capacitor. |
| Medical Infusion Pump | Point-of-Sale Terminal |
Use Scenario: Ensures critical therapy parameters remain intact during battery swap or power transition. IC Role / Device Role / Timing Role: Generates clean RST pulse on power-up and monitors WDI for motor control loop liveliness. Use Value: Guarantees MCU reset validity down to 1.0 V - meets IEC 60601-1 safety-critical power sequencing mandates. |
Use Scenario: Secures transaction logs and encryption keys in SRAM during brief UPS switchover or grid flicker. IC Role / Device Role / Timing Role: Uses MR for emergency hard reset and PFO to initiate secure shutdown before VCC drops below 2.4 V. Use Value: Eliminates need for discrete power-monitoring ICs and reduces BOM count by integrating switchover, reset, and watchdog. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809SEUR+T | Single active-high reset output; no watchdog, no PFI/PFO, no battery switchover - only basic reset generation. | Suitable for cost-sensitive, non-backup applications where only power-on reset is required. | Select when SRAM backup, early power-fail warning, or watchdog supervision are unnecessary. |
| TPS3808G12DBVR | Adjustable reset threshold (1.2–5.0 V); fixed 200 ms trec; no battery switchover or PFI/PFO - precision reset only. | Used in systems with non-standard supply rails or where VSW/VCC monitoring is handled separately. | Choose when fine-grained reset voltage setting is needed but battery backup and power-fail signaling are implemented externally. |
Compared with MAX809SEUR+T and TPS3808G12DBVR, STM805SM6E uniquely integrates battery switchover, PFI/PFO, and watchdog in one SO8 package - reducing board space and eliminating four external components typically required for equivalent functionality.
Availability
STM805SM6E is available at Aetrix Electronics and suitable for industrial PLC controllers, smart electricity meters, medical infusion pumps, and point-of-sale terminals requiring stable component supply across long production lifecycles.
Supply support for STM805SM6E 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.
The STM690/704/795/802/804/805/806 family was engineered specifically for robust microprocessor supervision in battery-backed embedded systems - emphasizing low quiescent current, guaranteed reset behavior under brownout, and integrated SRAM power management.
FAQ
What is the function of the Vccsw pin on STM805SM6E?
Vccsw is a push-pull output that goes high when VOUT switches to VBAT and low when VOUT reconnects to VCC. It is designed to drive the gate of an external PMOS transistor, enabling higher output current (>75 mA) for demanding LPSRAM loads beyond the internal switch capability.
Can STM805SM6E operate without a backup battery?
Yes. When no battery is used, connect both VBAT and VOUT to VCC. The device functions as a standard supervisor with RST, MR, WDI, and PFI/PFO - all core supervision features remain fully operational without battery dependency.
Is the RST output truly open-drain, and what pull-up value is recommended?
Yes, RST is open-drain active-high. STMicroelectronics recommends a 10 kΩ pull-up to VCC for standard 3 V operation. This ensures fast rise time (<100 ns) and noise immunity while limiting current to <300 µA during reset assertion.
How does the watchdog timer interact with the manual reset (MR) input?
When MR is asserted (low), the watchdog timer is disabled and reset is immediately triggered. Upon MR release, the timer resets and begins counting from zero. No watchdog timeout occurs during active MR, preventing spurious resets during intentional manual intervention.
STM805SM6E 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:
- 2.925V
- Output:
- Open Drain or Open Collector
- 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
STM805SM6E FAQ
1.How can I place an order for STM805SM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM805SM6E 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 STM805SM6E reliable?
The price and inventory of STM805SM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM805SM6E is usually 5 days.
3.What payment methods are accepted for STM805SM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM805SM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM805SM6E?
STM805SM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM805SM6E 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 STM805SM6E?
For technical support, including STM805SM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM805SM6E requirements.
6.How does Aetrix verify that STM805SM6E is sourced from the original manufacturer or authorized distributors?
All STM805SM6E 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 STM805SM6E meets industry standards.
7.What is the process for return or replacement of STM805SM6E?
All STM805SM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM805SM6E, 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 STM805SM6E part is unused and in its original packaging.
Return procedure for STM805SM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM805SM6E 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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EM6325CXSP5B-2.9+
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MCP130T-315I/TT
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