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STMicroelectronics STM804RM6F
- Part No.:
- STM804RM6F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM804RM6F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,943
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Product details
Overview
STM804RM6F from STMicroelectronics is a 3 V industrial-grade microprocessor supervisor IC with automatic battery switchover, active-high open-drain RST output, power-fail comparator (PFI/PFO), and manual reset input (MR). It guarantees reset assertion down to VCC = 1.0 V, features 200 ms typical reset timeout (trec), 1.6 s typical watchdog timeout, and draws only 40 µA typical supply current. It is used in embedded systems requiring non-volatile SRAM backup during main power loss.
For engineers reviewing the STM804RM6F datasheet, STM804RM6F pinout, STM804RM6F application, or STM804RM6F equivalent, key selection criteria include its open-drain active-high reset output, battery switchover threshold at 2.4 V, PFI/PFO interface for early power-fail warning, and compatibility with external LPSRAM retention circuits.
Technical Context
The STM804RM6F integrates a precision voltage reference and comparator monitoring VCC against a fixed reset threshold (~2.63 V), triggering RST when VCC drops below VRST or MR is asserted. Its internal watchdog timer (1.6 s typ) resets on WDI edge transitions and cannot be disabled by floating the pin.
Battery switchover occurs automatically when VCC falls below VSW = 2.4 V, connecting VBAT to VOUT via an internal P-channel MOSFET switch; Vccsw provides a push-pull logic signal indicating switchover state. The PFI/PFO pair delivers power-fail detection with 500 mV hysteresis and push-pull PFO output.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.63 V ±1.5% - ensures reliable MCU reset before brownout-induced instability |
| Reset Timeout (trec) | 200 ms (typ) - provides sufficient hold time for processor initialization after power-up |
| Watchdog Timeout | 1.6 s (typ) - detects firmware lockup in real-time embedded control loops |
| Supply Current | 40 µA (typ) at VCC = 3.3 V - enables low-power operation in always-on monitoring circuits |
| Battery Supply Current | 0.4 µA (typ) - minimizes backup battery drain during extended power-loss events |
| Operating Temperature | –40 °C to +85 °C - supports industrial environments without derating |
| Power-Fail Threshold | VPFI = 1.25 V ±3% - triggers PFO assertion before critical VCC collapse |
Pinout & Package
STM804RM6F is housed in an 8-pin SO8 (Small Outline Integrated Circuit) package with standard 1.27 mm pitch, RoHS-compliant lead-free finish, and JEDEC MS-012AC mechanical outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: PFO | Power-fail output | Push-pull active-low signal indicating imminent VCC failure; drives interrupt or flag lines directly |
| 2: VOUT | Supply output for LPSRAM | Switched output connected to VCC or VBAT; powers external low-power SRAM during main power loss |
| 3: VCC | Main supply input | Primary 3 V system rail; monitored for reset threshold violation and switchover control |
| 4: RST | Active-high reset output | Open-drain output requiring external pull-up; asserts high during reset condition to MCU reset pin |
| 5: VSS | Ground reference | Common return path for all internal circuitry and I/O pins |
| 6: MR | Manual reset input | Active-low input with internal 40 kΩ pull-up; initiates reset on button press without external components |
| 7: PFI | Power-fail input | Monitors auxiliary rail or scaled VCC; asserts PFO when voltage drops below 1.25 V |
| 8: VBAT | Backup battery input | Accepts 1.0–5.5 V battery; automatically powers VOUT when VCC falls below 2.4 V |
Key Features
| Feature | Design Value |
|---|---|
| Automatic battery switchover | VCC-to-VBAT transition at 2.4 V with 100 Ω internal switch resistance - preserves SRAM data without external FETs |
| Open-drain active-high RST | RST remains high during valid VCC and asserts high on fault - compatible with MCUs requiring active-high reset assertion |
| Integrated power-fail comparator | PFI/PFO pair with 1.25 V threshold and 500 mV hysteresis - enables early warning of supply collapse before reset triggers |
| Watchdog timer with edge-triggered clear | 1.6 s timeout cleared only on WDI rising/falling edges - prevents false timeouts from noise or static levels |
| Low quiescent current in battery mode | 0.4 µA typical VBAT current - extends coin-cell life to >10 years in standby backup applications |
Applications
| Industrial PLC Memory Backup | Medical Device Data Retention |
|---|---|
|
Use Scenario: Programmable logic controller retains configuration and runtime variables in external LPSRAM during AC mains interruption. IC Role / Device Role / Timing Role: STM804RM6F monitors 3.3 V rail, switches VOUT to backup battery at 2.4 V, and asserts RST to halt CPU while preserving SRAM contents. Use Value: Enables seamless recovery after power restoration without data corruption or reinitialization delay. |
Use Scenario: Portable infusion pump stores therapy parameters and dose history in non-volatile SRAM during battery swap or charging gap. IC Role / Device Role / Timing Role: Provides battery switchover, 200 ms trec hold time, and PFO-driven interrupt to initiate safe shutdown before VCC collapse. Use Value: Meets IEC 62304 Class C safety requirements for uninterrupted memory integrity during power transitions. |
| Smart Meter Firmware Protection | Automotive Telematics Logging |
|
Use Scenario: Electricity meter writes energy consumption logs to external SRAM; must survive brief grid dips without losing timestamped records. IC Role / Device Role / Timing Role: Uses WDI to verify MCU liveness and PFI to detect sagging 3.3 V rail from aging DC-DC converter, asserting RST before data write corruption. Use Value: Eliminates need for external watchdog IC and discrete switchover circuit, reducing BOM count by 3 components. |
Use Scenario: Vehicle telematics unit logs GPS and CAN bus events to SRAM during ignition-off periods powered by backup capacitor or battery. IC Role / Device Role / Timing Role: Monitors 3.3 V supply derived from vehicle battery; asserts RST and switches VOUT to VBAT when engine stops and alternator voltage collapses. Use Value: Guarantees SRAM retention for ≥24 hours on CR2032 (with 0.4 µA draw), supporting post-crash event logging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809RTRG+T | Fixed 2.63 V reset threshold, no watchdog, no battery switchover, push-pull RST | Lacks VBAT support and PFI/PFO; suitable only for basic reset-only use cases | Select when cost sensitivity outweighs need for backup power management and fail-warning capability |
| TPS3808G12QDBVRQ1 | Adjustable reset threshold (via resistor divider), 200 ms trec, no battery switchover, no PFI/PFO | Requires external components for threshold setting; lacks integrated power-fail detection and SRAM backup switching | Choose when precise reset voltage tuning is required and battery backup is handled separately |
Compared with MAX809RTRG+T and TPS3808G12QDBVRQ1, STM804RM6F uniquely integrates battery switchover, PFI/PFO, and watchdog in a single SO8 package-reducing board space and eliminating four external components required by alternatives.
Availability
STM804RM6F is available at Aetrix Electronics and suitable for industrial PLC memory backup, medical device data retention, smart meter firmware protection, and automotive telematics logging requiring stable component supply across extended product lifecycles.
Supply support for STM804RM6F 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.
STM804RM6F belongs to ST's legacy supervisor IC family targeting robust power-monitoring in resource-constrained embedded systems, emphasizing low-power battery backup, deterministic reset timing, and integrated fail-safe signaling.
FAQ
What is the function of the Vccsw pin on STM804RM6F?
Vccsw is a push-pull output that goes high when VOUT switches from VCC to VBAT, and low when VOUT reconnects to VCC. It provides a logic-level signal usable to drive the gate of an external PMOS transistor, enabling higher current (>75 mA) battery backup paths beyond the internal 100 Ω switch's capability.
Can STM804RM6F operate without a backup battery connected?
Yes. When no battery is used, VBAT and VOUT must both be connected to VCC. In this configuration, the device functions as a standard supervisor with reset, watchdog, and power-fail detection-without switchover-but retains full RST assertion guarantee down to VCC = 1.0 V.
Is the RST output truly open-drain, and what pull-up value is recommended?
Yes, RST is an open-drain active-high output per datasheet Figure 1 and Table 2. ST recommends a 10 kΩ pull-up to VCC for standard 3.3 V systems; values between 4.7 kΩ and 100 kΩ are acceptable depending on rise-time and noise immunity requirements.
How does the watchdog timer interact with the manual reset (MR) input?
The watchdog timer is cleared only by WDI edge transitions or during active reset assertion. When MR is pulled low, reset is asserted and the watchdog timer halts; it resumes counting only after reset de-asserts and WDI receives a valid edge-ensuring no interference between manual and watchdog-initiated resets.
STM804RM6F 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:
- 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
STM804RM6F FAQ
1.How can I place an order for STM804RM6F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM804RM6F 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 STM804RM6F reliable?
The price and inventory of STM804RM6F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM804RM6F is usually 5 days.
3.What payment methods are accepted for STM804RM6F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM804RM6F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM804RM6F?
STM804RM6F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM804RM6F 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 STM804RM6F?
For technical support, including STM804RM6F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM804RM6F requirements.
6.How does Aetrix verify that STM804RM6F is sourced from the original manufacturer or authorized distributors?
All STM804RM6F 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 STM804RM6F meets industry standards.
7.What is the process for return or replacement of STM804RM6F?
All STM804RM6F units undergo pre-shipment inspection (PSI). If there is an issue with STM804RM6F, 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 STM804RM6F part is unused and in its original packaging.
Return procedure for STM804RM6F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM804RM6F Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
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