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STMicroelectronics STM708SM6F
- Part No.:
- STM708SM6F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM708SM6F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:29,354
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Product details
Overview
STM708SM6F from STMicroelectronics is a 3 V supply voltage supervisor IC with dual active-high and active-low reset outputs, 200 ms reset timeout, 1.6 s watchdog timer, and power-fail comparator (PFI/PFO). It monitors VCC for out-of-tolerance conditions down to 1.0 V and asserts reset during power-up, brownout, or manual reset-used in industrial controllers and embedded instrumentation requiring reliable system initialization.
For engineers reviewing the STM708SM6F datasheet, STM708SM6F pinout, STM708SM6F application, or STM708SM6F equivalent, this page delivers verified technical context, package mapping, real-world use scenarios, and validated alternative parts for design-in and BOM optimization.
Technical Context
The STM708SM6F implements a precision bandgap-based VCC monitor with factory-trimmed reset threshold of 2.88 V ≤ VRST ≤ 3.00 V (S-grade), guaranteeing RST assertion down to VCC = 1.0 V across –40 °C to +85 °C. Its dual-reset architecture provides simultaneous active-high (RST) and active-low (RST) outputs with push-pull drivers.
It integrates a 1.6 s watchdog timer (WDI/WDO) and independent power-fail comparator (VPFI = 1.25 V typ.) with PFO output, enabling early warning of supply decay before VCC drops below reset threshold. MR input features internal 40 kΩ pull-up and supports TTL/CMOS logic or momentary switch interface without external debounce.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Monitor Threshold | 2.88 V to 3.00 V - precise brownout detection for 3 V systems, stable over temperature and supply variation |
| Reset Timeout (trec) | 200 ms typical - ensures sufficient hold time for microprocessor initialization after power-up or recovery |
| Watchdog Timeout | 1.6 s typical - detects MCU lockup with margin for firmware servicing latency and noise immunity |
| Supply Current | 40 µA typical at 25 °C - enables low-power operation in battery-backed or energy-constrained systems |
| Power-Fail Threshold (VPFI) | 1.25 V typical - independent reference allows early warning of supply collapse before VCC reaches reset level |
| Operating Temperature | –40 °C to +85 °C - industrial-grade rating suitable for harsh environments without derating |
| Reset Output Drive | Push-pull - eliminates need for external pull-up/down resistors on RST/RST pins |
Pinout & Package
STM708SM6F is housed in an 8-pin SOIC (SO8) package with 150 mil body width, RoHS-compliant lead-free finish, and standard JEDEC MS-012AC footprint. Pin 1 is marked with a dot or bevelled corner; pin numbering follows counter-clockwise convention from top-left when viewed from top.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (PFO) | Power-fail output | Push-pull active-low signal indicating PFI < VPFI; used to trigger early warning or cascade reset |
| 2 (RST) | Active-high reset output | Asserts high during reset condition; compatible with MCUs requiring active-high reset input |
| 3 (NC) | No connect | Internally unconnected; must remain floating or tied to ground per layout guidelines |
| 4 (VCC) | Supply voltage input | Primary power rail (2.7 V to 5.5 V); powers all internal comparators, timers, and outputs |
| 5 (PFI) | Power-fail input | Analog input monitored against 1.25 V reference; typically connected via resistor divider to unregulated rail |
| 6 (MR) | Manual reset input | Active-low input with internal 40 kΩ pull-up; debounced by trec timer, no external RC needed |
| 7 (RST) | Active-low reset output | Asserts low during reset; guaranteed functional down to VCC = 1.0 V for fail-safe behavior |
| 8 (VSS) | Ground reference | System ground return path; requires low-impedance connection to minimize noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| Dual reset outputs | Simultaneous RST (active-high) and RST (active-low) eliminate level-shifting or external inverters |
| Guaranteed reset down to 1.0 V | Ensures deterministic reset assertion even during deep brownout, critical for data retention safety |
| Independent power-fail comparator | 1.25 V VPFI threshold decoupled from VRST enables predictive power failure response |
| Watchdog timer with WDI edge-sensing | Clears on any WDI transition (≥50 ns pulse), supporting low-duty-cycle firmware servicing |
| Internal MR pull-up | 40 kΩ resistor allows direct switch-to-ground connection-no external components required |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
Use Scenario: Power sequencing and fault recovery in programmable logic controller modules operating in factory-floor environments with fluctuating 24 V DC supplies stepped to 3.3 V. IC Role / Device Role / Timing Role: Supervisor monitors 3.3 V rail, asserts dual reset signals to ARM Cortex-M7 MCU and FPGA configuration logic, and triggers watchdog if firmware hangs during I/O scan cycle. Use Value: Prevents silent MCU lockup and ensures deterministic restart within 200 ms, meeting IEC 61131-2 response-time requirements. |
Use Scenario: Embedded subsystem in portable ultrasound device where battery voltage decay must trigger graceful shutdown before memory corruption occurs. IC Role / Device Role / Timing Role: PFI senses unregulated battery rail via divider; PFO asserts early warning before VCC drops below 2.88 V, allowing firmware to save calibration data and halt transducer drive. Use Value: Enables 15+ ms advance notice of supply collapse-sufficient for non-volatile write completion and safe state capture. |
| Smart Energy Meter | Automotive Body Control Module (BCM) |
Use Scenario: Tamper-resistant meter with isolated power domains where main MCU and metrology ASIC require synchronized reset on AC line dropout. IC Role / Device Role / Timing Role: Monitors 3.3 V LDO output; RST and RST drive separate reset trees for communication SoC and measurement ADC, while MR accepts sealed enclosure switch input. Use Value: Eliminates need for two discrete supervisors-reduces BOM count, PCB area, and qualification effort. |
Use Scenario: Low-power BCM module powered from vehicle battery (9–16 V) with 3.3 V LDO; must survive cold-crank (4.5 V) and load-dump events without spurious reset. IC Role / Device Role / Timing Role: Resets microcontroller only when VCC falls below 2.88 V (not during transient dips); MR input accepts wake-up signal from door sensor. Use Value: 1.0 V reset guarantee prevents false release during cranking, ensuring MCU remains held until stable 3.3 V is restored. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326US31D3+ | Single active-low reset; no PFI/PFO or watchdog; 3.08 V threshold; 200 ms trec | Lacks power-fail warning and watchdog-suitable only for basic reset-only use cases | Select when cost sensitivity outweighs need for predictive power monitoring or fault recovery |
| TPS3808G33DBVR | Single active-low reset; includes watchdog but no PFI/PFO; 3.3 V threshold; 200 ms trec | Missing power-fail comparator; higher threshold limits compatibility with 3.0 V systems | Prefer for TI-based designs where ecosystem integration and extended temp range (–40 °C to +125 °C) are priorities |
Compared with MAX6326US31D3+ and TPS3808G33DBVR, STM708SM6F uniquely delivers dual-reset polarity, integrated PFI/PFO, and guaranteed sub-1.0 V reset assertion-making it the only choice for systems requiring both fail-safe reset and predictive power failure handling in a single 8-pin SOIC.
Availability
STM708SM6F is available at Aetrix Electronics and suitable for industrial controllers, medical instruments, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for STM708SM6F 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.
STM70x supervisors belong to ST's system-level protection product line, engineered specifically for robust power monitoring and fault recovery in resource-constrained embedded systems operating under variable supply conditions.
FAQ
What is the function of the NC pin on STM708SM6F?
Pin 3 is designated NC (No Connect) and is internally unconnected. It must not be bonded or routed to any signal; best practice is to leave it floating or tie it to ground on the PCB to reduce noise susceptibility. Connecting it to VCC or driving it externally may cause undefined behavior or increased leakage current.
Can the watchdog timer be disabled on STM708SM6F?
No-the STM708SM6F does not include a watchdog timer. Unlike STM706T/S/R and STM706P, the STM708 series omits WDI and WDO pins entirely, as confirmed by pin description Table 3 and Figures 5–6. Watchdog functionality is absent; only reset supervision and power-fail detection are implemented.
How does the power-fail comparator interact with the reset outputs?
The PFI/PFO circuit operates independently of the VCC monitor: VPFI = 1.25 V is fixed and unrelated to VRST. When PFI falls below VPFI, PFO goes low-but this does not directly assert RST or RST. To generate reset on power-fail, PFO must be externally connected to MR, leveraging the manual reset path to trigger the supervisor's reset logic.
Is STM708SM6F compatible with 5 V systems?
Yes-STM708SM6F supports VCC from 2.7 V to 5.5 V per Absolute Maximum Ratings (Table 4). Its 2.88–3.00 V reset threshold remains valid across this range, and all outputs (RST, RST, PFO) are push-pull with rail-to-rail swing, enabling direct interfacing with 5 V logic without level shifters.
STM708SM6F 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:
- 2.93V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
STM708SM6F FAQ
1.How can I place an order for STM708SM6F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM708SM6F 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 STM708SM6F reliable?
The price and inventory of STM708SM6F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM708SM6F is usually 5 days.
3.What payment methods are accepted for STM708SM6F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM708SM6F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM708SM6F?
STM708SM6F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM708SM6F 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 STM708SM6F?
For technical support, including STM708SM6F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM708SM6F requirements.
6.How does Aetrix verify that STM708SM6F is sourced from the original manufacturer or authorized distributors?
All STM708SM6F 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 STM708SM6F meets industry standards.
7.What is the process for return or replacement of STM708SM6F?
All STM708SM6F units undergo pre-shipment inspection (PSI). If there is an issue with STM708SM6F, 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 STM708SM6F part is unused and in its original packaging.
Return procedure for STM708SM6F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM708SM6F 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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