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STMicroelectronics STM708SM6E
- Part No.:
- STM708SM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM708SM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,587
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Product details
Overview
STM708SM6E from STMicroelectronics is a 3 V supply voltage supervisor IC with dual active-high and active-low reset outputs, 200 ms reset timeout, power-fail comparator (PFI/PFO), and manual reset input (MR). It monitors VCC for out-of-tolerance conditions down to 1.0 V and guarantees RST assertion across –40 °C to 85 °C industrial temperature range. Used in embedded controllers and instrumentation for reliable power-on and brownout reset generation.
For engineers reviewing the STM708SM6E datasheet, STM708SM6E pinout, STM708SM6E application, or STM708SM6E equivalent, key selection criteria include reset threshold tolerance (±2.5% for S-grade), PFI comparator reference (1.25 V typ.), trec stability over temperature (±5 ms), and compatibility with bi-directional MCU reset pins via series resistor interface.
Technical Context
The STM708SM6E implements independent precision comparators for VCC monitoring (VRST = 2.88–3.00 V for S-grade) and power-fail detection (VPFI = 1.25 V), each driving dedicated push-pull outputs. Its reset logic asserts RST and RST simultaneously on VCC drop, MR low, or watchdog timeout - though the STM708 variant excludes watchdog circuitry entirely.
Unlike STM706 variants, the STM708SM6E omits WDI/WDO pins and integrates no watchdog timer; instead it provides dual complementary reset outputs (RST and RST) and full PFI/PFO functionality in an 8-pin SOIC package. The internal trec generator ensures minimum 200 ms reset pulse width after power-up or fault recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Monitor Threshold | 2.88 V to 3.00 V (S-grade); ensures reset assertion before microcontroller VCC dropout at 3.0 V nominal supply. |
| Reset Timeout (trec) | 200 ms typical; guarantees minimum system initialization hold time after power-up or brownout recovery. |
| Power-Fail Reference (VPFI) | 1.25 V ±1.6%; enables early warning of supply collapse using external resistive divider on unregulated rail. |
| Supply Current | 40 µA typical at 25 °C; supports ultra-low-power battery-backed systems without compromising supervision integrity. |
| Operating Temperature | –40 °C to +85 °C; validated for industrial environments including factory automation and remote instrumentation. |
| RST Assertion Down to VCC | 1.0 V; maintains valid logic-level reset signal even during deep brownout, preventing MCU latch-up or undefined state. |
| PFO Output Type | Push-pull; eliminates need for external pull-up and allows direct connection to MR or interrupt inputs. |
Pinout & Package
STM708SM6E is housed in an 8-lead 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/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (PFO) | Power-fail output | Push-pull active-low signal indicating PFI < VPFI; used to trigger early shutdown or save-to-EEPROM sequence. |
| 2 (RST) | Active-high reset output | Asserts high when VCC < VRST, MR low, or fault condition; compatible with MCUs requiring active-high reset. |
| 3 (PFI) | Power-fail input | Monitors divided unregulated supply; threshold fixed at 1.25 V, independent of VRST comparator. |
| 4 (VCC) | Supply voltage input | Primary power rail (2.7–5.5 V); powers all internal comparators, timers, and output drivers. |
| 5 (MR) | Manual reset input | Active-low input with 40 kΩ internal pull-up; debounced by trec timer, requires no external RC. |
| 6 (VSS) | Ground | Reference return path for all comparators and outputs; must be low-impedance connection to system GND plane. |
| 7 (RST) | Active-low reset output | Asserts low under same conditions as RST; provides simultaneous complementary reset signaling for mixed-logic systems. |
| 8 (NC) | No connect | Unbonded pin; must remain floating - no routing or soldering permitted per STMicroelectronics design specification. |
Key Features
| Feature | Design Value |
|---|---|
| Dual complementary reset outputs | RST (active-low) and RST (active-high) enable direct interfacing with both legacy and modern MCUs without level-shifting. |
| Guaranteed reset down to 1.0 V VCC | Ensures deterministic reset assertion during severe brownout, eliminating risk of MCU runaway or memory corruption. |
| Independent power-fail comparator | 1.25 V VPFI reference allows early detection of supply decay using external resistor divider on pre-regulator rail. |
| 200 ms reset timeout (trec) | Internally generated, temperature-stable delay ensures sufficient time for oscillator stabilization and register initialization. |
| Industrial temperature range | –40 °C to +85 °C operation verified per AEC-Q100 stress testing; suitable for non-automotive industrial deployments. |
Applications
| Industrial PLC Controller | Smart Energy Meter |
|---|---|
|
Use Scenario: Power cycling during grid fluctuations causes repeated brownouts in field-deployed programmable logic controllers. IC Role / Device Role / Timing Role: STM708SM6E monitors 3.3 V supply and asserts both RST and RST to force controlled MCU reboot while PFO triggers EEPROM save prior to collapse. Use Value: Dual reset outputs eliminate need for external inverters; 1.0 V assertion guarantee prevents partial execution during deep undervoltage. |
Use Scenario: Meters experience transient dips on auxiliary 3 V rail due to RF burst transmission or load switching. IC Role / Device Role / Timing Role: PFI senses unregulated DC bus via 10:1 divider; PFO pulls MR low 5 ms before VCC drops below 2.9 V, initiating safe shutdown. Use Value: Independent 1.25 V VPFI reference enables precise timing margin between PFO alert and RST assertion. |
| Medical Diagnostic Handheld | Factory Automation I/O Module |
|
Use Scenario: Battery-powered ultrasound device undergoes rapid discharge cycles where VCC falls from 3.6 V to 2.7 V during operation. IC Role / Device Role / Timing Role: STM708SM6E holds RST low until VCC stabilizes above 2.88 V post-battery swap, blocking unsafe firmware execution. Use Value: 200 ms trec ensures crystal oscillator and ADC reference settle before release - critical for measurement repeatability. |
Use Scenario: DIN-rail mounted I/O modules endure wide ambient swings (–25 °C to 70 °C) and EMI-rich factory floor environments. IC Role / Device Role / Timing Role: MR tied to front-panel reset button; internal 40 kΩ pull-up eliminates external components while maintaining noise immunity. Use Value: SO8 package meets IPC-7351B land pattern standards; –40 °C to +85 °C rating ensures reliability across thermal cycling. |
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; 3.08 V threshold; no PFI/PFO; SOT23-3 package | Lacks dual reset outputs and power-fail warning; suited only for space-constrained, single-rail designs | Select only if board area is critical and PFI functionality is omitted from system architecture. |
| TPS3808G33DBVR | Active-low reset only; 3.3 V threshold; adjustable trec (200 ms default); no PFI/PFO; SOT23-6 | Requires external resistor for trec tuning; no early power-fail detection capability | Choose when precise 3.3 V supervision is required and system uses separate brownout monitoring circuitry. |
Compared with MAX6326US31D3+ and TPS3808G33DBVR, STM708SM6E uniquely delivers dual-reset signaling and integrated PFI/PFO in SO8 - enabling compact, function-complete supervision without external components or logic translation.
Availability
STM708SM6E is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, medical handheld diagnostics, and factory automation I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for STM708SM6E 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 STM70x supervisor family targets robust power monitoring in resource-constrained embedded systems, emphasizing guaranteed reset behavior, low quiescent current, and seamless integration with microprocessor reset architectures.
FAQ
What is the function of the NC pin on STM708SM6E?
Pin 8 is designated NC (no connect) and is internally unbonded. STMicroelectronics specifies that this pin must remain unconnected - no trace routing, soldering, or grounding is permitted. Doing so may compromise device reliability or cause undefined behavior due to internal die coupling.
Can STM708SM6E be used with a 5 V supply?
Yes - STM708SM6E operates across 2.7 V to 5.5 V VCC. Its 2.88–3.00 V reset threshold remains valid regardless of supply voltage, making it suitable for 5 V systems where a 3 V supervisor is needed to protect downstream 3.3 V logic. Supply current increases only marginally (to ~45 µA at 5.5 V).
How does the PFI/PFO function interact with the main reset outputs?
PFI and PFO operate independently from VCC monitoring: PFO asserts low when PFI falls below 1.25 V, regardless of VCC level. This allows early warning of supply decay before VCC reaches VRST. PFO can be wired to MR to generate a preemptive reset, but it does not directly control RST/RST unless externally connected.
Is STM708SM6E pin-compatible with STM706S?
No - STM708SM6E lacks WDI and WDO pins and substitutes NC for WDO. Its pin 1 is PFO (not WDO), pin 2 is RST (not WDI), and pin 8 is NC (not WDO). Direct replacement would require PCB redesign; functional equivalence exists only at the system level with appropriate schematic adaptation.
STM708SM6E 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:
- 2.93V
- 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
STM708SM6E FAQ
1.How can I place an order for STM708SM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM708SM6E 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 STM708SM6E reliable?
The price and inventory of STM708SM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM708SM6E is usually 5 days.
3.What payment methods are accepted for STM708SM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM708SM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM708SM6E?
STM708SM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM708SM6E 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 STM708SM6E?
For technical support, including STM708SM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM708SM6E requirements.
6.How does Aetrix verify that STM708SM6E is sourced from the original manufacturer or authorized distributors?
All STM708SM6E 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 STM708SM6E meets industry standards.
7.What is the process for return or replacement of STM708SM6E?
All STM708SM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM708SM6E, 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 STM708SM6E part is unused and in its original packaging.
Return procedure for STM708SM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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