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STMicroelectronics STM704SM6E
- Part No.:
- STM704SM6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM704SM6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,873
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Product details
Overview
STM704SM6E from STMicroelectronics is a 3 V industrial-grade microprocessor supervisory IC with manual reset input, automatic battery switchover, power-fail comparator (PFI/PFO), and guaranteed RST assertion down to VCC = 1.0 V. It provides active-low push-pull reset output, 200 ms typical reset timeout (trec), and operates from –40 °C to +85 °C in SO8 package - used for reliable system initialization and backup SRAM retention in low-power embedded controllers.
For engineers reviewing the STM704SM6E datasheet, STM704SM6E pinout, STM704SM6E application, or STM704SM6E equivalent, key selection criteria include reset threshold accuracy (2.63 V typ), battery switchover voltage (VSW = 2.4 V), PFI comparator reference (VPFI = 2.63 V), and absence of watchdog timer - distinguishing it from STM690/802/804/805 variants.
Technical Context
The STM704 implements a precision voltage monitor with internal 2.63 V reference to assert RST when VCC falls below VRST. Its MR input features a 40 kΩ internal pull-up and triggers reset while asserted and for 200 ms after release. The PFI/PFO pair provides early power-fail warning by comparing VCC or external voltage against VPFI.
Battery switchover is fully autonomous: when VCC drops below 2.4 V, VOUT disconnects from VCC and connects to VBAT via an internal P-channel MOSFET switch; Vccsw toggles to indicate switchover state. VOUT supplies external LPSRAM during main power loss, with <0.4 µA battery supply current in backup mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VRST) | 2.63 V (typ) - ensures reset assertion before MCU brown-out; guaranteed valid down to VCC = 1.0 V |
| Switchover Voltage (VSW) | 2.4 V - triggers automatic VOUT switching from VCC to VBAT to preserve SRAM data |
| Reset Timeout (trec) | 200 ms (typ) - holds RST low long enough for full MCU initialization and peripheral stabilization |
| Power-Fail Input Threshold (VPFI) | 2.63 V (typ) - matches VRST for consistent system-level power monitoring and graceful shutdown |
| Battery Supply Current | 0.4 µA (typ) - enables multi-year backup operation on coin-cell batteries |
| Operating Temperature | –40 °C to +85 °C - qualified for industrial environments without derating |
| Supply Current (VCC active) | 40 µA (typ) - minimizes impact on primary power rail in always-on monitoring applications |
Pinout & Package
STM704SM6E is housed in an 8-pin SO8 (Small Outline Integrated Circuit) package, 3.9 mm × 4.9 mm body, 1.27 mm pitch, RoHS-compliant lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - PFO | Power-fail output | Push-pull active-low signal indicating VCC drop below VSW or PFI < VPFI; drives interrupt or shutdown logic |
| 2 - VOUT | Supply output voltage | Switched output connected to VCC (when VCC > VSW) or VBAT (when VCC < VSW); powers external LPSRAM |
| 3 - VCC | Main supply input | 3 V nominal system supply; monitored for reset and switchover decisions |
| 4 - RST | Active-low reset output | Push-pull output asserted low during power-up, brown-out, or MR activation; directly interfaces MCU reset pin |
| 5 - PFI | Power-fail input | Monitors external voltage (e.g., unregulated rail) against VPFI = 2.63 V; tied to GND if unused |
| 6 - MR | Manual reset input | Active-low input with 40 kΩ internal pull-up; initiates reset on button press; no external components required |
| 7 - VBAT | Backup battery input | Accepts 1.0–5.5 V battery; automatically powers VOUT when VCC fails; connect to VCC if no battery used |
| 8 - VSS | Ground | System ground reference for all internal comparators and outputs |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset assertion at VCC = 1.0 V | Ensures fail-safe MCU reset even during deep brown-out conditions without battery assist |
| Automatic battery switchover at 2.4 V | Prevents SRAM data loss during main power interruption; supports seamless transition to backup supply |
| Integrated power-fail comparator (PFI/PFO) | Enables early warning of impending power loss - allows firmware-controlled save operations before VCC collapse |
| 200 ms reset timeout with no external capacitor | Eliminates timing component count and board space; trec is factory-trimmed and temperature-stable |
| 0.4 µA battery supply current | Extends coin-cell life beyond 10 years in typical SRAM backup configurations |
Applications
| Industrial PLC Controller | Smart Meter Data Logger |
|---|---|
Use Scenario: Maintains real-time clock and metering registers during AC mains interruption. IC Role / Device Role / Timing Role: Supervises 3 V MCU and LPSRAM; asserts RST on brown-out and switches VOUT to VBAT to retain critical kWh data. Use Value: Guarantees SRAM data integrity for ≥10 years on CR2032 battery due to 0.4 µA backup current and 2.4 V switchover point. |
Use Scenario: Captures last-valid energy readings before grid failure and stores them in non-volatile SRAM. IC Role / Device Role / Timing Role: Monitors VCC and PFI simultaneously; triggers PFO interrupt for firmware-initiated save, then maintains VOUT during outage. Use Value: VPFI = 2.63 V matches VRST, enabling synchronized reset and power-fail response - eliminating race conditions in save routines. |
| Medical Infusion Pump | POS Terminal with Secure Memory |
Use Scenario: Preserves therapy parameters and error logs during battery swap or power glitch. IC Role / Device Role / Timing Role: Provides MR-initiated reset for safety-critical reinitialization and VOUT-backed SRAM for audit trail storage. Use Value: RST guaranteed down to VCC = 1.0 V ensures deterministic reset even under marginal battery conditions - meeting IEC 62304 Class C requirements. |
Use Scenario: Secures transaction keys and session data in tamper-resistant SRAM during unexpected power loss. IC Role / Device Role / Timing Role: Supplies clean, switchover-protected VOUT to crypto SRAM; uses PFO to signal host controller for immediate key erasure. Use Value: 200 ms trec ensures sufficient time for secure memory wipe before VOUT collapses - satisfying PCI PTS v6.0 backup power timing mandates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM690TSA | Includes watchdog timer (1.6 s); same VRST (2.63 V), VSW (2.4 V), and SO8 package | Required where MCU lockup detection is mandatory (e.g., automotive ECUs); adds WDI pin and logic complexity | Select STM690TSA only if watchdog functionality is needed - STM704SM6E simplifies design where manual reset suffices |
| TPS3808G33DBVR | TI part with 3.3 V reset threshold (3.08 V min), no PFI/PFO, no battery switchover; SOT-23-6 package | Limited to basic reset supervision without SRAM backup or power-fail warning; smaller footprint but fewer functions | Choose TPS3808G33DBVR for cost-sensitive, space-constrained designs lacking battery backup or PFI needs |
Compared with STM690TSA and TPS3808G33DBVR, STM704SM6E uniquely balances industrial-grade reliability, integrated battery switchover, and power-fail warning in a single SO8 package - making it optimal for SRAM-retentive embedded systems where watchdog overhead is unnecessary.
Availability
STM704SM6E is available at Aetrix Electronics and suitable for industrial PLC controllers, smart meter data loggers, medical infusion pumps, and POS terminals requiring stable component supply across extended product lifecycles.
Supply support for STM704SM6E 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 sensing solutions for industrial, automotive, and consumer markets.
STM704 belongs to ST's legacy microprocessor supervisor family targeting robust, low-power system monitoring - specifically engineered for battery-backed SRAM retention and deterministic reset in harsh industrial environments.
FAQ
Does STM704SM6E include a watchdog timer?
No. STM704SM6E does not incorporate a watchdog timer - this function is explicitly excluded per the datasheet (Section 2.3: "NOT available on STM704/795/806"). Its supervision relies solely on VCC monitoring, MR input, and PFI comparison. For watchdog capability, consider STM690TSA or STM802TSA instead.
Can VBAT exceed VCC in STM704SM6E?
Yes. VBAT may be up to 5.5 V regardless of VCC level. The internal switchover circuit isolates VCC and VBAT paths, allowing VBAT to safely back up VOUT even when VCC is absent or at 0 V - provided VCC first rises above VRST (2.63 V) to initialize the device.
What is the function of the Vccsw pin?
Vccsw is a push-pull output that goes high when VOUT switches to VBAT (indicating backup mode) and low when VOUT reconnects to VCC. It can drive the gate of an external PMOS transistor to extend VOUT current capability beyond the internal 75 mA limit - useful for higher-capacity SRAM banks.
Is external capacitor required for reset timeout?
No. The 200 ms reset timeout (trec) is internally generated and factory-trimmed - no external RC network is needed. This eliminates component count, layout area, and tolerance-related timing drift, ensuring consistent reset duration across temperature and voltage.
STM704SM6E 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:
- 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
STM704SM6E FAQ
1.How can I place an order for STM704SM6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM704SM6E 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 STM704SM6E reliable?
The price and inventory of STM704SM6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM704SM6E is usually 5 days.
3.What payment methods are accepted for STM704SM6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM704SM6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM704SM6E?
STM704SM6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM704SM6E 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 STM704SM6E?
For technical support, including STM704SM6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM704SM6E requirements.
6.How does Aetrix verify that STM704SM6E is sourced from the original manufacturer or authorized distributors?
All STM704SM6E 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 STM704SM6E meets industry standards.
7.What is the process for return or replacement of STM704SM6E?
All STM704SM6E units undergo pre-shipment inspection (PSI). If there is an issue with STM704SM6E, 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 STM704SM6E part is unused and in its original packaging.
Return procedure for STM704SM6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM704SM6E Tags
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MIC826SYMT-TR
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APX803L20-29SA-7
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