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STMicroelectronics STM690SM6F
- Part No.:
- STM690SM6F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
STM690SM6F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,650
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Product details
Overview
STM690SM6F from STMicroelectronics is a 3 V industrial-grade microprocessor supervisory IC with integrated battery switchover, active-low push-pull RST output, power-fail comparator (PFI/PFO), and manual reset input (MR). 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 - enabling reliable system initialization and SRAM backup in low-power embedded controllers.
For engineers reviewing the STM690SM6F datasheet, STM690SM6F pinout, STM690SM6F application, or STM690SM6F equivalent, key selection criteria include guaranteed reset behavior below 1.0 V VCC, automatic VCC-to-VBAT switchover at 2.4 V threshold, dual reset outputs (RST/RST), and compatibility with external LPSRAM retention circuits.
Technical Context
The STM690SM6F integrates a precision voltage reference, comparator-based reset generator, and analog switchover circuitry that connects VOUT to VCC above 2.4 V (VSW) and to VBAT below it. Its RST output is push-pull active-low, asserted during VCC undervoltage, MR activation, or watchdog timeout (though watchdog is not implemented in STM690).
It features dedicated PFI/PFO for early power-fail detection, Vccsw to drive external PMOS for >75 mA load switching, and operates across –40 °C to +85 °C. Unlike STM795/804/805 variants, it lacks chip enable gating and open-drain RST - confirming its role as a core reset supervisor with battery backup support.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.63 V (typ), ensures deterministic MCU reset before brownout at 3 V rail |
| Reset Timeout (trec) | 200 ms (typ), provides sufficient hold time for full processor initialization | Supply Current | 40 µA (typ) at VCC = 3.3 V, enables long-term operation in battery-backed systems |
| Battery Supply Current | 0.4 µA (typ), minimizes drain on backup cell during extended VCC loss |
| Power-Fail Threshold (VPFI) | 2.55 V (typ), triggers PFO before critical VCC collapse to allow graceful shutdown |
| Switchover Voltage (VSW) | 2.4 V (typ), defines precise VCC-to-VBAT transition point for seamless SRAM retention |
| Operating Temperature | –40 °C to +85 °C, qualified for industrial environments without derating |
Pinout & Package
STM690SM6F is housed in an 8-pin SO8 (Small Outline Integrated Circuit) package, measuring 4.9 mm × 3.9 mm × 1.75 mm, with 1.27 mm pitch and gull-wing leads - compatible with standard reflow and wave soldering processes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: PFO | Power-fail output | Push-pull active-low signal indicating imminent VCC failure; drives interrupt or NMI line |
| 2: VOUT | Supply output voltage | Switched output connected to VCC or VBAT; powers external LPSRAM during main supply loss |
| 3: VCC | Main supply input | Primary 3 V system rail; monitored for reset generation and switchover control |
| 4: RST | Active-low reset output | Push-pull logic-low reset signal asserted during fault conditions; directly interfaces MCU RESET pin |
| 5: VSS | Ground | Common reference for all internal comparators and output drivers |
| 6: MR | Manual reset input | Active-low input with internal 40 kΩ pull-up; supports momentary switch or logic-level assertion |
| 7: WDI | Watchdog input | Not functional in STM690 - pin is no-connect per device family specification |
| 8: VBAT | Backup battery input | Accepts 1.0–5.5 V backup source; automatically engages when VCC falls below 2.4 V |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed Reset Below 1.0 V VCC | Ensures valid reset assertion even during deep brownout, critical for flash-safe MCU boot |
| Automatic Battery Switchover | VOUT transitions from VCC to VBAT at 2.4 V with <100 Ω on-resistance, preserving SRAM data without external FETs |
| Power-Fail Comparator (PFI/PFO) | Provides early warning of supply collapse via programmable VPFI threshold, enabling controlled save-and-shutdown sequences |
| 200 ms Reset Timeout (trec) | Internally generated delay meets JEDEC JESD78 requirements for robust reset pulse width |
| Industrial Temperature Range | –40 °C to +85 °C operation validated across process corners, eliminating need for external thermal compensation |
Applications
| Industrial PLC Controller | Smart Meter Data Logger |
|---|---|
|
Use Scenario: Maintains SRAM state during grid voltage sags or meter battery replacement. IC Role / Device Role / Timing Role: Supervises 3.3 V MCU supply, asserts RST on undervoltage, and switches VOUT to VBAT to retain metering registers. Use Value: Prevents data corruption during transient outages by guaranteeing reset integrity down to 1.0 V and enabling zero-interruption SRAM backup. |
Use Scenario: Preserves tariff and consumption history during AC power loss in AMI meters. IC Role / Device Role / Timing Role: Monitors main supply via PFI, triggers PFO interrupt for firmware-initiated save, then activates VOUT→VBAT switchover. Use Value: Delivers 0.4 µA battery current draw and 2.4 V switchover threshold to maximize coin-cell lifetime beyond 10 years. |
| Medical Infusion Pump | Point-of-Sale Terminal |
|
Use Scenario: Ensures safe shutdown and parameter retention when primary power fails mid-infusion cycle. IC Role / Device Role / Timing Role: Generates clean RST pulse to halt motor control MCU, while VOUT sustains real-time clock and configuration EEPROM. Use Value: Meets IEC 62304 safety requirements via guaranteed 200 ms trec and fail-safe reset assertion independent of VCC level. |
Use Scenario: Protects transaction logs and encryption keys during brief AC dropout or battery swap. IC Role / Device Role / Timing Role: Uses MR input for user-triggered reset and PFO to flag power anomaly before storage write completion. Use Value: Combines 40 µA quiescent current and push-pull RST to eliminate external pull resistors and reduce BOM count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM802SM6F | Identical pinout and reset functionality; differs only in reset threshold (2.63 V vs. 2.93 V) | Higher VRST better suited for 3.3 V systems with tighter tolerance margins | Select STM802 if system VCC nominal is 3.3 V ±3% and brownout must occur closer to rail |
| MAX809TRD2T | Single active-low reset output; no PFI/PFO, no battery switchover, no MR input | Lacks SRAM backup and power-fail warning - suitable only for basic reset-only use cases | Choose MAX809 only when cost sensitivity outweighs need for battery management and fault prediction |
Compared with STM802SM6F, STM690SM6F offers lower reset threshold for earlier intervention in marginal supplies; versus MAX809TRD2T, it adds full battery switchover, PFI/PFO, and manual reset - making it indispensable for data-retentive embedded systems.
Availability
STM690SM6F is available at Aetrix Electronics and suitable for industrial PLC controllers, smart meter data loggers, medical infusion pumps, and point-of-sale terminals requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for STM690SM6F 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 silicon solutions for automotive, industrial, and consumer markets since 1987.
The STM690 belongs to ST's high-reliability supervisor IC product line, engineered specifically for systems demanding guaranteed reset behavior, battery-backed memory retention, and early power-fail detection in harsh operating environments.
FAQ
Is the WDI pin functional on STM690SM6F?
No. The WDI pin is a no-connect in the STM690 variant per ST's device summary table and logic diagrams. Watchdog functionality is present only in STM690/802/804/805 - but explicitly excluded from STM690. Driving WDI has no effect; it may be left floating or tied to GND/VCC without impact.
Can STM690SM6F drive external SRAM directly without additional FETs?
Yes. VOUT delivers up to 75 mA with <100 Ω on-resistance when switching to VBAT, sufficient to power typical LPSRAM devices (e.g., Cypress CY14B101Q, ISSI IS62WV5128BLL). For loads exceeding 75 mA, use Vccsw to gate an external PMOS transistor as specified in Figure 11 of the datasheet.
What is the minimum VBAT voltage required for valid reset assertion?
VBAT must exceed 1.0 V to guarantee RST assertion during VCC loss, as confirmed in Section 2.1 of the datasheet. Below 1.0 V, reset behavior is not specified - therefore, coin cells (e.g., BR2032, 3.0 V) or supercapacitors charged to ≥2.4 V are recommended for reliable operation.
Does STM690SM6F support both push-button and logic-level manual reset?
Yes. The MR pin accepts either a momentary switch to GND or TTL/CMOS logic signals. It features an internal 40 kΩ pull-up resistor, so it remains inactive when left unconnected. No external components are needed for debounce - the internal timing ensures clean reset assertion even with mechanical switch bounce.
STM690SM6F 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:
- 2.925V
- 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
STM690SM6F FAQ
1.How can I place an order for STM690SM6F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM690SM6F 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 STM690SM6F reliable?
The price and inventory of STM690SM6F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM690SM6F is usually 5 days.
3.What payment methods are accepted for STM690SM6F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM690SM6F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM690SM6F?
STM690SM6F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM690SM6F 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 STM690SM6F?
For technical support, including STM690SM6F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM690SM6F requirements.
6.How does Aetrix verify that STM690SM6F is sourced from the original manufacturer or authorized distributors?
All STM690SM6F 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 STM690SM6F meets industry standards.
7.What is the process for return or replacement of STM690SM6F?
All STM690SM6F units undergo pre-shipment inspection (PSI). If there is an issue with STM690SM6F, 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 STM690SM6F part is unused and in its original packaging.
Return procedure for STM690SM6F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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