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STMicroelectronics STM704RDS6E
- Part No.:
- STM704RDS6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
STM704RDS6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,602
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Product details
Overview
STM704RDS6E from STMicroelectronics is a 3 V industrial-grade microprocessor supervisory IC with manual reset input, power-fail comparator (PFI/PFO), automatic battery switchover, 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 for embedded systems requiring reliable power monitoring and SRAM backup control.
For engineers reviewing the STM704RDS6E datasheet, STM704RDS6E pinout, STM704RDS6E application, or STM704RDS6E equivalent, key selection criteria include reset threshold accuracy, battery switchover behavior, PFI/PFO response timing, MR debounce tolerance, and compatibility with external LPSRAM backup schemes under brownout conditions.
Technical Context
The STM704 implements a precision voltage reference and comparator to monitor VCC against a fixed 2.63 V reset threshold (VRST) with ±1.5% tolerance. Its reset logic asserts RST low during VCC undervoltage, MR activation, or power-fail detection via PFI input - all triggering a 200 ms minimum reset pulse width (trec).
Battery switchover is managed by an internal P-channel MOSFET switch connecting VBAT to VOUT when VCC falls below 2.4 V (VSW); VOUT remains tied to VCC above that threshold. The PFO output is push-pull and asserts low on either PFI < VPFI (1.25 V typ) or VCC < VSW, providing early warning of supply collapse.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VRST) | 2.63 V ±1.5% - ensures MCU reset before core logic fails at 3 V nominal supply |
| Reset Timeout (trec) | 200 ms typ - guarantees sufficient hold time for processor initialization and memory stabilization |
| Power-Fail Threshold (VPFI) | 1.25 V typ - triggers PFO assertion before VCC drops below critical SRAM retention voltage | Switchover Voltage (VSW) | 2.4 V - initiates battery backup before VCC crosses VRST, preserving LPSRAM data integrity |
| Supply Current (ICC) | 40 µA typ - enables low-power operation in always-on monitoring circuits |
| Battery Supply Current (IBAT) | 0.4 µA typ - minimizes drain on backup coin cell during extended storage or standby |
| Operating Temperature | –40 °C to +85 °C - supports industrial-grade deployment without derating |
Pinout & Package
STM704RDS6E is housed in an 8-pin SO8 (Small Outline Integrated Circuit) package with 1.27 mm pitch, compliant with JEDEC MS-012, suitable for automated SMT assembly and thermal reliability in industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PFO | Power-fail output | Push-pull active-low signal indicating imminent VCC collapse or PFI undervoltage |
| PFI | Power-fail input | Monitors external supply rail; asserts PFO when voltage falls below 1.25 V threshold |
| MR | Manual reset input | Active-low logic input with 40 kΩ internal pull-up; debounced internally for push-button use |
| RST | Active-low reset output | Push-pull output asserted low during VCC undervoltage, MR activation, or power-fail event |
| VCC | Main supply input | 3 V nominal input powering internal circuitry and enabling VOUT connection to main rail |
| VOUT | SRAM supply output | Switched output connected to VCC above 2.4 V, or to VBAT below it - powers external LPSRAM |
| VBAT | Backup battery input | Accepts 1.0–5.5 V backup source; automatically engages when VCC drops below switchover point |
| VSS | Ground reference | System ground return path for all internal comparators, timers, and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RST assertion down to VCC = 1.0 V | Ensures deterministic reset even during deep brownout, critical for nonvolatile memory write completion |
| Automatic battery switchover with 100 Ω switch | Enables seamless LPSRAM backup without external FETs or diode-ORing, reducing BOM count |
| Power-fail comparator with independent PFI/PFO | Provides early warning of supply decay ≥1.25 V, allowing firmware-controlled save-and-shutdown sequences |
| 200 ms reset timeout with temperature-stable trec generator | Eliminates need for external RC timing components while maintaining specification across –40 °C to +85 °C |
| Internal 40 kΩ MR pull-up resistor | Permits direct push-button connection without external biasing, simplifying front-panel reset design |
Applications
| Industrial PLC Controller | Medical Infusion Pump |
|---|---|
Use Scenario: Maintains SRAM state during AC mains interruption while retaining calibration and dosage history. IC Role / Device Role / Timing Role: Supervisory IC providing battery-backed VOUT, PFO-triggered firmware save, and MR-initiated system reinitialization. Use Value: Prevents loss of critical therapy parameters during brief power dips, meeting IEC 60601-1 uptime requirements. | Use Scenario: Preserves real-time drug delivery logs and alarm history during battery swap or main power loss. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors 3.3 V rail for brownout and switches VOUT to backup coin cell upon VCC drop below 2.4 V. Use Value: Enables uninterrupted logging with <0.4 µA battery drain, extending coin-cell life beyond 5 years in standby. |
| Smart Energy Meter | Automotive Telematics Gateway |
Use Scenario: Captures last valid kWh reading and tamper event timestamp during grid outage. IC Role / Device Role / Timing Role: Power-fail detector asserting PFO to trigger EEPROM write before VCC collapses below 2.4 V. Use Value: Meets ANSI C12.20 Class 0.2 metering accuracy by guaranteeing data persistence through 200 ms trec window. | Use Scenario: Safeguards CAN message buffers and GPS position cache during vehicle ignition cycling. IC Role / Device Role / Timing Role: Reset supervisor ensuring microcontroller reset validity down to 1.0 V VCC, synchronized with battery switchover to VBAT. Use Value: Eliminates boot-loop risk during cold-crank transients by holding RST asserted until stable 3 V rail is restored. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACSA+ | Higher reset threshold (4.65 V), no PFI/PFO, no battery switchover | Limited to 5 V systems without backup SRAM support | Select only if operating at 5 V and battery backup is unnecessary |
| TPS3808G18DBVR | Adjustable reset threshold (via external resistor), no MR input, no PFI/PFO | Requires external components for manual reset and power-fail detection | Prefer when precise threshold tuning is required and board space allows added passives |
Compared with MAX691ACSA+ and TPS3808G18DBVR, STM704RDS6E uniquely integrates PFI/PFO, MR, and battery switchover in a single SO8 package - eliminating four external components typically needed for equivalent functionality in 3 V industrial systems.
Availability
STM704RDS6E is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, and automotive telematics gateways requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for STM704RDS6E 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.
The STM704 belongs to ST's microprocessor supervisory IC product line, engineered specifically for robust power monitoring, battery-backed memory preservation, and deterministic reset generation in harsh industrial environments.
FAQ
What is the function of the Vccsw pin on STM704RDS6E?
Vccsw is not present on STM704RDS6E. It appears only on STM795 and STM802–STM805 variants. STM704 uses VOUT directly for battery switchover and lacks the Vccsw output used to drive external PMOS transistors for higher current LPSRAM loads.
Does STM704RDS6E include a watchdog timer?
No. The STM704RDS6E does not include a watchdog timer. Per the official ST datasheet (DocID10519 Rev 10, Section 2.3), watchdog functionality is explicitly excluded from STM704 and STM806 variants - only STM690, STM802, STM804, and STM805 support WDI input and internal watchdog timing.
Can STM704RDS6E be used with a supercapacitor instead of a battery?
Yes. The device supports SuperCap™ and other backup sources per Section 2.10 of the datasheet. VBAT accepts 1.0–5.5 V, and the internal 100 Ω switchover switch handles typical supercap discharge profiles. Ensure VBAT > VCC during switchover and limit inrush with series resistance if required.
What is the maximum load current supported on the VOUT pin?
VOUT supports up to 75 mA continuous output current, as specified in the "Absolute Maximum Ratings" table (Section 5). Exceeding this may cause excessive voltage drop or thermal stress. For higher currents, ST recommends using Vccsw (not available on STM704) or external switching circuitry.
STM704RDS6E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.625V
- 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-TSSOP
STM704RDS6E FAQ
1.How can I place an order for STM704RDS6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM704RDS6E 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 STM704RDS6E reliable?
The price and inventory of STM704RDS6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM704RDS6E is usually 5 days.
3.What payment methods are accepted for STM704RDS6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM704RDS6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM704RDS6E?
STM704RDS6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM704RDS6E 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 STM704RDS6E?
For technical support, including STM704RDS6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM704RDS6E requirements.
6.How does Aetrix verify that STM704RDS6E is sourced from the original manufacturer or authorized distributors?
All STM704RDS6E 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 STM704RDS6E meets industry standards.
7.What is the process for return or replacement of STM704RDS6E?
All STM704RDS6E units undergo pre-shipment inspection (PSI). If there is an issue with STM704RDS6E, 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 STM704RDS6E part is unused and in its original packaging.
Return procedure for STM704RDS6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM704RDS6E Tags
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MIC826SYMT-TR
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APX803L20-29SA-7
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