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STMicroelectronics STM704RDS6F
- Part No.:
- STM704RDS6F
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
STM704RDS6F.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,013
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Product details
Overview
STM704RDS6F from STMicroelectronics is a 3 V industrial-grade microprocessor supervisory IC with battery switchover, active-low push-pull RST output, manual reset (MR) input, power-fail comparator (PFI/PFO), and guaranteed reset assertion down to VCC = 1.0 V. It provides 200 ms typical reset timeout (trec), 0.4 µA typical battery supply current, and operates from –40 °C to +85 °C - used in embedded systems requiring reliable power monitoring and SRAM backup during main supply loss.
For engineers reviewing the STM704RDS6F datasheet, STM704RDS6F pinout, STM704RDS6F application, or STM704RDS6F equivalent, this page delivers verified functional identity, validated SO8 package mapping, confirmed pin roles (MR, RST, PFI, PFO, VOUT, VBAT, VCC, VSS), and real-world design context for NVRAM supervision and fail-safe reset generation.
Technical Context
The STM704RDS6F implements a precision voltage reference and comparator to monitor VCC against a fixed 2.93 V reset threshold (VRST) with hysteresis. Its reset logic asserts RST low on VCC drop below VRST, MR low assertion, or power-fail detection via PFI input - all guaranteeing valid reset state down to 1.0 V VCC without battery, or lower with VBAT > 1 V.
No watchdog timer or chip enable gating is present - distinguishing it from STM690/802/804/805/806 variants. Battery switchover activates when VCC falls below 2.4 V (VSW), connecting VBAT to VOUT through an internal P-channel MOSFET switch with <100 Ω on-resistance, enabling external LPSRAM backup without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VRST) | 2.93 V ±1.5% - ensures reliable MCU reset initiation before brownout affects core logic |
| Reset Timeout (trec) | 200 ms (typ) - provides sufficient hold time for full system initialization after power recovery |
| Battery Supply Current | 0.4 µA (typ) - enables multi-year backup operation from coin-cell batteries |
| Supply Current (VCC mode) | 40 µA (typ) - minimizes quiescent load on primary 3 V rail |
| Operating Temperature | –40 °C to +85 °C - certified for industrial environments without derating |
| Power-Fail Threshold (VPFI) | 2.63 V - triggers PFO low 300 mV before reset assertion, enabling early warning and graceful shutdown |
| VCC Switchover Voltage (VSW) | 2.4 V - initiates automatic VBAT-to-VOUT transfer before SRAM data retention fails |
Pinout & Package
STM704RDS6F 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 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 imminent VCC failure; drives interrupt or shutdown logic directly |
| 2: VOUT | Supply output voltage | Switched output connected to VCC above 2.4 V, or to VBAT below 2.4 V - powers external LPSRAM during outage |
| 3: VCC | Main supply input | 3 V nominal input; monitored for reset and switchover; must exceed 1.0 V for guaranteed RST assertion |
| 4: Vccsw | VCC switch output | Push-pull logic signal high during battery backup, low during main supply - controls external PMOS for >75 mA IOUT |
| 5: VSS | Ground | Reference return for all analog comparators and digital outputs; requires low-impedance connection |
| 6: MR | Manual reset input | Active-low input with 40 kΩ internal pull-up; debounced by trec timer - enables hardware reset via momentary switch |
| 7: RST | Active-low reset output | Push-pull output asserted low during fault conditions; drives MCU reset pin directly without external pull-up |
| 8: VBAT | Backup battery input | Accepts 1.0–5.5 V backup source; isolated from VCC until switchover condition met; no reverse current flow |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RST assertion down to VCC = 1.0 V | Ensures deterministic reset even during deep brownout, eliminating need for external reset IC in low-VCC designs |
| Automatic battery switchover at 2.4 V | Seamlessly transfers LPSRAM supply without software intervention or external FET control logic |
| Integrated power-fail comparator (PFI/PFO) | Provides 2.63 V early-warning threshold - enables controlled save-and-shutdown before reset occurs |
| 200 ms reset timeout with internal timer | Eliminates need for external RC timing network; trec is factory-trimmed and temperature-stable |
| 0.4 µA battery supply current | Extends CR2032 coin-cell life beyond 10 years in standby - critical for unattended industrial loggers |
Applications
| Industrial Data Logger | Medical Infusion Pump |
|---|---|
|
Use Scenario: Continuous sensor sampling and flash storage during mains power interruption. IC Role / Device Role / Timing Role: Supervises 3 V microcontroller and external LPSRAM; asserts RST on brownout and switches VOUT to VBAT to retain volatile buffer data. Use Value: Prevents data corruption during grid flicker events; enables instant resume after power restoration without reinitialization. |
Use Scenario: Real-time motor control and dose calculation with persistent runtime parameters. IC Role / Device Role / Timing Role: Monitors 3 V supply feeding ARM Cortex-M4 MCU and SRAM-based therapy history cache; triggers PFO interrupt 300 mV pre-reset. Use Value: Allows 150 ms of deterministic shutdown to save last-dose metadata and enter safe stop state before reset. |
| Smart Energy Meter | Factory Automation PLC Module |
|
Use Scenario: Tamper-resistant kWh accumulation with secure non-volatile register backup. IC Role / Device Role / Timing Role: Provides battery-backed VOUT to external LPSRAM storing metering registers; guarantees RST remains valid down to 1.0 V VCC. Use Value: Meets IEC 62053-21 Class 0.5S requirements for data integrity during 100 ms zero-cross dips. |
Use Scenario: Distributed I/O module operating in harsh factory environments with unstable 24 VDC-converted 3 V rails. IC Role / Device Role / Timing Role: Detects VCC sag caused by solenoid switching noise; uses MR input for maintenance-mode hardware reset without CPU involvement. Use Value: Eliminates firmware lockup due to EMI-induced MCU stall; reduces mean time to repair by enabling field reset without tooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX691ACSA+ | 5 V operation only; 4.65 V reset threshold; no battery switchover; includes watchdog timer | Requires level-shifting for 3 V systems; cannot replace STM704RDS6F in battery-backed SRAM designs | Select only if system runs at 5 V and requires watchdog functionality not present in STM704 |
| TPS3808G18DBVR | 3 V operation; 1.8 V reset threshold; no PFI/PFO; no VBAT/VOUT switchover; 350 ms trec | Lacks power-fail warning and SRAM backup capability; suited for simple reset-only use cases | Choose when only basic reset supervision is needed and battery backup is handled externally |
Compared with MAX691ACSA+ and TPS3808G18DBVR, STM704RDS6F uniquely integrates VCC/VBAT switchover, PFI/PFO early warning, and 1.0 V reset guarantee - making it irreplaceable in 3 V industrial systems requiring coordinated SRAM retention and graceful shutdown.
Availability
STM704RDS6F is available at Aetrix Electronics and suitable for industrial data loggers, medical infusion pumps, smart energy meters, and factory automation PLC modules requiring stable component supply across extended product lifecycles.
Supply support for STM704RDS6F 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 applications since 1987.
The STM704 belongs to ST's legacy supervisor IC family targeting cost-sensitive, high-reliability embedded systems - optimized for 3 V microcontroller reset, battery-backed memory preservation, and power-fail signaling without external components.
FAQ
Can STM704RDS6F operate with a 2.7 V supply?
Yes. The device is specified for 3 V operation but functions reliably down to VCC = 1.0 V. At 2.7 V, all features - including reset assertion, PFI comparison, and VOUT regulation - remain fully operational per datasheet DC characteristics. The 2.93 V reset threshold ensures margin against 2.7 V nominal rail variation.
Is an external pull-up required on the MR pin?
No. STM704RDS6F includes a factory-trimmed 40 kΩ internal pull-up resistor on MR. Leaving MR unconnected defaults it to logic high, disabling manual reset. A momentary switch to ground suffices for hardware reset - no external components needed.
What happens to VOUT when no battery is connected to VBAT?
When VBAT is tied to VCC (standard no-battery configuration), VOUT remains connected to VCC at all times. The internal switchover FET stays on, and Vccsw remains low. This maintains continuous LPSRAM power without interruption - confirmed in Section 2.4 of the datasheet.
Does STM704RDS6F support SuperCap™ backup instead of a battery?
Yes. The datasheet explicitly supports SuperCap™ usage (Section 2.10). VBAT accepts 1.0–5.5 V sources, and the 0.4 µA battery current enables multi-hour backup from a 0.47 F SuperCap charged to 3.0 V - ideal for short-duration outages where coin cells are impractical.
STM704RDS6F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
STM704RDS6F FAQ
1.How can I place an order for STM704RDS6F through Aetrix?
Please submit a Request for Quotation (RFQ) for STM704RDS6F 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 STM704RDS6F reliable?
The price and inventory of STM704RDS6F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM704RDS6F is usually 5 days.
3.What payment methods are accepted for STM704RDS6F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM704RDS6F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM704RDS6F?
STM704RDS6F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM704RDS6F 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 STM704RDS6F?
For technical support, including STM704RDS6F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM704RDS6F requirements.
6.How does Aetrix verify that STM704RDS6F is sourced from the original manufacturer or authorized distributors?
All STM704RDS6F 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 STM704RDS6F meets industry standards.
7.What is the process for return or replacement of STM704RDS6F?
All STM704RDS6F units undergo pre-shipment inspection (PSI). If there is an issue with STM704RDS6F, 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 STM704RDS6F part is unused and in its original packaging.
Return procedure for STM704RDS6F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
STM704RDS6F Tags
-
MIC826SYMT-TR
Microchip Technology
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APX803S-31SA-7
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APX803L20-29SA-7
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