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STMicroelectronics STM818LDS6E
- Part No.:
- STM818LDS6E
- Manufacturer:
- STMicroelectronics
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
STM818LDS6E.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,921
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Product details
Overview
STM818LDS6E from STMicroelectronics is a 5 V microprocessor supervisor IC with integrated battery switchover, chip-enable gating, and watchdog timer-designed to protect external low-power static RAM (LPSRAM) during power loss. It guarantees RST assertion down to VCC = 1.0 V, delivers 7 ns max propagation delay for chip-enable gating, and features 200 ms typical reset timeout (trec) and 1.6 sec typical watchdog timeout.
For engineers reviewing the STM818LDS6E datasheet, STM818LDS6E pinout, STM818LDS6E application, or STM818LDS6E equivalent, this device is selected for systems requiring deterministic reset timing, seamless SRAM backup control, low-quiescent-current supervision (<40 µA), and active-low/high dual-reset outputs in industrial-grade operation (–40 °C to +85 °C).
Technical Context
The STM818LDS6E implements a precision voltage comparator monitoring VCC against a 4.63 V reset threshold (VRST), with hysteresis enabling clean power-up/power-down transitions. Its internal P-channel MOSFET switch enables automatic VCC-to-VBAT switchover at the lesser of VRST or VBAT (VSO), supporting battery-freshness seal activation and zero standby drain during storage.
Unlike other members of the STM8xx family, STM818 uniquely integrates chip-enable gating: E input controls ECON output only when reset is inactive, with 15 µs minimum pulse width guarantee and push-pull drive-enabling cycle-accurate LPSRAM enable/disable synchronized to reset state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC operating voltage | 5 V nominal; supports stable supervision across full industrial range without external regulation. |
| Reset threshold (VRST) | 4.63 V ±1.5%; ensures reliable MCU reset before critical logic voltage collapse. |
| trec (reset timeout) | 200 ms typical; provides sufficient hold time for processor initialization after power recovery. |
| Watchdog timeout (tWD) | 1.6 sec typical; detects firmware lockup with minimal latency while avoiding false triggers. |
| Chip-enable propagation delay | 7 ns max; enables precise LPSRAM access control aligned with CPU bus cycles. |
| Supply current (ICC) | 40 µA typical; minimizes system-level quiescent power in always-on supervisory mode. |
| Battery supply current (IVBAT) | 0.4 µA typical; extends backup battery life beyond years in SRAM-retention applications. |
Pinout & Package
STM818LDS6E is housed in an SO8 (Small Outline 8-pin) package, measuring 4.9 mm × 3.9 mm × 1.75 mm, with standard 1.27 mm pitch and gull-wing leads compatible with automated PCB assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: RST | Active-high reset output | Push-pull output asserted high during reset; drives MCU reset input directly without pull-up. |
| 2: VOUT | LPSRAM supply output | Switched output sourced from VCC or VBAT; powers external low-power SRAM during main power loss. |
| 3: PFO | Power-fail output | Push-pull signal indicating imminent VCC drop; not implemented on STM818 per datasheet Table 1. |
| 4: ECON | Conditioned chip-enable output | Asserted low only when E = low AND reset inactive; enables cycle-synchronized LPSRAM gating. |
| 5: E | Chip-enable input | Direct control input for ECON; tied low to enable gating; open or grounded if unused. |
| 6: MR | Manual reset input | Active-low push-button interface with internal 40 kΩ pull-up; debounced by trec timing. |
| 7: WDI | Watchdog input | Edge-sensitive input; toggling within 1.6 sec prevents reset; floating disables watchdog. |
| 8: VCC | Main supply input | 5 V primary power rail; monitored for reset assertion and used as VOUT source during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| Chip-enable gating with 7 ns max delay | Enables deterministic, sub-cycle LPSRAM enable/disable synchronized to CPU bus activity and reset state. |
| Guaranteed RST assertion to VCC = 1.0 V | Ensures robust reset signaling even during deep brown-out, preserving MCU state integrity. |
| Automatic battery switchover with freshness seal | Prevents battery discharge during storage; activates only after first VCC power-up, extending shelf life. |
| Dual active-low/high reset outputs (RST/RST) | Supports mixed-logic systems: drives both open-drain and push-pull reset inputs without level-shifting. |
| Low 40 µA supply current (typ) | Reduces system-level standby power without compromising supervision responsiveness or accuracy. |
Applications
| Industrial PLC Memory Backup | Medical Device Data Retention |
|---|---|
|
Use Scenario: Programmable logic controller retains configuration and runtime variables in external LPSRAM during AC mains interruption. IC Role / Device Role / Timing Role: STM818LDS6E monitors VCC, asserts RST to halt CPU, switches VOUT to VBAT, and gates LPSRAM CE via ECON to prevent write corruption during switchover. Use Value: Enables >10-year SRAM data retention on coin-cell battery with zero data loss during <500 ms power gaps. |
Use Scenario: Portable infusion pump stores therapy logs and calibration data in nonvolatile SRAM between battery swaps. IC Role / Device Role / Timing Role: Provides 200 ms trec-aligned reset hold, battery-freshness seal activation on first power-up, and 0.4 µA VBAT leakage to maximize battery service life. Use Value: Guarantees FDA-required audit trail persistence without external EEPROM or FRAM, reducing BOM cost and footprint. |
| Smart Meter Firmware Protection | Automotive Telematics Black Box |
|
Use Scenario: Electricity meter maintains firmware checksum and tamper-event timestamp during grid voltage sags. IC Role / Device Role / Timing Role: Uses WDI to detect MCU hang, triggers RST within 1.6 sec, and gates LPSRAM access via E/ECON to freeze memory state pre-reset. Use Value: Prevents corrupted firmware updates or lost event logs during transient brown-outs common in distribution networks. |
Use Scenario: Vehicle telematics unit records crash-triggered CAN data into SRAM before main power disconnects. IC Role / Device Role / Timing Role: Monitors 5 V supply from vehicle battery; asserts RST and switches VOUT to backup supercapacitor within 10 µs of VCC drop below 4.63 V. Use Value: Captures ≥2 sec of pre-crash CAN traffic using <100 µF supercap, enabled by ultra-low 0.4 µA VBAT drain. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisor-with-battery-switchover applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STM817LDS6E | Lacks chip-enable gating (E/ECON pins absent); no PFI/PFO; includes battery freshness seal. | Suitable for basic SRAM backup where CE control is handled externally or unnecessary. | Select when LPSRAM enable timing is managed by MCU GPIO or simpler logic-reduces pin count and layout complexity. |
| STM805LDS6E | Active-high-only RST output; no watchdog; no battery switchover; no E/ECON; includes PFI/PFO. | Designed for pure reset supervision in non-backup systems with early power-fail warning needs. | Choose for cost-sensitive applications needing only reset generation and power-fail alert-omits battery path entirely. |
Compared with STM817LDS6E and STM805LDS6E, STM818LDS6E uniquely combines chip-enable gating, dual-reset outputs, and battery switchover-making it the only option for systems requiring cycle-accurate, reset-synchronized LPSRAM access control during power transitions.
Availability
STM818LDS6E is available at Aetrix Electronics and suitable for industrial PLC memory backup, medical device data retention, smart meter firmware protection, and automotive telematics black box applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for STM818LDS6E 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.
STM8xx supervisors belong to ST's dedicated power-management and system-supervision product line, engineered specifically for deterministic reset generation, battery-backed memory protection, and fail-safe microcontroller interfacing in harsh industrial environments.
FAQ
Does STM818LDS6E support external watchdog disable via pin configuration?
Yes-watchdog functionality is disabled when the WDI pin is left floating or tri-stated. The datasheet specifies maximum allowable leakage current (10 µA) and load capacitance (200 pF) under this condition. No strap pin or register setting is required; hardware-level disable is achieved by omitting the WDI connection.
What is the maximum VBAT voltage allowed relative to VCC?
VBAT may exceed VCC without damage or functional impact. The internal switchover circuit uses the lesser of VRST (4.63 V) or VBAT as the switchover threshold (VSO), ensuring optimal battery utilization. Datasheet Section 2.4 explicitly permits VBAT > VCC and recommends connecting VBAT to VCC if no battery is used.
How does the battery freshness seal function on STM818LDS6E?
The battery freshness seal prevents VBAT discharge during storage by blocking the internal switchover path until VCC first exceeds VRST. Once activated, the seal remains latched; reactivation requires cycling VCC below VRST and back above it, as detailed in Section 2.12 of the datasheet. This extends shelf life by eliminating standby battery drain.
Can ECON be used to gate multiple LPSRAM devices simultaneously?
Yes-ECON is a push-pull output rated for 8 mA sink/source, capable of driving multiple LPSRAM CE inputs in parallel. The 7 ns max propagation delay and guaranteed 15 µs minimum pulse width ensure setup/hold timing compliance across typical LPSRAM families, including Cypress CY14B101 and ON Semiconductor CAT24C02-compatible devices.
STM818LDS6E 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:
- 4.65V
- 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
STM818LDS6E FAQ
1.How can I place an order for STM818LDS6E through Aetrix?
Please submit a Request for Quotation (RFQ) for STM818LDS6E 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 STM818LDS6E reliable?
The price and inventory of STM818LDS6E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STM818LDS6E is usually 5 days.
3.What payment methods are accepted for STM818LDS6E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STM818LDS6E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STM818LDS6E?
STM818LDS6E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STM818LDS6E 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 STM818LDS6E?
For technical support, including STM818LDS6E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STM818LDS6E requirements.
6.How does Aetrix verify that STM818LDS6E is sourced from the original manufacturer or authorized distributors?
All STM818LDS6E 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 STM818LDS6E meets industry standards.
7.What is the process for return or replacement of STM818LDS6E?
All STM818LDS6E units undergo pre-shipment inspection (PSI). If there is an issue with STM818LDS6E, 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 STM818LDS6E part is unused and in its original packaging.
Return procedure for STM818LDS6E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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