STMicroelectronics STM813LDS6E

Overview

STM813LDS6E from STMicroelectronics is a 5 V precision voltage supervisor IC with active-high reset output, watchdog timer, manual reset input (MR), and power-fail comparator (PFI/PFO). It asserts RST when VCC drops below 4.50–4.75 V, provides 200 ms reset timeout (trec), and guarantees RST assertion down to VCC = 1.0 V - used in industrial microcontroller systems requiring reliable power-on and brownout protection.

For engineers reviewing the STM813LDS6E datasheet, STM813LDS6E pinout, STM813LDS6E application, or STM813LDS6E equivalent, key selection criteria include reset threshold accuracy (±1.5% over temperature), push-pull RST/RST outputs, 1.6 s watchdog timeout, low 40 µA supply current, and TSSOP8 package compatibility with space-constrained embedded designs.

Technical Context

The STM813L integrates a precision bandgap reference, dual comparators (VCC monitor and PFI threshold), a 1.6 s watchdog timer with WDI edge-sensitive clearing, and independent push-pull RST (active-low) and RST (active-high) outputs. Its trec generator ensures minimum 200 ms reset pulse width after power-up or MR release.

It features guaranteed reset assertion down to VCC = 1.0 V at −40 °C to +85 °C, internal 40 kΩ MR pull-up, and VPFI = 1.25 V ±3% for early power-fail detection. The PFO output remains high until PFI falls below VPFI, enabling system-level undervoltage warning before VCC collapse.

Key Specifications

Pinout & Package

STM813LDS6E is housed in an 8-pin TSSOP package (3 mm × 3 mm body, 0.65 mm pitch), optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with MAX813L and TPS3808G33, STM813LDS6E uniquely delivers guaranteed reset down to 1.0 V, integrated power-fail warning with push-pull PFO, and edge-sensitive watchdog - making it the sole choice for robust 5 V industrial supervision where deterministic fail-safe behavior is non-negotiable.

Availability

STM813LDS6E is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, medical handheld diagnostics, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM813LDS6E 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 specializing in microcontrollers, power management, and analog ICs, with manufacturing facilities certified to ISO 9001 and IATF 16949 standards.

The STM813L belongs to ST's precision voltage supervisor product line, engineered specifically for industrial and automotive applications demanding high-accuracy reset thresholds, extended VCC operating margins, and integrated fault-detection features.

FAQ

What is the function of the WDO pin on STM813LDS6E?

The WDO (Watchdog Output) pin is an active-low push-pull output that goes low when the watchdog timer expires (after 1.6 s of no WDI transition) or when VCC drops below VRST. Unlike RST, WDO returns high immediately upon VCC recovery - enabling use as a standalone watchdog indicator or connection to MR for automatic reset initiation. It requires no external pull-up.

Can STM813LDS6E operate with a 3.3 V supply?

No. STM813LDS6E is specified only for 4.5 V to 5.5 V operation. Its internal voltage reference, comparators, and output drivers are calibrated for 5 V systems. Applying 3.3 V will result in improper reset assertion, failed watchdog timing, and undefined PFO behavior - confirmed by absolute maximum ratings and DC parameter tables in DocID10520 Rev 11.

How is the power-fail warning threshold set?

The PFI pin compares its input voltage against a fixed 1.25 V internal reference (VPFI). To configure early warning, connect PFI to a resistor divider from the unregulated supply rail - for example, a 100 kΩ/22 kΩ divider yields ~1.82 V at PFI, triggering PFO when input drops to ~2.2 V (i.e., ~300 mV before 5 V rail reaches 4.5 V reset threshold).

Does STM813LDS6E require external capacitors for stable operation?

No external bypass or timing capacitors are required. The device integrates all necessary references, comparators, and timers on-die. A 0.1 µF ceramic decoupling capacitor between VCC and VSS is recommended per standard PCB layout practice, but no capacitor is needed for reset timing, watchdog, or power-fail functionality - all parameters are internally trimmed and temperature-compensated.