STMicroelectronics STM706SDS6E

Overview

STM706SDS6E from STMicroelectronics is a precision 3 V supply voltage supervisor IC with active-low reset (RST), watchdog timer, manual reset input (MR), and power-fail comparator (PFI/PFO). It asserts reset for VCC < 2.88 V (S-grade), features 200 ms typical reset timeout (trec), 1.6 s watchdog timeout, and operates from –40 °C to +85 °C. It is used in industrial controllers and embedded systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the STM706SDS6E datasheet, STM706SDS6E pinout, STM706SDS6E application, or STM706SDS6E equivalent, key selection criteria include reset threshold tolerance (±2.5% at 2.88 V), guaranteed RST assertion down to VCC = 1.0 V, push-pull RST/RST outputs, PFI comparator reference (1.25 V typ.), and TSSOP8 package compatibility with space-constrained PCB layouts.

Technical Context

The STM706SDS6E integrates a precision bandgap-based voltage reference and comparator to monitor VCC against a fixed 2.88 V reset threshold (S-grade), with propagation delay under 30 µs across temperature. Its internal watchdog timer detects MCU lockup via WDI edge transitions and triggers WDO low after 1.6 s of inactivity.

It provides dual reset outputs (RST active-low, RST active-high), a debounced MR input with 40 kΩ internal pull-up, and an independent power-fail comparator (VPFI = 1.25 V) driving push-pull PFO - enabling early warning of supply collapse before VCC drops below the reset threshold.

Key Specifications

Pinout & Package

STM706SDS6E is housed in a RoHS-compliant 8-pin TSSOP (Thin Shrink Small Outline Package) with 3 mm × 3 mm body size and 0.65 mm lead pitch - optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361LUR29+T and TPS3808G33DBVR, the STM706SDS6E uniquely delivers integrated PFI/PFO, dual-polarity reset outputs, and guaranteed sub-1 V reset assertion - making it optimal for systems requiring predictive power failure handling and robust MCU interface flexibility.

Availability

STM706SDS6E is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, and smart energy meters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for STM706SDS6E 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 STM70x series was developed specifically for microprocessor supervisory functions in space- and power-constrained embedded systems, emphasizing precision threshold accuracy, low quiescent current, and multi-feature integration in compact packages.

FAQ

What is the exact reset threshold range for STM706SDS6E?

The STM706SDS6E is the 'S' grade variant, with a guaranteed reset threshold (V_RST) of 2.88 V to 3.00 V at 25 °C. This range is specified over full temperature (–40 °C to +85 °C) and supply voltage (1.0 V to 5.5 V), with typical normalized drift ≤ ±0.4% across temperature per Figure 16 in the datasheet.

Can the watchdog timer be disabled without adding external components?

Yes. The watchdog function is automatically disabled when the WDI pin is left floating (high-impedance), as stated in Section 2.2 and Section 3.3 of the datasheet. No pull-up or pull-down resistor is required - the internal leakage specification (≤10 µA) ensures reliable disablement with minimal board area impact.

How does the PFI/PFO function interact with the main reset circuit?

PFI and PFO operate independently from the VCC monitor: PFI compares against a fixed 1.25 V reference, not VRST. When PFI falls below this threshold, PFO goes low but does not assert RST unless externally wired to MR. This enables staged system response - e.g., initiating data save before hard reset - without coupling the two detection paths.

Is STM706SDS6E pin-compatible with other STM706 variants in TSSOP8?

Yes. All STM706x variants (T/S/R/P) in TSSOP8 (DS suffix) share identical pinout per Figures 4 and Table 3. Pin 1 = PFO, Pin 2 = RST, Pin 3 = PFI, etc. Function differences (e.g., RST vs RST polarity, watchdog presence) are implemented internally - no PCB redesign is needed when substituting within the same package.