STMicroelectronics STM706RM6F

Overview

STM706RM6F 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 threshold), 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 detection.

For engineers reviewing the STM706RM6F datasheet, STM706RM6F pinout, STM706RM6F application, or STM706RM6F equivalent, key selection criteria include reset threshold tolerance (±2.5% over temperature), push-pull RST output drive capability, watchdog timeout stability (1.6 s ±10%), and compatibility with bi-directional MCU reset pins via series resistor interface.

Technical Context

The STM706RM6F implements a dual-comparator architecture: one monitors VCC against a precision bandgap reference (VRST = 2.88–3.00 V) to trigger RST, while a second compares PFI against an independent 1.25 V reference (VPFI) to generate PFO. Reset assertion is latched and timed by an internal RC-based trec generator.

Its watchdog function operates independently of the reset comparator: WDI edge detection clears a 1.6 s monostable timer; timeout forces WDO low, which can be wired to MR to initiate system reset. Both RST and WDO are push-pull outputs capable of sinking ≥20 mA at VCC ≥ 3.0 V.

Key Specifications

Pinout & Package

STM706RM6F is housed in an 8-pin TSSOP package (3 mm × 3 mm body, 0.65 mm pitch), optimized for space-constrained PCB layouts while maintaining thermal and electrical performance comparable to SO8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US29D3+ and TPS3808G33DBVR, STM706RM6F delivers integrated watchdog supervision and predictive power-fail detection in a single TSSOP8 footprint - eliminating two discrete ICs and reducing BOM count while enabling faster system recovery and safer shutdown sequences.

Availability

STM706RM6F is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, smart energy meters, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM706RM6F 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, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STM70x series is ST's dedicated family of precision voltage supervisors targeting embedded systems requiring guaranteed reset behavior, watchdog safety, and power-fail prediction - optimized for reliability in harsh industrial and medical environments.

FAQ

Can STM706RM6F be used with a 3.3 V supply?

Yes. STM706RM6F operates over 1.0 V to 5.5 V and is specified for 3 V nominal systems, but its 2.88–3.00 V reset threshold makes it compatible with 3.3 V rails - it asserts reset only when VCC drops below 2.88 V, providing 150 mV noise margin and avoiding false triggers during normal regulation tolerance.

How is the watchdog timer disabled?

The watchdog timer is disabled by leaving WDI floating or tri-stating the driving source. The device draws <10 µA leakage on WDI in this state, and no timeout occurs. This configuration is confirmed in Section 2.2 of the datasheet and requires no external pull-up/down resistor.

What is the maximum capacitive load on the RST pin?

RST is rated for ≤50 pF total load capacitance per datasheet AC characteristics (Table 6). Exceeding this may increase propagation delay beyond 30 µs (max) and risk timing violations in fast-reset MCU interfaces - use short traces and avoid routing RST alongside high-speed signals.

Does STM706RM6F support reset extension via external capacitor?

No. STM706RM6F uses an internal RC-based trec generator fixed at 200 ms (typ.). Unlike some supervisors with CEXT pins, it does not support external timing capacitor adjustment - reset timeout is factory-trimmed and invariant across temperature and voltage.