STMicroelectronics STM706PAM6F

Overview

STM706PAM6F from STMicroelectronics is a precision 3 V supply voltage supervisor IC with active-high reset output, 2.59–2.70 V reset threshold, 200 ms reset timeout (trec), and integrated watchdog timer (1.6 s timeout). It monitors VCC for undervoltage conditions, provides manual reset (MR), power-fail detection (PFI/PFO), and operates from –40 °C to +85 °C in industrial systems requiring reliable microprocessor reset control.

For engineers reviewing the STM706PAM6F datasheet, STM706PAM6F pinout, STM706PAM6F application, or STM706PAM6F equivalent, key selection criteria include reset polarity (active-high RST), precise VCC threshold tolerance, guaranteed reset assertion down to VCC = 1.0 V, and compatibility with microprocessor bi-directional reset I/O interfaces.

Technical Context

The STM706PAM6F implements dual independent comparators: one for VCC monitoring (VRST = 2.59–2.70 V) and another for power-fail detection (VPFI ≈ 1.25 V), each driving dedicated push-pull outputs (RST and PFO). Its watchdog timer resets on WDI edge transitions and times out after 1.6 s (typ.) if no activity occurs.

Reset assertion is guaranteed down to VCC = 1.0 V, and the internal trec generator holds RST high for ≥200 ms after VCC recovery or MR release. The MR input includes a 40 kΩ internal pull-up, enabling direct switch-to-ground connection without external biasing.

Key Specifications

Pinout & Package

STM706PAM6F is housed in an 8-pin SOIC (SO8) package with 150-mil body width, compliant with JEDEC MS-012, and rated for industrial temperature operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM706RAM6F, STM706PAM6F delivers identical supervision accuracy but eliminates need for external level-shifting; versus MAX6326US26D3+, it adds watchdog and power-fail detection at minimal BOM cost increase, enhancing system robustness without footprint penalty.

Availability

STM706PAM6F is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded data loggers, medical handheld diagnostics, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM706PAM6F 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.

The STM70x product line delivers highly integrated, pin-compatible voltage supervisors targeting space-constrained industrial and embedded systems needing precise reset control, watchdog safety, and power-fail prediction without external components.

FAQ

What is the function of the WDO pin on STM706PAM6F?

The WDO (Watchdog Output) pin is a push-pull active-low output that goes low when the internal 1.6 s watchdog timer expires due to lack of WDI edge transitions. It also goes low during VCC undervoltage events. WDO can be connected to the MR pin to generate an automatic system reset upon timeout or supply failure, eliminating need for software intervention.

Can STM706PAM6F interface directly with a microcontroller that has a bidirectional reset pin?

Yes, but requires a 4.7 kΩ series resistor between RST and the MCU's reset I/O to prevent contention. This resistor isolates the STM706PAM6F's push-pull RST output from the MCU's internal pull-up/down drivers, allowing safe assertion and release without signal conflict or excessive current draw during state transitions.

How does the power-fail comparator (PFI/PFO) differ from the main VCC reset function?

The PFI/PFO circuit uses a separate 1.25 V internal reference, independent of the 2.59–2.70 V VCC reset threshold. PFI monitors an external voltage divider (e.g., from unregulated input) to detect supply degradation earlier than VCC collapse, enabling preemptive actions like data save or shutdown before the main reset triggers - typically providing 10–25 ms advance warning.

Is the MR input internally pulled up, and what happens if left unconnected?

Yes, MR has a 40 kΩ internal pull-up to VCC. If left unconnected (floating), MR remains logic high and does not assert reset. This allows MR to be omitted from PCB design unless manual reset functionality is required. For noise immunity in electrically noisy environments, a 0.1 µF capacitor from MR to GND is recommended.