STMicroelectronics STM708DS6E

Overview

STM708DS6E from STMicroelectronics is a 5 V precision voltage supervisor IC with dual active-low and active-high reset outputs, power-fail comparator (PFI/PFO), and manual reset input (MR). It asserts RST/RST for VCC < 4.25 V (typ), guarantees reset down to VCC = 1.0 V, and features 200 ms reset timeout (trec) and industrial-grade operation (–40 °C to +85 °C). Used in embedded microcontroller systems requiring reliable power-on reset and early power-fail warning.

For engineers reviewing the STM708DS6E datasheet, STM708DS6E pinout, STM708DS6E application, or STM708DS6E equivalent, key selection criteria include its dual-reset architecture, PFI threshold of 1.25 V (typ), push-pull RST/RST outputs, MR internal pull-up, and TSSOP8 package compatibility with space-constrained PCB layouts.

Technical Context

The STM708DS6E implements a dual-comparator architecture: one monitors VCC against a precision 4.25–4.50 V reset threshold (VRST), while a second compares PFI to a fixed 1.25 V reference (VPFI). Reset assertion is latched and held for trec = 200 ms after VCC recovery or MR release.

It provides two independent reset signals - active-low RST and active-high RST - both guaranteed functional down to VCC = 1.0 V, enabling direct interfacing with MCUs requiring either polarity. Unlike watchdog-equipped variants (e.g., STM706), the STM708 omits WDI/WDO, simplifying design where watchdog functionality is unnecessary.

Key Specifications

Pinout & Package

STM708DS6E is housed in an 8-pin TSSOP package (3 mm × 3 mm body, DS suffix), optimized for high-density PCB layouts. Pin functions are validated per STMicroelectronics DocID10520 Rev 11 (Figures 5–6, Table 3).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM706RDS6F, STM708DS6E removes watchdog circuitry to reduce cost and layout complexity while retaining identical reset accuracy and PFI capability; versus MAX692CPA+, it adds dual-reset polarity and PFI monitoring in a smaller TSSOP8 package with lower quiescent current.

Availability

STM708DS6E is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, smart energy meters, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for STM708DS6E 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 is ST's dedicated family of precision voltage supervisors targeting robust power-monitoring in resource-constrained embedded systems - emphasizing low power, guaranteed reset behavior, and ease of integration.

FAQ

What is the function of the NC pin on STM708DS6E?

Pin 3 is a no-connect (NC) terminal - internally unbonded and electrically isolated. It must remain unconnected on the PCB; routing traces or applying solder to this pin may cause mechanical stress or unintended coupling. ST confirms NC status in DocID10520 Rev 11, Table 3 and Figure 6.

Can STM708DS6E be used with a 3.3 V microcontroller?

No - STM708DS6E is specified only for 5 V operation (VCC = 4.5–5.5 V). Its VRST threshold (4.25–4.50 V) and internal references are calibrated for 5 V rails. For 3.3 V systems, ST recommends STM809 or STM810, which feature 3.08 V reset thresholds and compatible TSSOP8 packaging.

How does the PFI/PFO function provide early power-fail warning?

PFI compares an external voltage (via resistor divider) to a fixed 1.25 V internal reference. When input voltage drops such that PFI falls below 1.25 V, PFO asserts low - typically 5–10 ms before VCC crosses the 4.25 V reset threshold - enabling firmware to save state or shut down peripherals preemptively.

Is the MR pin internally pulled up, and what is its resistance value?

Yes - MR has an internal pull-up resistor of 40 kΩ (typical), confirmed in Section 2.1 of DocID10520 Rev 11. This allows direct connection of a momentary switch between MR and VSS without external components, and permits MR to float safely when unused.