STMicroelectronics STM6905TZEDS6F

Overview

STM6905TZEDS6F from STMicroelectronics is a quintuple ultralow-voltage supervisor IC with push-button reset functionality, designed for multi-rail power monitoring in embedded systems. It monitors five supply rails-two factory-trimmed fixed thresholds (3.078 V on VCC, 2.333 V on V2IN), three externally adjustable inputs using a 600 mV internal reference, and delivers an open-drain RST output with 210 ms typical power-on reset delay. It operates from 0.8 V to 5.5 V, draws only 12 µA typical supply current, and targets industrial-grade applications requiring reliable brownout detection and manual reset.

For engineers reviewing the STM6905TZEDS6F datasheet, STM6905TZEDS6F pinout, STM6905TZEDS6F application, or STM6905TZEDS6F equivalent, this page provides verified technical context, exact pin functions, real-world use cases in set-top boxes and multi-voltage systems, and validated alternative options with documented threshold and timing differences.

Technical Context

The STM6905TZEDS6F implements five independent voltage comparators: two with factory-programmed thresholds (VCC at 3.078 V ±1.8 % over temperature, V2IN at 2.333 V), and three high-impedance inputs (V3IN/V4IN/V5IN) referenced to a 600 mV internal bandgap. All comparators drive a shared open-drain RST output that asserts low when any monitored rail falls below its threshold or MR is pulled low.

Its reset assertion logic includes built-in hysteresis (0.5 % of VRST), glitch immunity (100 ns MR pulse rejection), and a guaranteed tREC timeout of 210 ms (Option E) after all supplies recover and MR returns high. The RST output remains valid down to VCC = 0.8 V, and MR features a 10 kΩ internal pull-up resistor.

Key Specifications

Pinout & Package

STM6905TZEDS6F is housed in an 8-pin MSOP (TSSOP8) package, 3 mm × 3 mm, RoHS-compliant and ECOPACK®-qualified. Pin pitch is 0.65 mm; thermal resistance θJA = 146 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STM6905TZEDS6F, STM6905TWEDS6F lowers the V2IN threshold for 1.8 V rail monitoring while maintaining identical timing and packaging, whereas STM6905SYEDS6F shifts both thresholds downward to suit 3.0 V system designs-neither offers pin-compatible replacement without circuit review.

Availability

STM6905TZEDS6F is available at Aetrix Electronics and suitable for set-top boxes, multi-voltage systems, and cable/satellite applications requiring stable component supply, long-term industrial-grade availability, and RoHS-compliant packaging.

Supply support for STM6905TZEDS6F 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The STM6905 belongs to ST's precision voltage supervisor product line, engineered specifically for robust, low-power multi-rail monitoring in space-constrained embedded systems where reliability across temperature and supply variation is critical.

FAQ

What is the minimum VCC voltage required for RST output validity?

The RST output is guaranteed functional for VCC ≥ 0.8 V. Below this level, internal biasing fails and RST state becomes undefined-even if other inputs remain above threshold. This enables early brownout detection before logic rails collapse, but requires system-level design to ensure VCC does not dip below 0.8 V during transient events without triggering unintended reset.

How do I configure V3IN, V4IN, and V5IN for a 1.8 V rail?

Use a resistor divider where VTRIP = 0.6 V × (R1 + R2)/R2 = 1.8 V. Solving yields R1/R2 ≈ 2.0. For example, R2 = 100 kΩ and R1 = 200 kΩ sets the trip point at 1.8 V. Ensure total divider current stays below 1 µA to avoid loading effects, and place a 100 nF capacitor at the divider node for noise immunity in noisy environments.

Does the STM6905TZEDS6F support simultaneous monitoring of five independent power domains?

Yes-VCC, V2IN, V3IN, V4IN, and V5IN operate as fully independent inputs. Each has its own comparator referenced to either factory-trimmed thresholds (VCC, V2IN) or the 600 mV internal reference (V3IN–V5IN). A fault on any one input asserts RST immediately, regardless of the state of others, enabling true five-domain fault coverage.

Is an external pull-up resistor required on the RST pin?

Yes-an external pull-up resistor to VCC is mandatory because RST is open-drain. ST recommends 10 kΩ for most applications. Without it, RST cannot drive high and remains floating or weakly pulled by parasitic paths, risking undefined processor behavior. The internal 10 kΩ pull-up on MR does not apply to RST.