STMicroelectronics ST890BD

Overview

ST890BD from STMicroelectronics is a P-channel high-side power switch with programmable current limiting (up to 1.2 A), thermal shutdown, active-low FAULT output, and 90 mΩ typical ON resistance in DFN8L 3×3 package. It operates from 2.7 V to 5.5 V and is used for load switching in portable equipment and PCMCIA/Access bus slots.

For engineers reviewing the ST890BD datasheet, ST890BD pinout, ST890BD application, or ST890BD equivalent, this page provides verified electrical parameters, validated SO8/DFN8L package mapping, confirmed current-limit programming behavior, thermal protection threshold (130 °C), and functional alternatives for high-side switching designs requiring fault reporting and overcurrent control.

Technical Context

The ST890BD implements a P-MOSFET-based high-side switch with integrated current-sense feedback loop and thermal sensing circuitry. Its current limit is set externally via R_SET connected between SET and GND, yielding ILIM = 1.24 V / R_SET × 1110, with ±10% tolerance across temperature.

It features dual-level protection: fast current-limit response (5 µs) for overload events above 1.2 A, and thermal shutdown at 130 °C (typ.) with 15 °C hysteresis. The open-drain FAULT pin asserts low during current limit, short-circuit (I_SC ≈ 1.2 × ILIM), or thermal trip conditions.

Key Specifications

Pinout & Package

ST890BD is available in DFN8L 3×3 mm package (ECOPACK® compliant), with exposed thermal pad not internally connected but recommended for PCB ground-plane connection to reduce R_thj-amb to 37.6 °C/W (JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current-limited power switch applications.

Compared with TPL7407LPWR and TPS22965DRLR, ST890BD uniquely combines programmable current limiting, thermal shutdown, and an open-drain FAULT output in a compact DFN8L package-enabling safer, more diagnostic-capable high-side switching in space-constrained portable and industrial systems.

Availability

ST890BD is available at Aetrix Electronics and suitable for PCMCIA slot power control, USB host port switching, and portable medical monitor power rails requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ST890BD 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, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ST890 product line delivers high-side power switches optimized for portable and embedded systems requiring precise current limiting, fault visibility, and thermal resilience in compact packages.

FAQ

What is the function of the SET pin on ST890BD?

The SET pin accepts an external resistor to ground that programs the output current limit (ILIM). Using the relationship ILIM = 1.24 V / R_SET × 1110, a 100 kΩ resistor yields ~1.2 A limit. This allows precise tailoring of overcurrent protection without changing the IC, supporting diverse load requirements across designs.

How does the FAULT pin behave during different fault conditions?

The FAULT pin is an open-drain output that pulls low during three distinct conditions: (1) output current reaches programmed ILIM, (2) output is shorted to ground (VO < 1.6 V), or (3) junction temperature exceeds 130 °C. It remains low until the condition clears and the device recovers, providing unambiguous fault status to the host controller.

Can ST890BD be used with 1.8 V logic control signals?

No. The ON input requires VIH ≥ 2.4 V (at V_IN = 5.5 V) or ≥ 2 V (at V_IN = 3.6 V) to reliably disable the switch. A 1.8 V logic signal falls below the guaranteed VIH threshold and may result in incomplete turn-off or erratic behavior; level-shifting is required for compatibility.

What is the thermal performance difference between SO8 and DFN8L packages?

The DFN8L 3×3 package achieves R_thj-amb = 37.6 °C/W on a JEDEC 4-layer board with exposed pad connected to ground plane, versus 160 °C/W for SO8 under similar conditions. This 4.2× improvement enables higher continuous current handling or operation in thermally constrained layouts without forced airflow.