STMicroelectronics ST890CD

Overview

ST890CD from STMicroelectronics is a 1.2 A current-limited, thermally protected high-side P-channel MOSFET power switch for load switching in 2.7–5.5 V systems. It features programmable current limit (up to 1.2 A), 90 mΩ typical ON resistance at 4.5 V, active-low FAULT indicator, and thermal shutdown at 130 °C. Used in PCMCIA and access bus slots for overcurrent-protected hot-swap power control.

For engineers reviewing the ST890CD datasheet, ST890CD pinout, ST890CD application, or ST890CD equivalent, key selection criteria include programmable ILIM via external resistor, open-drain FAULT signaling, SO8 package thermal resistance (160 °C/W), and undervoltage lockout (2.4–2.6 V).

Technical Context

The ST890CD implements a precision current-limiting loop with ISET bias current (0.5–3 µA) and VSET reference (1.178–1.302 V) to set ILIM via RSET = 1.24 V / ISET. Its fast current-loop response (5 µs) enables robust short-circuit protection at ISC ≈ 1.2 × ILIM when VO < 1.6 V.

Thermal protection activates at 130 °C (typ.) with 15 °C hysteresis, disabling the switch until junction temperature falls below 115 °C. The FAULT pin asserts low during current limit, short circuit, or thermal overload - all independently detectable via open-drain output with VOL ≤ 0.15 V at 1 mA sink.

Key Specifications

Pinout & Package

ST890CD is supplied in SO8 package (ECOPACK® compliant). The exposed pad on DFN8L variant is unconnected but recommended for thermal grounding; SO8 has no exposed pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS2051BDR and NIS5132MN, ST890CD uniquely combines programmable current limit, integrated FAULT reporting, and SO8 thermal performance - making it optimal for designs requiring tunable protection and diagnostic visibility in space-constrained 3–5 V systems.

Availability

ST890CD is available at Aetrix Electronics and suitable for PCMCIA slot power control, access bus hot-swap interfaces, and portable medical monitor power rails requiring stable component supply across industrial and embedded production cycles.

Supply support for ST890CD 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, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The ST890 product line delivers high-side power switches optimized for hot-swap, load-switching, and overcurrent-protected power distribution in portable and embedded 3–5 V systems.

FAQ

What is the minimum RSET value for ST890CD to achieve 1.2 A current limit?

Using the datasheet equation RSET = 1.24 V / ISET and ISET = 1110 µA at ILIM = 1.2 A, the calculated RSET is 1.117 kΩ. Standard 1.1 kΩ ±1% resistor yields ILIM ≈ 1.19 A - within specification. Lower values increase ILIM but risk exceeding absolute maximum ratings.

Can ST890CD drive capacitive loads above 100 µF safely?

Yes, but with caveats: the device's 5 µs current-loop response limits inrush energy, and thermal shutdown (130 °C) provides secondary protection. For >100 µF loads, add series resistance or soft-start circuitry to keep peak ILIM duration below 100 ms and avoid repeated FAULT assertion.

Is the FAULT pin compatible with 1.8 V logic systems?

No - the FAULT pin is open-drain with VOL ≤ 0.15 V at 1 mA sink, but its internal pull-down strength is specified only for 3.3 V/5 V pull-up. Driving a 1.8 V GPIO requires an external level translator or voltage divider to ensure valid low-level recognition below 0.63 V (35% of 1.8 V).

How does SO8 package thermal resistance affect continuous current rating?

With Rthj-amb = 160 °C/W (SO8, typical PCB), at 70 °C ambient and 130 °C max junction, allowable ΔT = 60 °C → max power = 60 / 160 = 375 mW. At 90 mΩ RON, this limits continuous current to √(0.375 / 0.09) ≈ 2.04 A - but ILIM is capped at 1.2 A, so thermal design governs transient overload, not steady-state.