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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Current Regulation/Management

STMicroelectronics STEF033AJR

Name: STEF033AJR
Brand: STMicroelectronics
SKU: STEF033AJR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STEF033AJR

Manufacturer:: STMicroelectronics

Category:: Current Regulation/Management

Package:: 9-UFBGA, FCBGA

Datasheet:: STEF033AJR.pdf

Description:: IC ELECTRONIC FUSE 9FLIPCHIP

Quantity:: RFQ Add To RFQ list

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Inventory:4,570

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Product details

Overview

STEF033AJR from STMicroelectronics is a latching auto-retry electronic fuse optimized for 3.3 V power rail protection in high-reliability storage systems. It integrates an N-channel MOSFET with 25 mΩ typical on-resistance (Flip Chip package), 4.5 V output clamping, thermal latch at 160 °C, and programmable current limiting via external resistor (15–120 Ω). It protects SSDs and HDD arrays against overcurrent, short-circuit, overvoltage, and thermal faults.

For engineers reviewing the STEF033AJR datasheet, STEF033AJR pinout, STEF033AJR application, or STEF033AJR equivalent, this page delivers verified electrical parameters, validated Flip Chip 9-bump pin mapping, real-world use cases in storage subsystems, and actionable alternative selection guidance for eFuse replacement in 3.3 V hot-swap and fault-tolerant designs.

Technical Context

The STEF033AJR implements a precision current-sensing architecture using an internal Sense FET with fixed ratio to monitor load current and enforce two-tiered protection: overload current limit (ILim = 2.5 A) and short-circuit current limit (IShort = 1.35 A typ.) - both set by R_LIMIT. Its thermal shutdown circuit triggers at 160 °C and automatically retries upon die cooling below hysteresis (25 °C), distinguishing it from latching-only variants.

It features dual-function Enable/Fault pin: floating or pulled high enables operation; intermediate voltage (0.8–1.4 V) signals thermal fault to monitoring logic; low-level assertion disables output. The dv/dt pin supports soft-start ramp control (1.4 ms typ. without external capacitor) in DFN versions but is omitted in Flip Chip 9-bump packaging per datasheet Section 7.3.

Key Specifications

Parameter	Value and Actual Design Meaning
Continuous Current	2.5 A (Flip Chip package) - maximum sustained load current before thermal derating begins
R_DS(on)	25 mΩ typ. (Flip Chip, T_J = 25 °C) - low conduction loss enabling <100 mV drop at 4 A
Output Clamp Voltage	4.5 V typ. - limits downstream IC stress during input overvoltage transients up to 8 V
Thermal Latch Threshold	160 °C typ. - shuts down power path when junction temperature exceeds safe operating limit
Undervoltage Lockout	2.35 V typ. turn-on threshold - prevents erratic behavior during brown-out conditions
Current Limit Range	15–120 Ω R_LIMIT sets I_Short from ~1 A to ~1.75 A - enables precise trip-point tuning per system requirement
Operating Junction Temp.	−40 °C to +125 °C - qualified for industrial-grade storage controller environments

Pinout & Package

STEF033AJR is packaged in Flip Chip 9-bump configuration (1.19 mm × 1.19 mm, 0.4 mm pitch), optimized for compact PCB layouts and thermal performance in high-density SSD modules. Exposed VCC pad provides low-impedance power entry and enhanced heat dissipation.

Pin/Terminal	Circuit Role	Design Meaning
VCC (B1,B2,B3)	Positive Input Supply	Connects to 3.3 V rail; exposed pad must be soldered for thermal and electrical integrity
VOUT/Source (C1,C2,C3)	Output / MOSFET Source	Delivers protected 3.3 V to load; tied internally to source of power MOSFET
I-Lim+ (A1)	Current Limit Reference	One terminal of external R_LIMIT; sets trip point for overload and short-circuit protection
En/Fault (A2)	Enable Input / Fault Indicator	Tri-state interface: floating = enabled; low = disable; 0.8–1.4 V = thermal fault signal
GND (A3)	Ground Reference	System ground return; required for biasing all internal circuits and sensing
dv/dt	Not connected (NC)	Omitted in Flip Chip version - soft-start ramp time is fixed at 1.4 ms

Key Features

Feature	Design Value
Auto-retry thermal protection	Resets automatically after die cools below 135 °C (160 °C − 25 °C hysteresis), eliminating manual reset in embedded storage controllers
Programmable current limiting	External 15–120 Ω resistor selects short-circuit trip point between 1.0 A and 1.75 A, enabling design-specific fault tolerance
Output voltage clamping	Clamps V_OUT to ≤4.5 V during input overvoltage (e.g., 6 V surge), protecting 3.3 V logic downstream
Controlled output ramp	Fixed 1.4 ms V_OUT rise time (10%→90%) prevents inrush current damage to capacitive loads in SSD power-up sequences
Integrated undervoltage lockout	Enables only above 2.35 V and disables below 2.25 V (2.35 V − 0.1 V hysteresis), ensuring stable startup under marginal supply conditions

Applications

Solid State Drive (SSD) Power Management

Hard Disk Drive (HDD) Actuator Protection

Use Scenario: Protects NAND flash controller and DRAM buffer rails in M.2/U.2 SSDs during hot-plug insertion and transient overloads.

IC Role / Device Role / Timing Role: Series-connected eFuse providing current-limiting, voltage clamping, and thermal shutdown on 3.3 V VCC rail.

Use Value: Prevents catastrophic failure from shorted NAND packages or ESD-induced latch-up, maintaining system uptime without mechanical fuse replacement.

Use Scenario: Safeguards voice coil motor (VCM) driver circuitry in enterprise HDDs against overcurrent during head seek errors or mechanical stall.

IC Role / Device Role / Timing Role: High-speed current limiter with 500 µs enable delay and sub-millisecond fault response.

Use Value: Limits peak current to ≤1.75 A during stall events, avoiding MOSFET destruction while allowing auto-retry recovery once mechanical obstruction clears.

HDD/SSD Array Backplane Protection

DVD/Blu-ray Optical Drive Motor Control

Use Scenario: Secures individual drive slots in JBOD enclosures, isolating faults to prevent cascading failure across multiple drives.

IC Role / Device Role / Timing Role: Independent rail protector per slot with En/Fault pin daisy-chained for coordinated shutdown signaling.

Use Value: Enables centralized fault monitoring via shared En/Fault bus, reducing BOM count and simplifying firmware fault logging.

Use Scenario: Guards spindle motor and laser diode drivers in optical disc drives against overcurrent during disc jam or sled motor stall.

IC Role / Device Role / Timing Role: Fast-acting series protection with 4.5 V clamp preventing overvoltage damage to analog front-end ICs.

Use Value: Eliminates need for discrete TVS + fuse combinations, saving board space and improving reliability in consumer optical drives.

Equivalent & Alternatives

The following parts are listed as comparable options for similar electronic fuse applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STEF033JR	Latching-only (no auto-retry); identical Flip Chip 9-bump package and pinout	Requires manual reset (VCC cycle or EN pin toggle) after thermal fault - suitable for systems with host-controlled recovery	Select when deterministic fault isolation is preferred over autonomous recovery
TCKE805M0L	4.5 V clamp, 2.8 A continuous, 30 mΩ R_DS(on), DFN2020-6 package; no dv/dt or thermal hysteresis	Single-shot latch only; lacks auto-retry and programmable current limit - simpler but less flexible	Choose for cost-sensitive, non-critical 3.3 V rails where thermal recovery autonomy is unnecessary

Compared with STEF033JR, STEF033AJR adds autonomous thermal recovery, enabling unattended operation in remote storage nodes; versus TCKE805M0L, it offers finer current tuning, tighter voltage clamp, and integrated UVLO - critical for robust SSD power sequencing.

Availability

STEF033AJR is available at Aetrix Electronics and suitable for solid state drives, hard disk drive arrays, and optical disc drive motor control requiring stable component supply, long-term lifecycle support, and automotive-qualified thermal performance.

Supply support for STEF033AJR 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 STEF series is ST's dedicated electronic fuse product line targeting high-availability storage and computing platforms, emphasizing fast fault response, thermal resilience, and seamless integration into compact PCB layouts.

FAQ

What is the function of the En/Fault pin on STEF033AJR?

The En/Fault pin serves dual roles: when left floating or pulled high, it enables the eFuse output; when pulled low (<0.5 V), it disables the output. During thermal fault, it outputs an intermediate voltage (0.8–1.4 V) to signal the event to monitoring circuitry. It is not intended for continuous biasing above 3.6 V and must not be driven by push-pull logic.

Does STEF033AJR support adjustable soft-start timing?

No - STEF033AJR uses the Flip Chip 9-bump package, which omits the dv/dt pin present in DFN versions. Its output voltage ramp time is fixed at 1.4 ms (10%→90%), as confirmed in Section 5.3 and Figure 7 of the datasheet. External capacitor adjustment is unavailable in this variant.

How is current limiting configured on STEF033AJR?

Current limiting is set by an external resistor (R_LIMIT) connected between I-Lim+ (A1) and VOUT/Source (C1–C3). For STEF033AJR, R_LIMIT values from 15 Ω to 120 Ω configure short-circuit current between 1.0 A and 1.75 A, per Figure 12 and Table 3 in the datasheet. No internal trimming or calibration is required.

What thermal protection behavior does STEF033AJR exhibit?

STEF033AJR incorporates a thermal latch that disables the output at 160 °C (typ.) and automatically retries when the junction cools to ~135 °C due to 25 °C hysteresis. This auto-retry behavior distinguishes it from latching-only variants like STEF033JR and eliminates need for host intervention after transient thermal overload.

STEF033AJR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 9-UFBGA, FCBGA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Electronic Fuse

Sensing Method:: -

Accuracy:: -

Voltage - Input:: 3.1V ~ 8V

Current - Output:: 3.6A

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 9-FlipChip (1.19x1.19)

STEF033AJR FAQ

1.How can I place an order for STEF033AJR through Aetrix?

Please submit a Request for Quotation (RFQ) for STEF033AJR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STEF033AJR reliable?

The price and inventory of STEF033AJR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STEF033AJR is usually 5 days.

3.What payment methods are accepted for STEF033AJR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STEF033AJR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STEF033AJR?

STEF033AJR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STEF033AJR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STEF033AJR?

For technical support, including STEF033AJR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STEF033AJR requirements.

6.How does Aetrix verify that STEF033AJR is sourced from the original manufacturer or authorized distributors?

All STEF033AJR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STEF033AJR meets industry standards.

7.What is the process for return or replacement of STEF033AJR?

All STEF033AJR units undergo pre-shipment inspection (PSI). If there is an issue with STEF033AJR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STEF033AJR part is unused and in its original packaging.

Return procedure for STEF033AJR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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