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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Distribution Switches, Load Drivers

STMicroelectronics L9347LF-TR

Name: L9347LF-TR
Brand: STMicroelectronics
SKU: L9347LF-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L9347LF-TR

Manufacturer:: STMicroelectronics

Category:: Power Distribution Switches, Load Drivers

Package:: 36-PowerBSSOP (0.433", 11.00mm Width)

Datasheet:: L9347LF-TR.pdf

Description:: IC PWR DRIVER N-CHAN 1:1 PWRSO36

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Product details

Overview

L9347LF-TR from STMicroelectronics is an intelligent quad low-side power switch IC designed for automotive ABS valve control, featuring two 5A conventional switches (Ch1–Ch2) and two 2.5A current-regulated channels (Ch3–Ch4), with typ. R_DS(ON) of 0.2 Ω and 0.35 Ω respectively, integrated Zener clamping (Ch1–Ch2) and freewheeling diodes (Ch3–Ch4), and real-time status monitoring per channel.

For engineers reviewing the L9347LF-TR datasheet, L9347LF-TR pinout, L9347LF-TR application in ABS systems, or L9347LF-TR equivalent for valve driver replacement, this page delivers verified electrical specs, diagnostic behavior, regulator accuracy (±10% over 250 mA–2.25 A), thermal shutdown thresholds (175–200 °C), and PowerSO-36 package layout - all confirmed from ST's official Rev 3 datasheet (Sept 2013).

Technical Context

The device implements dual-mode output architecture: Ch1/Ch2 use DMOS transistors with open-drain outputs and integrated Zener clamps (V_Z = 45–60 V) for fast inductive kickback suppression; Ch3/Ch4 employ digital PI regulation (K_P = 0.96, K_I = 0.126) synchronized to a 250 kHz external clock, measuring current during recirculation via a 1 Ω sense path.

Diagnostic logic includes independent push-pull status outputs per channel, short-circuit detection with 4–30 μs shutdown delay, selective overtemperature shutdown (175–200 °C), open-load detection (V_QU = 0.3–0.36×V_Q), and regulator drift comparison enabled by TEST pin - all filtered with configurable digital timers (t_sf = 4–8 μs, t_RE = 10 ms).

Key Specifications

Parameter	Value and Actual Design Meaning
R_DS(ON) (Ch1–Ch2)	0.2 Ω typ. at T_j = 25°C → enables <5A continuous conduction with ≤0.5W dissipation per channel at 1A
R_DS(ON) (Ch3–Ch4)	0.35 Ω typ. at T_j = 25°C → supports regulated 2.5A operation with stable current loop under load variation
Regulator accuracy	±10% for 250 mA–400 mA; ±6% for 400–800 mA; ±10% for 800 mA–2.25 A → ensures precise solenoid force control across duty cycle range
Output PWM frequency	3.9 kHz (64×250 kHz clock) → provides sufficient resolution for 2 kHz input PWM while minimizing audible noise in valves
Short-circuit response	t_SCP = 4–30 μs → protects against cable shorts before energy exceeds 50 mJ safe limit for inductive loads
Status delay time	t_D = 896–1024 μs → guarantees deterministic fault reporting aligned with system watchdog timing windows
Overtemperature threshold	T_th = 175–200 °C with 10 °C hysteresis → prevents thermal runaway while allowing transient junction peaks during ABS actuation

Pinout & Package

Package: PowerSO-36 with integrated cooling area - thermally optimized for high-power automotive PCB mounting, R_thJC = 2 K/W, rated for T_j up to 150°C continuous operation.

Pin/Terminal	Circuit Role	Design Meaning
Q1, Q2	Power Output (Ch1, Ch2)	5A-rated DMOS drain outputs with Zener clamp; require external flyback path only for non-clamped loads
Q3, Q4	Power Output (Ch3, Ch4)	2.5A current-regulated outputs; integrate freewheeling diodes D3/D4 and 1 Ω current sense path
IN1–IN4	Control Input	Schmitt-triggered, 2–6 V VIH; valid PWM range 10–90% for Ch3/Ch4; pull-down current 8–40 μA
ST1–ST4	Status Output	Push-pull, V_STL ≤ 0.4 V @ 40 μA, V_STH ≥ 2.5 V @ −40 μA; inverted on fault (e.g., open load, overload)
CLK, TEST, EN	System Control	250 kHz clock input (45–55% duty); TEST enables regulator drift comparison; EN globally disables all channels
PGND1–PGND4, GND	Ground Terminals	Separate power grounds per channel + logic ground → minimize crosstalk and enable individual open-load detection
VCC, VDD, VS	Supply Inputs	VCC/VDD = 4.5–5.5 V analog/digital supplies; VS = 4.8–18 V main supply; VS loss detected at 2–4.5 V

Key Features

Feature	Design Value
Integrated protection per channel	Short-circuit shutdown (4–30 μs), selective overtemperature shutdown (175–200 °C), open-load detection (0.3×V_Q threshold), supply-loss sensing (VS & PGND)
Dual-output architecture	Two 5A non-regulated channels with Zener clamping (V_Z = 45–60 V) + two 2.5A digitally regulated channels with 5 mA resolution and ±10% accuracy
Real-time diagnostics	Independent push-pull status outputs per channel; fault inversion logic with configurable filter times (t_sf, t_lf, t_RE)
Regulator-specific intelligence	Drift detection between Ch3/Ch4 via TEST pin; recirculation error shutdown (V_rerr = 45–60 V); regulation error status delay = 10 ms
ESD robustness	±4 kV HBM on Qx/Dx pins vs. common GND; ±2 kV per MIL-STD-883C - suitable for under-hood automotive environments

Applications

ABS Hydraulic Modulator Valve Control

Electronic Parking Brake Actuator

Use Scenario: Precise timed actuation of solenoid valves in ABS hydraulic units during emergency braking events.

IC Role / Device Role / Timing Role: Quad low-side driver delivering 5A pulses (Ch1–Ch2) and 2.5A regulated current (Ch3–Ch4) with sub-1 ms fault response and synchronized status feedback.

Use Value: Enables closed-loop pressure modulation via current-regulated channels while maintaining fail-safe shutdown on open-load or short-circuit faults.

Use Scenario: Driving dual electromagnetic actuators in electronic parking brake (EPB) systems requiring torque consistency over lifetime.

IC Role / Device Role / Timing Role: Current-regulated output (Ch3–Ch4) maintains 250–2250 mA within ±10% accuracy; drift detection identifies aging-induced current deviation before functional failure.

Use Value: Extends EPB system service life by detecting regulator mismatch early, avoiding unintended release due to degraded solenoid performance.

Engine Start-Stop Solenoid Driver

Transmission Shift Solenoid Interface

Use Scenario: Controlling starter motor engagement solenoids and fuel cutoff valves during engine auto-stop/start cycles.

IC Role / Device Role / Timing Role: Ch1–Ch2 deliver 5A switching with Zener clamping to suppress 60 V inductive spikes; EN pin enables global disable during cranking voltage dips.

Use Value: Prevents false triggering during battery voltage sag (down to 4.8 V) and eliminates need for external TVS/clamp components.

Use Scenario: Driving linear shift solenoids in automatic transmissions where current precision directly impacts gear engagement smoothness.

IC Role / Device Role / Timing Role: Ch3–Ch4 regulate output current using 2 kHz PWM input; status outputs feed transmission ECU for real-time solenoid health monitoring.

Use Value: Reduces shift jerk by maintaining ±6% accuracy in 400–800 mA range - critical for adaptive learning algorithms in modern AT control units.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad low-side valve driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
VND5E025AKTR-E	Single-channel 2.5A high-side driver; no current regulation; no integrated freewheeling diodes; SO-8 package	Requires external diodes and separate regulators for multi-channel ABS designs; lacks per-channel status and drift detection	Use only when consolidating single-valve control with high-side topology and minimal BOM count
TPS27082LDR	Quad 2.2A low-side switch; no current regulation; no Zener clamping; 1.2 Ω R_DS(ON); WQFN-32 package	Higher conduction loss limits peak current to 2.2A; lacks open-load detection on power grounds; no recirculation error handling	Select only for non-inductive or low-energy loads where thermal margin allows higher R_DS(ON)

Compared with L9347LF-TR, VND5E025AKTR-E offers high-side flexibility but requires full external support circuitry for ABS valve stacks, while TPS27082LDR provides smaller footprint and lower cost but sacrifices regulation accuracy, clamping protection, and diagnostic depth needed for safety-critical automotive valve control.

Availability

L9347LF-TR is available at Aetrix Electronics and suitable for automotive ABS systems, electronic parking brake modules, engine start-stop solenoid interfaces, and transmission shift solenoid drivers requiring stable component supply, long-lifecycle assurance, and AEC-Q100-compliant sourcing.

Supply support for L9347LF-TR 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, specializing in automotive-grade power ICs, microcontrollers, and sensors with ISO/TS 16949-certified manufacturing.

The L9347 belongs to ST's Intelligent Power Switch family, engineered specifically for high-reliability automotive body and chassis applications demanding integrated protection, diagnostics, and current regulation in harsh environments.

FAQ

What is the maximum allowable inductive energy the L9347LF-TR can safely dissipate during switching?

The device specifies EQ = 50 mJ as the absolute maximum switch-off energy for inductive loads. This value is derived from internal Zener clamping (Ch1–Ch2) and freewheeling diode ratings (Ch3–Ch4), validated under worst-case conditions (V_Q ≤ 60 V, I_Q ≤ 5A). Exceeding 50 mJ risks permanent damage to the DMOS structure or diode junctions, even with proper PCB copper pour and thermal vias.

How does the L9347LF-TR detect and respond to open-load conditions on regulated channels?

Open-load detection on Ch3–Ch4 relies on monitoring the freewheeling diode path voltage (V_rerr = 45–60 V threshold). If D3 or D4 is disconnected, recirculation current collapses, triggering immediate regulator shutdown and status output inversion within t_RE = 10 ms. The diagnostic table confirms this fault is latched until EN or IN is held low longer than t_D ≈ 1 ms.

Can the L9347LF-TR operate without an external 250 kHz clock signal?

No - the 250 kHz CLK input is mandatory for all functions. It synchronizes the digital PI regulator (Ch3–Ch4), enables clock watchdog (f_CLK,min = 10–100 kHz), and gates diagnostic filters (t_sf, t_lf). Omitting CLK disables regulation, invalidates status timing, and causes immediate fault indication on all STx outputs per Table 7 (detected errors).

What is the significance of the "drift detection" feature and how is it activated?

Drift detection compares PWM duty cycle outputs of Ch3 and Ch4 to identify aging-induced mismatches in current regulation. It is activated by asserting the TEST pin high while applying identical PWM inputs to IN3 and IN4. A >±14.3% difference in output PWM ratio triggers status inversion, indicating mechanical or magnetic degradation in paired solenoids - critical for predictive maintenance in EPB and ABS systems.

L9347LF-TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Package/Case:: 36-PowerBSSOP (0.433", 11.00mm Width)

Series:: -

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Switch Type:: General Purpose

Number of Outputs:: 4

Ratio - Input:Output:: 1:1

Output Configuration:: Low Side

Output Type:: N-Channel

Interface:: On/Off

Voltage - Load:: 4.8V ~ 18V

Voltage - Supply (Vcc/Vdd):: Not Required

Current - Output (Max):: 2.5A, 5A

Rds On (Typ):: -

Input Type:: Non-Inverting

Features:: Status Flag

Fault Protection:: Open Load Detect, Over Temperature

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: PowerSO-36, Bottom Pad

L9347LF-TR FAQ

1.How can I place an order for L9347LF-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L9347LF-TR 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 L9347LF-TR reliable?

The price and inventory of L9347LF-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9347LF-TR is usually 5 days.

3.What payment methods are accepted for L9347LF-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9347LF-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L9347LF-TR?

L9347LF-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L9347LF-TR 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 L9347LF-TR?

For technical support, including L9347LF-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9347LF-TR requirements.

6.How does Aetrix verify that L9347LF-TR is sourced from the original manufacturer or authorized distributors?

All L9347LF-TR 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 L9347LF-TR meets industry standards.

7.What is the process for return or replacement of L9347LF-TR?

All L9347LF-TR units undergo pre-shipment inspection (PSI). If there is an issue with L9347LF-TR, 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 L9347LF-TR part is unused and in its original packaging.

Return procedure for L9347LF-TR:

1.Submit a request within 90 days.

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

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