STMicroelectronics L6229N

Overview

L6229N from STMicroelectronics is a fully integrated 3-phase DMOS BLDC motor driver IC with Hall-effect sensor decoding logic, constant t_OFF PWM current control, and non-dissipative overcurrent protection. It delivers 2.8 A peak (1.4 A DC) output per phase, operates from 8–52 V supply, features R_DS(ON) = 0.73 Ω (typ. at 25 °C), supports up to 100 kHz switching, and integrates fast freewheeling diodes - used in factory automation end-points and small pump motor control.

For engineers reviewing the L6229N datasheet, L6229N pinout, L6229N application, or L6229N equivalent, key selection criteria include its 60°/120° Hall decoding flexibility, synchronous slow-decay rectification, tachometer output for closed-loop speed control, and bootstrap gate drive architecture requiring external RC timing networks on RCOFF/RCPULSE pins.

Technical Context

The L6229N implements a constant-off-time (COT) PWM current controller using an external RC network on RCOFF to set t_OFF (13–61 µs range), with internal 1 µs deadtime to prevent shoot-through. Its Hall decoding logic autonomously distinguishes 60° and 120° electrical spacing without configuration pins, enabling universal BLDC commutation.

It integrates a charge pump (VCP output, 600 kHz typ.) to generate VBOOT for high-side N-MOSFET gate drive, and uses a single sense resistor shared between SENSEA and SENSEB for current sensing - with blanking time (1 µs) and offset voltage (±5 mV) specified for accurate regulation under transient conditions.

Key Specifications

Pinout & Package

Available in PowerSO36 (slug-connected GND) and SO24 (20 + 2 + 2 pin count) packages. The SO24 variant uses pins 1, 6, 7, 18, and 19 as GND - all thermally tied to the exposed pad for PCB heat dissipation. PowerSO36 adds dedicated thermal slug (internally connected to pins 1, 18, 19, 36).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-phase BLDC motor driver applications.

Compared with STSPIN32F0A, L6229N offers simpler Hall-based commutation without firmware overhead but lacks digital control; versus TB6605FTG, it adds tachometer, brake, and wider voltage support - making it preferable for industrial speed-critical or safety-aware systems.

Availability

L6229N is available at Aetrix Electronics and suitable for factory automation end-points, home appliance fans, and small pumps requiring stable component supply across extended product lifecycles.

Supply support for L6229N 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, specializing in power management, motor control, and automotive-grade ICs with broad industrial qualification.

The L6229N belongs to ST's high-voltage intelligent power driver family, designed specifically for cost-effective, robust 3-phase BLDC motor control in resource-constrained embedded systems without microcontroller dependency.

FAQ

What is the minimum recommended value for the RCOFF timing resistor?

The datasheet specifies ROFF must be ≥20 kΩ to ensure stable t_OFF operation. Using 20 kΩ with 1 nF yields ~13 µs off-time - sufficient for most 24–48 V BLDC motors. Lower values risk premature monostable triggering due to noise sensitivity and reduced blanking margin.

Can L6229N drive a sensorless BLDC motor?

No - the L6229N requires three Hall-effect sensor inputs (H1–H3) for commutation and has no back-EMF sensing or zero-crossing detection circuitry. It is strictly a sensor-based driver; sensorless operation requires a different IC such as STSPIN32F0B or similar FOC-capable device.

How does the DIAG pin interface with the EN pin for automatic fault recovery?

DIAG is open-drain and sinks current during overcurrent or thermal events. Connecting DIAG directly to EN (with pull-up to 5 V) disables the driver until fault clears. For latched shutdown, add a reset button or MCU-controlled transistor; for auto-retry, use an RC delay on EN to hold disable for fixed recovery time before re-enabling.

What thermal derating applies when using the SO24 package on a 2-layer PCB?

With no added copper pour, R_th(j-amb) = 78 °C/W (Table 3, condition 4). At 1.4 A DC and 0.73 Ω R_DS(ON), power dissipation is ~1.5 W - resulting in ~117 °C junction rise above ambient. Derate maximum ambient to ≤33 °C for safe 150 °C T_j limit; adding 6 cm² copper on bottom layer reduces R_th to 55 °C/W, allowing 60 °C ambient.