STMicroelectronics L6569AD

Overview

L6569AD from STMicroelectronics is a high-voltage half-bridge gate driver IC with integrated programmable oscillator, designed for driving external N-channel MOSFETs and IGBTs in resonant lamp ballast and SMPS applications. It features 600V high-side rail capability, internal bootstrap diode structure, 1.25µs typical dead time, ±50V/ns dV/dt immunity, and 15.6V zener clamp on VS pin.

For engineers reviewing the L6569AD datasheet, L6569AD pinout, L6569AD application, or L6569AD equivalent, this page delivers verified technical context, validated pin functions, confirmed oscillator programming behavior, and real-world ballast design constraints - all grounded in ST's official documentation and demo board implementation.

Technical Context

The L6569AD integrates a programmable RC oscillator (20–200 kHz range), level-shifting circuitry for high-side drive, and patented internal bootstrap charge pump that replaces external diodes. Its logic accepts either internal oscillator timing or external CMOS-level signals applied to CF pin.

Under-voltage lockout (UVLO) with 1V hysteresis ensures safe startup at VS = 9V turn-on / 8V turn-off; the internal 120Ω LDMOS bootstrap switch synchronizes with LVG output with 50ns delay, enabling zero-voltage switching support in CFL ballasts.

Key Specifications

Pinout & Package

Package: SO8 (Small Outline, 8-pin, 1.27mm pitch), per STMicroelectronics mechanical drawing (D = 4.8–5.0 mm, E = 5.8–6.2 mm).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage half-bridge driver applications.

Compared with IR2153(D)PbF and IRS21844SPbF, the L6569AD uniquely combines oscillator integration, internal bootstrap diode replacement, and UVLO hysteresis in an SO8 package - reducing component count and layout sensitivity in cost-sensitive ballast and resonant converter designs.

Availability

L6569AD is available at Aetrix Electronics and suitable for compact fluorescent lamp ballasts, resonant LLC converters, induction heating systems, and BLDC motor inverters requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for L6569AD 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 power management, analog, and automotive-grade ICs with strong manufacturing control and broad distribution.

The L6569AD belongs to ST's legacy high-voltage AC-DC and lighting control product line, engineered specifically for cost-effective, high-reliability electronic ballast and resonant converter applications with integrated timing and bootstrap functionality.

FAQ

What is the key functional difference between L6569AD and L6569D?

The L6569AD and L6569D differ in startup sequence: the L6569AD uses the L6569A variant's controlled bootstrap initialization, where the low-side driver remains off until VS reaches 9V UVLO threshold before initiating the bootstrap charge cycle. This avoids unintended high-side conduction during brown-in conditions, improving reliability in universal-input ballasts.

Can the L6569AD drive IGBTs directly without gate resistors?

No - external gate resistors are required to control rise/fall times and suppress ringing. The L6569AD's 170mA/270mA drive strength is sufficient for typical IGBTs like STD2NB50-1, but datasheet-recommended values (e.g., Rg = 22Ω used in ST's demo board) must be applied to ensure safe switching and avoid latch-up under high dV/dt stress.

How does the internal bootstrap structure eliminate the need for an external diode?

The L6569AD uses a patented high-voltage LDMOS transistor (RON ≈ 120Ω) as a synchronous rectifier, driven in phase with the LVG output. When LVG goes high, the LDMOS closes the charging path from VS through the bootstrap capacitor (CBOOT), replacing the conventional diode with a low-loss, controllable switch synchronized to the low-side conduction period.

Is the oscillator frequency stable over temperature and supply voltage?

Yes - oscillator frequency exhibits ±5% variation over –40°C to +125°C (Fig.5) and maintains regulation across VS = 10–18V. The internal comparator thresholds (VCFL = 4.0V, VCFU = 8.0V) are trimmed for stability, and frequency drift is dominated by external RF/CF tolerance, not internal reference drift.