STMicroelectronics L4984DTR

The L4984DTR is a current-mode Power Factor Correction (PFC) controller produced by STMicroelectronics. It operates using line-modulated fixed-off-time (LM-FOT) control, enabling fixed-frequency operation for boost PFC converters in continuous conduction mode (CCM). This IC is packaged in a 10-pin SSOP package and is designed to provide a low-cost solution for CCM-operated boost PFC pre-regulators. It is compliant with EN61000-3-2 and JEIDA-MITI standards and is suitable for power ranges from a few hundred watts to over 1 kW.

The L4984DTR features a highly linear multiplier that reduces crossover distortion of the AC input current, allowing for wide-range mains operation with low Total Harmonic Distortion (THD). The output voltage is controlled by a voltage-mode error amplifier and an accurate internal voltage reference. The device also includes various protection features and a disable function for remote on/off control, making it compliant with the latest energy-saving requirements such as Blue Angel, ENERGY STAR, and Energy 2000.

• Line-modulated fixed-off-time (LM-FOT) control of CCM-operated PFC pre-regulators
• Proprietary LM-FOT modulator for nearly fixed-frequency operation
• Proprietary multiplier design for minimum THD of AC input current
• Fast “bi-directional” input voltage feedforward (1/V2 correction)
• Accurate adjustable output overvoltage protection
• Protection against feedback loop failure (latched shutdown)
• Inductor saturation protection
• AC brownout detection
• Digital leading-edge blanking on current sense
• Soft-start to limit peak current and prevent flux runaway
• 1% (at Tj = 25 °C) internal reference voltage
• Totem pole gate driver with active pull-down during UVLO and voltage clamp
• SSOP10 package

The L4984DTR is suitable for various applications, including:

• PFC pre-regulators for IEC61000-3-2 and JEIDA-MITI compliant Switch-Mode Power Supplies (SMPS) in excess of 1 kW
• Desktop PCs, servers, and web servers
• Compliance with energy-saving standards such as Blue Angel, ENERGY STAR, and Energy 2000

1. What is the primary function of the L4984DTR?

   The L4984DTR is a current-mode Power Factor Correction (PFC) controller designed for boost PFC converters operating in continuous conduction mode (CCM).

2. What package type does the L4984DTR come in?

   The L4984DTR comes in a 10-pin SSOP package.

3. What is the operating voltage range of the L4984DTR?

   The operating voltage range is from 10.3 V to 22.5 V.

4. What protection features does the L4984DTR include?

   The L4984DTR includes overvoltage protection, protection against feedback loop failure, inductor saturation protection, and AC brownout detection.

5. How does the L4984DTR improve line transient response?

   The device uses a proprietary “bi-directional” input voltage feedforward (1/V2 correction) to significantly improve line transient response during mains drops and surges.

6. What is the purpose of the soft-start feature in the L4984DTR?

   The soft-start feature limits peak current and extends off-time to prevent flux runaway in the initial cycles.

7. What is the capability of the gate driver output stage?

   The totem pole output stage is capable of 600 mA source current and 800 mA sink current.

8. Is the L4984DTR compliant with energy-saving standards?

   Yes, the L4984DTR is compliant with standards such as Blue Angel, ENERGY STAR, and Energy 2000.

9. What is the junction temperature operating range of the L4984DTR?

   The junction temperature operating range is from -40 °C to 150 °C.

10. What is the storage temperature range for the L4984DTR?

    The storage temperature range is from -55 °C to 150 °C.