Overview
The L4981AD, produced by STMicroelectronics, is a power factor correction (PFC) pre-regulator integrated circuit designed to achieve a high power factor of up to 0.99. Realized in BCD 60II technology, this IC contains all the necessary control functions for designing high-efficiency power supplies with sinusoidal line current consumption. It is suitable for systems with mains voltages ranging from 85 V to 265 V without the need for a line switch. The L4981AD operates in either fixed frequency (L4981A) or modulated frequency (L4981B) modes, optimizing the size of the input filter and maintaining sinusoidal line current without slope compensation.
Key Specifications
| Parameter | Value |
|---|---|
| IC Type | Power Factor Controller IC |
| Maximum Switching Frequency | 115 kHz |
| Start-up Supply Current | 0.3 mA |
| Maximum Supply Current | 16 mA |
| Mounting Type | Surface Mount |
| Package Type | SOIC |
| Pin Count | 20 |
| Dimensions | 13 x 7.6 x 2.35 mm |
| Maximum Operating Supply Voltage | 19.5 V |
| Minimum Operating Temperature | -40 °C |
| Maximum Operating Temperature | +125 °C |
Key Features
- Control Boost PWM up to 0.99 power factor
- Limit line current distortion to < 5%
- Universal input mains
- Feed forward line and load regulation
- Average current mode PWM for minimum noise sensitivity
- High current bipolar and DMOS totem pole output
- Low start-up current (0.3 mA typical)
- Under voltage lockout with hysteresis and programmable turn-on threshold
- Overvoltage and overcurrent protection
- Precise 2% on-chip reference externally available
- Soft start
Applications
The L4981AD is designed for use in high-efficiency power supplies, particularly those requiring power factor correction. It is suitable for a wide range of applications, including:
- AC/DC converters
- Switch-mode power supplies (SMPS)
- Systems with mains voltages between 85 V to 265 V
- Applications requiring high power factor and low line current distortion
Q & A
- What is the primary function of the L4981AD IC?
The primary function of the L4981AD IC is to provide power factor correction (PFC) to achieve a high power factor of up to 0.99 in power supplies.
- What are the operating frequency modes of the L4981AD?
The L4981AD can operate in either fixed frequency (L4981A) or modulated frequency (L4981B) modes.
- What is the maximum switching frequency of the L4981AD?
The maximum switching frequency of the L4981AD is 115 kHz.
- What is the start-up supply current of the L4981AD?
The start-up supply current of the L4981AD is 0.3 mA typical.
- What are the operating temperature ranges of the L4981AD?
The operating temperature ranges of the L4981AD are from -40 °C to +125 °C.
- Does the L4981AD have built-in protection features?
Yes, the L4981AD includes overvoltage and overcurrent protection features.
- What is the package type of the L4981AD?
The package type of the L4981AD is SOIC with 20 pins.
- What are the dimensions of the L4981AD package?
The dimensions of the L4981AD package are 13 x 7.6 x 2.35 mm.
- Is the L4981AD RoHS compliant?
Yes, the L4981AD is RoHS compliant with the Ecopack2 grade.
- What is the maximum operating supply voltage of the L4981AD?
The maximum operating supply voltage of the L4981AD is 19.5 V.
