KA3842AES

Product Overview

• Category: Integrated Circuit
• Use: PWM Controller
• Characteristics: High-performance, fixed-frequency current-mode controller
• Package: 8-pin SOIC (Small Outline Integrated Circuit)
• Essence: Regulates the output voltage of power supplies
• Packaging/Quantity: Available in reels of 2500 units

Specifications

• Input Voltage: 7V to 35V
• Output Voltage: Adjustable from 2.5V to 30V
• Operating Temperature: -40°C to +85°C
• Switching Frequency: 100kHz to 500kHz
• Duty Cycle Range: 0% to 100%
• Maximum Duty Cycle: 50%

Detailed Pin Configuration

1. VCC: Power supply input
2. GND: Ground reference
3. COMP: Error amplifier output
4. FB: Feedback pin for regulating output voltage
5. CS: Current sense input
6. RT/CT: Timing components connection
7. OUT: Output pin
8. SS/TR: Soft-start and shutdown control pin

Functional Features

• Current-mode control with adjustable duty cycle
• Internal oscillator with frequency range selection
• Soft-start function for controlled startup
• Overcurrent protection
• Under-voltage lockout
• Error amplifier for precise voltage regulation
• External synchronization capability

Advantages and Disadvantages

Advantages: - Wide input voltage range - Adjustable output voltage - High switching frequency - Efficient power conversion - Comprehensive protection features

Disadvantages: - Limited maximum duty cycle - Requires external timing components - Not suitable for high-power applications

Working Principles

The KA3842AES is a current-mode PWM controller that regulates the output voltage of power supplies. It operates by comparing the feedback voltage with a reference voltage and adjusting the duty cycle of the output waveform accordingly. This control mechanism ensures stable and accurate voltage regulation.

The internal oscillator generates a fixed-frequency signal, which determines the switching frequency of the power supply. By adjusting the timing components connected to the RT/CT pin, the switching frequency can be set within a specific range.

During startup, the soft-start function gradually increases the duty cycle, preventing excessive inrush current and ensuring a controlled and smooth power-up sequence.

Detailed Application Field Plans

The KA3842AES is commonly used in various applications, including:

1. Switching power supplies
2. Battery chargers
3. LED drivers
4. DC-DC converters
5. Offline flyback converters

Its versatility and wide input voltage range make it suitable for both consumer electronics and industrial applications.

Detailed and Complete Alternative Models

1. UC3842A: Similar functionality, different package (DIP-8)
2. SG3524: Higher switching frequency, additional features (e.g., dead-time control)
3. TL494: Enhanced precision, wider operating temperature range

These alternative models offer similar capabilities and can be considered based on specific requirements and design constraints.

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