Overview
The UC3842BD1R2G is a high-performance fixed frequency current mode controller produced by onsemi. It is part of the UC3842B series, which is specifically designed for off-line and DC-DC converter applications. This integrated circuit offers a cost-effective solution with minimal external components, making it ideal for a variety of power supply designs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Reference Output Voltage (IO = 1.0 mA, TJ = 25°C) | 4.95 | 5.0 | 5.05 | V |
| Line Regulation (VCC = 12 V to 25 V) | -2.0 | - | 20 | mV |
| Load Regulation (IO = 1.0 mA to 20 mA) | -3.0 | - | 25 | mV |
| Temperature Stability | -0.2 | - | - | mV/°C |
| Oscillator Frequency (TJ = 25°C) | 47 | 50 | 52 | kHz |
| Current Sense Input Voltage Gain | 2.85 | 3.0 | 3.15 | V/V |
| Maximum Current Sense Input Threshold | 0.9 | 1.0 | 1.1 | V |
| Output Current, Source or Sink | - | - | 1.0 | A |
| Output Voltage Low State (ISink = 20 mA) | - | - | 0.1 | V |
| Output Voltage High State (ISource = 20 mA) | - | - | 13.5 | V |
| Startup Threshold (VCC) | 8.5 | - | - | V |
| Operating Temperature Range | -40 | - | 105 | °C |
Key Features
- Trimmed Oscillator for Precise Frequency Control: The oscillator frequency is programmable using the timing components RT and CT, ensuring precise duty cycle control.
- Current Mode Operation: Supports operation up to 500 kHz, ideal for high-frequency applications.
- Automatic Feed Forward Compensation: Enhances stability and performance of the converter.
- Latching PWM for Cycle-By-Cycle Current Limiting: Ensures reliable current limiting and protection against overloads.
- Internally Trimmed Reference with Undervoltage Lockout: Provides a stable reference voltage and protects against undervoltage conditions.
- High Current Totem Pole Output: Suitable for driving power MOSFETs with high current requirements.
- Undervoltage Lockout with Hysteresis: Prevents the device from operating under low voltage conditions, ensuring reliable startup and operation.
- Low Startup and Operating Current: Minimizes power consumption during startup and operation.
- Pb-Free and Halide-Free: Compliant with environmental regulations.
Applications
The UC3842BD1R2G is designed for various power supply applications, including:
- Off-line converters
- DC-DC converters
- Switch-mode power supplies
- High-frequency power conversion systems
- Power management in industrial and consumer electronics
Q & A
- What is the primary function of the UC3842BD1R2G?
The UC3842BD1R2G is a high-performance fixed frequency current mode controller designed for off-line and DC-DC converter applications.
- What is the typical oscillator frequency of the UC3842BD1R2G?
The oscillator frequency is typically around 50 kHz, but it can be programmed using the timing components RT and CT.
- What is the maximum output current of the UC3842BD1R2G?
The maximum output current is 1.0 A.
- What are the key protective features of the UC3842BD1R2G?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and a latch for single pulse metering.
- What is the operating temperature range of the UC3842BD1R2G?
The operating temperature range is from -40°C to +105°C.
- Is the UC3842BD1R2G Pb-Free and Halide-Free?
Yes, the device is Pb-Free and Halide-Free, making it compliant with environmental regulations.
- What types of packages are available for the UC3842BD1R2G?
The device is available in SOIC-8 and SOIC-14 packages.
- How does the UC3842BD1R2G control the peak inductor current?
The peak inductor current is controlled by the error signal from the Error Amplifier Output/Compensation pin, which compares the current sense input voltage to a threshold level.
- What is the purpose of the undervoltage lockout feature?
The undervoltage lockout feature prevents the device from operating under low voltage conditions, ensuring reliable startup and operation.
- Can the UC3842BD1R2G be used in high-frequency applications?
Yes, the device supports current mode operation up to 500 kHz, making it suitable for high-frequency applications.
