Overview
The UC3843BD1R2G is a high-performance fixed frequency current mode controller produced by onsemi. It is part of the UC3842B and UC3843B series, which are specifically designed for off-line and DC-DC converter applications. These controllers offer a cost-effective solution with minimal external components, making them ideal for a variety of power management needs. The UC3843BD1R2G features a trimmed oscillator for precise duty cycle control, a temperature compensated reference, a high gain error amplifier, a current sensing comparator, and a high current totem pole output suitable for driving power MOSFETs.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC, VC | 30 | V |
| Total Power Supply and Zener Current (ICC + IZ) | 30 | mA |
| Output Current, Source or Sink | 1.0 | A |
| Output Energy (Capacitive Load per Cycle) | 5.0 | mJ |
| Current Sense, Voltage Feedback, Vref and Rt/Ct Inputs | -0.3 to +5.5 | V |
| Oscillator Frequency | 52 kHz (typical) | kHz |
| Output Current Sink/Source | 200 mA / 200 mA | mA |
| UVLO Thresholds | 8.5 V (on), 7.6 V (off) | V |
| Package Type | SOIC-8 |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 52 kHz (typical)
- Current Mode Operation up to 500 kHz
- Automatic Feed Forward Compensation
- Latching PWM for Cycle-By-Cycle Current Limiting
- Internally Trimmed Reference with Undervoltage Lockout
- High Current Totem Pole Output
- Undervoltage Lockout with Hysteresis
- Low Startup and Operating Current
- Pb-Free Packages Available
Applications
The UC3843BD1R2G is designed for off-line and DC-DC converter applications. It is particularly suitable for:
- Off-line power supplies
- DC-DC converters, including flyback, forward, and push-pull configurations
- Power management systems requiring high efficiency and reliability
Q & A
- What is the typical oscillator frequency of the UC3843BD1R2G?
The typical oscillator frequency is 52 kHz.
- What are the UVLO thresholds for the UC3843BD1R2G?
The UVLO thresholds are 8.5 V (on) and 7.6 V (off).
- What is the maximum output current of the UC3843BD1R2G?
The maximum output current is 1.0 A.
- What type of package is the UC3843BD1R2G available in?
The UC3843BD1R2G is available in an SOIC-8 package.
- Does the UC3843BD1R2G support Pb-free packaging?
- What are the key protective features of the UC3843BD1R2G?
The key protective features include 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 maximum VCC voltage for the UC3843BD1R2G?
The maximum VCC voltage is 30 V.
- How does the current sensing comparator work in the UC3843BD1R2G?
The current sensing comparator monitors the inductor current converted to a voltage by a sense resistor and compares it to a level derived from the error amplifier output.
- What is the typical output current sink/source capability of the UC3843BD1R2G?
The typical output current sink/source capability is 200 mA / 200 mA.
- Is the UC3843BD1R2G suitable for high-frequency applications?
