Overview
The UC3843BNG is a high-performance fixed frequency current mode controller produced by onsemi. It is specifically designed for Off-Line and DC-DC converter applications, offering a cost-effective solution with minimal external components. This integrated circuit 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 ideal for driving a power MOSFET. The UC3843BNG is tailored for lower voltage applications with undervoltage lockout (UVLO) thresholds of 8.5 V (on) and 7.6 V (off).
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC (Bias and Driver Voltages) | 30 | V |
| Total Power Supply and Zener Current (ICC + IZ) | 30 | mA |
| Output Current, Source or Sink (IO) | 1.0 | A |
| Output Energy (Capacitive Load per Cycle) | 5.0 | μJ |
| Reference Output Voltage (Vref) | 4.95 - 5.05 | V |
| Oscillator Frequency | 250 kHz (guaranteed) | kHz |
| UVLO Startup Threshold | 8.5 | V |
| UVLO Minimum Operating Voltage After Turn-On | 7.6 | V |
| Maximum Duty Cycle | 94 - 96% | % |
| Package Types | 8-pin DIP, SO-8, SO-14 |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz
- Current Mode Operation 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 and Halide-Free Packages Available
Applications
The UC3843BNG is specifically designed for Off-Line and DC-DC converter applications. It is suitable for various power supply designs, including:
- Off-Line Converters
- DC-DC Converters
- Power Supply Units (PSUs)
- Switch Mode Power Supplies (SMPS)
Q & A
- What is the primary function of the UC3843BNG?
The UC3843BNG is a high-performance fixed frequency current mode controller designed for Off-Line and DC-DC converter applications.
- What are the UVLO thresholds for the UC3843BNG?
The UVLO thresholds for the UC3843BNG are 8.5 V (on) and 7.6 V (off).
- What is the guaranteed oscillator frequency of the UC3843BNG?
The oscillator frequency is guaranteed at 250 kHz.
- What types of packages are available for the UC3843BNG?
The UC3843BNG is available in 8-pin DIP, SO-8, and SO-14 packages.
- What is the maximum output current of the UC3843BNG?
The maximum output current is 1.0 A.
- Does the UC3843BNG have protective features?
Yes, it includes protective features such as input and reference undervoltage lockouts, cycle-by-cycle current limiting, and a latch for single pulse metering.
- What is the maximum power supply voltage for the UC3843BNG?
The maximum power supply voltage (VCC) is 30 V.
- Is the UC3843BNG Pb-Free and Halide-Free?
Yes, the UC3843BNG is available in Pb-Free and Halide-Free packages.
- What is the typical operating temperature range for the UC3843BNG?
The operating temperature range varies by model but typically includes ranges from 0°C to 105°C.
- How is the oscillator frequency programmed in the UC3843BNG?
The oscillator frequency is programmed by the values chosen for the timing components RT and CT.
