Overview
The UC3843BVDG, produced by onsemi, is a high-performance fixed frequency current mode controller. It is specifically designed for Off-Line and DC-to-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 device includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and a latch for single pulse metering.
Key Specifications
| Rating | Symbol | Value | Unit |
|---|---|---|---|
| Bias and Driver Voltages | VCC, VC | 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) | W | 5.0 | mJ |
| Current Sense, Voltage Feedback, Vref and Rt/Ct Inputs | Vin | -0.3 to +5.5 | V |
| Reference Output Voltage | Vref | 4.95 to 5.05 | V |
| Minimum Operating Voltage After Turn-On (VCC) | VCC(min) | 7.0 to 8.2 | V |
| Startup Threshold (VCC) | VTHR | 7.8 to 9.0 | V |
| Oscillator Frequency | f | Up to 500 kHz | Hz |
| Duty Cycle | DC | 0 to 97% | % |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz, with operation up to 500 kHz
- Current Mode Operation
- 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
Applications
The UC3843BVDG is specifically designed for Off-Line and DC-to-DC converter applications. It is ideal for use in power supplies, switch-mode power converters, and other high-performance power management systems where precise control and reliability are crucial.
Q & A
- What is the primary application of the UC3843BVDG?
The UC3843BVDG is primarily used in Off-Line and DC-to-DC converter applications.
- What are the UVLO thresholds for the UC3843BVDG?
The UVLO thresholds for the UC3843BVDG are 8.5 V (on) and 7.6 V (off).
- What is the maximum output current of the UC3843BVDG?
The maximum output current of the UC3843BVDG is 1.0 A.
- What is the oscillator frequency range of the UC3843BVDG?
The oscillator frequency range of the UC3843BVDG is up to 500 kHz, with a guaranteed frequency of 250 kHz.
- Does the UC3843BVDG have protective features?
Yes, the UC3843BVDG includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and programmable output deadtime.
- What type of packages are available for the UC3843BVDG?
The UC3843BVDG is available in 8-pin dual-in-line and surface mount (SO-8) packages, as well as a 14-pin plastic surface mount (SO-14) package.
- Is the UC3843BVDG Pb-Free and Halide-Free?
Yes, the UC3843BVDG is Pb-Free and Halide-Free.
- What is the typical DC voltage gain of the error amplifier in the UC3843BVDG?
The typical DC voltage gain of the error amplifier is 90 dB.
- How is the oscillator frequency programmed in the UC3843BVDG?
The oscillator frequency is programmed by the values chosen for the timing components RT and CT.
- What is the power supply current during startup for the UC3843BVDG?
The power supply current during startup is typically 0.3 to 0.5 mA.
