Overview
The UC3843BDG is a high-performance fixed frequency current mode controller produced by onsemi. It is part of the UC3842B and UC3843B series, 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 designers seeking efficient power management solutions.
The device 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. Additionally, it 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
| Parameter | Symbol | Min | Typ | Max | 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 | ||
| Reference Output Voltage | Vref | 4.95 | 5.0 | 5.05 | V |
| Oscillator Frequency | fosc | 250 kHz | kHz | ||
| UVLO Thresholds (On/Off) | UVLO | 8.5 V / 7.6 V | V |
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 Device
Applications
The UC3843BDG is designed for use in off-line and DC-DC converter applications. It is particularly suited for:
- Off-line converters, especially those requiring lower voltage thresholds.
- DC-DC converters where precise duty cycle control and high current output are necessary.
- Power supply systems that require minimal external components and high reliability.
Q & A
- What is the primary function of the UC3843BDG?
The UC3843BDG 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 UC3843BDG?
The UVLO thresholds for the UC3843BDG are 8.5 V (on) and 7.6 V (off).
- What is the maximum output current of the UC3843BDG?
The maximum output current of the UC3843BDG is 1.0 A.
- What is the oscillator frequency guaranteed for the UC3843BDG?
The oscillator frequency is guaranteed at 250 kHz.
- Does the UC3843BDG have protective features?
Yes, it includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and programmable output deadtime.
- What types of packages are available for the UC3843BDG?
The UC3843BDG is available in 8-pin dual-in-line and surface mount (SOIC-8) packages, as well as 14-pin plastic surface mount (SOIC-14) packages.
- Is the UC3843BDG Pb-Free and Halide-Free?
Yes, the UC3843BDG is a Pb-Free and Halide-Free device.
- What is the maximum power supply voltage for the UC3843BDG?
The maximum power supply voltage (VCC, VC) is 30 V.
- What is the reference output voltage of the UC3843BDG?
The reference output voltage (Vref) is typically 5.0 V, with a range of 4.95 V to 5.05 V.
- Does the UC3843BDG support automatic feed forward compensation?
Yes, the UC3843BDG supports automatic feed forward compensation.
