Overview
The UC3844BVDR2G is a high-performance fixed frequency current mode controller produced by onsemi. This integrated circuit is specifically designed for off-line and DC-DC converter applications, offering a cost-effective solution with minimal external components. It features an oscillator, 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. The device includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and adjustable output deadtimes.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Reference Output Voltage | Vref | 4.95 | 5.0 | 5.05 | V |
| Oscillator Frequency | fOSC | - | 250 kHz | - | kHz |
| Oscillator Voltage Swing (Peak-to-Peak) | VOSC | - | 1.6 | - | V |
| Output Voltage High State | VOH | - | 5.0 | 6.2 | V |
| Output Voltage Low State | VOL | 0.8 | - | 1.1 | V |
| Output Current - Sink | ISink | - | 1.0 A | - | A |
| Output Current - Source | ISource | - | 1.0 A | - | A |
| Undervoltage Lockout (VCC) | - | 16 V (on), 10 V (off) | - | - | V |
| Operating Temperature Range | - | -40°C to +105°C | - | - | °C |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Current Mode Operation up to 500 kHz Output Switching Frequency
- Adjustable Output Deadtime from 50% to 70%
- 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 RoHS Compliant
Applications
The UC3844BVDR2G is suitable for various power conversion applications, including off-line and DC-DC converters. It is particularly useful in designs requiring high efficiency, reliability, and minimal external components. Common applications include power supplies, switch-mode power converters, and other high-performance power management systems.
Q & A
- What is the primary function of the UC3844BVDR2G? The UC3844BVDR2G 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 UC3844BVDR2G? The oscillator frequency is typically 250 kHz.
- What are the undervoltage lockout thresholds for the UC3844BVDR2G? The VCC comparator thresholds are 16 V (on) and 10 V (off), and the Vref comparator thresholds are 3.6 V (on) and 3.4 V (off).
- What is the output current capability of the UC3844BVDR2G? The output can source and sink up to 1.0 A.
- Is the UC3844BVDR2G Pb-Free and RoHS Compliant? Yes, the UC3844BVDR2G is Pb-Free and RoHS Compliant.
- What are the common applications of the UC3844BVDR2G? Common applications include off-line and DC-DC converters, power supplies, and other high-performance power management systems.
- How is the output deadtime adjustable in the UC3844BVDR2G? The output deadtime is adjustable from 50% to 70% using the timing components RT and CT.
- What is the operating temperature range of the UC3844BVDR2G? The operating temperature range is -40°C to +105°C.
- Does the UC3844BVDR2G have built-in protective features? Yes, it includes protective features such as input and reference undervoltage lockouts with hysteresis and cycle-by-cycle current limiting.
- Can the UC3844BVDR2G be synchronized with an external clock signal? Yes, it can be frequency-locked to an external system clock by applying a clock signal to the oscillator circuit.
