Overview
The UC2844BDR2, produced by onsemi, is a high-performance fixed frequency current mode controller. 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 an oscillator, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output, making it ideal for driving power MOSFETs. The device includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering. It also allows for adjustable output deadtimes from 50% to 70% through an internal flip-flop mechanism.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Bias and Driver Voltages | VCC, VC | - | - | 36 | 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 |
| Current Sense and Voltage Feedback Inputs | Vin | -0.3 | - | 5.5 | V |
| Error Amp Output Sink Current | IO | - | - | 10 | mA |
| Reference Output Voltage | Vref | 4.95 | 5.0 | 5.05 | V |
| Oscillator Frequency | - | - | 250 kHz | - | kHz |
| Output Voltage Swing High State | VOH | - | - | 6.2 | V |
| Output Voltage Swing Low State | VOL | - | - | 0.8 | V |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz
- Current Mode Operation to 500 kHz Output Switching Frequency
- Output Deadtime Adjustable 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
- AEC-Q100 Qualified and PPAP Capable for Automotive and Other Applications
Applications
The UC2844BDR2 is designed for off-line and DC-DC converter applications. It is particularly suited for power supply designs that require high efficiency, reliability, and minimal external components. These include but are not limited to:
- Switch Mode Power Supplies (SMPS)
- DC-DC Converters
- Power Factor Correction (PFC) Circuits
- Automotive Power Systems
- Industrial Power Supplies
Q & A
- What is the primary function of the UC2844BDR2?
The UC2844BDR2 is a high-performance fixed frequency current mode controller designed for off-line and DC-DC converter applications. - What is the oscillator frequency of the UC2844BDR2?
The oscillator frequency is guaranteed at 250 kHz. - What are the key protective features of the UC2844BDR2?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering. - How is the output deadtime adjusted in the UC2844BDR2?
The output deadtime can be adjusted from 50% to 70% using an internal flip-flop mechanism. - What is the maximum output current of the UC2844BDR2?
The maximum output current is 1.0 A. - Is the UC2844BDR2 Pb-Free and RoHS compliant?
Yes, the UC2844BDR2 is Pb-Free and RoHS compliant. - What are the typical applications of the UC2844BDR2?
The typical applications include switch mode power supplies, DC-DC converters, power factor correction circuits, and automotive power systems. - What is the reference output voltage of the UC2844BDR2?
The reference output voltage is 5.0 V. - How is the oscillator frequency programmed in the UC2844BDR2?
The oscillator frequency is programmed by the values selected for the timing components RT and CT. - Does the UC2844BDR2 have any automotive qualifications?
Yes, the UC2844BDR2 is AEC-Q100 qualified and PPAP capable for automotive and other applications.
