Overview
The UC3844BDG is a high-performance fixed frequency current mode PWM 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 an oscillator, 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, and a latch for single pulse metering. It also allows output deadtimes to be programmed from 50% to 70% using a flip-flop that blanks the output off every other oscillator cycle.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (VCC) | 30 | V |
| Oscillator Frequency | 250 kHz | kHz |
| Output Switching Frequency | Up to 500 kHz | kHz |
| Output Deadtime Adjustable | 50% to 70% | % |
| UVLO Thresholds (On/Off) | 16 V / 10 V | V |
| Output Current | ±1 A | A |
| Package Type | SOIC-14 | |
| Power Dissipation at TA≤25°C (SOIC-14) | 680 mW | mW |
| Storage Temperature Range | -65 to +150 °C | °C |
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 Packages are Available
Applications
The UC3844BDG is designed for off-line and DC-DC converter applications. It is particularly suitable for:
- Off-line converters due to its UVLO thresholds of 16 V (on) and 10 V (off)
- Boost, flyback, and other DC-DC converter topologies
- Power supply systems requiring high efficiency and reliability
- Automotive and industrial power management systems
Q & A
- What is the primary function of the UC3844BDG?
The UC3844BDG is a high-performance fixed frequency current mode PWM controller designed for off-line and DC-DC converter applications.
- What are the UVLO thresholds for the UC3844BDG?
The UVLO thresholds for the UC3844BDG are 16 V (on) and 10 V (off).
- What is the maximum output switching frequency of the UC3844BDG?
The maximum output switching frequency is up to 500 kHz.
- What types of packages are available for the UC3844BDG?
The UC3844BDG is available in 8-pin dual-in-line (DIP), 8-pin surface mount (SOIC-8), and 14-pin surface mount (SOIC-14) packages.
- Does the UC3844BDG have protective features?
- What is the typical oscillator frequency of the UC3844BDG?
The oscillator frequency is guaranteed at 250 kHz.
- Can the output deadtime be adjusted on the UC3844BDG?
- Is the UC3844BDG Pb-free and RoHS compliant?
- What is the maximum supply voltage for the UC3844BDG?
The maximum supply voltage is 30 V.
- What is the storage temperature range for the UC3844BDG?
The storage temperature range is -65 to +150 °C.
