Overview
The UC2844NG, 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 an oscillator, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output stage ideal for driving power MOSFETs.
Key Specifications
| Specification | Value | Unit |
|---|---|---|
| Output Switching Frequency | Up to 500 kHz | |
| Output Current (Source or Sink) | 1.0 A | |
| Output Energy (Capacitive Load per Cycle) | 5.0 μJ | |
| Reference Output Voltage | 4.95 to 5.05 V | V |
| Input Undervoltage Lockout (UVLO) Thresholds | 16 V (on), 10 V (off) | V |
| Operating Junction Temperature | -25 to +85°C | °C |
| Storage Temperature Range | -65 to +150°C | °C |
| Maximum Power Dissipation @ TA = 25°C | 862 mW (D suffix), 100 mW (N suffix) | mW |
| Thermal Resistance Junction-to-Air | 145°C/W (D suffix), 100°C/W (N suffix) | °C/W |
Key Features
- Current Mode Operation up 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
- Input Undervoltage Lockout with Hysteresis
- Low Startup and Operating Current
- Direct Interface with ON Semiconductor SENSEFET Products
- Pb-Free Packages Available
Applications
The UC2844NG is designed for off-line and DC-to-DC converter applications. It is particularly suited for high-performance power supply designs where cost-effectiveness and minimal external components are crucial. The device is ideal for use in:
- Off-line converters
- DC-to-DC converters
- High-power switching regulators
- Power MOSFET drive applications
Q & A
- What is the primary function of the UC2844NG?
The UC2844NG is a high-performance fixed frequency current mode controller designed for off-line and DC-to-DC converter applications.
- What is the maximum output switching frequency of the UC2844NG?
The UC2844NG can operate up to 500 kHz output switching frequency.
- What are the UVLO thresholds for the UC2844NG?
The UVLO thresholds are 16 V (on) and 10 V (off).
- What is the maximum output current of the UC2844NG?
The maximum output current is 1.0 A.
- What is the reference output voltage range of the UC2844NG?
The reference output voltage range is 4.95 to 5.05 V.
- What are the operating temperature ranges for the UC2844NG?
The operating junction temperature range is -25 to +85°C, and the storage temperature range is -65 to +150°C.
- What are the key protective features of the UC2844NG?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering.
- How does the UC2844NG handle output deadtime?
The output deadtime is adjustable from 50% to 70%, and an internal flip-flop blanks the output off every other oscillator cycle.
- What type of packages are available for the UC2844NG?
The device is available in 8-pin dual-in-line plastic package and 14-pin plastic surface mount (SOIC-14) package.
- What is the significance of the separate power and ground pins in the SOIC-14 package?
The separate power and ground pins for the totem pole output stage in the SOIC-14 package help reduce switching transient noise imposed on the control circuitry.
