Overview
The UC2845BDR2G is a high-performance fixed frequency current mode controller produced by ON Semiconductor. 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 suitable for driving a power MOSFET. The device includes protective features such as input and reference undervoltage lockouts, cycle-by-cycle current limiting, and adjustable output deadtimes.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Oscillator Frequency | fOSC | 48 | 250 | 52 | kHz |
| Output Current (Source or Sink) | IO | -1.0 | - | 1.0 | A |
| Output Voltage Swing High State | VOH | 5.0 | - | 6.2 | V |
| Output Voltage Swing Low State | VOL | 0.8 | - | 1.1 | V |
| Undervoltage Lockout Thresholds (On/Off) | Vth | 8.5/7.6 | - | - | V |
| Minimum Operating Voltage After Turn-On | VCC(min) | 7.0 | - | 7.6 | V |
| Unity Gain Bandwidth | BW | 0.7 | 1.0 | - | MHz |
| Power Supply Rejection Ratio | PSRR | 60 | 70 | - | dB |
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
Applications
The UC2845BDR2G is designed for use in off-line and DC-DC converter applications. It is particularly suited for:
- Switch-mode power supplies
- DC-DC converters
- Boost, flyback, and forward converters
- High-efficiency power conversion systems
Q & A
- What is the primary function of the UC2845BDR2G?
The UC2845BDR2G 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 UC2845BDR2G?
The oscillator frequency is guaranteed at 250 kHz.
- What are the undervoltage lockout thresholds for the UC2845BDR2G?
The undervoltage lockout thresholds are 8.5V (on) and 7.6V (off).
- What is the minimum operating voltage after turn-on for the UC2845BDR2G?
The minimum operating voltage after turn-on is 7.0V to 7.6V.
- Does the UC2845BDR2G support adjustable output deadtimes?
Yes, the output deadtimes are adjustable from 50% to 70%.
- What type of output stage does the UC2845BDR2G have?
The UC2845BDR2G has a high-current totem pole output stage.
- Is the UC2845BDR2G Pb-Free and RoHS Compliant?
Yes, the UC2845BDR2G is Pb-Free and RoHS Compliant.
- What are the typical package options for the UC2845BDR2G?
The device is available in 8-pin dual-in-line and surface mount (SOIC-8) packages, as well as a 14-pin plastic surface mount (SOIC-14) package.
- What is the unity gain bandwidth of the UC2845BDR2G?
The unity gain bandwidth is 0.7 to 1.0 MHz.
- What is the power supply rejection ratio (PSRR) of the UC2845BDR2G?
The power supply rejection ratio is 60 to 70 dB.
