Overview
The UC3845DR2 is a high-performance, fixed-frequency, current-mode PWM controller produced by ON Semiconductor. It is specifically designed for off-line and DC-to-DC converter applications, offering a cost-effective solution with minimal external components. This controller is tailored for lower voltage applications, making it suitable for a variety of power management needs.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (Vcc/Vdd) | 7.6 V to 30 V | V |
| Output Current | ±1 A | A |
| Switching Frequency | Up to 500 kHz | kHz |
| Maximum Duty Cycle | 48% | % |
| Operating Temperature | 0°C to 70°C | °C |
| Package Type | 14-SOIC | - |
| UVLO Thresholds | 8.5 V (on), 7.6 V (off) | V |
| Power Dissipation at TA≤25°C (14SOIC) | 680 mW | mW |
| Storage Temperature Range | -65°C to +150°C | °C |
Key Features
- Current Mode Operation with high gain error amplifier and current sensing comparator
- Trimmed oscillator for precise duty cycle control and adjustable output deadtime from 50% to 70%
- Automatic feed-forward compensation and latching PWM for cycle-by-cycle current limiting
- Undervoltage lockout (UVLO) with hysteresis and internal blanking pulse for oscillator control
- High current totem pole output stage capable of driving power MOSFETs directly
- Separate power and ground pins for the output stage to reduce switching transient noise
- Step-up and step-up/step-down functionality with boost and flyback topology support
- Isolation capable output configuration
Applications
The UC3845DR2 is suitable for various power management applications, including:
- Off-line and DC-to-DC converters
- Boost and flyback converters
- Step-up and step-up/step-down DC-DC converter applications
- Power supplies requiring high-frequency switching and efficient voltage regulation
Q & A
- What is the primary function of the UC3845DR2?
The UC3845DR2 is a fixed-frequency, current-mode PWM controller designed for off-line and DC-to-DC converter applications.
- What are the UVLO thresholds for the UC3845DR2?
The UVLO thresholds are 8.5 V (on) and 7.6 V (off).
- What is the maximum switching frequency of the UC3845DR2?
The maximum switching frequency is up to 500 kHz.
- What is the maximum duty cycle of the UC3845DR2?
The maximum duty cycle is 48%.
- What type of output stage does the UC3845DR2 have?
The UC3845DR2 has a high current totem pole output stage capable of driving power MOSFETs directly.
- What are the package options for the UC3845DR2?
The UC3845DR2 is available in a 14-SOIC package.
- What is the operating temperature range for the UC3845DR2?
The operating temperature range is from 0°C to 70°C.
- Does the UC3845DR2 support isolation capable output configurations?
- What are the typical applications for the UC3845DR2?
The UC3845DR2 is typically used in off-line and DC-to-DC converters, boost and flyback converters, and other power management applications.
- Is the UC3845DR2 RoHS compliant?
- What is the power dissipation at TA≤25°C for the 14SOIC package?
The power dissipation at TA≤25°C for the 14SOIC package is 680 mW.
