Overview
The UC3845BVD1G is a high-performance fixed frequency current mode controller produced by onsemi. It is part of the UC3844B and UC3845B series, which are specifically designed for off-line and DC-DC converter applications. These controllers offer a cost-effective solution with minimal external components, making them ideal for a variety of power management needs.
The device features an oscillator, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output. This configuration is well-suited for driving power MOSFETs and includes protective features such as input and reference undervoltage lockouts, cycle-by-cycle current limiting, and adjustable output deadtimes.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Oscillator Frequency | 250 kHz (typical) | kHz |
| Output Switching Frequency | Up to 500 kHz | kHz |
| Output Deadtime Adjustable | 50% to 70% | % |
| UVLO Thresholds (UC3845B) | 8.5 V (on), 7.6 V (off) | V |
| Maximum Output Current | 1 A | A |
| Maximum Power Supply Voltage | 36 V | V |
| Package Type | SOIC-8 | |
| Operating Temperature Range | -40°C to +105°C | °C |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- 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
- Undervoltage Lockout with Hysteresis
- Low Startup and Operating Current
- Pb-Free and RoHS Compliant Packages
Applications
The UC3845BVD1G is designed for off-line and DC-DC converter applications. It is particularly useful in:
- Power supplies for consumer electronics
- Industrial power systems
- Automotive power management
- Telecommunication equipment
- Other high-performance power conversion applications
Q & A
- What is the typical oscillator frequency of the UC3845BVD1G?
The typical oscillator frequency is 250 kHz.
- What is the maximum output switching frequency of the UC3845BVD1G?
The maximum output switching frequency is up to 500 kHz.
- What are the UVLO thresholds for the UC3845B?
The UVLO thresholds are 8.5 V (on) and 7.6 V (off).
- What is the maximum output current of the UC3845BVD1G?
The maximum output current is 1 A.
- What is the operating temperature range of the UC3845BVD1G?
The operating temperature range is -40°C to +105°C.
- What type of package is the UC3845BVD1G available in?
The UC3845BVD1G is available in an SOIC-8 package.
- Does the UC3845BVD1G have protective features?
- Is the UC3845BVD1G Pb-Free and RoHS compliant?
- What are some common applications of the UC3845BVD1G?
- How does the UC3845BVD1G handle current limiting?
The UC3845BVD1G features latching PWM for cycle-by-cycle current limiting.
