Overview
The UC3845BD1G is a high-performance fixed frequency current mode controller produced by onsemi. It is part of the UC3844B and UC3845B series, specifically designed for off-line and DC-to-DC converter applications. This integrated circuit offers a cost-effective solution with minimal external components, making it ideal for a variety of power management needs. The UC3845BD1G 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 power MOSFETs.
Key Specifications
| Parameter | Symbol | Value | Unit |
|---|---|---|---|
| Supply Voltage | VCC | 30 | V |
| Output Current | IO | ±1 | A |
| Oscillation Frequency | f | 47-57 | kHz |
| Reference Output Voltage | VREF | 4.90-5.10 | V |
| UVLO Start Threshold | VTH(ST) | 7.8-9.0 | V |
| UVLO Minimum Operating Voltage | VOPR(MIN) | 7.0-8.2 | V |
| Power Dissipation at TA≤25°C (8SOP) | PD | 460 | mW |
| Storage Temperature Range | TSTG | -65 to +150 | °C |
| Package Type | SOIC-8 |
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 UC3845BD1G is designed for off-line and DC-to-DC converter applications. It is particularly suited for use in power supplies, switch-mode power supplies, and other power management systems where high efficiency and reliability are crucial. Its features make it an excellent choice for applications requiring precise frequency control, high current output, and robust protective features.
Q & A
- What is the UC3845BD1G used for?
The UC3845BD1G is used for off-line and DC-to-DC converter applications, providing a cost-effective solution with minimal external components. - What is the typical operating frequency of the UC3845BD1G?
The oscillator frequency is guaranteed at 250 kHz, with the ability to operate up to 500 kHz output switching frequency. - What are the UVLO thresholds for the UC3845BD1G?
The UVLO start threshold is between 7.8V and 9.0V, and the minimum operating voltage after turn-on is between 7.0V and 8.2V. - What type of output does the UC3845BD1G have?
The UC3845BD1G has a high current totem pole output, suitable for driving power MOSFETs. - Does the UC3845BD1G have protective features?
Yes, it includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering. - What is the maximum power dissipation for the UC3845BD1G in an SOIC-8 package?
The maximum power dissipation at TA≤25°C for the SOIC-8 package is 460 mW. - Is the UC3845BD1G Pb-free and RoHS compliant?
Yes, the UC3845BD1G is Pb-free and RoHS compliant. - What is the storage temperature range for the UC3845BD1G?
The storage temperature range is -65°C to +150°C. - What package types are available for the UC3845BD1G?
The UC3845BD1G is available in SOIC-8 and PDIP-8 packages. - Can the output deadtime be adjusted on the UC3845BD1G?
Yes, the output deadtime can be adjusted from 50% to 70%.
