Specifications
| Attribute | Value |
| Package | Bulk,Tube |
| ProductStatus | Active |
| OutputType | Transistor Driver |
| Function | Step-Up, Step-Up/Step-Down |
| OutputConfiguration | Positive, Isolation Capable |
| Topology | Boost, Flyback |
| NumberofOutputs | 1 |
| OutputPhases | 1 |
| Voltage-Supply(Vcc/Vdd) | 7.6V ~ 30V |
| Frequency-Switching | Up to 500kHz |
| DutyCycle(Max) | 48% |
| SynchronousRectifier | No |
| ClockSync | No |
| ControlFeatures | Frequency Control |
| OperatingTemperature | 0°C ~ 70°C (TA) |
| MountingType | Through Hole |
| Package/Case | 8-DIP (0.300, 7.62mm) |
Overview
Description
The UC3845BNG is a high-performance, fixed-frequency current-mode PWM controller used primarily in off-line and DC-to-DC converter applications. It is designed for efficient power management and features an operating frequency up to 500 kHz. Key characteristics include a low start-up current (typical 0.5 mA), which facilitates energy-efficient operations, and a high-output drive capability suitable for MOSFET gate drive. The device also includes built-in protection features such as under-voltage lockout to ensure safe startup procedures and over-current protection to prevent damage from excessive load conditions. Its wide power supply range and robust performance make it suitable for a broad range of converters and power supplies, including those for consumer electronics, computers, and industrial equipment. The UC3845BNG is part of the UC384xB series, which is known for precise duty cycle control, enabling high regulation accuracy. Additionally, it is available in industry-standard pin configurations, making it easy to incorporate into various applications.
Equivalent
The UC3845BNG chip is a current mode PWM controller used in switch-mode power supplies. Equivalent products include:
1. UC3845AN
2. LM3845N
3. MC33025
4. SG3845
5. FAN3845
These alternatives typically offer similar functionalities and can be used in applications requiring current mode PWM control for efficient power supply design. Always verify pin compatibility and electrical specifications before substitution.
1. UC3845AN
2. LM3845N
3. MC33025
4. SG3845
5. FAN3845
These alternatives typically offer similar functionalities and can be used in applications requiring current mode PWM control for efficient power supply design. Always verify pin compatibility and electrical specifications before substitution.
Features
The UC3845BNG is a high-performance current-mode PWM controller designed for off-line and DC-to-DC converter applications. Key features include:
1. High-Speed Operation: The controller operates at a fixed frequency, typically up to 100 kHz, suitable for fast switching applications.
2. Current Mode Control: It provides peak current-mode control, improving response to line and load transients.
3. Low Startup Current: The device has a low startup current, reducing power consumption and enhancing efficiency.
4. Undervoltage Lockout (UVLO): It features UVLO with hysteresis to ensure proper startup conditions and prevent erratic operation when power is insufficient.
5. Precision Reference: A precise 5V reference ensures stable operation and accuracy.
6. Adjustable Duty Cycle: The maximum duty cycle is typically limited to less than 50%, optimizing converter design.
7. Output Drive: It has a totem-pole output able to source or sink high peak currents, which is ideal for driving power MOSFETs.
8. Protection Features: It includes built-in protection such as cycle-by-cycle current limiting and thermal shutdown.
These features make the UC3845BNG suitable for power supply designs requiring efficiency and reliability.
1. High-Speed Operation: The controller operates at a fixed frequency, typically up to 100 kHz, suitable for fast switching applications.
2. Current Mode Control: It provides peak current-mode control, improving response to line and load transients.
3. Low Startup Current: The device has a low startup current, reducing power consumption and enhancing efficiency.
4. Undervoltage Lockout (UVLO): It features UVLO with hysteresis to ensure proper startup conditions and prevent erratic operation when power is insufficient.
5. Precision Reference: A precise 5V reference ensures stable operation and accuracy.
6. Adjustable Duty Cycle: The maximum duty cycle is typically limited to less than 50%, optimizing converter design.
7. Output Drive: It has a totem-pole output able to source or sink high peak currents, which is ideal for driving power MOSFETs.
8. Protection Features: It includes built-in protection such as cycle-by-cycle current limiting and thermal shutdown.
These features make the UC3845BNG suitable for power supply designs requiring efficiency and reliability.
Pinout
The UC3845BNG is a high-performance current-mode PWM controller. It typically comes in an 8-pin package. Here is a concise description of its pin count and functions:
1. Pin 1 (Compensation/Comp): This pin is used for compensation of the control loop. It is connected to the output of the error amplifier and is used to stabilize the feedback loop.
2. Pin 2 (Voltage Feedback/VFB): This pin receives the voltage feedback from the output and feeds it into the error amplifier to regulate the output voltage.
3. Pin 3 (Current Sense/CS): This pin is for current sensing. It monitors the current through the power switch and is used to implement current-mode control.
4. Pin 4 (RT/CT): This pin sets the oscillator frequency. It connects to an external resistor-capacitor pair that determines the switching frequency.
5. Pin 5 (Ground/GND): This is the ground reference point for the IC.
6. Pin 6 (Output/Out): This pin provides the PWM output to drive the gate of a power switch, such as a MOSFET.
7. Pin 7 (VCC): This is the supply voltage pin for the IC.
8. Pin 8 (Vref): This pin provides a reference voltage output for precise control, typically used for internal biasing.
This configuration allows the UC3845BNG to efficiently control power converters.
1. Pin 1 (Compensation/Comp): This pin is used for compensation of the control loop. It is connected to the output of the error amplifier and is used to stabilize the feedback loop.
2. Pin 2 (Voltage Feedback/VFB): This pin receives the voltage feedback from the output and feeds it into the error amplifier to regulate the output voltage.
3. Pin 3 (Current Sense/CS): This pin is for current sensing. It monitors the current through the power switch and is used to implement current-mode control.
4. Pin 4 (RT/CT): This pin sets the oscillator frequency. It connects to an external resistor-capacitor pair that determines the switching frequency.
5. Pin 5 (Ground/GND): This is the ground reference point for the IC.
6. Pin 6 (Output/Out): This pin provides the PWM output to drive the gate of a power switch, such as a MOSFET.
7. Pin 7 (VCC): This is the supply voltage pin for the IC.
8. Pin 8 (Vref): This pin provides a reference voltage output for precise control, typically used for internal biasing.
This configuration allows the UC3845BNG to efficiently control power converters.
Manufacturer
The UC3845BNG is manufactured by ON Semiconductor. ON Semiconductor, now known as onsemi, is a leading global supplier of semiconductor-based solutions. The company provides a comprehensive portfolio of energy-efficient power and signal management, logic, discrete, and custom devices. onsemi’s products are used in various applications across multiple industries, including automotive, industrial, cloud, and IoT sectors. The company focuses on providing innovative solutions that enhance the performance and efficiency of electronic systems.
Application
The UC3845BNG is a high-performance current-mode PWM controller primarily used in power supply applications. Its key application areas include:
1. DC-DC Converters: Utilized for efficient voltage conversion and regulation in switching power supplies.
2. AC-DC Power Supplies: Employed in offline converters for household electronics and industrial equipment.
3. Battery Chargers: Used to control charging algorithms for various battery types, ensuring efficient and safe charging.
4. LED Drivers: Provides precise current control for LED lighting applications.
5. Motor Control: Suitable for controlling motor speed and torque in applications requiring precise power management.
Its ability to offer high-speed operation and precise control makes it suitable for these and other power management applications.
1. DC-DC Converters: Utilized for efficient voltage conversion and regulation in switching power supplies.
2. AC-DC Power Supplies: Employed in offline converters for household electronics and industrial equipment.
3. Battery Chargers: Used to control charging algorithms for various battery types, ensuring efficient and safe charging.
4. LED Drivers: Provides precise current control for LED lighting applications.
5. Motor Control: Suitable for controlling motor speed and torque in applications requiring precise power management.
Its ability to offer high-speed operation and precise control makes it suitable for these and other power management applications.
Package
The UC3845BNG is typically available in an 8-pin Dual Inline Package (DIP-8) or a Small Outline Integrated Circuit (SOIC-8) package. These package types are used for surface mounting or through-hole applications, providing convenient integration for power supply control in electronic circuits.