Overview
The UC3845BDG is a high-performance fixed frequency current mode controller produced by Onsemi. 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 ideal for driving a power MOSFET. The device includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering. The UC3845BDG is available in an 8-pin surface mount (SOIC-8) package and is Pb-free and RoHS compliant.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | VCC | - | - | 30 | V |
| Output Current | IO | - | - | ±1 A | A |
| Analog Inputs (Pin 2, 3) | V(ANA) | -0.3 | - | 6.3 | V |
| Error Amp Output Sink Current | ISINK (E.A) | - | - | 10 mA | mA |
| Power Dissipation at TA≤25°C (8SOP) | PD | - | - | 460 mW | mW |
| Storage Temperature Range | TSTG | -65 | - | +150 | °C |
| Oscillator Frequency | fOSC | - | 250 kHz | - | kHz |
| Output Deadtime Adjustable | - | 50% to 70% | - | - | % |
| UVLO Thresholds (On/Off) | - | 8.5 V / 7.6 V | - | - | V |
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 UC3845BDG is specifically designed for off-line and DC-DC converter applications. It is ideal for use in power supply systems, including switch-mode power supplies, DC-DC converters, and other high-performance power management circuits. The device's features make it suitable for a wide range of applications where efficient and reliable power conversion is required.
Q & A
- What is the primary function of the UC3845BDG?
The UC3845BDG is a high-performance fixed frequency current mode controller designed for off-line and DC-DC converter applications.
- What are the UVLO thresholds for the UC3845BDG?
The UVLO thresholds for the UC3845BDG are 8.5 V (on) and 7.6 V (off).
- What is the maximum output current of the UC3845BDG?
The maximum output current of the UC3845BDG is ±1 A.
- What is the oscillator frequency guaranteed at for the UC3845BDG?
The oscillator frequency is guaranteed at 250 kHz.
- What are the package options available for the UC3845BDG?
The UC3845BDG is available in an 8-pin surface mount (SOIC-8) package.
- Does the UC3845BDG have protective features?
Yes, the UC3845BDG 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 power dissipation at TA≤25°C for the 8SOP package?
The power dissipation at TA≤25°C for the 8SOP package is 460 mW.
- Is the UC3845BDG Pb-free and RoHS compliant?
Yes, the UC3845BDG is Pb-free and RoHS compliant.
- What is the storage temperature range for the UC3845BDG?
The storage temperature range for the UC3845BDG is -65°C to +150°C.
- Can the output deadtime be adjusted in the UC3845BDG?
Yes, the output deadtime can be adjusted from 50% to 70%.
