Overview
The UC3843BVD1G is a high-performance fixed frequency current mode controller produced by ON Semiconductor. It is part of the UC3842B and UC3843B series, which are specifically designed for off-line and DC-to-DC converter applications. These controllers offer a cost-effective solution with minimal external components, making them ideal for a variety of power management applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Reference Output Voltage (Vref) | 4.95 | 5.0 | 5.05 | V |
| Line Regulation (VCC = 12 V to 25 V) | -2.0 | - | 20 | mV |
| Load Regulation (IO = 1.0 mA to 20 mA) | -3.0 | - | 25 | mV |
| Temperature Stability | -0.2 | - | - | mV/°C |
| Output Voltage High State (ISource = 20 mA) | - | - | 6.2 | V |
| Output Voltage Low State (ISink = 20 mA) | 0.8 | - | 1.1 | V |
| Output Voltage Rise Time (CL = 1.0 nF, TJ = 25°C) | 50 | - | 150 | ns |
| Output Voltage Fall Time (CL = 1.0 nF, TJ = 25°C) | 50 | - | 150 | ns |
| Startup Threshold (VCC) | 8.5 | - | - | V |
| Minimum Operating Voltage After Turn-On (VCC) | 7.6 | - | - | V |
| Operating Junction Temperature (TJ) | -40 | - | 105 | °C |
| Storage Temperature Range (Tstg) | -65 | - | 150 | °C |
Key Features
- Trimmed Oscillator for Precise Frequency Control: The oscillator frequency is guaranteed at 250 kHz and can be programmed using the timing components RT and CT.
- Current Mode Operation: Supports operation up to 500 kHz.
- Automatic Feed Forward Compensation: Enhances stability and performance.
- Latching PWM for Cycle-By-Cycle Current Limiting: Ensures single pulse metering during any given oscillator cycle.
- Internally Trimmed Reference with Undervoltage Lockout: Provides a stable reference voltage and protects against undervoltage conditions.
- High Current Totem Pole Output: Capable of sourcing or sinking up to 1 A of current.
- Undervoltage Lockout with Hysteresis: Prevents the device from operating below the minimum voltage threshold.
- Low Startup and Operating Current: Minimizes power consumption.
- Pb-Free and Halide-Free: Compliant with environmental regulations.
Applications
The UC3843BVD1G is designed for use in various power management applications, including:
- Off-line converters
- DC-to-DC converters
- Switch-mode power supplies
- High-performance power management systems
Q & A
- What is the primary function of the UC3843BVD1G?
The UC3843BVD1G is a high-performance fixed frequency current mode controller designed for off-line and DC-to-DC converter applications.
- What is the oscillator frequency of the UC3843BVD1G?
The oscillator frequency is guaranteed at 250 kHz and can be programmed using the timing components RT and CT.
- What is the maximum output current of the UC3843BVD1G?
The device can source or sink up to 1 A of current.
- What are the undervoltage lockout thresholds for the UC3843BVD1G?
The startup threshold is 8.5 V, and the minimum operating voltage after turn-on is 7.6 V.
- What is the operating junction temperature range for the UC3843BVD1G?
The operating junction temperature range is from -40°C to 105°C.
- What is the storage temperature range for the UC3843BVD1G?
The storage temperature range is from -65°C to 150°C.
- Is the UC3843BVD1G Pb-Free and Halide-Free?
Yes, the device is Pb-Free and Halide-Free, making it compliant with environmental regulations.
- What types of packages are available for the UC3843BVD1G?
The device is available in 8-pin dual-in-line and surface mount (SOIC-8) packages, as well as a 14-pin plastic surface mount (SOIC-14) package.
- What are some key protective features of the UC3843BVD1G?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and a latch for single pulse metering.
- How does the current sensing comparator work in the UC3843BVD1G?
The current sensing comparator monitors the inductor current converted to a voltage by a sense resistor and compares it to a level derived from the error amplifier output, controlling the peak inductor current on a cycle-by-cycle basis.
