Overview
The UC3843BDR2 is a high-performance fixed frequency current mode controller produced by onsemi. It is specifically designed for off-line and DC-to-DC converter applications, offering a cost-effective solution with minimal external components. This integrated circuit features a trimmed oscillator for precise duty cycle control, 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, programmable output deadtime, and a latch for single pulse metering. It is available in various package options, including 8-pin dual-in-line and surface mount (SO-8) as well as 14-pin plastic surface mount (SO-14) with separate power and ground pins for the totem pole output stage.
Key Specifications
| Rating | Symbol | Value | Unit |
|---|---|---|---|
| Bias and Driver Voltages | VCC, VC | 30 | V |
| Total Power Supply and Zener Current | ICC + IZ | 30 | mA |
| Output Current, Source or Sink | IO | 1.0 | A |
| Output Energy (Capacitive Load per Cycle) | W | 5.0 | mJ |
| Reference Output Voltage | Vref | 4.95 - 5.05 | V |
| Oscillator Frequency | fOSC | Up to 500 kHz | kHz |
| UVLO Thresholds | VUVLO(on), VUVLO(off) | 8.5 V, 7.6 V | V |
| Maximum Power Dissipation @ TA = 25°C | Pd | Dependent on package | mW |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz, with operation up to 500 kHz
- Current Mode Operation
- 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 Halide-Free Packages Available
Applications
The UC3843BDR2 is designed for various power conversion applications, including:
- Off-Line Converters
- DC-to-DC Converters
- Switch Mode Power Supplies
- High-Efficiency Power Conversion Systems
Q & A
- What is the primary function of the UC3843BDR2?
The UC3843BDR2 is a high-performance fixed frequency current mode controller designed for off-line and DC-to-DC converter applications.
- What are the UVLO thresholds for the UC3843BDR2?
The UVLO thresholds are 8.5 V (on) and 7.6 V (off).
- What is the maximum oscillator frequency of the UC3843BDR2?
The oscillator frequency can be programmed up to 500 kHz.
- What type of output does the UC3843BDR2 have?
The UC3843BDR2 features a high current totem pole output.
- What protective features are included in the UC3843BDR2?
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.
- In what packages is the UC3843BDR2 available?
The device is available in 8-pin dual-in-line and surface mount (SO-8) as well as 14-pin plastic surface mount (SO-14) packages.
- What is the reference output voltage of the UC3843BDR2?
The reference output voltage is typically 5.0 V, with a range of 4.95 V to 5.05 V.
- Is the UC3843BDR2 Pb-Free and Halide-Free?
- What is the maximum output current of the UC3843BDR2?
The maximum output current is 1.0 A.
- What is the typical DC voltage gain of the error amplifier in the UC3843BDR2?
The typical DC voltage gain of the error amplifier is 90 dB.
