Overview
The UC3842BVDR2 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 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 suitable for driving power MOSFETs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Reference Output Voltage (I_O = 1.0 mA, T_J = 25°C) | 4.95 | 5.0 | 5.05 | V |
| Line Regulation (V_CC = 12 V to 25 V) | -2.0 | - | 20 | mV |
| Load Regulation (I_O = 1.0 mA to 20 mA) | -3.0 | - | 25 | mV |
| Temperature Stability | -0.2 | - | - | mV/°C |
| Output Voltage Low State (I_Sink = 20 mA) | 0.8 | - | 1.1 | V |
| Output Voltage High State (I_Source = 20 mA) | 5.0 | - | 6.2 | V |
| Output Voltage Rise Time (C_L = 1.0 nF, T_J = 25°C) | 50 | - | 150 | ns |
| Output Voltage Fall Time (C_L = 1.0 nF, T_J = 25°C) | 50 | - | 150 | ns |
| Maximum Power Dissipation @ T_A = 25°C | - | - | 700 | mW |
| Thermal Resistance, Junction-to-Air | - | - | 100 | °C/W |
Key Features
- Trimmed Oscillator: For precise duty cycle control.
- Temperature Compensated Reference: Ensures stable operation over a wide temperature range.
- High Gain Error Amplifier: With a typical DC voltage gain of 90 dB and a unity gain bandwidth of 1.0 MHz.
- Current Sensing Comparator: For cycle-by-cycle current limiting and peak inductor current control.
- High Current Totem Pole Output: Suitable for driving power MOSFETs.
- Protective Features: Including input and reference undervoltage lockouts with hysteresis, programmable output deadtime, and a latch for single pulse metering.
- Package Options: Available in 8-pin dual-in-line, surface mount (SOIC-8), and 14-pin surface mount (SOIC-14) packages.
Applications
- Off-Line Converters: Suitable for applications requiring high efficiency and reliability in off-line power supplies.
- DC-DC Converters: Ideal for DC-DC converter applications where precise control and high performance are necessary.
- Power Supplies: Used in various power supply designs where current mode control is preferred.
- Industrial Power Systems: Applicable in industrial power systems requiring robust and efficient power management.
Q & A
- What is the primary function of the UC3842BVDR2?
The UC3842BVDR2 is a high-performance, fixed-frequency current mode controller designed for off-line and DC-DC converter applications.
- What are the key features of the UC3842BVDR2?
Key features include a trimmed oscillator, temperature-compensated reference, high-gain error amplifier, current sensing comparator, and high-current totem pole output.
- What are the protective features of the UC3842BVDR2?
Protective features include input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and a latch for single pulse metering.
- What are the typical operating conditions for the UC3842BVDR2?
The device operates with a VCC range of 12 V to 25 V and an ambient temperature range that varies by package type (e.g., -40°C to +105°C for the SOIC-14 package).
- How is the oscillator frequency programmed in the UC3842BVDR2?
The oscillator frequency is programmed by the values chosen for the timing components RT and CT.
- What is the maximum output current of the UC3842BVDR2?
The maximum output current is 1.0 A.
- What are the package options available for the UC3842BVDR2?
The device is available in 8-pin dual-in-line, surface mount (SOIC-8), and 14-pin surface mount (SOIC-14) packages.
- How does the current sensing comparator work in the UC3842BVDR2?
The current sensing comparator monitors the inductor current and compares it to a level derived from the error amplifier output, controlling the peak inductor current on a cycle-by-cycle basis.
- What is the purpose of the error amplifier in the UC3842BVDR2?
The error amplifier provides a high-gain DC voltage gain and is used for external loop compensation to regulate the output voltage.
- Can the UC3842BVDR2 be used in industrial power systems?
Yes, the UC3842BVDR2 is suitable for use in industrial power systems where robust and efficient power management is required.
