Overview
The UC3842BDG 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 ideal for driving a power MOSFET.
Key Specifications
| Parameter | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | VCC | - | - | 30 | V |
| Output Current | IO | - | - | ±1 | A |
| Reference Output Voltage | VREF | 4.90 | 5.00 | 5.10 | V |
| Oscillation Frequency | f | 47 | 52 | 57 | kHz |
| Current Sense Input Voltage Gain | AV | 2.85 | 3.00 | 3.15 | V/V |
| Maximum Current Sense Input Threshold | Vth | 0.9 | 1.0 | 1.1 | V |
| Output Voltage Low State (ISink = 20 mA) | VOL | - | - | 0.4 | V |
| Output Voltage High State (ISource = 20 mA) | VOH | 13 | 13.5 | - | V |
| Startup Threshold (VCC) | VTH(ST) | 16.0 | - | 17.5 | V |
| Minimum Operating Voltage (After Turn On) | VOPR(MIN) | 8.5 | 10.0 | 11.5 | V |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz (programmable 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 Device
Applications
The UC3842BDG is designed for off-line and DC-DC converter applications. It is particularly suited for:
- Switch Mode Power Supplies (SMPS)
- DC-DC Converters
- High-Efficiency Power Conversion Systems
- Industrial Power Supplies
- Consumer Electronics Power Management
Q & A
- What is the primary function of the UC3842BDG?
The UC3842BDG is a high-performance, fixed-frequency current mode controller designed for off-line and DC-DC converter applications.
- What is the typical oscillator frequency of the UC3842BDG?
The oscillator frequency is typically 52 kHz, but it can be programmed up to 500 kHz.
- What are the undervoltage lockout (UVLO) thresholds for the UC3842BDG?
The UVLO thresholds are 16 V (on) and 10 V (off).
- What is the maximum output current of the UC3842BDG?
The maximum output current is ±1 A.
- What is the reference output voltage of the UC3842BDG?
The reference output voltage is typically 5.00 V.
- How is the oscillator frequency programmed in the UC3842BDG?
The oscillator frequency is programmed by the values chosen for the timing components RT and CT.
- What protective features are included in the UC3842BDG?
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.
- What are the package options for the UC3842BDG?
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.
- Is the UC3842BDG suitable for high-temperature applications?
The device can operate up to +105°C for certain versions, making it suitable for high-temperature applications.
- Is the UC3842BDG a Pb-Free and Halide-Free device?
Yes, the UC3842BDG is a Pb-Free and Halide-Free device.
