Overview
The UC3842AD8TRG4 is a current-mode PWM controller from Texas Instruments, part of the UCx84x family. This integrated circuit is designed to implement off-line and DC-to-DC fixed-frequency current-mode control schemes with a minimal number of external components. It features a low start-up current of less than 1 mA, automatic feedforward compensation, pulse-by-pulse current limiting, and enhanced load-response characteristics. The device includes an undervoltage lockout (UVLO) with hysteresis, double-pulse suppression, and a high-current totem-pole output stage suitable for driving N-channel MOSFETs.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC (Low impedance source) | - | - | 30 | V |
| IVCC (Self Limiting) | - | - | 30 mA | mA |
| VFB and VISENSE (Analog input voltage) | -0.3 | - | 6.3 | V |
| IOUTPUT (Output drive current) | - | - | ±1 A | A |
| ICOMP (Error amplifier output sink current) | - | - | 10 mA | mA |
| TJ (Junction temperature) | - | - | 150 °C | °C |
| Tstg (Storage temperature) | -65 | - | 150 °C | °C |
| TA (Operating free-air temperature) | 0 | - | 70 °C | °C |
| fOSC (Oscillator frequency) | 100 kHz | - | 500 kHz | kHz |
| VREF (Reference voltage) | 4.9 V | 5 V | 5.1 V | V |
Key Features
- Optimized for off-line and DC-to-DC converters
- Low start-up current (< 1 mA)
- Automatic feedforward compensation
- Pulse-by-pulse current limiting
- Enhanced load-response characteristics
- Undervoltage lockout (UVLO) with hysteresis
- Double-pulse suppression
- High-current totem-pole output stage
- Internally trimmed bandgap reference
- Up to 500-kHz operation
- Error amplifier with low output resistance
Applications
- Switching regulators of any polarity
- Transformer-coupled DC-DC converters
- Off-line power supplies
- DC-DC applications
Q & A
- What is the operating temperature range for the UC3842AD8TRG4?
The UC3842AD8TRG4 operates from 0°C to 70°C.
- What is the maximum output drive current of the UC3842AD8TRG4?
The maximum output drive current is ±1 A.
- What is the reference voltage of the UC3842AD8TRG4?
The reference voltage is between 4.9 V and 5.1 V.
- What is the oscillator frequency range of the UC3842AD8TRG4?
The oscillator frequency range is from 100 kHz to 500 kHz.
- Does the UC3842AD8TRG4 have undervoltage lockout (UVLO) with hysteresis?
Yes, it includes UVLO with hysteresis.
- What is the typical start-up current of the UC3842AD8TRG4?
The typical start-up current is less than 1 mA.
- What type of output stage does the UC3842AD8TRG4 have?
The UC3842AD8TRG4 has a high-current totem-pole output stage.
- Is the UC3842AD8TRG4 suitable for driving N-channel MOSFETs?
Yes, it is suitable for driving N-channel MOSFETs.
- What are the common applications of the UC3842AD8TRG4?
Common applications include switching regulators, transformer-coupled DC-DC converters, off-line power supplies, and DC-DC applications.
- What is the maximum duty cycle of the UC3842AD8TRG4?
The maximum duty cycle can be up to 100% depending on the specific device variant.
