Overview
The UC3842NG4 is a single-ended, 500kHz current-mode PWM (Pulse Width Modulation) controller produced by Texas Instruments. It is part of the UCx84x series, which is optimized for off-line and DC-to-DC converter applications. This integrated circuit is designed to implement fixed-frequency current-mode control schemes with a minimum number of external components. The UC3842NG4 features an internally trimmed bandgap reference, undervoltage lockout with hysteresis, and a high-current totem-pole output stage suitable for driving N-channel MOSFETs.
Key Specifications
| Parameter | Symbol | Value | Unit |
|---|---|---|---|
| Package | - | PDIP (P) | - |
| Pins | - | 8 | - |
| Operating Temperature Range | - | 0°C to 70°C | - |
| Supply Voltage | VCC | 30 | V |
| Output Current | IO | ±1 | A |
| Start-Up Current | IST | < 1 mA | - |
| Operating Frequency | f | Up to 500 kHz | - |
| Maximum Duty Cycle | D(Max) | 95% to 100% | - |
| Undervoltage Lockout Start Threshold | VTH(ST) | 14.5 to 17.5 V | - |
| Minimum Operating Voltage After Turn On | VOPR(MIN) | 8.5 to 11.5 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 with hysteresis
- Double-pulse suppression
- High-current totem-pole output
- 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 converters
Q & A
- What is the operating frequency range of the UC3842NG4?
The UC3842NG4 can operate up to 500 kHz.
- What is the start-up current of the UC3842NG4?
The start-up current is less than 1 mA.
- What is the maximum duty cycle of the UC3842NG4?
The maximum duty cycle is between 95% and 100%.
- What are the undervoltage lockout thresholds for the UC3842NG4?
The start threshold is between 14.5V and 17.5V, and the minimum operating voltage after turn-on is between 8.5V and 11.5V.
- What type of output stage does the UC3842NG4 have?
The UC3842NG4 has a high-current totem-pole output stage suitable for driving N-channel MOSFETs.
- What is the operating temperature range of the UC3842NG4?
The operating temperature range is from 0°C to 70°C.
- What are some common applications for the UC3842NG4?
Common applications include switching regulators, transformer-coupled DC-DC converters, off-line power supplies, and DC-DC converters.
- What is the package type and pin count of the UC3842NG4?
The UC3842NG4 comes in a PDIP (P) package with 8 pins.
- Does the UC3842NG4 have automatic feedforward compensation?
Yes, the UC3842NG4 features automatic feedforward compensation.
- What is the power dissipation at TA≤25°C for the UC3842NG4 in an 8DIP package?
The power dissipation at TA≤25°C for the 8DIP package is 1200 mW.
