Overview
The UC3843D8TRG4 is a fixed-frequency current-mode PWM (Pulse Width Modulation) controller produced by Texas Instruments. This component is part of the UCx84x family, which is designed for off-line and DC-DC converter applications. The UC3843D8TRG4 is particularly suited for applications requiring high precision and reliability, with features such as a trimmed oscillator, a temperature-compensated reference, and a high-gain error amplifier.
Key Specifications
| Parameter | Symbol | Min | Max | Unit | |
|---|---|---|---|---|---|
| Supply Voltage | VCC | - | - | 30 | V |
| Output Current | IO | - | - | ±1 | A |
| Analog Input Voltage | V(ANA) | -0.3 | - | 6.3 | V |
| Error Amp Output Sink Current | ISINK (E.A) | - | - | 10 | mA |
| Reference Output Voltage | VREF | 4.9 | 5 | 5.1 | V |
| Oscillation Frequency | fOSC | 47 | 52 | 57 | kHz |
| Maximum Duty Cycle | D(MAX) | 95 | 97 | 100 | % |
| Start-Up Current | IST | - | - | 1 | mA |
| Operating Supply Current | ICC(OPR) | - | - | 17 | mA |
| Operating Temperature Range | TA | 0 | - | 70 | °C |
Key Features
- Low Start-Up Current: The UC3843D8TRG4 has a start-up current of less than 1 mA, making it energy-efficient during initialization.
- Undervoltage Lockout (UVLO): Features UVLO with hysteresis to ensure the device operates within safe voltage ranges. The UC3843 has UVLO thresholds of 7.8V (on) and 7.0V (off).
- Precision Reference: Includes a 5V reference voltage that is trimmed for accuracy and stability.
- High-Gain Error Amplifier: Provides high gain for precise control and feedback in the PWM loop.
- Current Sensing Comparator: Allows for current-limit control and peak current determination.
- Totem-Pole Output Stage: Designed to source or sink high-peak currents, suitable for driving N-channel MOSFETs.
- Operating Frequency: Can operate up to 500 kHz, with a trimmed oscillator for precise duty cycle control.
- Maximum Duty Cycle: The UC3843 can operate within a 95% to 100% duty cycle range.
Applications
- Off-Line Power Supplies: Ideal for use in off-line power supplies due to its robust UVLO and hysteresis features.
- DC-DC Converters: Suitable for DC-DC converter applications requiring high precision and reliability.
- Switch-Mode Power Supplies: Used in various switch-mode power supply designs where current-mode control is necessary.
Q & A
- What is the operating temperature range of the UC3843D8TRG4?
The UC3843D8TRG4 operates from 0°C to 70°C.
- What is the maximum duty cycle of the UC3843D8TRG4?
The maximum duty cycle of the UC3843D8TRG4 is 95% to 100%.
- What is the start-up current of the UC3843D8TRG4?
The start-up current is less than 1 mA.
- What is the reference output voltage of the UC3843D8TRG4?
The reference output voltage is 4.9V to 5.1V.
- What is the purpose of the undervoltage lockout (UVLO) feature?
The UVLO feature ensures the device operates within safe voltage ranges, preventing damage from low voltage conditions.
- What is the typical operating supply current of the UC3843D8TRG4?
The typical operating supply current is 14 mA to 17 mA.
- Can the UC3843D8TRG4 drive N-channel MOSFETs?
Yes, the totem-pole output stage is designed to source or sink high-peak currents, making it suitable for driving N-channel MOSFETs.
- What is the maximum output current of the UC3843D8TRG4?
The maximum output current is ±1 A.
- What is the storage temperature range for the UC3843D8TRG4?
The storage temperature range is -65°C to 150°C.
- How does the oscillator frequency of the UC3843D8TRG4 get determined?
The oscillator frequency is determined by the selection of the timing resistor (RT) and the timing capacitor (CT).
