Overview
The UC1845AMDREPG4 is a current-mode PWM (Pulse Width Modulation) controller from Texas Instruments, part of the UC1842A/3A/4A/5A family. This IC is designed to control current-mode switched-mode power supplies and offers several improved features over its predecessors. It is pin-for-pin compatible with the UC3842/3/4/5 family but includes enhancements such as lower start-up current, improved oscillator discharge, and enhanced load response characteristics.
Key Specifications
| Parameter | Min | Max | Units | |
|---|---|---|---|---|
| VCC Voltage | - | - | 30 | V |
| Output Current, IO | - | - | ±1 A | A |
| Output Voltage (VREF) | 4.95 | 5 | 5.05 | V |
| Line Regulation Voltage | 6 | 20 | - | mV |
| Load Regulation Voltage | 6 | 25 | - | mV |
| Temperature Stability | 0.2 | 0.4 | - | mV/°C |
| Maximum Duty Cycle | 47% | 48% | 50% | % |
| Start-up Current | 0.3 | 0.5 | - | mA |
| Operating Supply Current | 11 | 17 | - | mA |
| UVLO Start Threshold | 7.8 | 8.4 | 9 | V |
| UVLO Minimum Operation Voltage After Turn On | 7 | 7.6 | 8.2 | V |
Key Features
- Enhanced Load Response Characteristics: Improved performance in handling load changes.
- Under-Voltage Lockout With Hysteresis: Ensures the IC operates within safe voltage ranges.
- Double Pulse Suppression: Prevents unwanted double pulses.
- High Current Totem Pole Output: Supports high current output requirements.
- Internally Trimmed Bandgap Reference: Provides a stable reference voltage.
- 500 kHz Operation: Supports high-frequency switching applications.
- Low RO Error Amp: Minimizes error in the error amplifier stage.
- Low Start-up Current: Guaranteed to be less than 0.5 mA.
- Oscillator Discharge Trimmed to 8.3 mA: Precise control over oscillator discharge.
Applications
- Switched-Mode Power Supplies: Ideal for current-mode control in SMPS designs.
- DC-DC Converters: Suitable for use in DC-DC conversion applications requiring high efficiency and reliability.
- Power Factor Correction (PFC) Circuits: Can be used in PFC circuits to improve power factor and efficiency.
- High-Frequency Switching Applications: Supports applications requiring high-frequency switching, such as in telecommunications and industrial power supplies.
Q & A
- What is the maximum operating temperature range for the UC1845AMDREPG4?
The UC1845AMDREPG4 operates over a temperature range of -55°C to 125°C.
- What is the typical start-up current for this IC?
The start-up current is guaranteed to be less than 0.5 mA.
- What is the maximum duty cycle for the UC1845A?
The maximum duty cycle for the UC1845A is 50%.
- What is the UVLO start threshold for the UC1845A?
The UVLO start threshold for the UC1845A is between 7.8 V and 9 V.
- What is the typical operating supply current for this IC?
The typical operating supply current is 17 mA.
- Does the UC1845AMDREPG4 support high-frequency operation?
Yes, it supports operation up to 500 kHz.
- What is the output voltage range of the internal reference?
The output voltage range of the internal reference is between 4.95 V and 5.05 V.
- Is the UC1845AMDREPG4 RoHS compliant?
Yes, the UC1845AMDREPG4 is RoHS compliant.
- What is the package type for the UC1845AMDREPG4?
The package type is SOIC (Small Outline Integrated Circuit).
- What are the key applications for the UC1845AMDREPG4?
Key applications include switched-mode power supplies, DC-DC converters, and power factor correction circuits.
