Overview
The UC2845ANG4 from Texas Instruments is a high-performance current-mode PWM controller, part of the UCx84xA family. This device is optimized for off-line and DC-DC converter applications, offering a cost-effective solution with minimal external components. It features a low start-up current of less than 0.5mA, trimmed oscillator discharge current, and enhanced load response characteristics. The UC2845ANG4 is designed to control current-mode or switched-mode power supplies efficiently.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Supply Voltage (VCC) | Up to 30 | V |
| Output Current (IOUT) | ±1 | A |
| Output Energy (Capacitive Load) | 5 | µJ |
| Oscillator Frequency (fOSC) | Up to 500 kHz | kHz |
| Operating Temperature Range | -40 to 85 | °C |
| Package Type | PDIP (8-pin), SOIC (8-pin), SOIC (14-pin) | |
| Start-Up Current | < 0.5 mA | mA |
| Reference Output Voltage (Vref) | 4.95 to 5.05 | V |
Key Features
- Optimized for Off-Line and DC-DC Converters
- Low Start-Up Current (< 0.5mA)
- Trimmed Oscillator Discharge Current
- 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 500kHz Operation
Applications
The UC2845ANG4 is specifically designed for off-line and DC-DC converter applications. It is suitable for various power supply designs, including boost, flyback, and forward converter topologies. This controller is ideal for use in high-performance power supplies where precise current-mode control is required.
Q & A
- What is the typical application of the UC2845ANG4?
The UC2845ANG4 is typically used in off-line and DC-DC converter applications, including boost, flyback, and forward converter topologies.
- What is the start-up current of the UC2845ANG4?
The start-up current of the UC2845ANG4 is less than 0.5mA.
- What is the maximum oscillator frequency of the UC2845ANG4?
The maximum oscillator frequency of the UC2845ANG4 is up to 500kHz.
- What are the key protective features of the UC2845ANG4?
The key protective features include undervoltage lockout with hysteresis, cycle-by-cycle current limiting, and double pulse suppression.
- What is the operating temperature range of the UC2845ANG4?
The operating temperature range of the UC2845ANG4 is -40°C to 85°C.
- What types of packages are available for the UC2845ANG4?
The UC2845ANG4 is available in PDIP (8-pin), SOIC (8-pin), and SOIC (14-pin) packages.
- What is the reference output voltage of the UC2845ANG4?
The reference output voltage of the UC2845ANG4 is between 4.95V and 5.05V.
- How does the UC2845ANG4 handle current sensing and limiting?
The UC2845ANG4 uses a current sense comparator and PWM latch to control the peak inductor current on a cycle-by-cycle basis, ensuring precise current limiting.
- What is the maximum output current of the UC2845ANG4?
The maximum output current of the UC2845ANG4 is ±1A.
- What is the purpose of the undervoltage lockout (UVLO) feature in the UC2845ANG4?
The UVLO feature ensures that the device operates only within a safe voltage range, preventing damage from low voltage conditions.
