Overview
The UC3845AM is a current-mode PWM (Pulse Width Modulation) controller integrated circuit produced by Microsemi Corporation. This device is specifically designed for off-line and DC-DC converter applications, requiring minimal external components. It features a trimmed oscillator for precise duty cycle control, a temperature-compensated reference, a high-gain error amplifier, and a current sensing comparator. The UC3845AM is suitable for various topologies including buck, boost, flyback, and forward converters.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Manufacturer | Microsemi Corporation | |
| Package | 8-DIP (0.300", 7.62mm) | |
| Product Status | Obsolete | |
| Output Type | Transistor Driver | |
| Function | Step-Up, Step-Down | |
| Output Configuration | Positive | |
| Topology | Buck, Boost, Flyback, Forward | |
| Number of Outputs | 1 | |
| Output Phases | 1 | |
| Voltage - Supply (Vcc/Vdd) | 7.6V ~ 30V | V |
| Frequency - Switching | Up to 500kHz | kHz |
| Duty Cycle (Max) | 48% | % |
| Synchronous Rectifier | No | |
| Operating Temperature | 0°C ~ 70°C (TA) | °C |
| Mounting Type | Through Hole | |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) |
Key Features
- Trimmed oscillator for precise duty cycle control
- Temperature-compensated reference
- High-gain error amplifier
- Current sensing comparator
- High current totem-pole output for driving a Power MOSFET
- Under Voltage Lockout (UVLO) with hysteresis
- Maximum duty cycle clamp
- Low start-up current
- Operating frequency up to 500 kHz
Applications
The UC3845AM is designed for use in various power management applications, including:
- Off-line power supplies
- DC-DC converters
- Buck, boost, flyback, and forward converters
- High-efficiency power supplies requiring precise control over the duty cycle
Q & A
- What is the UC3845AM used for?
The UC3845AM is used as a current-mode PWM controller for off-line and DC-DC converter applications.
- What are the key features of the UC3845AM?
Key features include a trimmed oscillator, temperature-compensated reference, high-gain error amplifier, current sensing comparator, and high current totem-pole output.
- What is the operating voltage range of the UC3845AM?
The operating voltage range is 7.6V to 30V.
- What is the maximum switching frequency of the UC3845AM?
The maximum switching frequency is up to 500 kHz.
- Does the UC3845AM support synchronous rectification?
No, the UC3845AM does not support synchronous rectification.
- What is the maximum duty cycle of the UC3845AM?
The maximum duty cycle is 48%.
- What is the operating temperature range of the UC3845AM?
The operating temperature range is 0°C to 70°C.
- What package types are available for the UC3845AM?
The UC3845AM is available in an 8-DIP package.
- Is the UC3845AM still in production?
No, the UC3845AM is listed as obsolete.
- What are some common applications for the UC3845AM?
Common applications include off-line power supplies, DC-DC converters, and various topologies such as buck, boost, flyback, and forward converters.
