Overview
The UC3845D8 is a current-mode PWM (Pulse Width Modulation) controller produced by Texas Instruments. This integrated circuit is part of the UCx84x series and is designed to implement off-line or DC-to-DC fixed-frequency current-mode control schemes with a minimal number of external components. It is optimized for use in various power management applications, including off-line and DC-to-DC converters.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Control Method | Peak Current Mode | |
| Duty Cycle (Max) | 50% | |
| Frequency (Max) | 500 kHz | |
| Frequency (Min) | 26 kHz | |
| Gate Drive (Typ) | 1 A | |
| Operating Temperature Range | 0 to 70 °C | |
| Package Type | SOIC (8-pin) | |
| UVLO Thresholds On/Off | 8.4/7.6 V | |
| Vin (Max) | 400 V | |
| Vin (Min) | 8.4 V | |
| Topology | Boost, Buck, Buck-Boost, Flyback, Forward | |
| RoHS Compliance | Yes |
Key Features
- Optimized for off-line and DC-to-DC converters
- Low start-up current (< 1mA)
- 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
- Error amplifier with low output resistance
Applications
The UC3845D8 is suitable for a variety of power management applications, including:
- Off-line power supplies
- DC-to-DC converters
- Boost, Buck, Buck-Boost, Flyback, and Forward converters
- High-frequency switching power supplies
- Power factor correction (PFC) circuits
Q & A
- What is the operating temperature range of the UC3845D8?
The operating temperature range is from 0°C to 70°C.
- What is the maximum switching frequency of the UC3845D8?
The maximum switching frequency is 500 kHz.
- What are the UVLO thresholds for the UC3845D8?
The UVLO thresholds are 8.4V for turn-on and 7.6V for turn-off.
- What is the typical gate drive current of the UC3845D8?
The typical gate drive current is 1 A.
- Is the UC3845D8 RoHS compliant?
Yes, the UC3845D8 is RoHS compliant.
- What are the supported topologies for the UC3845D8?
The supported topologies include Boost, Buck, Buck-Boost, Flyback, and Forward converters.
- What is the package type of the UC3845D8?
The package type is 8-pin SOIC.
- What is the minimum start-up current of the UC3845D8?
The minimum start-up current is less than 1mA.
- Does the UC3845D8 have an internally trimmed bandgap reference?
Yes, it does have an internally trimmed bandgap reference.
- What is the maximum input voltage for the UC3845D8?
The maximum input voltage is 400 V.
