Overview
The UC3845BVNG is a high-performance fixed frequency current mode controller produced by onsemi. This integrated circuit is specifically designed for off-line and DC-DC converter applications, offering a cost-effective solution with minimal external components. It features an oscillator, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output, making it ideal for driving power MOSFETs. The device is available in various package options, including 8-pin dual-in-line and surface mount (SO-8) as well as 14-pin surface mount (SO-14) with separate power and ground pins for the totem pole output stage.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Oscillator Frequency | - | 250 kHz | - | kHz |
| Output Switching Frequency | - | - | 500 kHz | kHz |
| UVLO Turn-On Threshold | 8.5 V | - | - | V |
| UVLO Turn-Off Threshold | 7.6 V | - | - | V |
| Minimum Operating Supply Voltage | 10 V | - | - | V |
| Maximum Operating Supply Voltage | - | - | 25 V | V |
| Output Current - Sink | 2.0 mA | - | 12 mA | mA |
| Output Current - Source | 2.0 mA | - | 12 mA | mA |
| Output Voltage Swing High State | 5.0 V | - | 6.2 V | V |
| Output Voltage Swing Low State | 0.8 V | - | 1.1 V | V |
| Maximum Duty Cycle | - | - | 50% to 70% | % |
| Minimum Operating Temperature | -40°C | - | - | °C |
| Maximum Operating Temperature | - | - | 105°C | °C |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz
- Current Mode Operation to 500 kHz Output Switching Frequency
- Output Deadtime Adjustable from 50% to 70%
- Automatic Feed Forward Compensation
- Latching PWM for Cycle-By-Cycle Current Limiting
- Internally Trimmed Reference with Undervoltage Lockout
- High Current Totem Pole Output
- Undervoltage Lockout with Hysteresis
- Low Startup and Operating Current
- Pb-Free Packages are Available
Applications
The UC3845BVNG is designed for off-line and DC-DC converter applications. It is particularly useful in:
- Off-line power supplies
- DC-DC converters
- Switch-mode power supplies
- High-efficiency power conversion systems
Q & A
- What is the primary function of the UC3845BVNG?
The UC3845BVNG is a high-performance fixed frequency current mode controller designed for off-line and DC-DC converter applications.
- What is the oscillator frequency of the UC3845BVNG?
The oscillator frequency is guaranteed at 250 kHz.
- What are the UVLO thresholds for the UC3845BVNG?
The UVLO turn-on threshold is 8.5 V, and the turn-off threshold is 7.6 V.
- What is the maximum output switching frequency of the UC3845BVNG?
The maximum output switching frequency is 500 kHz.
- What protective features does the UC3845BVNG include?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering.
- What package options are available for the UC3845BVNG?
The device is available in 8-pin dual-in-line and surface mount (SO-8) as well as 14-pin surface mount (SO-14) packages.
- Is the UC3845BVNG Pb-Free and RoHS compliant?
- What is the typical quiescent current of the UC3845BVNG?
The typical quiescent current is low, but specific values depend on the operating conditions.
- Can the output deadtime be adjusted on the UC3845BVNG?
- What is the maximum operating temperature of the UC3845BVNG?
