Overview
The UC3844BVD1 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 ideal for driving a power MOSFET. The device includes protective features such as input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering. The UC3844BVD1 is available in an 8-pin SOIC package and is RoHS compliant.
Key Specifications
| Characteristic | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Reference Output Voltage (IO = 1.0 mA, TJ = 25°C) | Vref | 4.95 | 5.0 | 5.05 | V |
| Oscillator Frequency | fOSC | - | 250 kHz | - | kHz |
| Output Current, Source or Sink | IO | - | - | 1.0 | A |
| Output Voltage Swing High State (RL = 15 k to ground, VFB = 2.3 V) | VOH | 5.0 | - | 6.2 | V |
| Output Voltage Swing Low State (RL = 15 k to Vref, VFB = 2.7 V) | VOL | 0.8 | - | 1.1 | V |
| Current Sense Input Voltage Gain | AV | 2.85 | 3.0 | 3.15 | V/V |
| Maximum Current Sense Input Threshold | Vth | 0.9 | 1.0 | 1.1 | V |
| Power Supply Voltage | VCC | - | - | 36 | V |
| Total Power Supply and Zener Current | ICC + IZ | - | - | 30 | mA |
Key Features
- Trimmed Oscillator for Precise Frequency Control
- Oscillator Frequency Guaranteed at 250 kHz
- Current Mode Operation up 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 and RoHS Compliant
- AEC-Q100 Qualified and PPAP Capable for Automotive and Other Applications
Applications
The UC3844BVD1 is designed for use in off-line and DC-DC converter applications. It is particularly suited for:
- Switch-mode power supplies
- DC-DC converters
- Off-line power supplies
- Automotive power systems (with NCV prefix)
- Other high-performance power management systems requiring precise current mode control
Q & A
- What is the primary function of the UC3844BVD1?
The UC3844BVD1 is a high-performance, fixed-frequency current mode controller designed for off-line and DC-DC converter applications.
- What is the typical oscillator frequency of the UC3844BVD1?
The oscillator frequency is guaranteed at 250 kHz.
- What are the key protective features of the UC3844BVD1?
The device includes input and reference undervoltage lockouts with hysteresis, cycle-by-cycle current limiting, and a latch for single pulse metering.
- What is the maximum output current of the UC3844BVD1?
The maximum output current is 1.0 A.
- Is the UC3844BVD1 RoHS compliant?
Yes, the UC3844BVD1 is Pb-Free and RoHS compliant.
- What are the typical applications of the UC3844BVD1?
It is used in switch-mode power supplies, DC-DC converters, off-line power supplies, and automotive power systems.
- What is the maximum power supply voltage for the UC3844BVD1?
The maximum power supply voltage is 36 V.
- How is the output deadtime adjustable in the UC3844BVD1?
The output deadtime can be programmed from 50% to 70% using an internal flip-flop.
- Does the UC3844BVD1 have any automotive qualifications?
Yes, with the NCV prefix, it is AEC-Q100 qualified and PPAP capable for automotive and other applications.
- What is the package type of the UC3844BVD1?
The UC3844BVD1 is available in an 8-pin SOIC package.
