Overview
The UC3844BDR2G is a high-performance, fixed-frequency current-mode PWM controller produced by onsemi. It is specifically designed for off-line and DC-DC converter applications, offering a cost-effective solution with minimal external components. This integrated circuit features a trimmed oscillator for precise frequency control, a temperature-compensated reference, a high-gain error amplifier, a current sensing comparator, and a high-current totem pole output stage ideal for driving power MOSFETs.
Key Specifications
| Parameter | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | VCC | - | - | 30 | V |
| Output Current | IO | - | - | ±1 A | A |
| Reference Output Voltage | VREF | 2.42 | 2.5 | 2.58 | V |
| Oscillator Frequency | - | - | 250 kHz | - | kHz |
| Maximum Duty Cycle | DC(max) | - | - | 50% | % |
| Undervoltage Lockout Start Threshold | VTH(ST) | 14.5 | 16.0 | 17.5 | V |
| Minimum Operating Voltage (After Turn On) | VOPR(MIN) | 8.5 | 10.0 | 11.5 | V |
| Output Voltage High State | VOH | 12.9 | 13.5 | - | V |
| Output Voltage Low State | VOL | 0.1 | 1.1 | - | V |
Key Features
- Trimmed oscillator for precise frequency control up to 500 kHz output switching frequency.
- Temperature-compensated reference with undervoltage lockout and hysteresis.
- High-gain error amplifier and current sensing comparator.
- High-current totem pole output stage for driving power MOSFETs.
- Output deadtime adjustable from 50% to 70%.
- Latching PWM for cycle-by-cycle current limiting.
- Low startup and operating current.
- Pb-free and RoHS compliant.
- Available in 8-pin dual-in-line and surface mount (SOIC-8 and SOIC-14) packages.
Applications
The UC3844BDR2G is specifically designed for off-line and DC-DC converter applications. It is suitable for use in:
- Switch-mode power supplies.
- DC-DC converters.
- Power factor correction circuits.
- Motor control and other high-performance power management systems.
Q & A
- What is the typical operating frequency of the UC3844BDR2G?
The typical operating frequency is 250 kHz, but it can be programmed up to 500 kHz output switching frequency.
- What are the undervoltage lockout thresholds for the UC3844BDR2G?
The undervoltage lockout start threshold is 16 V (on) and 10 V (off) for the UC3844B series.
- What is the maximum duty cycle for the UC3844BDR2G?
The maximum duty cycle is 50% for the UC3844B series.
- What types of packages are available for the UC3844BDR2G?
The device is available in 8-pin dual-in-line and surface mount (SOIC-8 and SOIC-14) packages.
- What are the key features of the UC3844BDR2G's oscillator?
The oscillator features precise frequency control, adjustable output deadtime, and an internal flip-flop for blanking the output every other clock cycle.
- How does the UC3844BDR2G protect against overcurrent conditions?
The device includes cycle-by-cycle current limiting and a latch for single pulse metering.
- What is the power supply rejection ratio (PSRR) of the UC3844BDR2G?
The PSRR is 60 dB to 70 dB.
- Is the UC3844BDR2G Pb-free and RoHS compliant?
Yes, the device is Pb-free and RoHS compliant.
- What are the typical output voltage levels for the UC3844BDR2G?
The high state output voltage is approximately 13.5 V, and the low state output voltage is approximately 0.1 V to 1.1 V.
- What is the storage temperature range for the UC3844BDR2G?
The storage temperature range is -65°C to +150°C.
