UC2845B: High Performance Current Mode PWM Controller
The UC3844B, UC3845B series are high performance fixed frequency current mode controllers. They are specifically designed for Off-Line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components. These integrated circuits feature an oscillator, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle-by-cycle current limiting, a latch for single pulse metering, and a flip-flop which blanks the output off every other oscillator cycle, allowing output deadtimes to be programmed from 50% to 70%. These devices are available in an 8-pin dual-in-line and surface mount (SO-8) plastic package as well as the 14-pin plastic surface mount (SO-14). The SO-14 package has separate power and ground pins for the totem pole output stage. The UCX844B has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off-line converters. The UCX845B is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
特性- 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
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数据表 (1)
封装图纸 (3)
产品订购型号
| 产品 | 状况 | Compliance | 封装 | MSL* | 容器 | 预算价格 (1千个数量的单价） |
|---|
| UC2845BD1G | Active | Pb-free
Halide free | SOIC-8 | 751-07 | 1 | Tube | 98 | $0.2 |
| UC2845BD1R2G | Active | Pb-free
Halide free | SOIC-8 | 751-07 | 1 | Tape and Reel | 2500 | $0.48 |
| UC2845BDG | Active | Pb-free
Halide free | SOIC-14 | 751A-03 | 1 | Tube | 55 | $0.2 |
| UC2845BDR2G | Active | Pb-free
Halide free | SOIC-14 | 751A-03 | 1 | Tape and Reel | 2500 | $0.48 |
| UC2845BNG | Active | Pb-free
Halide free | PDIP-8 | 626-05 | NA | Tube | 50 | $0.48 |
订购产品技术参数
| Product | Topology | Control Mode | fsw Typ (kHz) | Stand-by Mode | UVLO (V) | Short Circuit Protection | Latch | Soft Start | VCC Max (V) | Drive Cap. (mA) |
|---|
| UC2845BD1G | Flyback | Current Mode | 52 | No | Yes | Yes | No | No | 30 | 200 / 200 |
| UC2845BD1R2G | Flyback | Current Mode | 52 | No | Yes | Yes | No | No | 30 | 200 / 200 |
| UC2845BDG | Flyback | Current Mode | 52 | No | Yes | Yes | No | No | 30 | 200 / 200 |
| UC2845BDR2G | Flyback | Current Mode | 52 | No | Yes | Yes | No | No | 30 | 200 / 200 |
| UC2845BNG | Flyback | Current Mode | 52 | No | Yes | Yes | No | No | 30 | 200 / 200 |
