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The UC284xB family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally implemented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lockout featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFETs, is low in the off-state.
Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC2842B and UC2844B have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications The corresponding thresholds for the UC2843B and UC2845B are 8.5V and 7.9V. The UC2842B and UC2843B can operate to duty cycles approaching 100%. A range of the zero to < 50 % is obtained by the UC2844B and UC2845B by the addition of an internal toggle flip flop which blanks the output off every other clock cycle.
主要特性
- LOW START-UP AND OPERATING CURRENT
- UNDERVOLTAGE LOCKOUT WITH HYSTERESIS
- INTERNALLY TRIMMED REFERENCE WITH UNDERVOLTAGE LOCKOUT
- CURRENT LIMITING
- TRIMMED OSCILLATOR FOR PRECISE FREQUENCY CONTROL
- CURRENT MODE OPERATION TO 500kHz
- OSCILLATOR FREQUENCY GUARANTEED AT 250kHz
- LATCHING PWM FOR CYCLE-BY-CYCLE
- HIGH CURRENT TOTEM POLE OUTPUT
- AUTOMATIC FEED FORWARD COMPENSATION
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| 产品型号 | 供货状态 | 封装 | 等级规格 | 符合RoHS级别 | 材料声明** |
|---|---|---|---|---|---|
| UC2842BD1 | 批量生产 | SO-8 | 工业 | Ecopack2 | |
| UC2842BD1013TR | 批量生产 | SO-8 | 工业 | Ecopack2 | |
| UC2842BN | 批量生产 | DIP-8 | 工业 | Ecopack2 |
(**) st.com上提供的材料声明表单可能是基于包装系列中最常用的封装的通用文档。因此，它们可能不是100%适用于特定的设备。有关特定设备的信息，请联系 销售支持 。
