UC2841 Series
32-V, 1-A , 0.5MHz off-line PWM controller , -20C to 85C
Manufacturer: Texas Instruments
Catalog(2 parts)
| Part | Supplier Device Package | Voltage - Supply (Vcc/Vdd)▲▼ | Voltage - Supply (Vcc/Vdd)▲▼ | Output Phases▲▼ | Duty Cycle (Max)▲▼ | Mounting Type | Synchronous Rectifier▲▼ | Package / Case | Package / Case▲▼ | Package / Case▲▼ | Number of Outputs▲▼ | Function | Output Type | Topology | Output Configuration | Operating Temperature▲▼ | Operating Temperature▲▼ | Clock Sync▲▼ | Control Features | Frequency - Switching▲▼ | Package / Case▲▼ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Texas Instruments UC2841NBuck, Boost, Flyback, Forward Converter Regulator Positive, Isolation Capable Output Step-Up, Step-Down, Step-Up/Step-Down DC-DC Controller IC 18-PDIP | 18-PDIP | 32 V | 8 V | 1 ul | 0.949999988079071 ul | Through Hole | 18-DIP | 0.007619999814778566 m | 0.007619999814778566 m | 1 ul | Step-Down, Step-Up, Step-Up/Step-Down | Transistor Driver | Boost, Buck, Flyback, Forward Converter | Isolation Capable, Positive | -25 °C | 85 °C | Current Limit, Enable, Frequency Control, Ramp, Reset, Soft Start | 500000 Hz | |||
Texas Instruments UC2841DWBuck, Boost, Flyback, Forward Converter Regulator Positive, Isolation Capable Output Step-Up, Step-Down, Step-Up/Step-Down DC-DC Controller IC 18-SOIC | 18-SOIC | 32 V | 8 V | 1 ul | 0.949999988079071 ul | Surface Mount | 18-SOIC | 0.007493000011891127 m | 1 ul | Step-Down, Step-Up, Step-Up/Step-Down | Transistor Driver | Boost, Buck, Flyback, Forward Converter | Isolation Capable, Positive | -25 °C | 85 °C | Current Limit, Enable, Frequency Control, Ramp, Reset, Soft Start | 500000 Hz | 0.007499999832361937 m |
Key Features
• All Control, Driving, Monitoring, and Protection Functions IncludedLow-current, Off-line Start CircuitVoltage Feed Forward or Current Mode ControlGuaranteed Duty Cycle ClampPWM Latch for Single Pulse per PeriodPulse-by-Pulse Current Limiting Plus Shutdown for Over-Current FaultNo Start-up or Shutdown TransientsSlow Turn-on Both Initially and After Fault ShutdownShutdown Upon Over- or Under-Voltage SensingLatch Off or Continuous Retry After FaultPWM Output Switch Usable to 1A Peak Current1% Reference Accuracy500kHz Operation18 Pin DIL PackageAll Control, Driving, Monitoring, and Protection Functions IncludedLow-current, Off-line Start CircuitVoltage Feed Forward or Current Mode ControlGuaranteed Duty Cycle ClampPWM Latch for Single Pulse per PeriodPulse-by-Pulse Current Limiting Plus Shutdown for Over-Current FaultNo Start-up or Shutdown TransientsSlow Turn-on Both Initially and After Fault ShutdownShutdown Upon Over- or Under-Voltage SensingLatch Off or Continuous Retry After FaultPWM Output Switch Usable to 1A Peak Current1% Reference Accuracy500kHz Operation18 Pin DIL Package
Description
AI
The UC1841 family of PWM controllers has been designed to increase the level of versatility while retaining all of the performance features of the earlier UC1840 devices. While still optimized for highly-efficient boot-strapped primary-side operation in forward or flyback power converters, the UC1841 is equally adept in implementing both low and high voltage input DC to DC converters. Important performance features include a low-current starting circuit, linear feed-forward for constant volt-second operation, and compatibility with either voltage or current mode topologies.
In addition to start-up and normal regulating PWM functions, these devices include built in protection from over-voltage, under-voltage, and over-current fault conditions with the option for either latch-off or automatic restart.
While pin compatible with the UC1840 in all respects except that the polarity of the External Stop has been reversed, the UC1841 offers the following improvements:
1. Fault latch reset is accomplished with slow start discharge rather than recycling the input voltage to the chip.
2. The External Stop input can be used for a fault delay to resist shutdown from short duration transients.
3. The duty-cycle clamping function has been characterized and specified.
The UC1841 is characterized for -55°C to +125°C operation while the UC2841 and UC3841 are designed for -25°C to +85°C and 0°to +70°C, respectively.
The UC1841 family of PWM controllers has been designed to increase the level of versatility while retaining all of the performance features of the earlier UC1840 devices. While still optimized for highly-efficient boot-strapped primary-side operation in forward or flyback power converters, the UC1841 is equally adept in implementing both low and high voltage input DC to DC converters. Important performance features include a low-current starting circuit, linear feed-forward for constant volt-second operation, and compatibility with either voltage or current mode topologies.
In addition to start-up and normal regulating PWM functions, these devices include built in protection from over-voltage, under-voltage, and over-current fault conditions with the option for either latch-off or automatic restart.
While pin compatible with the UC1840 in all respects except that the polarity of the External Stop has been reversed, the UC1841 offers the following improvements:
1. Fault latch reset is accomplished with slow start discharge rather than recycling the input voltage to the chip.
2. The External Stop input can be used for a fault delay to resist shutdown from short duration transients.
3. The duty-cycle clamping function has been characterized and specified.
The UC1841 is characterized for -55°C to +125°C operation while the UC2841 and UC3841 are designed for -25°C to +85°C and 0°to +70°C, respectively.