IC REG CTRLR BOOST/FLYBACK 8DIP Hello everyone! UC3845 is a high-performance fixed-frequency current-mode controller designed for offline and DC-to-DC converter applications, providing designers with a cost-effective solution that requires minimal external components. This article mainly introduces circuit, pinout, datasheet and other detailed information about ON Semiconductor UC3845.
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Sep 18, 2021
Rosemary Quiller
#236 Current Mode PWM SMPS controller UC3842 /UC3843 / UC3844 / UC3845 Functional Description
IC REG CTRLR BOOST/FLYBACK 8DIP
Hello everyone! UC3845 is a high-performance fixed-frequency current-mode controller designed for offline and DC-to-DC converter applications, providing designers with a cost-effective solution that requires minimal external components. This article mainly introduces circuit, pinout, datasheet and other detailed information about ON Semiconductor UC3845.
UC3845N
UC3845 is a high-performance fixed-frequency current-mode controller designed for offline and DC-to-DC converter applications, providing designers with a cost-effective solution that requires minimal external components. These integrated circuits have fine-tunable oscillators, precise duty cycle control, temperature compensation references, and high-gain error amplifiers. The current sampling comparator and high current totem pole output are ideal devices for driving power MOSFETs.The UC3842 and UC3844 have UVLO thresholds of 16V (on) and 10V (off). The UC3843 and UC3845 are 8.5V(on) and 7.9V (off).
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 of every other oscillator cycle, allowing output dead times to be programmed for 50% to 70%.
These devices are available in an 8−pin dual−in−line plastic package as well as the 14−pin plastic surface mount (SOIC−14). The SOIC−14 package has separate power and ground pins for the totem pole output stage. The UCX844 has UVLO thresholds of 16 V (on) and 10 V (off), ideally suited for off−line converters. The UCX845 is tailored for lower voltage applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
In total, UC3845 is specially designed for low voltage applications.
Symbol
Footprint
3D Model
• 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
• Input Undervoltage Lockout With Hysteresis
• Low Startup And Operating Current
• Direct Interface With ON Semiconductor SENSEFET Products
• Pb−Free Packages Are Available
ON Semiconductor UC3845N technical specifications, attributes, parameters and parts with similar specifications to ON Semiconductor UC3845N.
| Product Attribute | Attribute Value | |
|---|---|---|
| Mount | Through Hole | |
| Mounting Type | Through Hole | |
| Package / Case | 8-DIP (0.300, 7.62mm) | |
| Number of Pins | 8Pins | |
| Operating Temperature | 0°C~70°C TA | |
| Packaging | Tube | |
| Published | 2002 | |
| JESD-609 Code | e0 | |
| Part Status | Obsolete | |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) | |
| Number of Terminations | 8Terminations | |
| ECCN Code | EAR99 | |
| Terminal Finish | Tin/Lead (Sn/Pb) | |
| Terminal Position | DUAL | |
| Terminal Pitch | 2.54mm |
| Product Attribute | Attribute Value | |
|---|---|---|
| Frequency | 275kHz | |
| Base Part Number | UC384* | |
| Function | Step-Up, Step-Up/Step-Down | |
| Number of Outputs | 1Output | |
| Output Voltage | 5.1V | |
| Output Type | Transistor Driver | |
| Input Voltage-Nom | 15V | |
| Analog IC - Other Type | SWITCHING CONTROLLER | |
| Operating Supply Current | 30mA | |
| Output Configuration | Positive or Negative, Isolation Capable | |
| Output Current | 1A | |
| Voltage - Supply (Vcc/Vdd) | 7.6V~30V | |
| Control Features | Frequency Control | |
| Topology | Boost, Flyback | |
| Control Mode | CURRENT-MODE |
| Product Attribute | Attribute Value | |
|---|---|---|
| Frequency - Switching | 500kHz | |
| Input Voltage (Max) | 25V | |
| Control Technique | PULSE WIDTH MODULATION | |
| Rise Time | 45ns | |
| Synchronous Rectifier | No | |
| Fall Time (Typ) | 35 ns | |
| Switcher Configuration | SINGLE | |
| Max Duty Cycle | 50 % | |
| Duty Cycle (Max) | 48% | |
| Height Seated (Max) | 4.45mm | |
| Width | 7.62mm | |
| RoHS Status | Non-RoHS Compliant | |
| Lead Free | Contains Lead |
Functional Block Diagram
Marking Diagrams
| Part Number | Description | Manufacturer |
| UC2845DR2POWER CIRCUITS | IC,SMPS CONTROLLER,CURRENT-MODE,BIPOLAR,SOP,14PIN,PLASTIC | Freescale Semiconductor |
Package Dimensions
On Semiconductor is a manufacturer engaging itself in reducing energy use, also the premier supplier of high-performance silicon solutions for energy-efficient electronic products. The company's product line includes power and signal management, logic, discrete and custom devices to help customers solve their unique design challenges in automotive, communications, computers, consumer electronics, industrial, LED lighting, medical, military, aerospace and power applications. Fast and cost-effective.
The company operates a world-class, value-added supply chain and network including manufacturing plants, sales offices and design centers in key markets in North America, Europe and the Asia-Pacific region.
Download datasheets and manufacturer documentation for ON Semiconductor UC3845N.
Download datasheets and manufacturer documentation for UC3845N
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