link to page 2 Atmel U2008B2.Pin ConfigurationFigure 2-1. Pinning ISENSE 1 8 OUTPUT Cϕ 2 7 VSYNC AtmelU2008B CONTROL 3 6 Rϕ GND 4 5 -VS Table 2-1. Pin Description PinSymbolFunction 1 ISENSE Load current sensing 2 Cϕ Ramp voltage 3 CONTROL Control input/compensation output 4 GND Ground 5 -VS Supply voltage 6 Rϕ Ramp current adjustment 7 VSYNC Voltage synchronization 8 OUTPUT Trigger output 2.1Mains Supply, Pin 5 The Atmel® integrated circuit U2008B, which also contains voltage limiting, can be connected via D and R to the mains supply, see Figure 1-2 on page 2. Supply voltage, between pin 4 1 1 (pos., ⊥) and pin 5, is smoothed by C . 1 The series resistance R1 can be calculated as follows: V – V M Smax R = 0.85 × --------------- 1max 2 × Itot where: V = Mains voltage M V = Maximum supply voltage Smax I = I + I = Total current compensation tot Smax x I = Maximum current consumption of the IC Smax I = Current consumption of the external components x Operation with externally stabilized DC voltage is not recommended. 3 4712D–AUTO–03/11 Document Outline Features Applications 1. Description 2. Pin Configuration 2.1 Mains Supply, Pin 5 2.2 Voltage Monitoring 2.3 Phase Control, Pin 6 2.4 Automatic Retriggering 2.5 Current Synchronization, Pin 8 2.6 Voltage Synchronization with Mains Voltage Compensation, Pin 7 2.7 Load Current Detection, Pin 1 3. Absolute Maximum Ratings 4. Thermal Resistance 5. Electrical Characteristics 6. Ordering Information 7. Package Information 8. Revision History