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| MC34670 |
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3 page 
Analog Integrated Circuit Device Data Freescale Semiconductor 3 34670 PIN CONNECTIONS PIN CONNECTIONS Figure 3. 34670 Pin Connections Table 1. 34670 Pin Definitions Pin Number Pin Name Formal Name Definition 1, 2 VPWR Positive Supply Voltage Input This is the most positive power supply input. The load connects between this pin and the VOUT pin. 3 RCLA Classification Resistor Connect a resistor between RCLA and VIN to select the class of the PD. 4 UVLO Undervoltage Lookout Used to adjust the undervoltage lookout threshold voltage, connected to VIN to use the default threshold voltage. 5 TEST1 Test pins Connect to VIN in application mode. 6 TEST2 7 FREQ Frequency Adjustment Adjusts the internal oscillator frequency by connecting a resistor between FREQ and VIN. 8 ILIM Inrush Current Limit Used to adjust the inrush current limit of the isolation switch, add a resistor between ILIM and VIN. 9 VIN Negative Supply Voltage This is the most negative power supply input. 10 VIN 11, 12 VOUT Output Voltage This pin is the drain of the internal Power MOSFET (high current path). 13 VOUT Output Voltage This pin is the drain of the internal Power MOSFET (low current path). 14 RESET RESET Output (active low) This is an active-low RESET output signal. This pin is referenced to VOUT. 15 SS Soft Start Input Connect an external capacitor to SS. The internal current source charges the capacitor and generates a soft-start ramp. 16 COMP Compensation Pin COMP is the output of the error amplifier and is available for feedback compensation. COMP is pulled-up by an internal 5.0 k Ω resistor to 5.0 V. 17 FB Feedback Input This is the inverting input of the error amplifier. In non-isolated applications it’s connected to the secondary output through a resistor divider. 18 CS Current Sense The current sense pin CS senses a voltage that is proportional to the current through the sense resistor. 19 GATE Gate Driver Output GATE drives the gate of the external power MOSFET. GATE sources and sinks up to 1.0 A. 20 VDD VDD Output VDD mainly supplies the gate of the external power MOSFET. Connect a capacitor from VDD to VOUT. 1 2 3 5 4 6 7 8 9 10 20 11 12 13 14 15 16 17 18 19 VPWR VPWR RCLA UVLO TEST1 TEST2 FREQ ILIM VIN VIN VDD GATE CS FB COMP SS RESET VOUT VOUT VOUT |
