Datasheet ADP3050 (Analog Devices) - 5

Data Sheet ADP3050 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SWITCH 1 8 IN BOOST 2 ADP3050 7 GND BIAS 3 6 TOP VIEW SD FB (Not to Scale)
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4 5 COMP
00125- Figure 2. Pin Configuration
Table 3. Pin Function Descriptions Pin No. Mnemonic Description
1 SWITCH Switch Node. This pin is the emitter of the internal NPN power switch. The voltage at this pin switches between VIN and approximately −0.5 V. 2 BOOST Boost Pin. This pin is used to provide a boosted voltage (higher than VIN) for the drive stage of the NPN power switch. With the higher drive voltage, the power switch can be saturated, greatly reducing the switch power losses. 3 BIAS Bias Input Pin. Connect this pin to the regulated output voltage to maximize system efficiency. When this pin is above 2.7 V, most of the ADP3050 operating current is taken from the output instead of the input supply. Leave unconnected if not used. 4 FB Feedback Pin. This feedback pin senses the regulated output voltage. Connect this pin directly to the output (fixed output versions). 5 COMP Compensation Node. This pin is used to compensate the regulator with an external resistor and capacitor. This pin is also used to override the control loop. However, the voltage on this pin should not exceed 2 V, because the pin is internally clamped to ensure a fast transient response. Use a pull-up resistor if this pin is to be pulled higher than 2 V. 6 SD Shutdown Pin. Use this pin to turn the device on and off. If this feature is not needed, tie this pin directly to IN. 7 GND Ground Pin. Connect this pin to local ground plane. 8 IN Power Input. Connect this pin to the input supply voltage. An input bypass capacitor must be placed close to this pin to ensure proper regulator operation. Rev. C | Page 5 of 20 Document Outline Features Applications Functional Block Diagram General Description Revision History Specifications Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Setting the Output Voltage Applications Information ADIsimPower Design Tool Inductor Selection Continuous Mode Discontinuous Mode Inductor Core Types and Materials Choosing an Inductor Output Capacitor Selection Choosing an Output Capacitor Catch Diode Selection Choosing a Catch Diode Input Capacitor Selection Discontinous Mode Ringing Setting the Output Voltage Frequency Compensation Current Limit/Frequency Foldback Bias Pin Connection Boosted Drive Stage Start-Up/Minimum Input Voltage Thermal Considerations Board Layout Guidelines Typical Applications 5 V to 3.3 V Buck (Step-Down) Regulator Inverting (Buck Boost) Regulator Dual Output SEPIC Regulator Outline Dimensions Ordering Guide