DEMO MANUAL DC2177A-B LT3062 45V V , Micropower, IN Low Noise, 200mA LDO Description Demonstration circuit 2177A-B features the LT 3062, a and there is also a 50V tantalum polymer capacitor on the micropower, low noise and low dropout voltage linear input to dampen ringing that may occur when the input is regulator. The input voltage ranges from 2.1V to 45V and hot-plugged using long leads. the maximum output current is 200mA. A resistor divider The LT3062 saves energy by being micropower and low determines the output voltage, and a jumper adjusts the dropout. The LT3062 has excellent regulation and fast divider to set the output voltage to either 1.2V, 1.5V, 1.8V, response to load transients and also tolerates wide input 2V, 2.5V, 3.3V, 5V or a voltage that is user-programmed voltage variations. but requires the installation of a resistor. The output uses The LT3062 targets systems with inputs that are battery- a 10F ceramic capacitor and the internal reference is powered or have multiple sources. DC2177A-B features bypassed with a 10nF capacitor to reduce output noise the LT3062 in the 8-lead 2mm 3mm DFN package. The and program the soft-start. There is also a 10nF feedfor- LT3062 data sheet must be read in conjunction with this ward capacitor to improve load transient response and demo manual to properly use or modify demo circuit decrease noise at higher output voltages. The position of DC2177A-B. the VOUTEN jumper either pulls up the SHDN pin to the input supply through a 100k resistor, shorts SHDN to Design files for this circuit board are available at ground or floats the SHDN pin so it can be driven directly DEMO MANUAL DC2177A-B Quick s p D To use DC2177A-B to evaluate the performance of the 3. Increase the load to the desired output current. Verify LT3062, refer to Figure 1 for the proper measurement that the V voltage is as programmed by the jumper. OUT equipment setup and follow the procedure below: Note: If the output voltage is low, temporarily disconnect 1. With the input supply and load off and turned down, the load to make sure that it is not set too high. make all connections according to Figure 1. Make sure 4. Once the proper output voltage is established, adjust the the jumper to set VOUT is in the proper position for the input voltage and load within the operating range and desired output voltage and the VOUTEN jumper is in observe the output voltage regulation, low quiescent the ON position. current, shutdown operation and other parameters. 2. Turn on the input supplies and increase them to the desired input voltages. Note When Setting The Input Voltage: An input voltage that is too close to the programmed output voltage (too low) may cause dropout operation and a loss of output voltage regulation. Also, an input voltage that is too high above the output may increase power dissipation to an unacceptable level. dc2177abf 2 ure roce tart