Schematic for the NCP 1421 Demonstration Board h 9/9/2003 1 T1 D 2 4 3 V_BAT V_Bat D TP1 R1 220K V_Bat C2 10pF R3 470K U1 NCP1421DMR2 BAT FB + - LBI/EN 2 C1 22uF LBO C REF 3 4 LBI/EN T2 REF R4 270K C4 220nF T3 D1 MBR0520LT1 3.3V/5V Select Vref Shut Down VOUT C5 22uF C T4 LX 7 GND LX 330K JP1 B VOUT JP3 Low Voltage Start up R5 Voltage Select b Driver GND JP2 TP6 VOUT 8 Logic LBO h C3 * VOUT 6 GND True Shutdown Driver L1 5.6uH TP2 R2 300K Control Low Voltage Start up 1 GND FB 5 TP7 GND B SHDN 500 mA Sync-Rect PFM Step-Up DC-DC converter with True-Cutoff and Ring-Killer ON Semiconductor Hong Kong Design Limited Floor 2, No.1, Science Park East Avenue Hong Kong Science Park Pak Shek Kok, N.T., Hong Kong A Project : NCP1421 Demo Board h Section : Department : Approved By : Drawn By : Samuel Lai File: D:\PROJECT\..\1421REV1.SCH Homepage : www.onsemi.com FAX : 26890095 1 2 3 Tel : 26890088 4 Rev 1 Size: Letter 1 Sheet 1 of Date: Print Date: 9-May-2003 A