SC4201 POWER MANAGEMENT Pin Configuration Ordering Information Top View Part Number (1) P ackag e SC4201IMSTR MSOP-8 S C 4201E V B Evaluation Board Note: (1) Only available in tape and reel packaging. A reel contains 2500 devices. (MSOP-8) Pin Descriptions Pin Pin Name 1 RT Pin Function Oscillator frequency is configured by connecting resistor R from RT to ground. Values for R can be selected to provide desired 3 phase or 4 phase output frequencies. FOUT ≈ {[1.25 /(15pF x Rt )]/ phase} 2 VD D The power input connection for the device. 3 SYNC SYNC is a positive edge triggered input with a threshold of 1.5V. SYNC should be grounded when not required or connected to an external synchronization clock with frequency higher than the on board oscillator frequency (with respect to internal clock). 4 A Logic level output clock. Phase "A". 5 B Logic level output clock. Phase "B". 6 C Logic level output clock. Phase "C". 7 D Logic level output clock and phase selection pin. Default operation 4 phase/2 phase (90°/180°). Tie D to VDD to select 3 phase operation through A, B and C 120° out of phase. 8 GND Reference ground and power ground for all functions. Block Diagram 2002 Semtech Corp. 3 www.semtech.com SC4201 POWER MANAGEMENT Application Information Diagram in Figure 1 shows multi-phase operation of several power converters with fixed switching frequency FSW. VDD Ph A sync +3 to 6V = Fsw SYNC Ph B sync C Ph C sync C Ph D Vout 3 L PWM = Fsw GND Vout 2 L PWM = Fsw RT Vout1 L PWM C PWM Vout 4 L sync = Fsw C optional 3 or 2/4 Phases SC4201 Figure 1 2002 Semtech Corp. 4 www.semtech.com SC4201 POWER MANAGEMENT Application Information (Cont.) Diagram in Figure 2 demonstrates a multi-phase operation of a single power supply with current sharing through the individual phases and with fixed switching frequency FSW. VDD Ph A PWM sync +3 to 6V L = Fsw SYNC Ph B PWM sync L = Fsw Vout C RT Ph C PWM sync L = Fsw GND Ph D PWM L sync = Fsw optional 3 or 2/4 Phases SC4201 Figure 2 2002 Semtech Corp. 5 www.semtech.com SC4201 POWER MANAGEMENT Application Information (Cont.) Diagram in Figure 3 assumes variable switching frequency FSW, e.g. resonant power converters. This circuit will require additional “FSW Control” block, which is a task for a power designer. VDD Ph A sync +3 to 6V PWM L ~ Fsw SYNC Ph B sync PWM L ~ Fsw Vout C Fsw control RT Ph C sync PWM L ~ Fsw GND Ph D sync PWM L ~ Fsw optional 3 or 2/4 Phases SC4201 Figure 3 2002 Semtech Corp. 6 www.semtech.com SC4201 POWER MANAGEMENT Application Information (Cont.) Diagram in Figure 4 demonstrates a synchronous operation of two (or more) SC4201 controllers. If the “time delay” circuit is to be employed then 6-phase, 8-phase and other configurations become possible. Power Section of choice +3 to 6V VDD Ph A sync PWM L V DD Ph A +3 to 6V ~ Fsw Time Delay (optional) SYNC Ph B sync PWM L SYNC Ph B RT Ph C GND Ph D ~ Fsw Vout C Fsw control RT Ph C sync PWM L ~ Fsw GND Ph D sync PWM L ~ Fsw SC4201 - A optional 3 or 2/4 Phases SC4201 - B Figure 4 2002 Semtech Corp. 7 www.semtech.com SC4201 POWER MANAGEMENT Evaluation Board Schematic 3 Phase - 4 Phase +3 to 6V R3 1k U1 SC4201 1 RT GND 8 2 VDD D 7 D Out 3 SYNC C 6 C Out 4 A B 5 B Out Run - Sync Sync J1 R1 15k C1 1.0 C2 0.1 A Out R2 100K C3 22pF C4 22pF C5 22pF C6 22pF Top View Layout 2002 Semtech Corp. 8 www.semtech.com SC4201 POWER MANAGEMENT Outline Drawing - MSOP-8 Land Pattern - MSOP-8 Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 2002 Semtech Corp. 9 www.semtech.com