Datasheet LTC3874-1 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | PolyPhase Step-Down Synchronous Slave Controller with Sub-Milliohm DCR Sensing |
| Pages / Page | 22 / 10 — operaTion. 3 PHASE OPERATION. 3 PHASE + 1 PHASE OPERATION. 4 PHASE … |
| File Format / Size | PDF / 1.0 Mb |
| Document Language | English |
operaTion. 3 PHASE OPERATION. 3 PHASE + 1 PHASE OPERATION. 4 PHASE OPERATION. 6 PHASE OPERATION. Figure 1. Multiphase Operation
Model Line for this Datasheet
Text Version of Document
LTC3874-1
operaTion 3 PHASE OPERATION 3 PHASE + 1 PHASE OPERATION
CH0 CH1 CH1 CH2 CH0 CH1 0° 240° 120° 0° 180° 60° 300° LTC3866 LTC3874-1 LTC3884-1 LTC3874-1 CLKOUT SYNC SYNC SYNC PHASMD = 1/3 INTVCC PHASMD = 1/3 INTVCC
4 PHASE OPERATION 4 PHASE OPERATION
CH1 CH2 CH0 CH1 CH1 CH2 CH0 CH1 0° 180° 90° 270° 0° 180° 90° 270° LTC3774 LTC3874-1 LTC3884-1 LTC3874-1 CLKOUT SYNC SYNC SYNC PHASMD = FLOAT PHASMD = GND PHASMD = INTVCC
6 PHASE OPERATION 6 PHASE OPERATION
CH1 CH2 CH0 CH1 CH0 CH1 CH1 CH2 CH0 CH1 CH0 CH1 0° 120° 240° 60° 180° 300° 0° 180° 60° 300° 120° 240° LTC3774 LTC3874-1 LTC3874-1 LTC3884-1 LTC3874-1 LTC3874-1 CLKOUT SYNC SYNC SYNC SYNC SYNC PHASMD = INTVCC PHASMD = GND PHASMD = 2/3 INTVCC PHASMD = 1/3 INTVCC PHASMD = 2/3 INTVCC 38741 F01
Figure 1. Multiphase Operation Frequency Selection and Phase-Locked Loop
flowing out of the FREQ pin, so the user can program the
(FREQ and SYNC Pins)
controller’s switching frequency with a single resistor to The selection of switching frequency is a trade-off be- GND. A curve is provided later in the application section tween efficiency and component size. Low frequency showing the relationship between the voltage on the FREQ operation increases efficiency by reducing MOSFET pin and switching frequency (Figure 5). A phase-locked switching losses, but requires larger inductance and/or loop (PLL) is integrated in the LTC3874-1 to synchronize capacitance to maintain low output ripple voltage. The the internal oscillator to an external clock source on the switching frequency of the LTC3874-1 controllers can be SYNC pin. The PLL loop filter network is integrated inside selected using the FREQ pin. If the SYNC pin is not be- the LTC3874-1. The phase-locked loop is capable of lock- ing driven by an external clock source, the FREQ pin can ing to any frequency within the range of 250kHz to 1MHz. be used to program the controller’s operating frequency The frequency setting resistor should always be present from 250kHz to 1MHz. There is a precision 10µA current to set the controller’s initial switching frequency before locking to the external clock. 38741f 10 For more information www.linear.com/LTC3874-1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Application Related Parts
operaTion 3 PHASE OPERATION 3 PHASE + 1 PHASE OPERATION
CH0 CH1 CH1 CH2 CH0 CH1 0° 240° 120° 0° 180° 60° 300° LTC3866 LTC3874-1 LTC3884-1 LTC3874-1 CLKOUT SYNC SYNC SYNC PHASMD = 1/3 INTVCC PHASMD = 1/3 INTVCC
4 PHASE OPERATION 4 PHASE OPERATION
CH1 CH2 CH0 CH1 CH1 CH2 CH0 CH1 0° 180° 90° 270° 0° 180° 90° 270° LTC3774 LTC3874-1 LTC3884-1 LTC3874-1 CLKOUT SYNC SYNC SYNC PHASMD = FLOAT PHASMD = GND PHASMD = INTVCC
6 PHASE OPERATION 6 PHASE OPERATION
CH1 CH2 CH0 CH1 CH0 CH1 CH1 CH2 CH0 CH1 CH0 CH1 0° 120° 240° 60° 180° 300° 0° 180° 60° 300° 120° 240° LTC3774 LTC3874-1 LTC3874-1 LTC3884-1 LTC3874-1 LTC3874-1 CLKOUT SYNC SYNC SYNC SYNC SYNC PHASMD = INTVCC PHASMD = GND PHASMD = 2/3 INTVCC PHASMD = 1/3 INTVCC PHASMD = 2/3 INTVCC 38741 F01
Figure 1. Multiphase Operation Frequency Selection and Phase-Locked Loop
flowing out of the FREQ pin, so the user can program the
(FREQ and SYNC Pins)
controller’s switching frequency with a single resistor to The selection of switching frequency is a trade-off be- GND. A curve is provided later in the application section tween efficiency and component size. Low frequency showing the relationship between the voltage on the FREQ operation increases efficiency by reducing MOSFET pin and switching frequency (Figure 5). A phase-locked switching losses, but requires larger inductance and/or loop (PLL) is integrated in the LTC3874-1 to synchronize capacitance to maintain low output ripple voltage. The the internal oscillator to an external clock source on the switching frequency of the LTC3874-1 controllers can be SYNC pin. The PLL loop filter network is integrated inside selected using the FREQ pin. If the SYNC pin is not be- the LTC3874-1. The phase-locked loop is capable of lock- ing driven by an external clock source, the FREQ pin can ing to any frequency within the range of 250kHz to 1MHz. be used to program the controller’s operating frequency The frequency setting resistor should always be present from 250kHz to 1MHz. There is a precision 10µA current to set the controller’s initial switching frequency before locking to the external clock. 38741f 10 For more information www.linear.com/LTC3874-1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Operation Applications Information Typical Application Related Parts
