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180

° Out of Phase Synchronization (SYNC)

VI(SYNC)

VO(PH)

Internal Oscillator

VO(PH)

VO(SYNC)

TPS54350-EP

SGLS308 – OCTOBER 2005

The SYNC pin is configurable as an input or as an output, per the description in the previous section. When

operating as an input, the SYNC pin is a falling-edge triggered signal (see Figure 3, Figure 4, and Figure 19).

When operating as an output, the signal's falling edge is approximately 180

° out of phase with the rising edge of

the PH pins. Thus, two TPS54350 devices operating in a system can share an input capacitor and draw ripple

current at twice the frequency of a single unit.

When operating the two TPS54350 devices 180

° out of phase, the total RMS input current is reduced. Thus

reducing the amount of input capacitance needed and increasing efficiency.

When synchronizing a TPS54350 to an external signal, the timing resistor on the RT pin must be set so that the

oscillator is programmed to run at 90% to 110% of the synchronization frequency.

NOTE:

Do not use synchronization input for designs with output voltages >10 V.

Figure 3. SYNC Input Waveform

Figure 4. SYNC Output Waveform

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