Datasheet

SYNC

200P

DEADTIME

ONE-SHOT

I = f (RT)

CLK

SYNC

LM5026

SYNC

LM5026

UP TO 5 TOTAL

DEVICES

LM5026

SNVS363D –AUGUST 2005–REVISED APRIL 2013

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Figure 25. Sync from Multiple Devices

Multiple LM5026 devices can be synchronized together simply by connecting the devices SYNC pins together as

shown in Figure 25. Care should be taken to ensure the ground potential differences between devices are

minimized. In this configuration all of the devices will be synchronized to the highest frequency device. The

internal block diagram of the oscillator and synchronization circuit is shown in Figure 26. The SYNC I/O pin is a

CMOS buffer with pull-up current limited to 200 µA. If an external device forces the SYNC pin low before the

internal oscillator ramp completes its charging cycle, the ramp will be reset and another cycle begins. If the

SYNC pins of multiple LM5026 devices are connected together, the first SYNC pin that pulls low will reset the

oscillator RAMP of all other devices. All controllers will operate in phase when synchronized using the SYNC I/O

feature. Up to five LM5026 devices can be synchronized using this technique.

Figure 26. Oscillator Sync I/O Block Diagram

Thermal Protection

Internal Thermal Shutdown circuitry is provided to protect the integrated circuit in the event the maximum junction

temperature is exceeded. When activated, typically at 165°C, the controller is forced into a low power standby

state with the output drivers and the bias regulator disabled. The device will restart after the thermal hysteresis

(typically 25°C). During thermal shutdown, the soft-start capacitor is fully discharged and the controller follows a

normal start-up sequence after the junction temperature falls to the operating level.

Product Folder Links: LM5026