DB4679 Rev 1

5/16

L5964

Description

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1

Description

L5964 is a dual step-down switching regulator with internal power switches and a low drop-

out linear/standby regulator. All the regulators have independent supply voltages, enables,

power goods and thermal protections.

The switching regulators have selectable voltage supervisors and power goods, and

selectable current limits. The LDO has power good and fixed current limitation.

The two DC-DC converters can work in free-run condition, with frequency selectable

between two values, 270 kHz or 2.2 MHz, or synchronize themselves to an external clock

(SYNCIN pin). They are 180° out of phase, while the synchronization output signal

(SYNCOUT pin) is 90° out of phase with the first regulator. The phase shift simplifies the use

of two ICs in the same application (4 DC/DCs regulators).

DC-DC1 and DC-DC2 current limits can be independently set through the pins OCPSET1

and OCPSET2 respectively. Two current limits are available, 2 A (1.7 A min) and 3.5 A

(3.7 A min). For operation > 2 A, 20 V, with less than 0.5 V forward voltage and 2 A at room

temperature, Schottky diodes placed as close to the PHASE1/2 pins as possible, to ground

are required.

The high operating frequency allowed by the synchronization input helps to reduce AM and

FM interferences and grants the use of small and low cost inductors and capacitors.

The L5964 can manage the microcontroller supply. A configurable reset output and a

configurable watchdog input are available.

This IC finds application in the automotive segment, where load dump protection and wide

input voltage range are mandatory. L5964 has been qualified for car passenger cars, with a

standard 14 V battery. The total quiescent current, when both DC/DCs and LDO are

disabled, is less than 10 µA.

The product is available in LQFP64 exposed pad up package. The slug, whenever possible,

has to be connected to the ground plane.