DESCRIPTION

The L4955 is a family of monolithic ultra very low drop linear regulators designed to supply the most recent microprocessors.

The dropout voltage is only 0.75V (Typ.) at 5A, directly dependent on the output current conditions. Realized in BCDII technology, it has on board a charge pump to properly drive an N-channel power mos Transistor with 150m? of RDSON.

It operates from a 4.5V minimum supply, with a very low quiescent current irrespective of the load; a minimum of 22μF output capacitor is required for stability.

The on-chip trimming techniques improve the precision of the available output voltages to ±2.

■ UP TO 5A OUTPUT CURRENT

■ ±2 PRECISE OUTPUT VOLTAGES

■ FAST TRANSIENT RESPONSE

■ 0.75V TYP. DROP OUT VOLTAGE AT 5A

■ OPERATING INPUT VOLTAGEFROM 4.5V

■ ADJUSTABLE VERSION:

? VO = 1.26V

? INHIBIT (IQ = 120μA TYP.)

? POWER GOOD

? PROGRAMMABLE CURRENT LIMIT

? HEPTAWATT PACKAGE

■ FIXED VERSION:

? 3.3V, 5.1V OUTPUTS

? VERSAWATT PACKAGE

VERY LOW QUIESCENT CURRENT

SHORT CIRCUIT PROTECTION (Foldback function)

THERMAL SHUTDOWN

APPLICATIONS

■ PENTIUM? AND POWER PC? SUPPLIES

■ POST REGULATOR FOR SMPS

■ LOW COST SOLUTION FOR 5V TO 3.3V CONVERSION

■ LOW COST BATTERY CHARGER

■ CONSTANT CURRENT REGULATOR

■ SUITABLE FOR APPLICATION WITH STANDBY FEATURE