otherwise noted. (Continued)

Efficiency vs Output Current

(V

Efficiency vs Output Current

(V

20057415

20057416

Efficiency vs Output Current

(V

(Circuit in Figure 4)

Efficiency vs Output Current

(V

(Circuit in Figure 4)

20057417

20057418

Device Information

The LM2619 is a simple, step-down DC-DC converter opti-

mized for powering circuits in mobile phones, portable com-

municators, and similar battery powered RF devices. It is

based on a current-mode buck architecture, with synchro-

nous rectification in PWM mode for high efficiency. It is

designed for a maximum load capability of 500mA in PWM

mode. Maximum load range may vary from this depending

on input voltage, output voltage and the inductor chosen.

The device has all three of the pin-selectable operating

modes required for powering circuits in mobile phones and

other sophisticated portable devices with complex power

management needs. Fixed-frequency PWM operation offers

full output current capability at high efficiency while minimiz-

ing interference with sensitive IF and data acquisition cir-

cuits. During standby operation, hysteretic PFM mode re-

duces quiescent current to 160µA typ. to maximize battery

life. Shutdown mode turns the device off and reduces battery

consumption to 0.02µA (typ).

ciency is typically 96% for a 200mA load with 3.6V output,

3.9V input. The efficiency can be further increased by using

a schottky diode like MBRM120L as shown in Figure 4. PWM

mode quiescent current is 600µA typ. The output voltage can

be set from 1.5V to 3.6V by using external feedback resis-

tors.

Additional features include soft-start, current overload pro-

tection, over voltage protection and thermal shutdown pro-

tection.

The LM2619 is constructed using a chip-scale 10-pin thin

micro SMD package. This package offers the smallest pos-

sible size, for space-critical applications such as cell phones,

where board area is an important design consideration. Use

of a high switching frequency (600kHz) reduces the size of

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