Top View

Bottom View

A1

A3

Vin

EN

FB

SW

GND

Vin

EN

GND

SW

FB

C1

C3

B2

A3

A1

C3

C1

B2

LM3679

SNVS510A – SEPTEMBER 2007 – REVISED FEBRUARY 2008

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DESCRIPTION CONTINUED

The device offers superior features and performance for mobile phones and similar portable applications with

complex power management systems. Automatic intelligent switching between PWM low-noise and PFM low-

current mode offers improved system control. During PWM mode operation, the device operates at a fixed-

frequency of 3 MHz (typ). PWM mode drives loads from ~ 80mA to 350mA max. Hysteretic PFM mode extends

the battery life by reducing the quiescent current to 16 µA (typ) during light load and standby operation. Internal

synchronous rectification provides high efficiency. In shutdown mode (Enable pin pulled low), the device turns off

and reduces battery consumption to 0.01 µA (typ).

The LM3679 is available in a lead-free (No PB) 5-bump DSBGA YZR package, 0.6mm height, and in an ultra thin

0.3mm height YPD package. Using the YPD package along with specific external components, allows for a low

profile solution size with a max height of 0.55mm. A switching frequency of 3 MHz (typ) allows use of tiny

surface-mount components. Only three external surface-mount components, an inductor and two ceramic

capacitors, are required. .

CONNECTION DIAGRAM AND PACKAGE MARK INFORMATION

Figure 3. 5 Bump DSBGA YZR and YPD Package (YPD package to be released soon)

PIN DESCRIPTIONS

Pin #

Name

Description

A1

Power supply input. Connect to the input filter capacitor (Figure 1).

A3

GND

Ground pin.

C1

EN

Enable pin. The device is in shutdown mode when voltage to this pin is <0.4V and enabled

when >1.0V. Do not leave this pin floating.

C3

FB

Feedback analog input. Connect directly to the output filter capacitor (Figure 1).

B2

SW

Switching node connection to the internal PFET switch and NFET synchronous rectifier.

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

2

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