Fairchild FAN5350 service manual

FAN5350 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

FAN5350 — 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

March 2010

Features

 3MHz Fixed-Frequency Operation  16µA Typical Quiescent Current  600mA Output Current Capability  2.7V to 5.5V Input Voltage Range  1.82V Fixed Output Voltage  Synchronous Operation  Power-Save Mode  Soft-Start Capability  Input Under-Voltage Lockout (UVLO)  Thermal Shutdown and Overload Protection  6-Lead 3 x 3mm MLP  5-Bump 1 x 1.37mm WLCSP

Applications

 Cell Phones, Smart-Phones  Pocket PCs  WLAN DC-DC Converter Modules  PDA, DSC, PMP, and MP3 Players  Portable Hard Disk Drives

Description

The FAN5350 is a step-down switching voltage regulator that delivers a fixed 1.82V from an input voltage supply of 2.7V to 5.5V. Using a proprietary architecture with synchronous rectification, the FAN5350 is capable of delivering 600mA at over 90% efficiency, while maintaining a very high efficiency of over 80% at load currents as low as 1mA. The regulator operates at a nominal fixed frequency of 3MHz at full load, which reduces the value of the external components to 1µH for the output inductor and 4.7µF for the output capacitor.

At moderate and light loads, pulse frequency modulation is used to operate the device in power-save mode with a typical quiescent current of 16µA. Even with such a low quiescent current, the part exhibits excellent transient response during large load swings. At higher loads, the system automatically switches to fixed-frequency control, operating at 3MHz. In shutdown mode, the supply current drops below 1µA, reducing power consumption.

The FAN5350 is available in a 6-lead Molded Leadless Package (MLP) and a 5-bump Wafer Level Chip Scale Package (WLCSP).

Ordering Information

Part Number

FAN5350UCX -40°C to 85°C

FAN5350MPX -40°C to 85°C

For Fairchild’s definition of Eco Status, please vis it: http://www.fairchildsemi.com/company/green/rohs_green.html.

Please refer to tape and reel spec i f i cations at www.fairchildsemi.com

Operating

Temperature Range

Package

5-Ball, Type-1 WL-CSP, 1x1.37mm, .5mm Pitch

6-Lead, Molded Leadless Package (MLP), Dual, JEDEC MO-229, 3mm Square, Extended DAP

; http://www.fairchildsemi.com/packaging.

Eco

Status

Green Tape and Reel

Packing Method

V

4

Typical Applications

4.7µF

IN

VIN

EN

C

IN

GND

A1

A3

B2

C1

C3

SW

FB

4.7µF

L1

1µH

V

OUT

C

OUT

.7µF

C

OUT

PGND

1 6

AGND

V

OUT

FB

P1

2 5

(GND)

3 4

L1

1µΗ

Figure 1. WLCSP, Bumps Facing Down Figure 2. MLP, Leads Facing Down

Block Diagram

VIN

SW

EN

4.7µF

C

IN

FAN5350 — 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

V

IN

EN

FB

Bias

1.8V

Reference

+

Modulator

-

3MHz OSC

Current Limit

Logic

Zero Crossing

Driver

SW

GND

Figure 3. Block Diagram

Pin Configurations

A1

VIN

A3

GND

A3 A1

FAN5350 — 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

VIN

EN

B2

C1 C3

SW

FB

SW

FB

B2

C3 C1

Figure 4. WLCSP - Bumps Facing Down Figure 5. WLCSP - Bumps Facing Up

AGND

FB

1 6

P1

2 5

(GND)

3 4

VINPGND

SW

EN

Figure 6. 3x3mm MLP - Leads Facing Down

Pin Definitions

WLCSP

Pin # Name Description

A1 VIN

A3 GND

C1 EN

C3 FB

B2 SW

Power Supply Input.

Ground Pin. Signal and power ground for the part.

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

when >1.2V. Do not leave this pin floating.

Feedback Analog Input. Connect directly to the output capacitor.

Switching Node. Connection to the internal PFET switch and NFET synchronous rectifier.

EN

MLP

Pin # Name Description

1 PGND

2 AGND

3 FB

4 EN

5 SW

6 VIN

Power Ground Pin. Power stage ground. Connect PGND and AGND together via the board ground plane.

Analog Ground Pin. Signal ground for the part.

Feedback Analog Input. Connect directly to the output capacitor.

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

when >1.2V. Do not leave this pin floating.

Switching Node. Connection to the internal PFET switch and NFET synchronous rectifier.

Power Supply Input.

FAN5350 — 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.

Symbol Parameter Min. Max. Unit

VIN

TJ Junction Temperature -40 +150 °C

T

TL Lead Temperature (Soldering 10 Seconds) +260 °C

ESD

Input Voltage with respect to GND -0.3 6.0 V

Voltage on any other pin with respect to GND -0.3 VIN V

Storage Temperature -65 +150 °C

STG

Human Body Model 4.5

Electrostatic Discharge Protection Level

Charged Device Model

MLP 1.5

WLCSP 2.0

Machine Model 200 V

kV

Recommended Operating Conditions

The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings.

Symbol Parameter Min. Typ. Max. Unit

VCC Supply Voltage Range 2.7 5.5 V

I

Output Current 0 600 mA

OUT

L Inductor 0.7 1.0 3.0 µH

CIN Input Capacitor 3.3 4.7 12.0 µF

C

Output Capacitor 3.3 4.7 12.0 µF

OUT

TA Operating Ambient Temperature -40 +85 °C

TJ Operating Junction Temperature -40 +125 °C

Thermal Properties

Symbol Parameter Min. Typ. Max. Units

Θ

JA_WLCSP

Θ

JA_MLP

Junction-to-Ambient Thermal Resistance

(1)

Note:

1. Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 1s2p boards in accordance to JESD51- JEDEC standard. Special attention must be paid not to exceed junction temperature T

at a given ambient temperate TA.

J(max)

180

49

°C/W

Electrical Characteristics

Minimum and maximum values are at VIN = 2.7V to 5.5V, TA = -40°C to +85°C, C otherwise noted. Typical values are at T

= 25°C, VIN =3.6V.

A

Symbol Parameter Conditions Min. Typ. Max. Units

Power Supplies

= C

IN

= 4.7µF, L = 1µH, unless

OUT

FAN5350 — 3MHz, 600mA Step-Down DC-DC Converter in Chip-Scale and MLP Packaging

IQ Quiescent Current

Device is not switching, EN=V

16 µA

IN

Device is switching, EN=VIN 18 25 µA

I

Shutdown Supply Current VIN = 3.6V, EN = GND 0.05 1.00 µA

(SD)

Rising Edge 1.8 2.1

V

Under-Voltage Lockout Threshold

UVLO

V

Enable HIGH-Level Input Voltage 1.2 V

(ENH)

V

Enable LOW-Level Input Voltage 0.4 V

(ENL)

I

Enable Input Leakage Current EN = VIN or GND 0.01 1.00 µA

(EN)

Falling Edge 1.75 1.95

Oscillator

f

Oscillator Frequency 2.5 3.0 3.5 MHz

0SC

Regulation

= 0 to 600mA 1.775 1.820 1.865 V

I

VO Output Voltage Accuracy

LOAD

CCM 1.784 1.820 1.856 V

tSS Soft-Start EN = 0 -> 1 300 µs

Output Driver

R

DS(on)

PMOS On Resistance V

= VGS = 3.6V 180

IN

NMOS On Resistance VIN = VGS = 3.6V 170

I

PMOS Peak Current Limit Open-Loop

LIM

T

Thermal Shutdown CCM Only 150 °C

TSD

T

Thermal Shutdown Hysteresis 20 °C

HYS

(2)

650 800 900 mA

Note:

2. The Electrical Characteristics table reflects open-loop data. Refer to Operation Description and Typical Characteristic for closed-loop data.

V

mΩ