Fairchild FAN5358 service manual

August 2011

FAN5358 2MHz, 500mA, SC70 Synchronous Buck Regulator

FAN5358 — 2MHz, 500mA, SC70 Synchronous Buck Regulator

Features

 2MHz Nominal-Frequency Operation  25µA Typical Quiescent Current  500mA Output Current Capability  2.7V to 5.5V Input Voltage Range  1.0 to 1.8V Fixed Output Voltages  Low Ripple, Light-Load PFM Mode  Internal Soft-Start  Input Under-Voltage Lockout (UVLO)  Thermal Shutdown and Overload Protection  6-lead 2 x 2.2mm SC70

Applications

 Cell Phones, Smart Phones  3G, 4G, WiFi  Netbooks

®

, WiMAX™, and WiBro® Data Cards

®

, Ultra-Mobile PCs

Typical Application

Description

The FAN5358 is a step-down switching voltage regulator that delivers a fixed output from an input voltage supply of 2.7V to

5.5V. Using a proprietary architecture with synchronous rectification, the device is capable of delivering 500mA and maintaining a very high efficiency of over 80% at load currents as low as 1mA. The regulator operates at a nominal frequency of 2MHz, which reduces the value of the external components to as low as 2.2H 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 25µA. Even with such a low quiescent current, the part exhibits excellent transient response during large load swings. In shutdown mode, the supply current drops below 1µA, reducing power consumption.

FAN5358 is available in a 6-lead SC70 package.

L1

SW

1

GND GND

2

U1

VOUT

C

OUT

Figure 1. FAN5358 Typical Application

3

VIN

6

5

EN

4

C

IN

Table 1. External Components for Figure 1

U1 fSW L1 CIN C

FAN5358 2MHz

2.2H 2.2F 4.7F

OUT

Trademarks are the property of their respective owners.

Ordering Information

FAN5358 — 2MHz, 500mA, SC70 Synchronous Buck Regulator

Part Number

FAN5358S710X

FAN5358S712X 1.2V

FAN5358S713X 1.3V

FAN5358S718X 1.8V

Note:

1. Other voltage options are available on request. Contact a Fairchild representative.

Switching

Frequency

2MHz

Output Voltage

1.0V

(1)

Temperature

Range

–40 to +85°C SC70-6 Tape and Reel

Pin Configuration

SW

GND

VOUT

1

2

3

VIN

6

GND

5

EN

4

Figure 2. Pin Assignments (Top View)

Pin Definitions

Package

Packing

Method

Pin # Name Description

1 SW

2, 5 GND

3 VOUT

4 EN

6 VIN

Switching Node. Connect to output inductor.

Ground. Power and IC ground. All signals are referenced to this pin.

V

/ Feedback. Connect to output voltage.

OUT

Enable. The device is in shutdown mode when the voltage to this pin is <0.4V and enabled when >1.2V.

Do not leave this pin floating.

Input Voltage. Connect to input power source and C

.

IN

FAN5358 — 2MHz, 500mA, SC70 Synchronous Buck Regulator

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. Units

VIN

TJ Junction Temperature -40 +150 °C

T

STG

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

ESD Electrostatic Discharge Protection Level

Note:

2. Lesser of 6.0V or VIN + 0.3V

Input Voltage with Respect to GND -0.3 6.0 V

Voltage on Any Other Pin with Respect to GND -0.3 V

IN

+0.3V

(2)

V

Storage Temperature -65 +150 °C

Human Body Model, JESD22-A114

Charged Device Model, JESD22-C101

2

kV

1

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. Units

VCC Supply Voltage Range 2.7 5.5 V

I

Output Current 0 500 mA

OUT

L Inductor 2.2 µH

CIN Input Capacitor 2.2 µF

C

Output Capacitor

OUT

(3)

4.7

TA Operating Ambient Temperature –40 +85 °C

TJ Operating Junction Temperature –40 +125 °C

μF

Thermal Properties

Symbol Parameter Min. Typ. Max. Units

ΘJA Junction-to-Ambient Thermal Resistance

Notes:

3. Refer to Operation Description section for guidance on maximum C

4. Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 2s2p 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)

(4)

285 °C/W

capabilities.

OUT

FAN5358 — 2MHz, 500mA, SC70 Synchronous Buck Regulator

Electrical Characteristics

Minimum and maximum values are at VIN = 2.7V to 5.5V, TA = -40°C to +85°C, circuit of Figure 1 unless otherwise noted. Typical values are at T

Symbol Parameter Conditions Min. Typ. Max. Units

Power Supplies

IQ Quiescent Current No Load, EN=VIN 25 48 µA

I

Shutdown Supply Current EN = GND 0.05 1.00 µA

(SD)

V

Under-Voltage Lockout Threshold Rising VIN 2.4 2.6 V

UVLO

V

Oscillator

Regulation

Output Driver

Note:

5. The Electrical Characteristics table reflects open-loop data. Refer to Operation Description and Ty pical Characteristic for

Under-Voltage Lockout Hysteresis 225 mV

UVHYST

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)

f

Switching Frequency In PWM Mode 2 MHz

OSC

VO

Output Voltage Accuracy

tSS Soft-Start From EN Rising Edge 70 µs

R

DS(on)

I

T

LIM

TSD

HYS

PMOS On Resistance VIN = VGS = 3.6V 750

NMOS On Resistance VIN = VGS = 3.6V 650

PMOS Peak Current Limit Open-Loop

Thermal Shutdown 150 °C

Thermal Shutdown Hysteresis 20 °C

closed-loop data.

= 25°C, VIN =3.6V.

A

1.0V I

1.2V I

1.3V I

1.8V I

= 0 to 500mA -4.5 +4.5

LOAD

= 0 to 500mA -4.5 +4.5

LOAD

= 0 to 500mA -4.5 +4.5

LOAD

= 0 to 500mA -4.0 +4.0

LOAD

(5)

750 850 1150 mA

%

m m

Block Diagram

EN

VOUT

GND

REF

RAMP

GEN

U1

LOGIC

&

GATE

DRIVE

Q1

Q2

VIN

SW

GND

L1

C

IN

VOUT

C

OUT

Figure 3. IC Block Diagram